patterns of inheritance

Question 1

what is continuous variation

Answer 1

when the individual in a population vary within a range and there’s no distinct categories

e.g height
normal distribution curve

Question 2

what is discontinuous variation

Answer 2

when there are 2 or more distinct categories and no intermediates

e.g blood type

Question 3

what is phenotypic variation

Answer 3

the variation in an organisms phenotype

displayed characteristics

Question 4

how does genotyping variation affect phenotypic variation

Answer 4

alleles vary between organisms of the same species so genotype varies. sexual reproduction, meiosis, crossing over and independent assortment also cause genotypes to vary

Question 5

what are polygenic and monogenic characteristics

Answer 5

polygenic- inherited characteristics that show continuous variation and are influenced by many genes

monogenic- inherited characteristics that show discontinue variation are influenced by only one gene

Question 6

how does the environment affect phenotypic variation

Answer 6

variation can be caused by diffeeence in the environment e.g food, climate, lifestyle

genotype influence characterises an organism is born with but environment factors can affect the developed these characteristics

Question 7

what is a gene

Answer 7

a short section of DNA which codes for a protein

Question 8

what is an allele

Answer 8

an alternate version. of the same gene

Question 9

what is a locus

Answer 9

the position in the chromosome where a particular allele is found

Question 10

what is a genotype

Answer 10

the allele an organism has

Question 11

what is phenotype

Answer 11

the characteristics of an organism produced by the alleles

Question 12

what are codominant alleles

Answer 12

both alleles are expressed in the phenotype and neither is recessive

Question 13

what is monogenic inheritance

Answer 13

the inheritance of a characteristic controlled by a single gene

Question 14

phenotypic ratios for different types of cross

Answer 14

monogenic 3:1
dihybrid 9:3:3:1
codominiant 1:2:1

Question 15

what is sex linkage

Answer 15

when the allele that codes for the characteristic is found on sex chromosome

Question 16

what are the sex chromosomes for males and females

Answer 16

XY male
XX female

Question 17

what is an autosome

Answer 17

any chromosome that is not a sex chromosome

Question 18

what is autosomal linkage

Answer 18

genes on the same autosome are linked as they aren’t split up during independent assortment and allele will be passed together

they can only be split up during crossing over so the closer together they are the less likely they will be split up

Question 19

what is epistasis

Answer 19

when an allele of one gene mask/ blocks the expression of the alleles on another gene

Question 20

what effects do dominant epistatic alleles have

Answer 20

having at least one copy will result in masking of other genes

Question 21

what effect do recessive epistatic alleles have

Answer 21

having 2 copies will mask the expression of other genes

Question 22

phenotypic ratio for epistatic genes

Answer 22

recessive epistatic allele
homozygous recessive and homozygous dominant
9:4:3

dominant epistatic allele
12:3:1

Question 23

what is the chi squared test

Answer 23

a statistical test use to see if the results of an experiment supports a theory

Question 24

what is a null hypothesis

Answer 24

the hypothesis should be that there is no significant different between the observed and expected value

Question 25

how can you reject / accept the null hypothesis

Answer 25

if chi squared value is greater then critical value reject null

then other way round allie