Intro to Microbial Genetics and DNA Replication

Question 1

3 processes of genetic information flow

Answer 1

DNA replication
Transcription
Translation

Question 2

Gene

Answer 2

Functional unit of genetic information

Question 3

Genes are made up of what molecule?

Answer 3

Deoxyribonucleic acid (DNA)

Question 4

Difference between gene and protein designation in writing

Answer 4

Gene names are italicized and written in lower case

Protein names are not italicized and written in upper case

Question 5

Genome

Answer 5

All genetic material in cell or virus

Question 6

Bacterial genomes consist of ____ (usually) or more DNA chromosomes

Answer 6

One

Question 7

Genotype

Answer 7

Specific set of genes carried in genome

Question 8

Phenotype

Answer 8

Set of observable characteristics

Question 9

Operon

Answer 9

Cluster of genes plus regulatory elements controlling them

Question 10

Promoter

Answer 10

Where RNA polymerase binds to begin transcription

Question 11

Operator

Answer 11

Where repressor proteins can bind to block transcription

Question 12

Inducers

Answer 12

Molecules that can bind repressors, preventing them from binding to operators and thus enabling transcription to occur

Question 13

Polycistronic mRNA: enabled to directly become proteins, or needs further modification?

Answer 13

Needs further modification to become proteins

Question 14

3 parts of DNA

Answer 14

Sugar (deoxyribose)
Nitrogenous base (adenine, guanine, cytosine, thymine)
Phosphate group

Question 15

Purines vs pyrimidines: which bases fall into which category?

Answer 15

Purines: adenine and guanine (remember “pure as gold”)
Pyrimidines: cytosine, thymine

Question 16

Sugar + base + phosphate group =

Answer 16

Deoxynucleotide

Question 17

Each strand of DNA consists of what?

Answer 17

Deoxynucleotides connected by phosphodiester bonds

Question 18

Two strands of DNA are connected by what type of bonds?

Answer 18

Hydrogen bonds

Question 19

Base pairing rules: what pairs with what, how many hydrogen bonds

Answer 19

A pairs with T (2 hydrogen bonds)

G pairs with C (3 hydrogen bonds)

Question 20

What are the designations of the two paired DNA strands? Which is the hydroxyl end and which is the phosphate end?

Answer 20

5’ and 3’ ends
3’ end is hydroxyl
5’ end is phosphate

Question 21

Two strands of DNA are referred to as ____.

Answer 21

Antiparallel

Question 22

DNA size is expressed as _____. 1,000 ____ equals 1 ____.

Answer 22

Base pairs

1000 base pairs = 1 kilobase (kb)

Question 23

E. coli chromosome: how many kb? What is the relative size of E. coli’s chromosome considered to be?

Answer 23

4640 kb or 4.64 mega (million) Mbp

Average size

Question 24

Mycoplasma chromosome: one of the biggest or smallest chromosomes amongst the bacteria? Size?

Answer 24

One of the smallest

580 kb encoding 480 proteins

Question 25

Is DNA arranged in a double helix in prokaryotic cells as it is in eukaryotic cells?

Answer 25

Yes

Question 26

How is prokaryotic DNA arranged (shape, closed or open, how coiled)?

Answer 26

Usually circular, closed, supercoiled molecule

Question 27

Nucleoid

Answer 27

Loops or domains of packed bacterial DNA

Question 28

Eukaryotic DNA: linear or circular?

Answer 28

Linear

Question 29

How is eukaryotic DNA packed?

Answer 29

Wrapped around proteins (histones)

Question 30

Histones + DNA = ?

Answer 30

Nucleosomes

Question 31

Genes in human genome are interrupted by what?

Answer 31

Introns

Question 32

How is archaeal DNA packing like that of bacteria? How is it like that of eukaryotes?

Answer 32

Archaea have circular chromosomes like bacteria that is wrapped around histones like eukaryotes

Question 33

Semiconservative model of DNA replication

Answer 33

When strands separate during DNA replication, each strand serves as a template for the synthesis of a new strand

Question 34

DNA replication in eukaryotes vs prokaryotes: bidirectional or unidirectional?

Answer 34

Bidirectional for both

Question 35

DNA replication in eukaryotes vs prokaryotes: multiple or single origins of replication (ori)?

Answer 35

Eukaryotes: multiple oris Prokaryotes: one ori

Question 36

DNA replication in prokaryotes: how many replication forks? Does replication proceed in the same direction for both, or in opposite directions?

Answer 36

2 forks | Proceeds in opposite directions

Question 37

How is ori selected in prokaryotic DNA replication?

Answer 37

DnaA protein binds DNA in ori only

Question 38

ter region

Answer 38

Site where replication is terminated

Question 39

DNA polymerase catalyzes DNA synthesis in which direction?

Answer 39

5' to 3' direction

Question 40

3 things DNA polymerase needs to replicate DNA

Answer 40

Template Deoynucleotide triphosphates (dNTPs) Primer (usually RNA) with 3' hydroxyl group

Question 41

Do most bacteria have one or several DNA polymerases? What is the name of the major DNA replication enzyme?

Answer 41

Most bacteria have several DNA polymerases | DNA Pol III is the major DNA replication enzyme

Question 42

Single strand binding proteins (SSBs)

Answer 42

Prevent hydrogen bonds from reforming across two DNA strands | Stabilize single stranded DNA

Question 43

DNA gyrase

Answer 43

Underwinds DNA by cutting one DNA strand, passing the other through the gap, and sealing it

Question 44

DNA gyrase is a target for what antibiotic? What class does it fall under?

Answer 44

Ciprofloxacin | Quinolone

Question 45

DnaB helicase

Answer 45

Breaks hydrogen bonds between strands of DNA

Question 46

DNA primase

Answer 46

Primes replication by laying down RNA primer

Question 47

Leading strand of DNA is synthesized in what direction? Is this synthesis continuous or discontinuous?

Answer 47

5' to 3' | Continuous

Question 48

Lagging strand of DNA is synthesized in what direction? Is this synthesis continuous or discontinuous?

Answer 48

3' to 5' | Discontinuous

Question 49

Segments of primer used in lagging strand synthesis are called what?

Answer 49

Okazaki fragments

Question 50

What DNA polymerase removes RNA primers and fills in the gaps with DNA?

Answer 50

DNA Pol I

Question 51

Ligase

Answer 51

Seals fragments of DNA together in DNA synthesis