175 terms

IB Biology

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genotype
the alleles of an organism
phenotype
the characteristic of an organism
dominant allele
an allele that has the same effect on the phenotype when present in both homozygous and heterozygous states
co-dominant alleles
pair of alleles that both affect the phenotype when present in a heterozygote
recessive alleles
an allele that only has an effect on the phenotype when in homologous state
locus
the particular position on homologous chromosomes of a gene
homozygous
having two identical alleles of a gene
heterozygous
having two different alleles of a gene
carrier
an individual that has one copy of a recessive gene that causes a genetic disease in individuals who are homozygous for this allele
test cross
testing a suspected heterozygote by crossing with a known homozygous recessive
karyotype
a photograph of the chromosomes in a cell
independent assortment
the order of which the maternal and paternal chromosomes in a homologous pair line up
crossing over (meiosis I)
chromosomes cross over at the chiasmata, and exchange sections of DNA
non disjunction
chromosomes do not separate correctly, resulting in gametes containing an extra copy of a chromosome or missing a chromosome
Meiosis: Prophase II
DNA condenses
Nuclear membrane breaks down
Spindle fibres form
Meiosis: Metaphase II
Individual chromosomes line up along the equator of the cell
Spindle fibres attach to the centromeres
Meiosis: Anaphase II
Chromosomes split at the centromere
Sister chromatids move to opposite poles of the cell
Meiosis: Telophase II
Spindle fibres break down
Nuclear membrane forms
Chromosomes de-condense/uncoil/unwind
Cytokenises then occurs
Meiosis: Prophase I
Chromosomes condense
Nuclear membrane breaks down
Centriols move to opposite poles
Spindle fibres form
Homologous chromosomes pair up
Meiosis: Metaphase I
Homologous chromosomes line up along the equator of the cell
Spindle fibres attach to the centromeres
Meiosis: Anaphase I
Homologous chromosomes are pulled to opposite poles
Meiosis: Telophase I
Nuclear membrane forms
Spindle fibres break down
Chromosomes de-condense/uncoil/unwind
Cytokenises then occurs
*does not occur in plant cells
independent assortment occurs:
during Meiosis I (Metaphase I)
crossing over occurs:
during Meiosis I (Metaphase I)
non-disjunction occurs:
during Meiosis I or II (Anaphase)
homologous chromosome
chromosomes with the same genes in the same sequence
meiosis
a reduction division of a diploid nucleus to form haploid nuclei
insertion/deletion mutation
bases are inserted into or deleted from the DNA
substitution mutation
some of the base sequence is swapped for different nucleotides
gene
a heritable factor that controls a specific characteristic
allele
one specific form of a gene
differs from other alleles by one or a few bases
occupies the same gene locus as other alleles of the gene
genome
the whole of the genetic information of an organism
gene mutation
a change to the base sequence of a gene
enzyme
organic/biological catalysts
active site
region on the surface of an enzyme to which substrates bind
denaturation
permanent structural change in a protein, usually resulting in permanent loss of its biological properties
Lock & Key model shows enzymes are:
reusable
specific
not chemically changed or consumed
translation
translating the sequence of bases on the mRNA molecule into a sequence of amino acids
transcription
formation of an RNA strand complementary to the DNA strand by RNA polymerase
1 gene = 1 polypeptide
one gene -> one mRNA -> one polypeptide -> one protein
primary protein structure
amino acid chain
secondary protein structure
can form proteins
tertiary protein structure
3D shape forms globular protein
quaternary structure
2 or more tertiary proteins join
genetic code
codons composed of triplets of bases
cell respiration
controlled release of energy from organic compounds in cells to form ATP
main photosynthetic pigment
chlorophyll
glycolysis (cell respiration)
glucose in the cytoplasm is broken down into pyruvate with a small yield of ATP
alcoholic fermentation occurs in:
plants and funghi
alcoholic fermentation converts:
pyruvate into ethanol and CO2
lactic fermentation occurs in:
animals
lactic fermentation converts:
pyruvate into lactate
anaerobic respiration occurs in:
cytoplasm
aerobic respiration occurs in:
mitochondrion
aerobic respiration converts:
pyruvate into CO2 and H2O with large yield of ATP
photosynthesis converts:
light energy into chemical energy
photolysis (photosynthesis)
split water molecules to form hydrogen and oxygen
fixation (photosynthesis)
energy from ATP and hydrogen (from photolysis) convert an inorganic form of an element to an organic form
directly measure rate of photosynthesis:
increase in biomass of plant
CO2 intake
O2 release
factors which affect the rate of photosynthesis
light intensity
CO2 concentration
temperature
factors which affect enzyme activity
temperature
pH
substrate concentration
DNA and RNA differences
sugar
bases
number of strands
bonds between monosaccharides
glycocidic
bonds between amino acids
peptide
most frequently occurring chemical elements
H N O C
elements in living organisms (besides 4 main elements) and their roles
Na P S Ca Fe
4 properties of water, and their impacts on living organisms
thermal
cohesive
transparent
solvent
organic compound
produced in living organisms
contains C
expect carbonates, oxides of carbon, and hydrogen carbonates
inorganic compound
not produced by living organisms
usually do not contain C
elements in carbohydrates
C O H
elements in fats
C O H
elements in protein
C O H N P often S
elements in nucleic acids
C O H N P
3 monosaccharides
glucose, galactose, fructose
3 disaccharides
maltose, lactose, sucrose
3 polysaccharides
cellulose, starch, glycogen
bases of DNA
adenine
thymine
guanine
cytosine
bases of RNA
adenine
uracil
guanine
cytosine
bonds within DNA strand
covalent
bonds between DNA strands
hydrogen
condensation
form new bonds by removing a water molecule
hydrolysis
break bonds by adding a water molecule
in gel electrophoresis:
fragments of DNA move in an electric field and are separated according to their size
gel electrophoresis of DNA used in:
DNA profiling
outcomes of human genome project
produce new drugs based on gene sequences
study how genes influence human development
information on evolution, migration, origin
easier identification of genetic diseases
clone
a group of genetically identical organisms or a group of cells derived from a single parent cell
two current genetically modified living things:
salt tolerant tomato plants
factor IX (human blood clotting) in sheep milk
herbicide resistance in crops
cell theory
-all cells come from pre-existing cells
-all living organisms are composed of cells
-cells are the smallest unit of life
evidence for cell theory
electron microscopes
light microscopes
functions of life:
movement
respiration
sensation
growth
reproduction
excretion
nutrition
types of organisms which carry out functions of life:
unicellular and multicellular
properties of multicellular organisms:
show emergent properties
stem cells: (2)
-retain capacity to divide
-ability to differentiate along different pathways
uses of stem cells:
-Alzheimers/dementia
-spinal cord injuries
-Parkinson's disease
organelles within prokaryotic (E. coli):
cell wall
plasma membrane
flagelli
pili
cytoplasm
nucleoid
ribosomes
plasmids
division of prokaryotic cells:
binary fision
bacteria (type of cell):
prokaryotic
organelles within plant cell:
mitochondrion
chloroplast
Golgi apparatus
vacuole
ribosomes and RER
cell wall
plasma membrane
cytoplasm
nucleus
organelles within animal cell (liver):
Golgi apparatus
ribosomes and RER
mitochondrion
lysosome
nucleus
plasma membrane
cytoplasm
cytoplasm
fluid component of cells
where organelles occur
plasma membrane
controls entry and exit of materials
cell wall
provides structure and support for cell
flagelli
for movement
pili
for adhesion
ribosomes
site of protein synthesis
plasmid
naked, circular piece of DNA
nucleoid
where genetic material is found
Golgi apparatus
store, modifies and package proteins
transports proteins into vesicles to be transported out of the cell
mitochondrion
site of aerobic respiration
lysosome
vesicle containing digestive enzymes
nucleus
contains genetic material
rough endoplasmic reticulum
transports proteins to Golgi apparatus
vacuole
stores watery sap
when full, has high osmotic pressure, keeping cell turgid
extracellular component of plants
cell wall
-Shape
-prevents excessive Water uptake
-holds against force of Gravity
extracellular component of animals
secrete glycoproteins
-shape
-adhesion
-movement
diffusion
the passive movement of particles from an area of high concentration to a region of low concentration
osmosis
the passive movement of water molecules across a partially permeable membrane from a region of lower solute concentration to a region of higher solute concentration
membrane protein functions
hormone building sites
immobilised enzymes
cell adhesion
cell-to-cell communication
channels for passive transport
pumps for active transport
tumours (cancer) are the result of:
uncontrolled cell division
can occur in any organ or tissue
interphase
an active period in life of a cell when many metabolic reactions occur, incl.
-protein synthesis
-DNA replication
-increase in number of mitochondria and/or chloroplast
processes involving mitosis
growth
asexual reproduction
tissue repair
embryonic development
intrinsic protein
transport molecules across membrane
extrinsic protein
cell division
glycoprotein attached- cell recognition/communication
functions of lipids (3)
energy storage
thermal insulation
waterproof layer
protect organs & nerves
buoyancy
carbohydrates in animals
glucose- energy source
lactose- carb source for suckling animals
glycogen- energy source & storage compound
carbohydrates in plants
fructose- sweetness attracted animals to disperse seeds
sucrose- transported from leaves to other locations of plants by vascular tissue
cellulose- primary component of cell walls
examples of lipids
phospholipid
triglyceride
lipid structure
3 fatty acids + glycerol
examples of proteins
hormones
enzymes
haemoglobin
antibodies
protein structure
amino acids -> peptide -> polypeptide
examples of nucleic acids
DNA, RNA
nucleic acids structure
nucleotides -> polynucleotide
property of DNA replication
semi-conservative
codon found on:
mRNA
anti-codon found on:
tRNA
in cell respiration, glucose...
in the cytoplasm is broken down by glycolysis into pyruvate with a small yield of ATP
species
a group of organisms that can interbreed and produce fertile offspring
habitat
the environment in which a species normally lives or the location of a living organism
population
a group of organisms of the same species who live in the same area at the same time
community
a group of populations living and interacting with each other in an area
ecosystem
a community and its abiotic environment
ecology
the study of relationships between living organisms and between organisms and their environment
autograph
an organism that synthesises its organic molecules from simple inorganic substances
examples of autographs
algae
grass
trees
cyanbacteria
heterotroph
and organism that obtains organic molecules from other organisms
examples of heterotrophs
animals
plants
zooplankton
consumer
an organism that ingests other organic matter that is living or recently killed
detritivore
an organism that ingests non living organic matter
saprotroph
an organism that lives on or in living organic matter, secreting digestive enzymes into it and absorbing the products of digestion
sex linkage
when the gene controlling the characteristic is on the sex chromosome, so the characteristic is associated with the gender
karyotypes organised by:
length of the chromosome
position of the centromere
pattern of bands on the chromosome
chromosome
coiled piece of DNA
biomass ratio (producer : top predator)
producer : top predator
largest biomass : smallest biomass
what are the benefits of cloning?
reproductive- infertile couples can have children...
therapeutic- allow tissue replacement, improving medical outcomes
*read more about ToK issues
examples of current uses of genetically modified crops or animals
drought tolerant crops
herbicide resistant crops
salt tolerant tomato plants
factor VIII in goat milk
advantages of genetically modified crops or animals
more productive farming, higher yielding of crops, more profit for farmers, medical improvements
disadvantages of genetically modified crops or animals
allergies, higher costs of GM foods, cross contamination
importance of the source of the polymerase enzyme in PCR
from an organism coming from high temperature environments to ensure it does not denature during PCR process
how does a mutated gene affect the protein molecule?
-protein folds differently
-creates a different shape
-functions differently
crossing over
non sister chromatids of a homologous pair cross over at the chiasmata and exchange pieces of DNA
this alters the combination of alleles of each chromosome
ventilation
a process in which gases are moved across the respiratory surface
gas exchange
the process by which oxygen diffuses from the air in the alveoli to the blood in the capillaries
ventilation is important to...
maintain the concentration gradients between the air and the blood (by bringing fresh air into the alveoli and removing stale air)
gas exchange occurs in...
what occurs
the alveoli
O2 from inhaled air diffuses into the bloodstream
CO2 from blood diffuses into the alveolus to be exhaled
2 important factors that maintain the conc. gradients for O2 and CO2
ventilation replenished the O2 in the alveolous and removes CO2
blood surrounding alveolus is deoxygenated (b/c of constant flow of blood through the capillaries)
features that make alveolus efficient for gas exchange
thin- more efficient exchange
moist- O2 dissolves before it diffuses
large SA- for maximum diffusion
highly vascularised- blood transports the gases to and from the cells of the body
ventilation- maintains conc. gradients of O2 and CO2
inhalation
intercostal muscles- contract
diaphragm- contracts
volume of chest cavity- increases
pressure inside chest cavity- decreases
how breathing is controlled
the level of CO2 in the blood is the stimulus the brain responds to in determining the breathing rate
difference in mitosis and meiosis
2 diploid cells prod. vs 4 haploid cell prod.
stomatic cells vs sex cells
do not line up vs line up
1 stage vs 2 stages
how water is a coolant
- H bonds between H2O molecules
- breaking H bonds requires E/ removes heat
- H bonds must break when H2O evaporates/vaporises
types of cells present in reproductive system
sex AND autosomal
examples of monosaccharides
fructose
glucose
galactose
ribose
deoxyribose
ribulose
the source of O2 released by p/s
water
NOT CO2
what does not occur during interphase
cytokinesis
sign something is alive
metabolism