Micro Unit 2: Chapter #7

Question 1

Define prokaryotic chromosomes

Answer 1

Single circular chromosome in nucleoid

Question 2

Define plasmids

Answer 2

Small DNA replicate independently

Question 3

Define mutations

Answer 3

Heritable change of genome

• lead to change in genotype which changes phenotype also

Question 4

List the 4 mutations

Answer 4

1. Silent
   2.Missense
2. Nonsense
3. Frameshift

Question 5

Define silent mutations and its effects

Answer 5

Code same amino acid = no effect on protein

-No effect?

Question 6

Define missense mutations and its effects

Answer 6

Change in DNA inserts different amino acid= changes protein

-beneficial + detrimental

Question 7

Define non-sense mutations and its effects

Answer 7

Normal codon changed to stopping codon (changes protein)

-detrimental

Question 8

Define frameshift mutations and its effects

Answer 8

Reading frame MRNA shifts = non-functional proteins

-detrimental

Question 9

Define genetic recombination/ DNA transfer

Answer 9

Exchange of DNA - whole genes

Question 10

Define recombinants

Answer 10

Bacteria gain nucleotides (DNA)

Question 11

How does transformation occur?

Answer 11

Cell takes DNA fragments/genes released by dead organisms

Uses: human growth hormones (HGH) and human insulin

Question 12

How does transduction occur?

Answer 12

DNA transferred one bacteria to another using bacteriophages (replicating virus)

Uses: scarlet fever and hemorrhagic colitis

Question 13

How does conjugation occur?

Answer 13

Plasmid transfers to another bacteria through pilus (adhesion)

Question 14

What are the main plasmid categories?

Answer 14

1. Resistance (R) plasmids - antibiotics
2. Virulence plasmids- allow pathogenicity

Question 15

Give the 3 genetic characteristics recipient bacteria acquire in transfer mechanisms

Answer 15

1. Increased virulence: adhesion,capsules, enzymes
2. New nutrient/ metabolic capabilities: increased adaptation
3. Resistance: antibiotics

Question 16

What are superbugs and why are they so dangerous?

Answer 16

R-plasmids and genes become adapted and resistant to antibiotics

-* very hard to kill*

Question 18

What are the infections caused by these superbugs? Why are they known as nosocomial infections?

Answer 18

MRSA and VRE

• antibiotics encourage evolutional resistance
• increases susceptibility

Question 19

What is the genetic transfer mechanism in which superbugs become resistant to antibiotics?

Answer 19

Conjugation

Question 20

Which genetic mechanism does E. coli acquire ability to produce toxins?

Answer 20

Transformation

Question 21

A plasmid is?

Answer 21

Extrachromosomal DNA

Question 22

Which is not a mechanism of genetic transfer between cells?

Answer 22

Transcription

Question 23

Which is true of conjugation?

Answer 23

Conjugation requires a sex pilus extending from the surface of a cell

Question 24

Before mutations can affect a population permanently, they must be _?

Answer 24

Lasting, inheritable, and beneficial

Question 25

3 effects of point mutations are?

Answer 25

Substitution, deletion, and insertion

Question 26

Insertions and deletions in the genetic code are also called __ mutations

Answer 26

Frameshift