inherited change

Question 1

genotype

Answer 1

The genotype is the genetic constitution of an organism.

Question 2

Phenotype

Answer 2

The phenotype is the expression of this genetic constitution and its interaction with the environment.

Question 3

pure breeding

Answer 3

homozygous for that particular gene

Question 4

codominance

Answer 4

both alleles are expressed in the phenotype

Question 5

multiple alleles

Answer 5

more than two alleles (only 2 can be present the loci of an individuals homologous chromosomes).

Question 6

how many pairs of chromosomes in a human

Answer 6

23

Question 7

sex linked

Answer 7

any gene that is carried on either the X or Y chromosome

Question 8

example of an X linked genetic disorder

Answer 8

haemophilia (blood clots more slowly and so can lead to persistent internal bleeding). This is because they are unable to create the functional protein that is required in the blood clotting process.

Question 9

dihybrid cross

Answer 9

involves 2 gene locus

Question 10

how to recognise co-dominance

Answer 10

There will be one more phenotype than the number of alleles there are.

Question 11

who will X linked recessive effect more

Answer 11

X linked recessive will effect males more (there is a one in two chance of them getting it, as opposed to a 1/4 chance for females as they have two X chromosomes, but males only have one).

Question 12

who will X linked dominant effect more

Answer 12

X linked dominant will effect females more (as there is double the opportunity to get the dominant allele as they have two X chromosomes as opposed to one).

Question 13

who will Y linked effect more

Answer 13

Y linked will only effect males (as females cannot have a Y chromosome).

Question 14

autosomal linkage

Answer 14

where two or more genes are carried on the same autosome.

Question 15

How to recognise autosomal linkage

Answer 15

Recognising autosomal linkage: 4 phenotypes with 2 massively over represented and 2 massively underrepresented.

Question 16

epistasis

Answer 16

when the allele of one gene affects or masks the expression of another in the phenotype.

Question 17

degrees of freedom for chi squared

Answer 17

number of classes - 1

Question 18

criteria for the chi squared test

Answer 18

sample size must be relatively large (over 20)
data must fall into discrete categories
only raw counts (no %, rates etc…)
it is used to compare experimental results with theoretical ones.

Question 19

Chi squared table

Answer 19

observed | expected | O-E | (O-E)squared| (O-E)squared / E