genetics

Question 1

what are autosomes

Answer 1

all other chromosomes that are not sex chromosomes

Question 2

define homogametic

Answer 2

female XX

Question 3

describe haemophillia

Answer 3

-passed on the X chromosome
- recessive disorder
- blood clots slowly because DNA that codes for blood clotting proteins aren’t coded for
-
-

Question 4

which genes are said to be linked

Answer 4

genes on the same autosome

Question 5

what is the genetic ratio for a recessive epistatic allele in a dihybrid cross

Answer 5

9:3:4

Question 6

define epistasis

Answer 6

a gene at one location can mask the expression of a gene at another location

Question 7

what is the genetic ratio of a dominant epistatic allele in a dihybrid cross

Answer 7

12:3:1

Question 8

define codominance

Answer 8

where both alleles are expressed in the phenotype

Question 9

define genotype

Answer 9

it describes all the alleles an organism has

Question 10

define phenotype

Answer 10

observable characteristics of an organism. it is a result of the interaction between expression of the genotype and the environment

Question 11

define a gene

Answer 11

a length of DNA

Question 12

what did gregor mendel investigate

Answer 12

seed shape - where round shape is dominant to a wrinkled shape

seed colour where yellow seeds are dominant to a green coloured seed

Question 13

what is expected ratio in a dihybrid cross of RRGG rrgg

Answer 13

9:3:3:1

Question 14

what conclusions can be drawn when expected ratios do not align with observed ratios

Answer 14

linked genes
- epistasis

Question 15

what does it meant by having multiple alleles

Answer 15

where there are more than two alleles, of which only two may be present at the loci of an individuals homologous chromosomes

Question 16

which is longer X or Y chromosome

Answer 16

X

Question 17

what does the length of the X chromosome mean for the world

Answer 17

as the X chromosome is longer than the Y there is no equivalent portion on the Y chromosome. therefore those controlled by recessive characteristics will appear more frequently on the male chromosome

Question 18

why would linked genes not remain together during meiosis

Answer 18

crossing over

Question 19

what type of data does a chi squared test produce

Answer 19

categorical

Question 20

REMEMBER

Answer 20

FOR DEGREES OF FREEDOM IN A CHI SQUARED = NUMBER OF CLASSES MINUS 1

Question 21

what are condition for gene linkage

Answer 21

no crossing over therefore all the linked genes remain together during meiosis

Question 22

if genes are further apart on the homologous chromosome what does this mean

Answer 22

it is more likely that they will be separated by crossing over and will not gene linked