Exam Review Unit 5

Question 1

Genotype

Answer 1

The actual alleles inherited Ex. AA

Question 2

Phenotype

Answer 2

Physical trait an organism shows Ex. Purple flower color

Question 3

Allele

Answer 3

Different versions of a gene

Question 4

Dominant

Answer 4

The allele that will be expressed if present

Question 5

Recessive

Answer 5

The allele that is only expressed in the homozygous state

Question 6

Heterozygous

Answer 6

Different alleles Ex. Aa

Question 7

Homozygous

Answer 7

Same alleles Ex. AA or aa

Question 8

Tell the phenotype for the following genotypes, if purple is dominant to white.

1. WW 2. Ww 3. ww

Answer 8

1. WW 2. Ww 3. ww
2. Purple 2. Purple 3. White

Question 9

Cross a heterozygous purple plant with a white plant. Find phenotypic and genotypic ratios.
(do on separate piece of paper)

Answer 9

Ww x ww

Phenotypic Ratio: 50% Purple, 50% White

Genotypic Ratio: 50% Ww, 50% ww

Question 10

A dominant gene that codes for red eye color in fruit flies is represented by the symbol W, while the recessive white eye gene is represented by the symbol w. If a parent fly with the genotype WW is crossed with a parent of the genotype Ww, what percentage the offspring will have red eyes?

Answer 10

100%

Question 11

In flowers, if purple is dominant to white and tall is dominant to short, cross a plant that is white and short with a plant that is heterozygous for both traits. If 12 flowers bloom, predict how many will be purple and short based on your Punnett Square.

Answer 11

wwtt x WwTt

3 out of 12 flowers will be purple and short

Question 12

1) The father is type A heterozygous, the mother is type B heterozygous.
Phenotypic Ratio:

2) The father has type O blood, the mother has type AB blood.
Phenotypic Ratio:

Answer 12

25% Type AB, 25% Type A, 25% Type B, 25% Type O

50% Type A, 50% Type B

Question 13

Incomplete Dominance

Answer 13

Heterozygous phenotype is a blend of other two traits.
Ex. Red and white flowers make pink flowers

Question 14

Codominance

Answer 14

Heterozygous phenotype shows both of the other traits fully and separately.
Ex. Red and white flowers make speckled flowers.

Question 15

Multiple Alleles

Answer 15

More than 2 versions of 1 gene.
Ex. Three alleles (versions) of the gene for blood type = A, B and i (or IA, IB, i)

Question 16

Polygenic Inheritance

Answer 16

More than 1 gene determines a trait; usually results in a range in phenotypes
Ex. Height, personality, skin color, etc.

Question 17

Sex-Linked

Answer 17

Genes that usually travel on the X sex chromosome; males only get 1 copy, females get 2 copies
Ex. Colorblindness

Question 18

Linked Genes

Answer 18

Genes physically located close together on a chromosome tend to be inherited together.
Ex. Red hair and freckles

Question 19

Mutation

Answer 19

Any change in DNA

Question 20

Causes of a mutation

Answer 20

Mistakes made in replication, protein synthesis, mitosis, or meiosis, mutagens, or viruses

Question 21

Mutagen

Answer 21

Chemical that can cause mutations Ex. UV rays

Question 22

Gene Mutation

Answer 22

Change in one section of DNA, affecting one gene

Question 23

Chromosome mutation

Answer 23

Change affecting multiple genes on a chromosome

Question 24

Nondisjunction

Answer 24

Failure of chromosomes to separate correctly during meiosis, resulting in an abnormal number of chromosomes

Question 25

Genetic Engineering

Answer 25

Purposeful manipulation of genes in order to get desired traits