Unit 6, Topic 7: Mutations

Question 1

a permanent change in a DNA sequence

Answer 1

Mutations

Question 2

underlying genetic makeup, consisting of both physically visible and non-expressed alleles, of an organism

Answer 2

Genotype

Question 3

observable traits expressed by an organism

Answer 3

Phenotype

Question 4

failure of synapsed homologs to completely separate and migrate to separate poles during the first cell division of meiosis

Answer 4

Nondisjunction

Question 5

process by which one segment of a chromosome dissociates and reattaches to a different, nonhomologous chromosome

Answer 5

Translocation

Question 6

detachment, 180° rotation, and reinsertion of a chromosome arm

Answer 6

Inversion

Question 7

a base pair is removed from the DNA sequence

Answer 7

Deletion

Question 8

transfer of genes between unrelated species

Answer 8

Horizontal gene transfer

Question 9

process in which external DNA is taken up by a cell

Answer 9

Transformation

in prokaryotes: the cell takes in DNA shed by other prokaryotes

Question 10

process by which prokaryotes move DNA from one individual to another using a pilus

Answer 10

Conjugation

Question 11

genes are transferred from one organism to another through copying and inserting process

Answer 11

Transposition

Question 12

mutation that affects a single base

Answer 12

Point mutation

Question 13

multiple copies of genes

Answer 13

Duplication

Question 14

process by which a bacteriophage moves DNA from one prokaryote to another

Answer 14

Transduction

Question 15

when pyrimidines and purines replace each other

Answer 15

Substitution

Question 16

How can mutations lead to natural selection?

Answer 16

They can lead to developments of new traits that help an organism survive

Question 17

Are substitutions are small or large scale mutations?

Answer 17

small

Question 18

Differentiate between silent, missense, and nonsense mutations. Predict which would be most detrimental and why?

Answer 18

nonsense because it can prematurely stop translation which can prevent the formation of the correct protein

Question 19

Mutations can be detrimental, beneficial, or neutral. Give an example of a mutation that is detrimental and an example where it is beneficial.

Answer 19

Detrimental: a mutation that causes rapid weight gain
Beneficial: a mutation that gives longer claws to cats
Neutral: a mutation that doesn’t affect the phenotype of an organism

Question 20

If one bacterial cell has a gene that is promoting its survival, explain how other bacterial cells can benefit from it.

Answer 20

that one cell can reproduce with the others and create more bacterial cells that will have that same gene

Question 21

Describe the mutation that causes cystic fibrosis.

Answer 21

Deletion of phenylalanine on amino acid 508

Question 22

change in an organism’s genotype can cause a change in the organism’s (blank).

Answer 22

phenotype

Question 23

What does it mean if a gene/trait is “evolutionarily conserved”?

Answer 23

A gene that has remained essentially unchanged throughout evolution

Question 24

Describe transformation. Are all bacteria competent?

Answer 24

The prerequisite for bacteria to undergo transformation is its ability to take up free, extracellular genetic material

Question 25

Describe the process of conjugation

Answer 25

the process by which one bacterium transfers genetic material to another through direct contact

Question 26

Describe the process of transduction

Answer 26

A bacteriophage passes DNA from one bacteria cell to another (transfer of DNA from one cell to another via a viral vector)

Question 27

What are the two reproductive cycles of bacteriophages? Describe each.

Answer 27

lytic (virulent) or lysogenic (temperate). Lytic phages take over the machinery of the cell to make phage components. They then destroy, or lyse, the cell, releasing new phage particles Bacteriophages: a virus that parasitizes a bacterium by infecting it and reproducing inside it