Exam 3

Question 1

Substitution

Answer 1

Replacement of one nucleotide (A,T,C,G) for another

Question 2

Insertion

Answer 2

Addition of one or more nucleotides to a gene. Results in “frame-shift” mutations

Question 3

Deletion

Answer 3

Removal of one or more nucleotides from a gene. Results in a frame-shift mutation

Question 4

Silent

Answer 4

No change in the sequence of amino acids

Question 5

Missense

Answer 5

An amino acid becoming another amino acid. change in primary structure of the protein

Question 6

Nonsense

Answer 6

Change in amino acid to STOP codon

Question 7

Frameshift

Answer 7

Caused by insertions or deletions. Reading frame to shift

Question 8

Consequence of Silent

Answer 8

No change in phenotype

Question 9

Consequence of Missense

Answer 9

Change in primary structure of protein; may be beneficial, neutral, or deleterious

Question 10

Consequence of Nonsense

Answer 10

Leads to mRNA breakdown or shortened polypeptide chain, usually deleterious

Question 11

Incomplete Dominance

Answer 11

The heterozygote has a phenotype that is intermediate to both homozygous phenotypes. Here we see that the heterozygote (Rr) is pink, which is the intermediate of red (RR) and white (rr).

Question 12

Codominance

Answer 12

The heterozygote has a phenotype that express both homozygous phenotypes. Here we see that the heterozygote (Rr) expresses BOTH red and white petals. Remember that blood type AB is an example of codominance! The phenotype expresses contains both A and B antigens

Question 13

What are the three situations in which mitotic cell division occurs

Answer 13

development of multicellular organisms, maintenance, and repair of organs and tissues

Question 14

what are the 5 stages of mitosis

Answer 14

prophase, prometaphase, metaphase, anaphase, telophase

Question 15

what would be the consequences if a cell underwent mitosis but not cytokinesis

Answer 15

the two cells do not fully separate - single cell with two nuclei

Question 16

what determines a genotype

Answer 16

genotype is the genetic composition of a cell or organism

Question 17

Define a phenotype

Answer 17

the observable factors

Question 18

with regard to mutations, what is the meaning of harmful

Answer 18

it does something harmful to the individual

Question 19

with regard to mutations, what is the meaning of beneficial

Answer 19

provides some sort of advantage to the organism in its environment

Question 20

with regard to mutations, what is the meaning of neutral

Answer 20

you can’t tell that it did anything, no benefit or harm

Question 21

what is the purpose of a test cross

Answer 21

to determine the genotype of an unsure dominant phenotype

Question 22

why are some complex traits also called quantitative traits

Answer 22

because the phenotype is measured on a scale with only small intervals between similar indivividuals

Question 23

examples of complex traits

Answer 23

height, weight, hair color, blood pressure

Question 24

what are some factors that influence variation in complex traits

Answer 24

Environmental factors: sunlight, moisture, or nutrition. Genetic: multiple genes affecting a single trait

Question 25

why does it not make sense to try to separate the effects of genes and the environment

Answer 25

the effects of genes and the environment in a single individual are so intimately related

Question 26

what is twin concordance

Answer 26

the percentage of cases in which both members of a pair of twins show the trait when it is known that at least one member shows it