Chapter 9: Microbial Genetics

Question 1

structural genes

Answer 1

genes that code for proteins

Question 2

regulatory genes

Answer 2

genes that control gene expression

Question 3

how may chromosomes does the human cell have

Answer 3

46

Question 4

how many chromosomes doe e. coli have

Answer 4

1

Question 5

where is DNA replicated in prokaryotes

Answer 5

cytoplasm

Question 6

where is DNA replicated in eukaryotes

Answer 6

nucleus

Question 7

transcription

Answer 7

DNA is copied to mRNA with RNA polymerase

Question 8

translation

Answer 8

ribosome translates language of nitrogen bases to proteins

Question 9

what are introns

Answer 9

“trash” DNA that does not code for anything

Question 10

how are introns cleaned

Answer 10

with ribozymes

Question 11

basic DNA structure

Answer 11

deoxyribose sugar
phosphate group
nitrogenous base
- nucleotides bonded to form a sugar-phosphate backbone

Question 12

DNA strands are ___________ to one another.

Answer 12

antiparallel

Question 13

what is the semiconservative process

Answer 13

Parent DNA is uncoiled. Strands are separated and serve as templates. Complementary strands are synthesized.

Question 14

what is the replication site and replication forks

Answer 14

The origin of replication site is where replication is initiated. Replication forks is where DNA is synthesized.

Question 15

what happens in DNA replication

Answer 15

1. Helicase unwinds the DNA, forming a replication fork and two template strands, the leading and lagging strands.
   2a. The leading strand is oriented 3’ - 5’ so DNA can be synthesized continuously and smoothly.
   2b. The lagging strands runs the opposite way (5’ - 3’) so synthesis involves several steps and is done backwards.
2. A primase adds an RNA primer to direct DNA polymerase III. This creates an Okazaki fragments, unlinked segments of RNA primer and new DNA.
3. DNA polymerase I replaces RNA primers with complementary DNA nucleotides.
4. Unjoined ends of nucleotides, nick, are conjoined with ligase.

Question 16

what is a codon

Answer 16

three consecutive nitrogen bases

Question 17

what does tRNA do

Answer 17

• translates mRNA into protein
• provides anticodon

Question 18

what is the universal language of life

Answer 18

genetic code

Question 19

what are the three stages of transcription

Answer 19

1. initiation
2. elongation
3. termination

Question 20

initiation

Answer 20

RNA polymerase binds to promoter region where DNA is unwound

Question 21

elongation

Answer 21

adds nucleotides complimentary to the template strand

Question 22

termination

Answer 22

RNA polymerase recognizes STOP

Question 23

what is the start codon

Answer 23

AUG; methionine

Question 24

what are the termination codons

Answer 24

UGA, UAG, UAA

Question 25

how many times does the translation of one codon happen per second

Answer 25

17

Question 26

where does translation occur

Answer 26

cytoplasm

Question 27

where does transcription

Answer 27

nucleus

Question 28

what percentage of the human genome are exons

Answer 28

2%

Question 28

what are exons

Answer 28

DNA that can be encoded; unlike introns

Question 29

Lac operon segments

Answer 29

1. regulator: codes for repressor 2. control locus: has promoter and operator 3. structural locus: codes for enzyme needed to catabolize lactose

Question 30

spontaneous mutation

Answer 30

random change in DNA with no known cause

Question 31

induced mutation

Answer 31

caused by mutagens

Question 32

point mutation

Answer 32

addition, deletion, or substitution of nitrogen bases

Question 33

missense mutation

Answer 33

changes a single amino acid - can be unnoticeable or severe

Question 34

nonsense mutation

Answer 34

changes normal codon to a stop codon

Question 35

silent mutation

Answer 35

base changed, but amino acid stays the same

Question 36

back-mutation

Answer 36

mutated gene changes back to original form

Question 37

frameshift mutation

Answer 37

insertion or deletion of a base that changes the entire mRNA is altered

Question 38

wild-type sequence

Answer 38

non mutated

Question 39

inversion mutation

Answer 39

bases exchange places

Question 40

conjugation

Answer 40

plasmid transferred through direct contact with the use of a pilus

Question 41

transformation

Answer 41

DNA comes from a dead cell

Question 42

transduction

Answer 42

donor is a lysed bacterial cell

Question 43

transposons

Answer 43

"jumping genes"