Topic 4 Flashcards
What has happened to the variety of life over time?
It has grown extensive but is now being threatened by human activity
What are the 3 definitions of biodiversity
Variety of life
Variety of a species that belongs to each different group of organisms
The diversity within a species
what is the equation for the heterozygosity index
H= No. of heterozygotes / no. of individuals in a population
what is the equation for calculating the index of diversity
D= N(N-1)/En(n-1)
what does N stand for in the index of diversity
number of organisms of all species
what does n stand for in the index of diversity
total no of organisms of each species
what does E stand for in the index of diversity
sum of
what does niche mean
the way an organism exploits its environment
what is a behavioural adaptation?
the actions by an organism that hekp them to survive or reproduce
what is a physiological adaptation?
the internal workings of organisms that help them to survive and reproduce
What is an anatomical adaptation
the structures we can see when we can see when we observe or dissect an organism
what is evolution
the change in allele frequency in a population over time
why might natural selection cause evolution
genetic variation occurs through mutations becomes favourable more likely to survive and reproduce
what is the hardy weinberg equation
p^2 + 2pq + q^2=1
What does p^2 represent
homozygous dominant
What does 2pq represent?
heterozygous
What does q^2 represent?
homozygous recessive
what can reproductive isolation lead to?
accumulation of different genetic information in populations potentially leading to the formation of a new species
How are species categorised
binomial system
What is classification?
a means of organising variety of life based on relationships between organisms using differences and similarities in phenotype and genotype
what are the hierarchal groups
Kingdom Phylum Class Order Family Genus Species
What are the 3 domains?
Bacteria, Archaea, Eukarya
what are the two main differences between plant and animal cells
cell walls and chloroplast
where is starch stored
amyloplasts
what surround the vacuole
vacuolar membrane - tonoplast
what makes the cytoplasm in one cell continuous with the next
plasmodesmata
what is a pit
where the cell wall is thin as only the first layer of cellulose is deposited
what is the middle lamella
a layer that cements the primary cell walls together of adjoining cell walls
what is the difference between starch and cellulose
B-glucose and A-glucose
what is the difference between A and B glucose
1,6 bonds make up starch and 1,4 glyosidic bonds make up cellulose
what reaction forms between the -OH groups of starch and cellulose
condensation
what bond forms between the -OH groups of starch and cellulose
glyosidic
due to the ….. bonds in cellulose, it is unbranched/branched
1,4 bonds and unbranched
what bonds form between cellulose chains
hydrogen bonds
what do bundles of cellulose chains form
microfibrils
what polysaccharides make cellulose a very strong structure
hemicelluloses and pectins
what polysaccharide is very important in the makeup of the middle lamella
pectin
what makes xylem so strong
lignin
what makes the xylem cells dead
autolysis- tonoplast breaks down and enzymes break down cell contents
what does xylem carry
water
what does water diffuse out through
down a diffusion gradient
how does water move through the xylem
a transpiration stream bound by cohesion tension theory
how does cohesion tension theory work
H-bonds between water molecules strong cohesive forces water evaporates and pulled up
what order do the 3 parts of the stem go in (outside first)
sclerenchyma, phloem and xylem
what is the function of the sclerenchyma
support
what is the function of the xylem
support and transportation of water and minerals
what is the function of phloem
translocation of organic solutes
what are the 3 properties of plant fibres that make them ideal for humans
Long thin Strong Flexible
why do plants need nitrate ions
nitrate ions are needed to make amino acids- cell cytoplasm is largely made of protiens
what do plants need calcium ions
calcium helps make the structure of the cell walls and permeability of the membrane
why do plants need magnesium ions
to make chlorophyll (yellow without)
what is it called when organic molecules move within the phloem
translocation
what is the purpose of the companion cell
perform metabolic functions that maintain the sieve tube
what is the difference between the sieve tube and companion cell
companion cell still has nucleus, mitochondria, ribosomes and rough ER unlike the sieve tube
what are sinks
places where photosynthetic products are unloaded eg roots
what are sources
places where photosynthetic products are gathered eg leaf
how do roots help plants survive in the winter
starch stored in roots. When growth starts again in spring, starch is converted back to sugar
which direction does xylem travel
upwards
which direction does phloem travel
downwards
what is a double blind trial
when both patient and doctors don’t know who has real drug
what happens in phase of 1 testing?
different doses healthy volunteers
what happens in phase 2 of testing?
volunteers with disease small group
what happens in phase 3 of testing?
large group one group placebo and other drug
what 5 factors effect bacterial growth rate
nutrients pH Temperature Sufficient oxygen no build up of toxic waste products
what are 3 reasons why fossil fuels are not sustainable
increases CO2 levels oil reserves will runout eventually plastics generate non-biodegradable waste
give 2 ways that genetic diversity can be lost
genetic drift and inbreeding depression
what is genetic drift
the change in allele frequency over time
What is inbreeding depression?
the accumulation of the homozygous recessive genotypes which have negative effects due to a small breeding pool
how might studbooks effect the natural breeding pattern
poor breeders must be encouraged and good breeders must be limited
how do seed banks make sure that germination is still viable? and what happens if its not?
they are tested every 10years and if viability is dropping they will be germinated and seeds recollected.
