Genetics (Topic 7A)

Question 1

a gene is…

Answer 1

a section of DNA that is a sequence of nucleotide bases and determines a single characteristic

Question 2

multiple alleles are…

Answer 2

if more than two alleles for each gene are present in the gene pool

Question 3

co dominant is when…

Answer 3

both alleles contribute to the phenotype

Question 4

modification is…

Answer 4

any change to the phenotype. it is not inherited by the future generation

Question 5

alleles are…

Answer 5

different forms of the same gene

Question 6

phenotype is…

Answer 6

the physical and observable characteristics of an organism that is determined by an organisms alleles and environment

Question 7

recessive alleles need to be inherited from _____ _____ to be expressed in the _____

Answer 7

both parents
phenotype

Question 8

homozygous dominant is…

Answer 8

an organism that has inherited two dominant alleles

Question 9

homozygous recessive is…

Answer 9

an organism that has inherited to two recessive alleles

Question 10

heterozygous is when…

Answer 10

an organism that has inherited one dominant and one recessive allele

Question 11

a mutation is…

Answer 11

any change to the genotype caused by change in DNA and can be inherited

Question 12

genotype is…

Answer 12

the genetic makeup of an organism

Question 13

dominant alleles only….

Answer 13

need to inherit one from parents to be expressed in phenotype

Question 14

incomplete dominance is when…

Answer 14

neither allele is dominant, both are equally giving an intermediate

Question 15

what are the three blood groups?

Answer 15

A, B and O

Question 16

which blood groups are dominant?

Answer 16

A and B

Question 17

which blood group is recessive?

Answer 17

O

Question 18

sex linkage occurs when…

Answer 18

the genes for a certain characteristic are carried on the sex chromosome

Question 19

which chromosome is longer X or Y?

Answer 19

X

Question 20

chromosome __ is longer than __ so it ______more alleles

Answer 20

X
Y
carries

Question 21

red green colour blindness is caused by a _____ allele

Answer 21

recessive

Question 22

males only inherit __ allele from their ______

Answer 22

1
mother

Question 23

are men colourblind if they inherit one allele for colour blindness

Answer 23

yes

Question 24

is colour blindness more prevalent in men or women?

Answer 24

men

Question 25

dihybrid crosses investigate….

Answer 25

the inheritance of two characteristics

Question 26

epistasis is when…

Answer 26

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

Question 27

autosomal linkage is…

Answer 27

when two or more genes are located on the same chromosome

Question 28

autosomal linked genes are more…

Answer 28

likely to be inherited together

Question 29

the ____ of the loci of the _ genes on the chromosomes the ____ the chance of recombination forming

Answer 29

closer 2 lower

Question 30

recombinants are…

Answer 30

new combinations of phenotypes that prove linkage is not complete

Question 31

how are recombinants produced?

Answer 31

crossing over of chromatids

Question 32

the chi squared test is used to…

Answer 32

test if the observed frequency matches the expected frequency

Question 33

the null hypothesis states that

Answer 33

there is no statistically significant difference between the observed frequency and the expected frequency

Question 34

if the value for x^2 exceeds the critical value then…

Answer 34

you reject the null hypothesis

Question 35

degrees of freedom =

Answer 35

no. of categories - 1

Question 36

what does 2pq stand for in the hardy-weinberg principle?

Answer 36

heterozygous

Question 37

the specific point of a gene on the chromosome is called the...

Answer 37

locus

Question 38

the gene pool is...

Answer 38

all of the alleles present in a population

Question 39

Why are males more likely to inherit a sex linked recessive condition than females? 2 marks

Answer 39

1. males only need to inherit one allele to have the characteristic 2. whereas, females need two recessive alleles

Question 40

A grey body long winged fly is crossed with a black bodied short winged fly. Explain these results: Grey B + long W - 223 Black B + short W - 218 2 marks

Answer 40

1. The genes for colour and wing length are linked 2. There is no crossing over