Mr Dewhurst- patterns of inheritance

Question 1

what is interspecific variation

Answer 1

variation between different species

Question 2

what is intraspecific variation

Answer 2

variation within species

Question 3

how can the number if dopamine receptors influence obesity

Answer 3

people over eat to try and feel the pleasure of being full

Question 4

what is continuous variation

Answer 4

controlled by both genes and environment
any feature that can me measured and put on distribution graph e.g., height, weight

Question 5

what is discontinuous variation

Answer 5

qualitative- cannot be measured as is categories which are put into bar chart
controlled by small number of genes e.g., blood group, eye colour

Question 6

allele

Answer 6

different versions of the same gene

Question 7

genotype

Answer 7

alleles an organism has

Question 8

phenotype

Answer 8

characteristics displaced by organism

Question 9

what is the difference between dominant and recessive alleles

Answer 9

dominant- always expressed if present
recessive- only expressed if homozygous (same allele on each chromosome)

Question 10

what is epistasis

Answer 10

more than one gene affecting characteristic

Question 11

polygenic

Answer 11

multiple genes affect characteristic

Question 12

monogenic

Answer 12

controlled by one gene

Question 13

what is etiolation

Answer 13

plants don’t get enough light, grow long and spindly to find light

Question 14

what is chlorosis

Answer 14

plant doesn’t produce enough chlorophyll as there is a lack f magnesium which is the prosthetic group if chlorophyll

Question 15

what is meant by dihybrid

Answer 15

two characteristics controlled by different genes

Question 16

what is codominance

Answer 16

both alleles are expressed and neither is recessive (both capital) - results in different function

Question 17

what is meant by a gene being recessive

Answer 17

codes for a non functioning protein

Question 18

What is meant by a recessive epistasis gene

Answer 18

There is a masked dominant allele, without that other genes don’t appear
E.g without the Y gene , no orange can be present even if orange is also dominant

Question 19

What is meant by dominant epistasis gene

Answer 19

One dominant gene, copy of it masks expression of another gene
- e.g for colour white in squash plants only get other gene is homozygous recessive is present- then need dominant allele for either yellow or green

Question 20

What is epistasis

Answer 20

One gene masking or suppressing expression of another

Question 21

What is autosomal linkage

Answer 21

Some genes are inherited - on the same chromosome so not random/independent

Question 22

What is an auto some

Answer 22

Chromosome that is not sex chromosome

Question 23

how do you calculate chi-squared

Answer 23

add up all observed values, divide into genotypic ratio
this gets expected value
observed- expected value
square the value
divide by the expected value
add up sum of these value to give x2

Question 24

how do you calculate degrees of freedom

Answer 24

n-1 (no.of categories- 1 )

Question 25

when do we accept the null hypothesis

Answer 25

if the observed value is less than the critical value as the results aren't significant at p value of 0.05 as we can be sure that its not down to other variables as the value isn't high enough

Question 26

What is recombinant dna

Answer 26

New combination of alleles on the chromosome once they have been crossed over

Question 27

What is the ratio for genes of different chromosomes for what we expect the gametes to be in autosomal linkage

Answer 27

1:1:1:1

Question 28

What is the ratio for what we expect from genes on the same chromosome in autosomal linkage

Answer 28

1:1

Question 29

How do we test if our expected value of autosomal linkage is significant to our observed

Answer 29

Chi-squared

Question 30

What is the ratio for recessive epistasis

Answer 30

9:3:4