patterns of inheritance

Question 1

chlorosis

Answer 1

lack of cells producing chlorophyll for photosnythesis = yellow plant

Question 2

causes of chlorosis

Answer 2

lack of light- chlorphyll production reduced to conserve resources . chlorosis only occurs when plant gets no light

mineral deicienncies- lack of iron or manesium- iron needed as cofactor by enzymes that make chlorophyll and mangesium found at heart of chlorophyll molecule . withotu these, plants cant make chlorophyll

.virus infections - interfere w cell metabolism- caues yellowing as syntehssi of chlorphyll no longer supported!

Question 3

animal body mass

Answer 3

determined by combination of genetic + environmental factors . obesity caused by envionmental factors
eg amount + quality of foods eaten . can also be caused by result of genetic make up - eg mutation on chromosome 7 in a mouse caues change in fatty deposition causing mouse to be obese

Question 4

multiple alleles

Answer 4

some genes- have multiple alleles; eg blood group determined by genes with multiple alleles : (Io is recessive whereas IA and IB are both codominant

Question 5

why would the actual ratio of offspring differ ?

Answer 5

becuase fertillisation of gametes is a random process so in a small sample, there could be a skewed ratio

.genes being studies are both on same chromosome, these are known as linked genes ; if no crrossing over occurs, teh alleles for two characteristics will alawys be inherited together

Question 6

recombinant frequency equation

Answer 6

number of recombinant offspring/total number of offspring

50 precent= no linkage

Question 7

null hypothesis for chi squared test?

Answer 7

no significant difference between what we expect and what we observe !

Question 8

creating genetic variation

Answer 8

. genetic variations relies on different combinations of alleles in organism caused by random fusion of gametes at fertillisation. resutls in vast genetic variation seen between individuals of same species

combination of alleles= genotype

Question 9

modifications

Answer 9

changes that environment makes to phenotype

Question 10

example of epistasis

Answer 10

gene regulation ; in lac operonn- controls activity of structural genes !

Question 11

epistatic

Answer 11

gene that affects the expression of another gene

Question 12

hypostatic

Answer 12

gene that is affected by another gene

Question 13

hardy weinberg terminology

Answer 13

p^2= homozygous dominant

q^w = homoygous recessive

2pq= heteroxygous

Question 14

p^2 + 2pq + q^2 = 1

Answer 14

hardy weinberg principle

Question 15

normal distribution in genetics ?

Answer 15

frequency of alelles at extreme ends are reduced due to stabillising selection

Question 16

types of normal distributin sleection

Answer 16

diversifying selection - 2 bell curves instead of one

directional- bell curve shifts to one direction

stabiliing selection- majority of population moves towards the middle of the bell curve- bell curve becomes taller

Question 17

sympatric speciation examples

Answer 17

. mole rates interbreed so much between species that the offspring cannot breed with each other

. plants- pollen everywhere - causes lots of hybrid plants to be born and are reproductively isolated from parents

Question 18

what causes post zygotic reproduction barriers ?

Answer 18

hybridisation ( offspring are so different that they cannot breed with each other and thus are different species )

Question 19

what causes pre zygotic reproductio nbarriers

Answer 19

( barriers before fertillsiation) –> unfavoruable behaviour- eg one bird hating another birds song therefore not breeding with it + different breeding seasons therefore organisms cannot breed!

Question 20

population genetics

Answer 20

investigates how allele frequencies change over time - change in allele frequency is the basis of evolution

1. density dependent factors are dependent on population size- competition, predation, parasitism, communicable disease
2. density dependent factors affect populations of all sizes in same way eg- climate change + human activities

Question 21

advantage of genetic bottleneck

Answer 21

could lead to beneficial mutation that could lead to a quicker development of a new species