Upgrade to remove ads
Terms in this set (507)
strands of DNA are made up of repeating units called __________
nucleotide is made up of:
four types of bases:
what links the phosphate and sugar, and isn't easily broken and joins nucleotides into a permanent strand ?
strong chemical bonds
deoxyribose sugar diagram
antiparallel DNA strands diagram
bases are held together by?
weak hydrogen bonds
what are prokaryotes?
organisms that lack true membrane bound nucleus
where is the DNA found in prokaryotes?
example of prokaryote
what are eukaryotes?
organisms that have a membrane bound nucleus that stores their genetic information
example of eukaryotes
fungi, animals and plants
organisation of chromosomal DNA in prokaryotes?
organisation of chromosomal DNA in eukaryotes?
linear and circular ( in mitochondria and chloroplasts)
plasmids are found in one type of eukaryote
linear chromosome diagram
circular chromosome diagram
(found in chloroplast and mitochondria)
DNA is wrapped around ___________ ___________
packaging proteins or histones
DNA can reproduce itself and this is called ____________
DNA replication stages
1) DNA double helix unwinds
2) weak hydrogen bonds break causing 2 strands to separate (unzipped)
3) free DNA nucleotide joins complimentary pair on open strand
4) weak hydrogen bonds reform between base pairs
5)strong chemical bond forms between both nucleotides
6)newly formed daughter DNA (identical to original) begins to wind into double helix
what enzyme controls stage 5 of DNA replication?
what does DNA polymerase need to be present before it can start replicating DNA?
DNA replication can only happen from __ to __ because DNA polymerase enzymes can only add nucleotides towards the 3' end
5' to 3'
DNA replication diagram
this strand is replicated continuously
this strand is replicated in fragments
fragments on lagging strand are joined then together using the enzyme DNA _______
DNA unwinding occurs at multiple locations along a DNA molecule at ___________ ______
what is Polymerase chain reaction used for?
to amplify DNA fragments in vitro and so creates many identical copies of the fragments
what does vitro mean?
outside the cell
initial requirements for PCR
-heat tolerant (Taq) polymerase
example of DNA template for PCR
what are complimentary primers needed for in PCR
to target specific DNA
what is a thermal cycling
a cycle consisting of three steps carried out at different temperatures
five uses of practical applications of PCR
-diagnosis of genetic disorders
example of use of PCR for DNA fingerprinting
semen, blood, tissue from crime scene/ tissue typing / paternal testing
example use of PCR for diagnosis of genetic disorders
embryonic cell DNA for paternal testing
example use of PCR for investigating evolution
example use of PCR for research
cancer cell research and viruses
example use of PCR for archeological studies
studying remains of extinct species
stages of PCR
2) annealing of primers
3) DNA extension
what happens during denaturation of PCR?
the mixture is heated to 95 degrees to break hydrogen bond between bases (Taq polymerase does not denature) and separate DNA strands (denatures DNA)
what happens during annealing of primers in PCR?
cooled down to 55 degrees, this allows complimentary primers to anneal (form hydrogen bond) to target sequences on single stranded DNA
what happens during DNA extension in PCR?
mixture heated to 72 degrees, the optimum temperature for the Taq polymerase to extend the complimentary strand in a 5' to 3' direction
temperature for stage 1 of PCR
temperature for stage 2 of PCR
temperature for stage 3 of PCR
72 degrees (optimum temp for Taq polymerase)
how are specific primers chosen for PCR?
the primer is complimentary the specific target sequences at the 2 ends of the region to be amplified
what is the role of Taq DNA polymerase in PCR?
produces replicate of DNA strand of the target DNA
an organisms __________ is determined by the sequence of bases in its genes- genetic code
an organisms ___________ is determined by the protein synthesised when the genes are expressed
3 steps to ones phenotype
1) DNA base sequence determines genotype
2) proteins synthesised when genes expressed
3) proteins determines phenotype
the genetic code used in ___________ ___ ____________ is found in all forms of life
transcription and translation
proteins produced are affected by ______ ___ ______ cellular environmental signs
intra and extra
mRNA is transcribed from DNA in the NUCLEUS and translated into proteins by ribosomes in the ______________
proteins have a large variety of structure and shapes resulting in a wide range of _____________
amino acids are linked by __________ _____ to form proteins. polypeptide chains fold the 3D shape of a protein, held together by hydrogen bonds and other interactions between amino acids.
gene expression diagram
where does translation of DNA happen ?
the sugar present in RNA nucleotide
number of strands of RNA
complimentary base pair of adenine in RNA
three types of RNA
mRNA, rRNA, tRNA
what does mRNA (messenger) do?
carry a copy of the DNA code from the nucleus to the ribosome
what does rRNA (ribosomal) do?
rRNA and proteins form the ribosome
what does tRNA (transfer) do?
carry a specific amino acid to the ribosome to be inserted into a protein
what is genetic code?
the information that DNA contains that takes the form of a code
codons are the ________ _____ for the genetic code
how many bases makes up a codon ?
3 (giving 64 different combos)
what does RNA polymerase do in transcription?
moves along DNA unwinding and unzipping the double helix and synthesising a primary transcript of RNA from RNA nucleotides by complementary base pairing
the primary transcript mRNA is made up of ______ ____ ______
introns and exons
what are introns?
non-coding sequence of DNA (non-coding regions)
what are exons?
sequence of DNA that codes for proteins (coding regions)
what is a mature transcript?
after introns are cut out and removed from the primary transcript and then exons are spliced together forming the mature transcript
alternative RNA splicing diagram
what is alternative RNA splicing?
a primary transcript can form different mRNA molecules depending on which exons are included in the mature mRNA
how does the mRNA leave the nucleus?
through a nuclear pore into the cytoplasm
the tRNA has triplet bases called ___________
each tRNA carries a specific ___________ _____
the triplet codons on the mRNA are recognised by the anticodons on tRNA which ___________ the genetic code into a sequence of amino acids
an ________ within the ribosome is responsible for joining adjacent amino acids with peptide bond
the mRNA codon AUG (tRNA=UAC)
the mRNA codons UAA, UAG, UGA
where does translation happen?
mRNA is translated into ________
the message of mRNA is made up of _____ ________ called codons
post translational modifiction
this process makes changes to the chemical structure of the polypeptide chain by:
-cutting and combining polypeptide chains
-adding phosphate or carbohydrate groups
therapeutic value of stem cells?
you can use stem cells to repair or replace damaged or diseased tissue
examples of use of stem cells
-bone marrow transplants to treat cancer
-potential to treat diabetes, alzheimer's disease, parkinson disease
what can stem cells be used as for research?
they can be used as models of real tissue for drug testing, understanding disease progression, induced pluripotent stem cells (IPS)
what is differentiation?
the process in which unspecialised cells become specialised for a particular function
all body (somatic) cells contain ___ of the genetic information to produce every cell in the body during differentiation
in differentiation many genes remain switched __
in differentiation some genes that control ________________ features of specialised cell are switched on
in differentiation unnecessary genes are switched ___
are the only site of mitosis in plants and the point of plant growth
two types of meristem
- apical, in the roots and shoots
-lateral, in stems that increase
embryonic stem cells
they have the potential to become different types of cells and undergo mitosis indefinitely (under the correct conditions). They are described as PLURIPOTENT
adult stem cells
they maintain the growth and repair of the body, there are many types of adult stem cells which have a narrower differentiation potential because their genes are already switched off. they are MULTIPOTENT
model answer on how stem cells can be used treat a disease
disease: diabetes, alzheimer's, parkinson
the stem cells are directed to differentiate into specific cell types to replace damaged/ diseased tissue
reasons FOR the use of embryonic stem cells of research
- have the potential to benefit humanity
-can be used in research and help patients with medical problems
-at 14 days or less an embryo is not sentient (does not have a brain, nervous system, consciousness)
-stem cell uses embryos that were from IVF but were not used so they would be destroyed anyway
reasons AGAINST use of embryonic stem cells
-a human life begins when a sperm cell fuses with an egg cell and it is inviolable (sacred and must not be harmed)
- a unique version of DNA is created at conception
-violates the sanctity of life
solutions to the ethical problems of stem cell research
-induced pluripotent stem cells (IPS)
is an organisms entire hereditary information encoded in DNA
only __ of the genome is made up of genes, the other 98% have other functions
the 98% of the genome which is not made up of genes have what two functions
-regulation of transcription
-transcription of non-translated RNA
transcription of non- translated RNA
these types are transcribed but not translated into proteins, tRNA and rRNA
regulation of transcription
RNA polymerase is unable to start transcription on its own. it needs transcription factors, these can take the form of activators (help and start) and repressors (prevent)
single gene mutation
involves the alteration of a DNA nucleotide sequence
single gene mutations impact ___________ nucleotides and can be a SUBSTITUTION, DELETION, INSERTION
single gene mutation can either be _______ or ____________ mutation
occur at a single point i.e. SUBSTITUTION
(generally not too harmful as only one amino acid is affected so the protein will probably be functional)
frame shift mutation
this changes the open reading frame by moving it one base pair forward or backward i.e. DELETION OR INSERTION
(generally more harmful since all the amino acids in the primary structure of the protein will have changed from the mutation onwards, protein likely to be non-functional)
substitutions can have three different impacts
a single amino acid is changed
inserts a STOP codon, produces a truncated protein
this does not change the protein sequence
mutations in non-protein coding sequences can also impact protein expression in two ways
-splice site mutations (can alter post-transcriptional mRNA processing)
-regulatory sequence mutations (can alter gene expression)
naturally occurring mutations occur ____________ and _______________
randomly and spontaneously
example of mutagenic agents
gamma rays, x-rays and UV light
some mutagens are also _____________ (cancer causing mutations)
mutations are considered to be the raw material of ___________ as it gives rise to better genes and alternative genes which natural selection can act upon
four types of chromosome mutations
section is deleted
section is duplicated
section is flipped
section of two different chromosomes switch places
organisms that contain more than 2 sets of chromosomes e.g. triploid, tetraploid
polyploidy occurs due to errors during _____________ of chromosomes during cell division (total nondisjunction of spindle fibres)
polyploidy is common is ________ species
polyploidy plants tend to be ________ (increased yield)
closely related plants species can be crossed to form polyploids, the plants show HYBRID VIGOUR, resulting in HIGHER yield, disease RESISTANCE and drought RESISTANCE
importance of polyploidy in evolution
-provides additional material upon which natural selection can work on
-they are more vigorous/disease resistant/ grow faster
the changes in organisms over generations as a result of genomic variation
evolution of species involves 4 main categories of change
-selection (natural, sexual)
DNA can be transferred in two ways
vertical transfer occurs through _______ and _________ reproduction
in prokaryotes DNA can be passed in two ways
-vertical (asexual reproduction)
-horizontal (where DNA is passed within the same generation)
how can horizontal transfer of DNA happen in prokaryotes
-direct DNA transfer
some prokaryotes can also transfer DNA to ______________
1) temporary bridge forms between two bacterial cells that differ in genome
2) transfer of plasmid happens
3) the donor cell is unchanged, the recipient cell now has a copy of the plasmid
is the NON-RANDOM increase in the frequency of DNA sequences that increase survival and the NON-RANDOM decrease in DELETERIOUS sequences
stages of natural selections
1)more offspring are produced than the environment will support and a large number die before reaching reproductive age
2)as members of a species are not all identical (show variation) some will be more suited to the environment than others
3)these individuals whose phenotype are more favourable survive and pass on their genes to the next generation, while those less suited die and do not pass on their genes
4)over many generations, the best phenotypes are selected
natural selection of characteristics that increase reproductive success
sexual selection is NON-RANDOM and operates in two ways
-male-male competition (for access to mates and territory)
example of male-male competition
example of female choice
some individuals have better ___________ success than others and these traits are selected for
any any characteristic that shows ____________ ________ (e.g. height, mass) can be affected by selection
selection pressure goes against extreme variants and favours the intermediate versions of a trait. Leads to a reduction in genetic diversity
common during period of environmental change. selection favours a version which was initially less common
selection pressure selects extreme versions of a trait at the expense of the intermediate version, can result in the population being split into two distinct groups. driving force behind SPECIATION
example of stabilising selection
natural human birth mass, babies of very low body mass are more susceptible to fatal diseases and those of a very high birth mass encounter difficulties passing the mothers pelvis
example of directional selection
european black bears, increased average body size during the ice age, since a larger body losses less heat, a larger body is of survival value int he cold climates
example of disruptive selection
plant and animal breeding involving artificial selection of extremely large and small varieties e.g. dogs
is the RANDOM increase or decrease in frequency of genetic sequences, it differs from natural selection which is non-random
evolution due to genetic drift is not influenced by __________ or __________________ pressures
genetic drift has the greatest influence in ________ populations
genetic drift occurs due to 2 things
these change the DNA but not the proteins structure, they cannot influence natural selection but can alter genetic drift
a small part of a large population is removed, that population will continue to diverge from the initial population through random changes
a group of organisms that can interbreed to produce fertile offspring
Is the formation of new biological species by evolutionary changes
2 types of speciation that can occur
gene flow between 2 populations is prevented by a GEOGRAPHICAL BARRIER
example of allopatric speciation
darwin finches, separated by sea
2 or more populations live in close proximity to one another in the same environment yet they become genetically isolated, gene flow is prevented by BEHAVIOURAL or ECOLOGICAL BARRIERS or by the occurrence of POLYPLOIDY in plants.
sympatric speciation is promoted by ________________ selection
example of sympatric speciation
form where the ranges of two closely related species overlap. Within the zone members of the two species interbreed.
if one disappears, breaking the chain, then they may become ___________ ____________
what can genomic sequencing be used for?
to determine the order of nucleotide bases for genes or even entire genomes
what was the first sequencing method ever used
what are the more modern techniques for genomic sequencing?
using fluorescent labelling of modified nucleotides and bioinformatics to determine base sequencing
the use or development of statistical analysis and computers (software tools) to understand/ produce biological data
what other genomes have been sequenced apart from the human genome?
-disease causing organisms (e.g. viruses and bacteria)
-pest species (mosquitos)
-model organisms used in research (mouse of fruit fly)
this involves the comparison of genome sequences:
-from different species
-from members of the same species
-from cancerous cells and normal cells
highly conserved genes
these genes are very similar across species, and are often involved in basic cellular processes
study of genome comparison can be used to understand ______________ changes
is the study of evolutionary relatedness between organisms
sequence of evolutionary events can be determined using:
-genome sequencing comparisons
-fossil evidence (using half life)
-the quantity of molecular differences between 2 groups is a measure of how long ago they shared a common ancestor
major events in evolution
-evolution of life on earth
-evolution of cells resembling prokaryotes
-evolution of last universal ancestor (prokaryote)
-evolution of cyanobacteria (prokaryote able to photosynthesise)
-evolution of eukaryotes
-evolution of multicellular organisms
-evolution of animals
-evolution of vertebrates
-evolution of land plants
three domains of life
_______________ RNA (rRNA) nucleotide sequences have been studies because they are shared by all living things
sequencing a persons DNA is becoming ________ and ___________
the probability of getting a disease is predicted, if an individual is at high risk, preventative measures can be taken
personalisation of drug doses based on genetic information of drug metabolising pathways
ethical issues with personal genomics
GENETIC DISCRIMINATION may occur - insurance companies, banks and others may decline service or increase premium as a result of finding less desirable traits e.g. degenerative diseases
set up to check the experimental method. i.e. if new fertiliser was being tested in a field trial a positive control would be plots with existing fertiliser
set up to be sure that the variable under investigation is causing the result. i.e. if new fertiliser was being tested in a field trial then plot with no fertiliser would act as negative control
explain why cells need to carry out DNA replication
so new cells have the same genetic material as the original cell or to maintain the number of chromosomes in new cells
effect of mutation of regulatory sequences
alters the way in which genes are expresses in the phenotype
effect of splice site mutations
can cause introns to be left in the mature mRNA, leading to altered protein
How are hybrid zones maintained?
-the hybrid offspring are less fit or sterile and are eliminated by natural selection
-members of each species recolonise the hybrid zone and undergo further hybridisation to repopulate the zone
Process by which light is taken in and retained by a leaf.
Graph showing the quantity of light absorbed by a pigment at different wavelengths of light.
Graph showing the rate of photosynthesis by a green plant at different wavelengths of light.
Yellow pigments which absorb light and pass the energy to chlorophyll.
Green pigments which absorb light in the red and blue regions of the spectrum.
Technique used to separate the components of a mixture that differ in their degree of solubility in a solvent.
Variety of plant obtained from natural species by selection and/or genetic manipulation and maintained by cultivation.
Ability to access food of adequate quantity and quality to feed the world's population.
Process by which light bounces off a leaf surface.
Process by which light passes through a leaf.
Term referring to a level in a food chain or pyramid.
Enzyme which catalyses the synthesis of ATP from ADP and Pi.
Second stage of photosynthesis during which carbon dioxide is taken up and sugar is synthesised.
electron transport chain
Group of protein molecules in the membrane of a chloroplast which makes energy available to pump H+ ions across the membrane and to split water molecules.
Metabolite in the Calvin cycle used to regenerate RuBP and make sugar.
Product of photolysis of water which becomes attached to NADP.
First stage of photosynthesis during which light energy is converted to chemical energy.
Compound which accepts hydrogen released during photolysis of water.
Product of photolysis of water which is required for aerobic respiration.
Breakdown of water during the light-dependent stage of photosynthesis.
ribulose bisphosphate (RuBP)
Metabolite in the Calvin cycle which acts as the carbon dioxide acceptor.
Enzyme which fixes carbon dioxide by attaching it to RuBP.
Raw material which becomes split into oxygen and hydrogen during photolysis.
Referring to alleles of genes whose expression results in the formation of harmful characteristics.
Alteration of an organism's genome by the insertion of a DNA sequence from a different organism.
Establishing the order of the nucleotide bases all the way along an organism's DNA.
Improved condition shown by offspring of crosses between two different parental strains.
Process by which one variety of an organism is crossed with a different variety to try to produce offspring better than either parent.
Process by which close relatives are bred with one another and prevented from breeding at random.
Deterioration in the quality of a strain of natural outbreeders that have been forcibly inbred.
Process involving the mating of unrelated members of the same species.
Disordered arrangement of replicate treatments to eliminate bias.
One of several copies of a treatment set up to reduce the effect of experimental error.
Process by which only the organisms with the best features are chosen as parents of the next generation.
Procedure carried out between an organism whose genotype for a trait is unknown and an organism who is homozygous recessive for the trait.
Way in which a plot is dealt with compared with other plots.
Weed that completes its lifecycle within one year.
Reduction of a pest population by the deliberate introduction of one of its natural enemies.
Means of control of weeds, pests and pathogens using herbicides, pesticides and fungicides.
Type of non-selective herbicide that destroys all green plant tissue which it meets.
Agricultural practice whereby each of a series of different crop plants is grown in turn on the same piece of ground.
Traditional, non-chemical, means of controlling weeds, pests and pathogens that affect crop plants.
integrated pest management
Combination of techniques including chemical, biological and cultural means of control.
Vast population of a single species cultivated for economic efficiency.
Weed that continues to grow for several years.
Non-biodegradable chemical whose molecules accumulate along a food chain.
Chemical used to control pests.
Type of pest that survives treatment by a pesticide and enjoys a selective advantage.
Type of herbicide that mimics plant growth substances and kills broad-leaved plants by stimulating their growth to a harmful extent.
Type of herbicide that is absorbed by a plant and transported internally to all parts where it has a lethal effect.
Unwanted plant that poses economic problems when it is able to multiply among, and compete with, a crop.
altered level of activity
Behaviour involving extreme expression such as hyper-aggression or excessive sleeping.
Moral values and rules that ought to govern human conduct.
List of all the different observed behaviours shown by an animal.
Study of animal behaviour.
Behaviour that is directed inappropriately towards the animal itself, another animal or its surroundings.
Process that arouses and directs the behaviour of an animal to satisfy one of its basic needs.
Type of test that gives an animal a choice between two conditions to determine which one it prefers.
Access to company of other members of the animal's own kind.
Behaviour pattern in the form of repetitive movements lacking in variation.
Animal's quality of life, regarded as acceptable if the animal can behave naturally, grow well and live free of disease.
Gradual change in parallel of two symbiotic organisms which increases their level of adaptation to suit a dependent or interdependent relationship.
Mode of transmission of parasites which occurs when an infected host physically encounters another host.
Partner that is harmed by loss of resources to a parasite in a symbiotic relationship.
Relationship that exists between the two partners involved in a mutualistic relationship.
Symbiotic relationship where both partners benefit.
Partner that benefits by obtaining resources from a host in a symbiotic relationship.
Symbiotic relationship where one organism benefits at the expense of another organism.
Form of parasite which, on being released, is able to survive adverse conditions for a long time before meeting a new host.
Ecological relationship between organisms of two different species that live in direct contact with one another.
Organism that carries a parasite from one host to another.
Type of social behaviour used to concede defeat to a dominant rival.
Close relationship among female primates in a social group where reproductive success can increase social status.
Unselfish behaviour unfavourable to the donor but which benefits the recipient.
Method of obtaining food that benefits subordinate animals in addition to the group's dominant leader.
Member of a social group able to intimidate all other members without being attacked in return.
Process by which primates clean one another's fur while reducing tension within their social group.
Type of species that plays a critical role in the structure and working of an ecosystem.
Process which favours acts of apparent altruism carried out to help close relatives.
Type of social behaviour where adult primates provide offspring with food and protection.
Unit consisting of several members of a species who live together and respond to one another.
Graded order of rank among members of a social group resulting from aggressive behaviour.
An individual's level of rank in a social hierarchy.
Ritualised behaviour used to intimidate a rival without engaging in a real fight.
Non-reproductive member of an insect colony that co-operates with close relatives to ensure the survival of the young.
Total variation that exists among all living things.
Reduction in the quality of a natural ecosystem as a result of human activity.
Most prevalent species that determines the appearance and composition of the community.
Number of distinct ecosystems present in a defined area.
Irreversible loss of a species.
Measure of the number or percentage of species irreversibly lost per unit of time.
State found among members of a population resulting from genetic variation.
Consequence of human activity leading to possible extinction of many species.
Area surrounded by a dissimilar ecosystem that cannot be colonised by the enclosed area's species.
mass extinction event
Disruptive occurrence that changes the global environment and causes species to perish.
The largest terrestrial animals belonging to a region or period of time.
Feature of an ecosystem based on the richness of its species and their relative abundance.
Result of the wiping out of a significant percentage of a population and its genetic diversity, leaving it ill-equipped to adapt to environmental change.
Cause of the bottleneck effect, typically a natural disaster.
climate change modelling
Computer programmes that use quantitative methods to simulate the effect of various factors on climate.
Protection and careful management of natural resources.
Global warming by infra-red rays trapped in the Earth's atmosphere by certain gases.
Narrow strip of quality habitat by which a species can move between habitat fragments.
Formation of several fragments whose total surface area is less than that of the original habitat.
Foreign species that has been cultivated intentionally or released accidentally by human activities.
Term for a naturalised species that has spread rapidly and has out-competed native species.
Non-native species that has established itself within wild communities.
Removal and use of a species at a rate that exceeds their maximum rate of reproduction.
Return to and resettlement in a habitat following local extinctions.
What is mutagenesis?
Increasing the rate of mutations using a mutagenic agent.
Examples of mutagenic agents?
Ultraviolet light, X-Rays and Mustard gas
What are the problems with strains which have been improved by mutagenesis?
They are often genetically unstable so can undergo reverse mutations and revert back to original state.
What do improved strains of bacteria often lack?
An inhibitory control mechanism - this leads to overproduction of a product.
Which process can bring about new genotypes in fungi and yeast?
Selective breeding in eukaryotes using sexual reproduction
What is a downside of breeding programmes?
Desired results are not always guaranteed
What is recombinant DNA technology?
Transfer of genetic material from one organism to another
Why might we want to insert genes to another organism?
Genes that amplify specific steps in a metabolic pathway = increased product yield ; Genes that remove inhibitory control of a metabolic pathway = increased product yield ; Genes that cause the organism to secrete the product into the surrounding environment - easy collection of product ; Genes which prevent the organism surviving in external environments = safety control mechanism
What is recombinant DNA?
DNA which contains host DNA and DNA from another source.
What is a restriction endonuclease?
An enzyme which cuts DNA into fragments at particular sequences.
What is a restriction site?
A genetic sequence which is recognised by a restriction endonuclease
When are restriction endonucleases used?
To remove the required DNA from the donor and to open the plasmids which will receive the DNA
What is meant by sticky ends?
When the cut ends of DNA overlap
What is DNA ligase?
The enzyme used to seal DNA fragments back together
What is a vector?
Something which is used to carry DNA from the genome of one organism to the genome of another (e.g. plasmid)
What are the same restriction endonucleases used to cut the gene and the plasmid?
So that the stick ends of the gene and the plasmid are complementary.
What must be present in a vector for it to be effective?
Restriction site, origin of replication and marker gene
What is the origin of replication
The genes which control the replication of the plasmid and the regulatory sequences which control gene expression
What is the function of marker genes?
To allow us to know if the recombinant gene has been taken up by the bacteria. E.g. only bacteria with the required gene will have a marker gene for antibiotic resistance so only bacteria which survive on that antibiotic have taken up the new gene.
What are the limitations of using prokaryotes to produce eukaryotic proteins in recombinant DNA technology?
They do not carry out splicing and they lack the ability to carry out post-translational modification
How do we overcome the limitations of prokaryotes in recombinant DNA technology?
Use eukaryotes like yeast although they all have more demanding culture conditions.
What is an ethical issue surrounding the use of microorganisms?
Pharmaceutical companies only spend time researching things that will make them money therefore treatments for common diseases are widely researched where as rare disorders are less likely to be cured. ; Companies want to patent their products but can a naturally occurring protein really be patented? ; Due to inability to patent genetic sequences companies keep them secret which some people argue hinders scientific progress.
Which regulatory requirements must be passed before a microbiological product can be produced?
It poses no harm to staff which manufacture it ; It is safe for use by consumers ; It is pure and not contaminated by microorganisms ; It is fit for purpose and accurately matches its product description
Why are micro-organisms used in industry
They are easy to culture, they reproduce and grow quickly, their food substrate is often cheap, they produce many different useful products, they are generally highly adaptable and make use of a wide variety of substrates and their metabolism can be easily manipulated
What is meant by growth medium?
A mixture of chemicals which microorganisms are grown in / on.
What is found in a growth medium?
Energy source and supply of raw materials that can be used to make complex molecules needed for their growth.
What forms of growth media are there?
Broth (liquid) / Agar (solid)
What is a complex growth media?
Contains Specific compounds like vitamins or fatty acids which are required by the microorganisms.
What is a simple growth media?
only contains simple chemicals as the organisms can make all of the amino acids required for protein synthesis
What is an example of a complex growth media ingredient?
Why are culture conditions kept sterile?
To avoid contamination by other microorganisms.
What is the name for the technique which allows us to keep conditions sterile?
Which abiotic factors must we control when working with microorganisms?
Temperature, oxygen concentration and pH
What is a fermenter / bioreactor?
A large vessel which can be used to culture large quantities of microorganisms.
How do we maintain conditions in bioreactors / fermenters?
Probes and computers which automatically adjust and regulate conditions.
What is the definition of growth?
An irreversible increase in dry biomass.
What is dry biomass?
The mass of an organism minus the water present.
Why is dry biomass more reliable than fresh biomass?
An organism's water content can vary frequently.
Why is dry biomass sometimes not a useful measure of growth?
It kills the organisms.
Which measure of growth can be used for unicellular organisms?
Measuring the increase in cell number over a period of time.
What is generation time / doubling time?
The time needed for a population to double in number.
What are the four phases of growth in microbes?
Lag phase, log/exponential phase, stationary phase, death phase.
What happens in the lag phase?
Little change in cell number as cells adjust to new growth medium and begin to induce enzymes required to metabolise their substrate.
What happens during the log / exponential growth phase?
The cells multiply at the maximum rate as long as there are no limiting factors.
What happens during the stationary growth phase?
The cells death rate equals the birth rate. Nutrients begin to run out and secondary metabolites start to build up.
What happens during the death phase?
Substrates and nutrients run out and / or toxic metabolites build up to a concentration which leads to the death of the cells. The death rate now exceeds the birth rate.
What is meant by a viable cell count?
Number of cells which are alive and capable of reproduction.
What is meant by total cell count?
Number of cells dead or alive.
What is primary metabolism?
Period of active growth where substrates are being broken down to produce primary metabolites (e.g. amino acids) which are necessary for growth.
What is secondary metabolism?
Phase where secondary metabolites which are not necessary for growth but may provide an ecological advantage to the organism are produced (e.g. antibiotics).
When does primary metabolism occur?
During lag phase and log phase
When does secondary metabolism occur?
During the stationary phase
How can we manipulate an organism's metabolism to overproduce a useful product?
1. Adding inducers to make sure certain enzymes continue working 2. Adding precursors from earlier points in the pathway to ensure the pathway continues 3. Adding an inhibitor to prevent metabolites that you want to collect being broken down by later enzymes
How can wild strains of micro-organisms be improved?
Mutagenesis, selective Breeding and recombinant DNA technology
Why may we want to improve a micro-organism?
Improved genetic stability, ability to grow on low-cost nutrients, ability to vastly overproduce target compounds and allow easy harvesting of target product
What do we call conditions which are beyond an organism's tolerable limits for its normal metabolic rate?
What is dormancy?
A period where organisms have a reduced metabolic rate.
What is predictive dormancy?
When organisms become dormant before the onset of adverse conditions.
What is consequential dormancy?
When organisms become dormant after the onset of adverse conditions.
Where is consequential dormancy more common?
In regions where conditions change suddenly and unpredictably.
What is hibernation?
A form of dormancy that helps an organism survive cold temperatures.
What happens to organisms during dormancy?
Rate of metabolism decreases, heart rate and breathing rate decreases and body temperature decreases
What is aestivation?
A form of dormancy that helps an organism survive hot temperatures / drought.
What happens to organisms during aestivation?
Rate of metabolism decreases, heart rate and breathing rate decreases and body temperature decreases Rate of metabolism decreases
Give an example of an organism that uses hibernation?
Give an example of an organism that uses aestivation?
What is daily torpor?
An organism's metabolic rate is greatly reduced for a period of time in every 24 hour cycle.
Give an example of an organism which uses daily torpor?
Birds - hummingbird
What is migration?
The regular movement by members of a species from one place to another.
Why do organisms migrate?
To avoid periods of metabolic adversity like food shortages or low temperatures.
Why do we study migration?
To find out: When organisms migrate, where they go, how long they stay, how long they live and when they return to their territory
Which specialised techniques can be used for studying migration?
Ringing / banding, electronic tagging, colour marking and using transmitters which send GPS signals
What is innate behaviour?
Behaviour which is inherited and inflexible.
What is learned behaviour?
Behaviour which is gained by experience and is flexible.
Which type of behaviour is thought to play a primary role in migration?
What is a displacement experiment?
When an organism is moved from its original migratory path and released somewhere else.
What is a cross-fostering experiment?
When a member of one species is raised with another species to find out if behaviour is learned or innate.
What is an extremophile?
An organism which can survive in extreme conditions.
How are extremophiles able to survive?
They usually have enzymes which function well at high temperatures; They can remove electrons from inorganic molecules to generate ATP.
What is a conformer?
An organism which cannot control its metabolic rate and its internal environment is dependent on its external environment.
What are the disadvantages of being a conformer?
Narrow ecological niche and cannot tolerate change
What is an advantage of being a conformer?
Low metabolic costs.
What is a regulator?
An organism which can control its internal environment using physiological mechanisms.
What is an advantage of being a regulator?
Can exploit a wide range of ecological niches
What is a disadvantage of being a regulator?
High metabolic costs.
Give an example of a conformer?
Give an example of a regulator?
What is homeostasis?
Maintaining a stable internal environment.
What is negative feedback control?
A change from the optimum conditions is detected by receptors a corrective mechanism is switched on to bring the conditions back to the optimum.
What is a receptor?
Something which detects change in a condition.
What is an effector?
Something which brings about a change in response to messages from receptors.
How are messages sent between receptors and effectors?
Nerve impulses or hormones.
Why do organisms need to maintain stable body temperatures?
1. To ensure that enzymes have optimum conditions to maintain high metabolic rates. 2. To ensure high diffusion rates of substances. 3. Temperature affects the ability of nerves to send nerve impulses.
Which part of the brain detects changes in blood / body temperature?
What is a thermoreceptor and where are they found?
Detect changes in blood temperature, found in hypothalamus and skin.
How does the hypothalamus receive and send signals?
What are the effectors in thermoregulation?
Sweat glands, skin arterioles, hair erector muscles and skeletal muscles
Describe how sweat glands bring body temperature back to normal when it experiences high temperatures.
increase sweat production, heat energy is used to evaporate the water from the body lowering the body temperature
Describe how metabolic rate changes to bring body temperature back to normal when it experiences high temperatures.
Describe how skin arterioles bring body temperature back to normal when it experiences high temperatures.
arterioles widen increasing blood supply closer to surface of the skin so more heat is lost by radiation.
Describe how hair erector muscles bring body temperature back to normal when it experiences high temperatures.
Relax mean hairs are lowered so less insulating air trapped reducing body temperature
Describe how sweat glands bring body temperature back to normal when it experiences low temperatures.
Decrease sweat production, less heat energy is used to evaporate the water from the body increasing the body temperature
Describe how skin arterioles bring body temperature back to normal when it experiences low temperatures.
vasoconstriction- arterioles narrow decreasing blood supply closer to surface of the skin so less heat is lost by radiation
Describe how hair erector muscles bring body temperature back to normal when it experiences low temperatures.
contract mean hairs stand on end so more insulating air trapped increasing body temperature
Describe how skeletal muscles bring body temperature back to normal when it experiences low temperatures.
shivering which produces heat
Describe how metabolic rate changes to bring body temperature back to normal when it experiences lowtemperatures.
What is meant by metabolic rate?
The quantity of energy used per unit time.
How can metabolic rate be measured?
By measuring the oxygen uptake, heat production or carbon dioxide production.
Which pieces of equipment can be used to measure metabolic rate?
Respirometer or calorimeter.
Where does blood enter the heart?
Where does blood leave the heart?
What do we call the circulatory system of a fish?
Single circulatory system
What do we call the circulatory system of amphibians (and reptiles)?
What do we call the circulatory system of mammals and birds?
Why are incomplete double systems less efficient than complete double?
There is mixing of oxygenated and deoxygenated blood in incomplete so cells are not receiving the maximum quantity of oxygen.
How many chambers does a fish heart have?
How many chambers does an amphibian heart have?
3 - Two atriums, one ventricle
How many chambers do bird and mammal hearts have?
4 - Two atriums, two ventricles.
Which organisms have the most efficient lungs?
Describe the lungs in amphibians.
Small thin walled sacs without alveoli.
Why are amphibian lungs less efficient than mammals, reptiles and birds?
They can exchange gases through their skin so only need lungs for periods of vigorous activity.
Describe the lungs in mammals and reptiles.
Bronchioles ending in many thin walled, moist alveoli which create a large surface area for efficient gas exchange allowing them to support high metabolic rates.
Describe the lungs in birds.
Parabronchi create large surface area for gas exchange and constant supply of fresh area makes this very efficient.
How do animals adapt to low oxygen niches e.g. high altitude?
Increased production of red blood cells
How do animals adapt to low oxygen niches e.g. deep diving?
1. Collapse lungs to reduce buoyancy which allows them to dive quicker using less energy. 2. Slow heart rate to reduce oxygen use.
What is VO2 max?
The maximum volume of oxygen that the body can take up and use during intense exercise.
Why is VO2 max used as an indication of fitness?
Higher VO2 max, higher level of fitness.
How is VO2 max measured?
Exercising at high intensity and measuring oxygen uptake.
What is cellular respiration?
A series of enzyme controlled reaction which results in the release of energy from food and regenerates the supply of ATP.
What is aerobic respiration?
Respiration which occurs in the presence of oxygen.
What is fermentation?
Respiration which occurs without oxygen.
What is the summary equation for aerobic respiration?
Glucose + oxygen -> carbon dioxide + water + 38 ATP
What is the summary equation for fermentation in animals (and some bacteria)?
Glucose -> Pyruvate -> Lactate
What is the summary equation for fermentation in plants and yeast?
Glucose -> Pyruvate -> Carbon dioxide + ethanol
What is ATP?
A high energy chemical compound with three phosphates.
What is ADP?
A low energy chemical compound with two phosphates.
How is ATP generated in the cell?
ADP is joined to Pi to create ATP which results in energy being stored.
What happens when ATP is broken down?
Energy is released.
How is it that organisms have a fixed quantity of ATP at all times in their bodies?
As ATP is broken down more ATP is regenerated.
What is phosphorylation?
The addition of phosphate to a molecule- acts as a transfer of energy and makes the molecule more reactive.
Where does the first stage of respiration take place?
What happens in the first stage of respiration?
Glucose -> Pyruvate; NAD -> NADH because DEHYDROGENASE releases electrons and hydrogen ions from the intermediates; 2 ATP used in energy investment phase; 4 ATP made in energy payoff phase
What is the second stage of aerobic respiration known as?
Citric acid cycle
Where does the second stage of aerobic respiration take place?
Matrix of the mitochondria
What happens in the second stage of aerobic respiration?
Pyruvate -> Acetyl group + Carbon dioxide.
What is required for the second stage of aerobic respiration to occur?
What is the final stage of aerobic respiration which results in the generation of most of the ATP?
Electron transport chain
Where does the final stage of aerobic respiration take place?
The christae of the mitochondria, proteins which make up the electron transport chains are found in the inner membrane.
What is the role of NADH and FADH2 in the final stage of aerobic respiration?
They deliver high energy electrons and hydrogen ions to the electron transport chain.
What is the function of the high energy electrons in the final stage of aerobic respiration?
They provide the energy to pump hydrogen ions across the membrane.
What is the function of the hydrogen ions in the final stage of aerobic respiration?
The hydrogen ions flow back into the matrix of mitochondria causing ATP synthase to produce ATP from ADP + Pi.
What is the function of oxygen in the final stage of aerobic respiration?
Acts as the final hydrogen and electron acceptor. Combines with hydrogen and electrons to form water.
What is the main respiratory substrate?
Which stage of respiration can sugar molecules enter?
Which stage of respiration can fat molecules enter?
Broken into glycerol which enters in glycolysis and fatty acids which enter into the citric acid cycle.
Which stage of respiration can protein molecules enter?
Broken down into amino acids and are deaminated before entering either glycolysis or citric acid cycle.
Which enzyme is responsible for the synthesis of ATP molecules?
Which enzyme removes hydrogen and electrons from molecules during respiration?
What is metabolism?
All of the enzyme controlled chemical reactions that take place within cells.
What is meant by an anabolic pathway?
Synthesis reaction that requires energy.
What is meant by a catabolic pathway?
Breakdown reaction that releases energy.
What is an example of an anabolic pathway?
Amino acids -> Proteins
What is an example of a catabolic pathway?
Glucose -> Carbon Dioxide and Water (in presence of oxygen)
Why are irreversible steps necessary in some metabolic pathways?
To commit the metabolic pathway to continuing.
Why are reversible steps necessary in some metabolic pathways?
To keep substrates at the required concentrations.
Why are alternative routes necessary in some metabolic pathways?
Allows reactions to proceed with different substrates and enzymes.
What are membranes made out of?
Phospholipids and proteins
Describe the structure of the membrane?
Phospholipid bilayer, flexible, fluid
What are the roles of proteins in the membranes?
Pumps, pores, enzymes, receptors and structural
Why are membranes important?
They increase the rate of reaction.
How are genes and metabolic pathways linked?
Genes need to be expressed to provide the enzymes for metabolic pathways.
What is an enzyme?
A biological catalyst that lowers the activation energy of reactions.
What is activation energy?
The energy required for the reactants to reach the transition state.
What is the transition state?
The point at which the bonds in the substrate(s) are breaking ready to being the reaction to make the product(s).
What is meant by the "induced fit model"?
When the substrate binds to the enzyme the active site changes shape slightly to fit more closely around the substrate.
What is meant by "affinity"?
Why are enzymes specific?
They only work on substrates which have a high affinity for the active site
Which factors can affect the rate of enzyme activity?
Temperature, pH, substrate concentration and presence of inhibitors
Where can signal molecules which control enzyme action come from?
Intracellular environment or extracellular environment.
What is an inhibitor?
A substance which decreases the rate of an enzyme controlled reaction.
What is a competitive inhibitor?
An inhibitor which works by binding to the active site of the enzyme because it has a similar shape to the substrate.
How can the effects of a competitive inhibitor be overcome?
By increasing the substrate concentration.
What is a non-competitive inhibitor?
An inhibitor which works by binding to the enzyme at a site away from the active site which causes the active site to change shape.
How can some enzymes be activated?
Binding of an activator which makes it take on its active shape.
What is end-product inhibition? (Sometimes known as feedback inhibition)
As the concentration of the end product builds up it can bind to the first enzyme in the pathway thus slowing down the pathway.
How is end-product inhibition useful?
It prevents the build up of end products and the wasteful breakdown of intermediates.
What are protein pores for?
Allow diffusion across membranes.
What are protein pumps for?
Active transport across membranes.
How would you calculate a percentage change / percentage increase / percentage decrease?
--------- x 100
How can a scientist make their results more reliable?
Repeat the experiment.
If the experiment is on people, they could include more people in the trial (increase their sample size).
How do you set up a valid experiment?
You should ensure that you only change the independent variable. All other variables must be controlled.
What is the independent variable?
The factor that you are deliberately changing from trial to trial.
What is the dependent variable?
The thing that you are measuring in the experiment (the results).
When setting up a table of results, what goes in the left hand side column and what goes in the right hand side column?
The independent variable goes in the left hand side column. The dependent variable goes in the right hand column.
How can you get full marks for the label of a graph axis?
Copy the heading of the table over EXACTLY and remember to include units if they are needed.
How can you get full marks for making a scale on a graph?
- the numbers go beyond the highest data point
- the scale allows you to plot a curve that takes up more than 50% of the y axis
- the scale means that you don't need to break a box into thirds etc when you are plotting (you can only split a box in half accurately).
THIS SET IS OFTEN IN FOLDERS WITH...
Higher Biology Unit 2: Metabolism
higher biology - unit 2
PCR - Higher/ Higher Human Biology
YOU MIGHT ALSO LIKE...
Ch 6 Bacterial growth, nutrition, and differentiat…
bio final review
60 Question Quizlet
OTHER SETS BY THIS CREATOR
Edinburgh University Chinese 1 - All Voc…
NPCR Chinese Vocab (up to week 12) (simplified)
NPCR Chinese 1 - Vocab (Traditional)
NPCR Chinese Vocab *week 6*
OTHER QUIZLET SETS
Deviance and control theories
volcs 1 & 2
Superficial muscles of the anterior forearm
Final Part 1