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Higher Biology - Super Set
All 3 units combined
Terms in this set (439)
Give some examples of human activities which are contributing to current extinction events?
Overexploitation/Habitat degredation/Introducing invasive species/Pollution/climate change
What are the measurable components of biodiversity?
Genetic diversity, species diversity, ecosystem diversity
What is species diversity?
The species richness - number of different species and The relative abundance - proportion of each species present
How can having a dominant species affect species diversity?
Dominant species reduces relative abundance of other species which lowers species diversity.
What is genetic diversity?
Number and frequency of alleles present in a population
What is ecosystem diversity?
Number of distinct ecosystems in an area.
What is the bottleneck effect?
When a large percentage of population is lost leading to reduced genetic diversity of survivors. Can lead to inbreeding depression.
Which factors can affect biodiversity of an island?
Size of island and Distance from mainland
How does habitat fragmentation affect biodiversity?
Leads to reduced habitat area so reduced resources. Lowers biodiversity as species have to compete for resources and some will become extinct.
Why are habitat corridors used?
To join habitat fragments allowing members to colonise an area and to mate.
What is meant by an introduced species?
Foreign species moved intentionally or accidentally into a new area.
What is meant by a naturalised species?
Foreign species who are able to survive and reproduce in their new habitat.
What is meant by an invasive species?
Foreign species who reproduce rapidly and outcompete with native species
Which factors allow introduced species to become invasive?
Free of their usual competitors, predators, pests and parasites so can outcompete native species.
What is meant by overexploitation?
Removing organisms from environment faster than they can be replaced by reproduction.
What is meant by social hierarchy?
The order of feeding dependant on social status
Why can a social hierarchy be beneficial?
Means that aggression is ritualised, keeps real fighting to a minimum, ensures fittest individuals survive to pass on genes, leads to experienced leadership
What are the advantages of cooperative hunting?
Larger kills than when hunting alone; Individuals gain more energy than if hunting individually; Subordinates benefit from share of kill as well as dominant individuals
What are the benefits of social defence?
Increased protection, more chance of seeing predators
What is meant by altruism?
When the donor is harmed by the behaviour but the recipient benefits
What is meant by reciprocal altruism?
When the altruistic act is returned to donor in future
What is meant by kin selection?
Providing resources or protection to related individuals - donor gains indirectly through survival of offspring who have some shared genes with donor
Why do social insects provide resources to their queen?
Queen is related to all members of hive so workers benefit indirectly through queen passing on genes she shares with workers
What is a keystone species?
A species which plays a vital role for the survival of other species in an ecosystem (e.g. bees acting as pollinators)
Why do primates have long periods of parental care?
To allow for offspring to learn complex social behaviours
What methods are used in social groups to reduce conflict?
What is meant by ritualistic display?
Making self look bigger and more threatening e.g. baring teeth, raising heckles, banging chest
What is meant by appeasement behaviour?
Reverse of threat display to show submission. Includes behaviours like grooming, submissive facial expressions, certain body postures, sexual presentation
Which factors can influence the social structures of primate groups?
Ecological niche, resource distribution and taxonomic group
What is meant by an alliance?
Relationships formed between individuals which increase social status, maintained by grooming
How can alliances benefit organisms?
Increases social status of individuals which can lead to increased access to food or mates
What is meant by symbiosis?
Co-evolved relationship between members of two different species
What are the two types of symbiosis?
Parasitism and mutualism
What is meant by parasitism?
When the parasite benefits by gaining energy or resources and the host is harmed
What is a parasite?
An organism which gains energy from the host at the hosts expense
What is meant by mutualism?
When both species benefit from the relationship
What is a vector?
Carries a parasite from host to host
Why might parasite lifecycles involve the use of a secondary host?
If they have no method of locomotion, allows them to survive until back in contact with primary host
What are some examples of mutualism?
Coral polyps and zooxanthella - coral benefits by receiving carbohydrates from photosynthesis and zooxanthella get secure habitat.
What are the costs of providing good animal welfare (using free-range farming techniques)
Financial cost of providing high quality food and protection from predators; lower yield per unit area
What are the benefits of providing good animal welfare (using free-range farming techniques)
Higher value of product, good public relations, healthier animals, lower risk of disease spread
What are some indicators of poor animal welfare?
Misdirected behaviour, stereotypy, failure of reproductive or parental behaviour, altered levels of activity
How can poor animal welfare be overcome?
Enriching animals environment, providing company
What is the term which describes the study of animal behaviour?
What is meant by monoculture?
Growing a crop with only one species, increases chances of pest or disease outbreak
What is a perennial plant?
Lives for many years
What is an annual plant?
Life cycle occurs in one year
What traits do perennial weeds have?
Storage organs and vegetative reproduction
What traits do annual weeds have?
Large number of seeds, long term seed viability, short life cycle, grow rapidly
What is a fungicide?
What is a herbicide?
What is an insecticide?
When would you use a selective herbicide?
On grass crops where only weeds with broad leaves are affected
When would a systemic herbicide be useful?
If weed has underground storage structures that could regrow if left behind
What are some examples of cultural methods of crop protection?
Growing a cover crop; Ploughing; Removal of alternative hosts; Crop rotation
What would be the characteristics of an ideal pesticide?
Specific to pest, short lived, safe
What is bioaccumulation?
When the pesticide remains in tissues over time and builds up faster than it can be removed
What is biomagnification?
When the concentration of pesticide increases at each trophic level in food chain and can reach toxic levels near top
What is biological control?
Use of a natural predator to control pest species
What are the risks associated with organisms used for biological control?
Could become invasive, could eliminate other species, could reduce biodiversity
What is integrated pest management?
Use of biological control and chemical control
What is meant by productivity?
Rate at which plants generate new biomass
What is meant by economic yield?
Mass of desired product (e.g. grain)
What is meant by biological yield?
Total plant biomass produced (includes unneeded parts)
The purpose of replicating treatments in a field trial is to?
Take into account the variability within the plants being grown
The purpose of carefully selection of treatments in a field trial?
To ensure valid comparisons can be made
The purpose of randomising treatments in a field trial?
To eliminate bias when measuring the effects of treatments
Which characteristics may plant breeders try to select for?
Improved yield; Improved resistance to pests or disease; Ability to thrive in particular environments
What is meant by discrete variation?
Fits into discrete categories
What type of inheritance causes discrete variation?
Single gene inheritance
What is meant by continuous variation?
Wide range of characteristics
What type of inheritance causes continuous variation?
What is a test cross?
Used to identify organisms with unknown genotypes
How is a test cross conducted?
Cross unknown with homozygous recessive
What is meant by inbreeding?
Crossing related individuals
What is meant by outbreeding?
Crossing unrelated individuals
Why is inbreeding useful?
Ensures offspring receive alleles for desired characteristics
Why can inbreeding be harmful?
It can lead to inbreeding depression
What is meant by inbreeding depression?
A build up of homozygous recessive deleterious alleles
Why is inbreeding depression less likely to occur in plants?
Years of natural selection eliminates deleterious alleles
What is meant by an F1 hybrid?
Produced by cross between two genetically dissimilar parents who have desired traits
Why can the F1 hybrid be useful?
Show hybrid vigour - increased yield, fertility or other beneficial characteristics
How can offspring showing the desired F1 traits be maintained?
Back cross with parents or maintain and continue to breed original parents
Why is the F2 generation produced by crossbreeding often not useful?
Shows genetic variability so not all offspring will show desired traits
Why can the F2 be sometimes useful?
Introduces new variation
How could breeders identify organisms with particular alleles without doing test crosses?
How could breeders create organisms with particular alleles without breeding?
What is an action spectrum?
Shows the rate of photosynthesis at different wavelengths of light.
What is an absorption spectrum?
Shows which wavelengths of light have been absorbed by plant.
Which wavelengths of light are absorbed by chlorophyll?
Which wavelengths of light are absorbed by the carotenoids?
What is the advantage of having the carotenoid pigments?
It extends the range of wavelengths of light that can be absorbed by plants.
What are the three fates of light when it strikes a leaf?
Absorbed, reflected, transmitted
Describe what happens in photolysis?
Light energy excites electrons which are passed into electron transport chains to generate ATP.
Energy is used to split water into hydrogen which is picked up by NADP and oxygen which is evolved.
Describe what happens in the calvin cycle?
Carbon dioxide combines to RuBP to form intermediates. Intermediates are combined with hydrogen supplied by NADPH and ATP is used to form G3P. G3P molecules are either combined or used to regenerate RuBP.
Which enzyme is responsible for fixing Carbon Dioxide to RuBP?
Which coenzyme combines with hydrogen and takes it to the calvin cycle?
What happens to the glucose made by photosynthesis?
Either used in respiration, used to synthesise starch, used to synthesis cellulose or used in other biosynthetic pathways.
What is food security?
Having access to a sufficient quantity and sufficient quality of food.
What is meant by sustainable food production?
Growing food without degrading natural resources on which agriculture depends.
How can we improve crop production with limited area for crop growing?
Growing higher yielding cultivars; Protecting crops from weeds and pests; Using fertilisers; Identifying and reducing the limiting factors of photosynthesis
Why is farming livestock less efficient than farming crops?
Energy is lost at each trophic level
What is genomics?
The study of genomes.
What is a mutation?
A change in an organisms DNA
What is meant by "genome".
All of an organisms hereditary information encoded within its DNA.
What is cellular differentiation?
The process by which an unspecialised cell becomes a specialised cell.
What is meant by genotype?
The sequence of DNA bases
Which process occurs in the cells before mitosis to ensure each daughter cell gets identical copies of the genetic material?
DNA is composed of repeating units called
What is evolution?
The process of gradual change in the characteristics of a population that occurs over many generations.
What is meant by phenotype?
The physical and chemical state of the cell determined by the proteins that are synthesised.
A DNA nucleotide is made of
Deoxyribose sugar, phosphate, base
Where on the DNA strand does DNA replication take place?
What is vertical inheritance?
DNA is passed from parents down to offspring.
How does differentiation occur?
Some genes are switched off and others on.
What is the function of the coding regions of the genome?
Transcribed and translated to make proteins.
What are gene/point mutations?
A change in one (or a few) bases in an organisms DNA sequence in one gene.
What is a restriction endonuclease?
An enzyme which cuts DNA at a specific sequence.
What is gene expression?
A gene being transcribed and translated to make a protein.
The DNA bases are
Adenine, Guanine, Thymine, Cytosine
Which enzyme is needed for DNA replication?
What is bioinformatics?
The use of computers and statistics to analyse DNA sequences.
What is meant by a specialised cell?
A cell with a specific structure and function.
What are the functions of the non-coding regions of the genome?
Transcribed but not translated to make tRNA, rRNA and RNA fragments
Protect the ends of chromosomes from fraying
What are the three gene mutations?
Substitution, Insertion, Deletion
What is horizontal inheritance?
DNA passed from one cell to another,
Which types of organisms have had their genomes sequenced?
Model organisms, Pest species, Viruses and bacteria
Which organisms use vertical gene transfer?
What happens in substitution?
One base is swapped with another base.
What makes a cell become specialised?
Expressing genes which make proteins specific to the cells.
What chemical elements are proteins made of?
Carbon, hydrogen, oxygen, nitrogen.
What is a primer?
A small chain of DNA which provides a starting point for DNA polymerase.
The shape of a DNA molecule
What subunits are proteins made of?
Which direction does DNA polymerase work in?
5' -> 3' direction.
The 5' end of DNA has what at the end?
What is a stem cell?
An unspecialised cell with the potential to self-renew by mitosis or differentiate into specialised cells.
How can you tell how closely related species are from the genomes?
The more similarities there are in the DNA sequences the more closely related the species are.
What happens in deletion?
One base is removed from the DNA sequence.
Which organisms can use horizontal gene transfer?
Prokaryotes -> Prokaryotes
Prokaryotes -> Eukaryotes
Viruses -> Prokaryotes
Viruses -> Eukaryotes
What is a polypeptide?
A chain of amino acids joined by peptide bonds.
What is phylogenetics?
The study of evolutionary relatedness.
What is the role of DNA polymerase?
To add free DNA nucleotides to the 3' end of a growing DNA strand.
The 3' end of DNA has what at the end?
What is a meristem?
A region of unspecialised cells in a plant capable of cell division.
What happens in insertion?
One base is added to the DNA sequence.
What are the benefits of horizontal gene transfer?
Can lead to rapid evolutionary change.
How can we produce phylogentic trees?
Using fossil records and sequence data .
Which mutations have a frameshift effect?
Insertion and deletion.
What is an embryonic stem cell?
A stem cell with the potential to become any of the cells required in your body.
Which type of bond joins two amino acids together?
Which enzyme joins fragments of DNA together?
These bonds hold adjacent nucleotides together
Covalent bonds / Strong Chemical bonds
What is a downside of horizontal gene transfer?
There is some risk as not all genes are helpful, some may be harmful.
What type of bonds occur between amino acids that lead to folding of polypeptides?
Hydrogen bonds and sulphur bridges
These bonds hold the strands of DNA together and are found between complementary bases
Which strand of DNA is synthesised continuously?
What is meant by a frameshift mutation?
A mutation which alters every amino acid after the mutation leading to a faulty protein being produced.
What word can be used to describe the potential of embryonic stem cells to become any of the body cells?
What is a molecular clock?
A way of working out how long ago species diverged by looking at the number of mutations that have taken place. The rate of mutations is relatively stable.
What is natural selection?
The non-random increase in frequency of genetic sequences which increase an organisms chances of survival.
What gives a protein its function?
The shape of the protein gives the protein its function.
Which strand of DNA is synthesised discontinuously?
Which DNA base pairs with Adenine?
What is an Tissue (adult) stem cell?
A stem cell with the potential to become a narrow range of cells required in the body.
What is meant by a missense mutation?
Leads to a different amino acid being used so a different protein is produced.
What is sexual selection?
The non-random increase in frequency of genetic sequences which increase an organisms chances of successfully reproducing.
What are the three domains of life?
Bacteria, Archaea, Eukaryotes.
What is the sequence of evolution of life on earth?
Prokaryotes -> Photosynthesis -> Eukaryotes -> Multicellular organisms -> Animals -> Vertebrates -> Land plants
Describe the process of natural selection?
Organisms which are better suited to their environment are more likely to survive and reproduce and are more likely to pass on their genes to the next generation.
What is meant by a nonsense mutation?
Premature stop codon inserted. Different / no protein produced.
What word can be used to describe the narrow differentiation potential of tissue (adult) stem cells?
What gives a protein its shape?
The order of the amino acids and the folding of the polypeptide chain.
What is meant by discontinuous replication?
Strand is synthesised in fragments
Which DNA base pairs with Guanine?
What is a eukaryote?
Organism with membrane bound organelles and a true membrane bound nucleus.
What is needed in the cell to allow DNA replication?
Template DNA, primers, DNA polymerase and ligase (enzymes), free DNA nucleotides, ATP
What determines the order of amino acids in a polypeptide chain?
The order of DNA bases in the gene which codes for the protein.
What is function of Tissue (adult) stem cells?
They provide a supply of differentiated cells needed for growth and repair in organisms.
What is meant by a neutral mutation?
A mutation which leads to the same amino acid being produced so no change in protein produced.
What are the three ways that natural selection can affect the frequency of particular traits?
What is the use of personal genomics?
Knowing the risk of developing diseases
What is pharmacogenetics?
Being able to prescribe medication that is personalised to a persons genome to make sure it is the correct drug and dosage.
What is meant by directional selection?
The mean trait shifts towards one of the traits that was less common previously.
What is meant by a silent mutation?
A different but chemically similar amino acid is used to protein still functions correctly.
How can stem cells be used therapeutically?
- In bone marrow transplants to treat leukaemia
- To treat damaged cornias
- To grow skin grafts to treat burns
Which process produces a primary mRNA transcript?
What is a prokaryote?
Organism which does not have a nucleus and does not have membrane bound organelles.
Where is DNA found in eukaryotes and what form are they in?
Linear chromosomes in the nucleus
Circular chromosomes in the mitochondria and chloroplast
Which enzyme is required to make a molecule of mRNA?
What is meant by the frequency of mutation?
How often the mutation occurs.
What is meant by stabilising selection?
The mean trait is maintained and more organisms sow the mean trait reducing genetic diversity.
What are the ethical issues associated with personal genomics?
- Potential bias from employers
- Potential bias from life insurance
- Potential distress from knowing about risks of disorders.
What is meant by disruptive selection?
The extreme versions of the trait are favoured resulting in two new mean traits. The intermediate traits become less common.
How often do mutations occur?
Randomly and rarely.
What are the differences between RNA and DNA
RNA - single stranded DNA - double stranded
RNA - uracil DNA - Thymine
Which organisms are eukaryotes?
Animals, plants, fungi (yeast)
How can stem cells be used in research?
- To study cellular processes
- To use as model cells in drug testing
- To investigate causes of disease
Which organisms are prokaryotes?
What is a mutagen / mutagenic agent?
Something which increases the frequency of mutations.
Which process allows us to amplify DNA in vitro?
Polymerase Chain Reaction (PCR)
Give an example of a mutagenic agent?
Mustard gas, U.V. radiation, X-Rays
Where is DNA found in prokaryotes and in what form?
Large circular chromosome, plasmids
What is the first stage in transcription?
RNA polymerase unwinds and unzips DNA strand.
What are the stages of PCR?
1. Heating up to 94C-96C
2. Cooling to 50C -65C
3. Heating up to 72C
What is a plasmid?
Small ring of DNA
How can mutations alter gene expression?
If a mutation occurs DNA sequence that regulates transcription then this can lead to transcription being halted.
What are the ethical implications of using stem cells in medicine or research?
- Using embryonic stem cells leads to embryos being destroyed which some people believe is murder
- Embryonic stem cells come from embryos which would have been destroyed any way so people believe they should be used for good
How can you tell if two organisms are the same species?
If they can interbreed to form fertile offspring then they are the same species.
Which mutation can lead to introns being left in the mature mRNA transcript?
Splice site mutations.
What is the role of RNA polymerase in transcription?
Unwinds and unzips the DNA double helix. Adds RNA nucleotides to form a molecule of mRNA.
Which eukaryotes contain plasmids?
What is mRNA?
What is speciation?
The formation of new species.
How are mutations beneficial for evolution?
They provide new variation upon which natural selection can act.
How is DNA packaged in linear chromosomes?
Tightly wound around proteins called histones
What are some of the future therapeutic uses of stem cells?
Treatment of parkinson's or alzheimer's disease.
Why is DNA said to be antiparallel?
One strand runs in the 3'->5' direction, the other runs in the 5' -> 3' direction.
What is required for PCR?
Primers, DNA (Taq) Polymerase, Free DNA nucleotides, Template DNA, buffer
What is the function of mRNA?
To carry a complimentary copy of the DNA sequence from the chromosomes in the nucleus to the ribosome in the cytoplasm.
What is a chromosome mutation?
A change in the number or sequence of genes on a chromosome.
Summarise the events in speciation.
1. Isolating barrier
3. Natural Selection
4. Many generations
5. Two new species are formed
Why is buffer required in PCR?
To keep a stable pH
What is a ribosome made of?
rRNA and protein
What is an induced pluripotent stem cell?
A stem cell produced by taking differentiated cells and reprogramming them to revert back to becoming stem cells.
What are the chromosome mutations called?
Translocation, Inversion, Deletion, Duplication
What are the three types of isolating barriers?
Geographical, ecological, behavioural.
What is the function of the ribosome?
The site of protein synthesis.
What is an application of PCR?
Paternity testing, crime scene analysis and working out evolutionary relationships
What happens during translocation?
Genes from one chromosome become attached to the end of another chromosome.
What is sympatric speciation?
Speciation which occurs as a result of a behavioural barrier.
Which process allows the formation of a mature mRNA transcript?
What is allopatric speciation?
Speciation which occurs as a result of a geographical or ecological barrier.
What happens in inversion?
The order of genes gets swapped around (ABC becomes CBA).
What happens in duplication?
Some of the genes become copied and inserted into the chromosome.
What is an exon?
A coding section of mRNA
Why is DNA heated to 94C-96C in PCR?
To separate the two DNA strands by breaking the hydrogen bonds between complimentary bases.
What happens in deletion?
Some of the genes are removed from the chromosome.
What is an intron?
A non-coding section of mRNA
How can duplication result in new characteristics?
The original information is still present so the genes can function. If mutations occur in the extra copies of the gene they can lead to new characteristics.
What happens during splicing?
The introns are removed and the exons are joined together to make the mature mRNA transcript.
Where does transcription begin?
At a start codon
Why is DNA cooled to 50C -65C during PCR?
To allow the primers to anneal to their target sequences.
Why is DNA heated to 72C during PCR?
To allow DNA polymerase / Taq Polymerase to build new strands by adding free DNA nucleotides.
What is a codon?
Three bases on mRNA which codes for one amino acid
Why are two primers needed in PCR?
One primer for each strand
What is meant by a positive control in PCR?
A control with a known sequence of DNA to show that all of the components are working.
What is tRNA?
What is the function of tRNA?
Have an anti-codon which is complementary to a codon on mRNA. Carries specific amino acids to the ribosome.
What is meant by a negative control in PCR?
A control which lacks a DNA sequence to show that there is no contamination.
What is an anticodon?
Three bases on a tRNA molecule which matches with a codon on mRNA.
What is the process which synthesises a protein using the information carried in mRNA?
Where does translation end?
Which process can allow many different proteins to be produced from one gene?
How many codons code for one amino acid?
How many bases are in a codon?
How many bases code for one amino acid?
all the chemical reactions taking place within a cell
most chemical reactions occur as part of integrated and interconnected pathways, catalysed by enzymes
is a degradation reaction that releases energy
bio-synthesis reaction that uses energy
___ acts as an important means of energy transfer between reactions
most metabolic pathways have both ___________ ____ ______________ steps
reversible and irreversible
are pathways that exists through substances that allow certain stages controlled by enzymes to be bypassed
the cell membrane
separates the intracellular environment from the extracellular environment
the cell membrane ___________ the flow of materials into and out of the cell
proteins embedded in membranes allow various functions to be carried out
transport molecule that contains pores, the provide channels for specific substances to diffuse across membrane
allow molecules of a particular size to pass through the membrane
protein pores allow ___________ diffusion
pumps allow __________ _____________
enzymes in membrane __________ reactions
smaller compartments have __________ volume to surface area ratio
high surface area of membranes allows:
the high concentration of substances to be maintained and faster reaction rates to be achieved
the amount of chemical change per unit of time
the energy required to achieve the transition state and start a chemical reaction
enzymes ________ the activation energy and by doing so increase the reaction rate
an attraction or force between particles that cause them to combine
the substrate binds readily to the enzyme because it has ________ ___________ for the active site
the product is released because it has a _____ __________ for the active site
orientation of reactants
if two or more substances are involved in the reaction, the shape of the active site ensure that they come together in the best orientation to facilitate the chemical reaction
activation energy diagram enzymes
induced fit of enzymes
when the active site changes shape to create a tighter fit around substrate, returns to original shape after product is released
ways of increasing rate of enzyme activity
- changing temperature towards optimum
- changing pH towards optimum
- increasing substrate concentration
ways of decreasing substrate concentration
- changing temperature away from optimum
- changing pH away from optimum
- decreasing substrate concentration
- use of an inhibitor
why does the reaction rate increase as the substrate concentration increases?
because more of the available active sites can become occupied by substrate molecule
when does the reaction rate become constant
when the concentration is reached whereby all active sites are occupied
inhibitor on enzyme activity
completely changes the active site so no matter how much you increase substrate concentration it wont increase enzyme activity
slowly the substrates out compete the inhibitor so it will increase to same end point as having no inhibitor but slower
when an end product of a reaction binds to an enzyme at the start of the reaction to prevent the overproduction of the end product
competitive inhibitors bind on the _______ _____ of the enzyme
where do non-competitive inhibitors bind
not on the active site but can alter its shape
structure of ATP
composed of one molecule of adenosine bonded to three molecules of inorganic phosphate
what is phosphorylation?
the addition of a phosphate group to a molecule
a series of metabolic pathways which brings about the release of energy which is stored as ATP
3 stages of cellular respiration
glycolysis, citric acid cycle, electron transport chain
are involved in glycolysis and the citric acid cycle, they remove H+ ions and electrons from compounds
what happens to the H+ ions and electrons after they are removed by dehydrogenase enzymes?
then passed to coenzymes NAD or FAD
what are the H+ ions and electrons used for?
to generate ATP during ATP synthesis
what happens during glycolysis?
-occurs in cytoplasm
-intermediates are phosphorylated before ATP is generated
-NET gain of 2ATP
-glucose is split into 2 pyruvate molecules
what happens during the citric acid cycle?
-occurs in the matrix of the mitochondria
-acetyl coenzyme A combines with oxaloacetate
-citrate is formed
-H+ ions and electrons are accepted by NAD and FAD
-2ATP and CO2 is generated
what happens during the electron transport chain and ATP synthesis?
-receives H+ ions and electrons from coenzymes NAD and FAD
-is a collection of proteins present on the inner membrane of the mitochondria
-energy from electrons is used by ATP synthase to generate ATP
-H+ ions and oxygen combine to form water
how much ATP is generated through aerobic respiration?
what are the two stages of glycolysis?
-energy investment phase
-energy payoff phase
what happens in energy investment phase?
the intermediates are phosphorylated and 2 molecules of ATP are used to provide phosphates for the phosphorylation
what happens in the energy payoff phase?
4 molecules of ATP are produced and the hydrogen ions and electrons are released and accepted by NAD
NET gain of glycolysis?
what happens during breakdown of pyruvate?
pyruvate is broken down into an acetyl group and carbon dioxide, the acetyl group combines with a molecule of coenzyme A and produces acetyl coenzyme A, more hydrogen ion and electrons are released and accepted by NAD
what happens to the carbon dioxide from the breakdown of pyruvate?
it is released as a by product
where does the electron transport chain occur?
inner membrane of the mitochondria
what do the NADH and FADH2 also release doing ETC?
high energy electrons which provide energy for the active transport of H+ ions across the membrane
what happens to the electrons after they come out of ETC?
they combine with oxygen, the final electron acceptor, and at the same time oxygen combines with a pair of hydrogen ions to form water
what happens during ATP synthesis?
hydrogen ions that have been pumped across membrane diffuse back into the matrix of the mitochondria through protein ATP synthase causing part of protein to spin, enzyme ATP synthase is able to catalase regeneration of ATP from ADP+Pi
what happens if oxygen is absent, for animals?
the pyruvate is converted into lactate (lactic acid)
what happens if oxygen is absent, for plants and yeast ?
the pyruvate is converted into ethanol and carbon dioxide
overview of respiration
carbohydrate stored by plants
carbohydrate stored by animals
what do starch and glycogen act as?
respiratory substrates as they can be broken down to release glucose as required
what happens to proteins when required as a respiratory substrate?
proteins in the diet are broken down to their component amino acids, amino acids in excess for body's requirements for protein synthesis undergo deamination forming urea and respiratory pathway intermediates
the energy consumed by an organism per unit time
how can energy consumption be measured indirectly?
-rate of oxygen consumption
-rate of carbon dioxide production
-rate of heat production
measures changes to air being pumped through a sealed chamber for example oxygen and carbon dioxide content and temperature
measures temperature change of water being passed through a sealed chamber
_______ metabolic rates require efficient delivery of oxygen to cells
circulatory system of fish
have a single circulatory system, one atrium on ventricle. The blood is delivered at high pressure to the gills after being pumped from the heart but is at low pressure by the time it reaches the body
circulatory system of amphibians and reptiles
have an incomplete double circulatory system. 2 atriums and one ventricle. some mixing of oxygenated blood from the lungs and deoxygenated blood from body occurs in the ventricle, tissue blood in incompletely oxygenated
circulatory system of mammals and birds
have a complete double circulatory system. 2 atriums and ventricles completely separated by a septum
which is the most efficient circulatory system?
mammals and birds, it enables an endothermic (warm blooded) vertebrate to deliver large quantities of oxygen to respiring tissues which release heat during metabolism and keep its body warm
birds are very active vertebrates and so have a very efficient system of gas exchange that allows them to obtain the large quantities of oxygen needed for their high ____________ _________
birds have a system of large ____ _____ associated with their lungs, which are designed to keep the air flowing through the lungs in one direction rather than having to go in and out by the same route
what happens when a bird breaths in?
fresh air fills its posterior air sacs, stale air moves into the anterior air sacs from the lungs. when the bird breaths out, the fresh air passes from the posterior sacs to the lungs and the stale are passes from the anterior sacs to the outside
lungs of amphibians
They only use their lungs for gas exchange when very active. lungs are small, thin walled and without alveoli. have a relatively smaller surface area for gas exchange compared to mammals.
how do amphibians exchange gas when not active?
through their skin
lungs of reptiles and mammals
lungs with branched system of tubes called bronchioles ending in many thin walled, moist alveoli, providing a large surface area for the efficient exchange of gases.
some organisms show ______________ adaptions that enable them to survive in and exploit low oxygen niches
example of low oxygen niches
-deep in the ocean
how do humans respond to high altitudes?
increase number of red blood cells by up to 20%, takes several weeks for this adapt to take effect
as oxygen levels increases, so can ____________ _____
what is one way to determine aerobic fitness?
measure the maximum rate as which the body is able to take up and use oxygen, known as VO2 max
we control the _______________ variable
the dependent variable depends on the __________________
what external abiotic factors can affect an organisms metabolic rate?
organism will be either one of two categories, conformers or ___________
cannot alter their metabolic rate and conform to the condition in the environment, their internal environment is dependent upon the external environment
alter their metabolic rate to maintain a steady state, they regulate their internal environment
conformers have low __________ _____ as they do not expend energy maintaining their internal environment
where must conformers live?
in stable environments as they are less adaptable
how can conformers maintain an stable metabolic rate?
using behavioural responses, for example lizards sunbathe to control body temperature
conformers have a _________ ecological niche
regulators occupy a vast range of __________ _______
to maintain homeostasis, organisms require ____________ ______________
System of maintaining homeostasis in a regulator organism
Use of negative feedback in regulation of body temperature in mammals. Either ectotherms or endotherms
how the hypothalamus controls temperature?
-the skin has thermo receptors that detect changes in the temperature
-nerve impulses sent to the hypothalamus relaying this information
-the hypothalamus also contains thermo receptors
-hypothalamus sends out nerve impulses to effectors to return body temp to normal levels
the two main mechanisms employed by the skin to regulate body temperature in a mammal
the blood vessels that supply blood to the skin dilate (widen), increasing the amount of blood flowing to the skin. this increases the surface area from which heat can be lost to environment by radiation
Blood vessels supplying blood to the skin constrict ( narrow) reducing the amount of blood flowing to the skin. as a result less heat is lost by radiation from the surface of the body
how else does the body cool down?
- sweat glands in the skin secrete sweat which cools the body down when it evaporates from the skin
-decreasing metabolic rate as it reduces the amount of heat energy produced
how else does the body warm up?
-less sweat is produced to conserve heat
-shivering warms the body up, as does increasing the rate of metabolism (generates more heat energy)
how do hairs in the sublayer of the skin help keep heat?
when the body is cold, nerve impulses from the hypothalamus contract the erector pili muscles, causing the hairs to stand up. this traps a layer of air close to the body, which acts as a insulator. more effective in furry animals than in humans
reduction in metabolic rate enables _________ during a period when the cost of continued metabolic activity would be too high
a period of suspended growth and development in response by the organism to tolerate adverse conditions
when an organism becomes dormant before the arrival of the adverse conditions
when an organism becomes dormant after the arrival of the adverse condition
hibernation can be consequential or ________________
what does hibernation allow animals (usually mammals) to survive?
adverse cold conditions
what happens during hibernation?
the animals metabolic rate drops with a resulting decrease in body temperature, heart rate and breathing rate
the bare minimum of energy is used during hibernation for what?
to maintain vital cellular activities using fat stores built over the summer
aestivation is an example of ________________ dormancy
what does aestivation allows animals to survive?
periods of excessive drought or heat during the summer
a period of reduced activity and metabolism in organisms as part of a 24 hour cycle. additional decrease in breathing rate, body temperature and heart rate
torpor decreases the rate of ___________ _________________ at a time when searching for food would likely be unsuccessful or risk of predation is too high
what kind of animals is daily torpor often found in?
organisms with high metabolic rate
is the regular movement by the members of a species from one place to another over a relatively long distance
migration avoids ______________ __________ caused by shortage of food and low temperatures by expanding energy to relocate to a more suitable environment
what does long distance migration normally involve?
an annual round trip between two regions that both provide favourable condition for each part of the year
specialised techniques for studying migration
-ringing with metal bands
-tracking using transmitters
ringing with metal bands
a metal band carrying a birds individual identification number is attached to birds leg. of the bird is recaptured then its information can be recorded
a small circular tag is attached to the hind wing of a monarch butterfly. this carries a code entered in a database. if the tag is recovered at a later date, the route and distance covered by the butterfly can be determined
tracking using transmitters
lightweight transmitters are glued to the animals body or implanted under its skin. the transmitter emits signals that are picked up by satellites, signals are beamed back to ground stations
advantage of tracking using transmitters
they provide the most accurate information so far on the exact locations of flyways used by birds during their migratory cycle
disadvantage of tracking using transmitters
are expensive and may have a drag effect on some small birds
what can migration be influenced by
inate or learned behaviour
is inherited and inflexible. this pattern of behaviour is performed in the same way by every member of the species
begins after birth and is gained by experience. it is flexible and occurs as a result of trial and error and the transmission of knowledge and skills among the members of a social group
are organisms that live in extreme conditions. most belong to the domain archaea. many live in hydrothermal vents
these organisms thrive at high temps, thermophile bacteria have heat tolerant enzymes such as heat tolerant polymerase (used in PCR)
what are considered microorganisms?(3 domains of life)
archaea, bacteria and some species of eukaryotes
in general why are microorganisms used?
because of their adaptability, ease of cultivation and speed of growth
well known products from microorganisms
why microorganisms are useful?
- they are easy to cultivate
-the reproduce and grow quickly
-their food substrate is often a cheap substance (or even a waste product from another source )
-they produce many different useful products
-their metabolism can be manipulated relatively easily
microorganisms are normally grown under controlled conditions in a laboratory, they can be grown in two ways:
- in a growth medium called broth jar
- on a solid medium called agar jelly
all processes will provide the following growth requirements:
- energy source ( chemical or light)
- simple chemical compounds
- suitable environmental condtions
some microorganisms can synthesise all the ____________ ________ e.g. amino acids they require if provided with simple chemical compounds
other microorganisms must be provided with complex compounds as they are unable to synthesis, such as _______ ______ and ____________
fatty acids and vitamins
factors that need to be controlled:
- sterility (eliminate contaminants)
- concentration of oxygen
- glucose concentration
what does using a fermenter allow?
a variety of environmental conditions to be monitored and controlled. this is done by computers when industrial sized fermenters are used
the time required for a population of unicellular organism to double in number
why does the pattern of growth of a population of microorganisms change over time?
- nutrients provided are used up
- metabolites produced by the microorganisms being secreted (released outside the cell)
growth of microorganism (phases of growth)
little to no increase in cell numbers. the cells are adjusting to growth medium and show increased metabolic activity, they are making substrates and turning on enzymes. flat line
the enzymes may need to be ________ in the lag phase for use in metabolising the new substrates
the cells grow and multiply as maximum rate, providing there is no limiting factor. steep incline line
nutrients begin to run out and/or secondary metabolites produced by the microbe start to build up. at this point the rate of production of new cells is equal to the rate of death of old cells. line is level.
what happens when there is a build up of secondary metabolites?
it can have a toxic effect and causes rate of cell division to decrease
the lack of nutrient substrate and/or the accumulation of high concentration of toxic metabolites leads to death phase. number of cells dying now exceeds the number of new cells being produced. steep decline
total cell count
the number of cells in a culture
viable cell count
the number of living cells in a culture
production of primary metabolites essential for growth e.g. amino acids
substances produced which are not associated with growth but can confer an ecological advantage
difference/original x 100
__________ ____________ of different strains (sexually reproducing organisms) or encouraging horizontal gene transfer between asexual strains also improves wild strains
increase _____________ (mutation rate) using mutagenic agents such as UV, radiation and mutagenic chemicals also improves wild strains
another way to improve wild strains is by genetic modification using ______________ _____ _____________
recombinant DNA technology
what is recombinant DNA?
DNA created artificially
genetic alteration of bacteria
plasmids and chromosomal DNA can be transferred between cells or taken up from the environment
recombinant DNA technology
an enzyme extracted from bacteria which is used to cut up the DNA into fragments
can be fluorescent proteins or genes for antibiotic resistance, scientists can select the cells that are for example glowing green and know they also contain gene of interest
a site that is cut open by restriction enzymes to allow the gene to be transferred or be inserted
a specific short sequence of DNA bases that is cut by restriction enzyme
recombinant plasmids and artificial chromosomes are used as these to carry DNA between organisms
a gene that is used by scientists to identify if recombinant DNA has been taken up into cells
a sequence of DNA that controls the expression of a gene
origin of replication
the site on a plasmid that allows it to control its own replication (self- replication)
DNA that has been created artificially that allows for longer sequences of DNA to be transferred between organisms
combines complementary sticky ends on the vector with the target sequence e.g. seals the gene into the plasmid
what is a limitation of using eukaryotic animal/plant recombinant DNA in prokaryotic cells?
when the eukaryotic gene is expressed in the prokaryotic cells the required polypeptide may fold incorrectly or may lack post translational
why may eukaryotic animal/plant recombinant DNA lack post translation?
as splicing and post translational modification doesn't occur in prokaryotes as they have no introns
is a source of harm or danger
how is use of microorganisms tightly controlled?
products must meet specific requirements such as:
-they must not cause any risk to staff manufacturing them
-must to safe to use by consumers
-it must be pure and free from microorganisms that could contaminate the environment
the likelihood of that harm occurring
THIS SET IS OFTEN IN FOLDERS WITH...
higher biology - unit 2
higher biology - unit 3
Higher Biology - Unit 3
Higher Biology 1.3 Gene expression
OTHER SETS BY THIS CREATOR
N4 Cell Biology 2: DNA
N5 1.1 Cell Structure