Microbial Genetics

Question 1

Genome

Answer 1

All genetic information about a cell

Question 2

Genetic code

Answer 2

Set of rules that determine how a nucleotide sequence is converted to an amino acid sequence of a protein

Question 3

Chromosome

Answer 3

Necessary
Circular
DOuble stranded
Large
DNA

Question 4

Plasmids

Answer 4

Carry traits not necessary to survival
Circular
Double stranded
SMALL
Bacteria may have more than one

Question 5

Transposons

Answer 5

Jumping genes

Question 6

Components of nucleotides?

Answer 6

Nitrogen base
Pentose sugar
Phosphate group

Question 7

What are nitrogen bases?

Answer 7

Ring of nitrogen and carbon
Very basic, having high pH

Question 8

Types of nitrogen bases?

Answer 8

Purines (9 member double ring)
Pyrimidines (6 member single ring)

Question 9

What are the 2 purines?

Answer 9

Adenine (A)
Guanine (G)

Question 10

What are the pyrimidines?

Answer 10

Cytosin (C)
Thmine (T)
Uracil (8)

Question 11

What are the types of pentose sugars in nucleotides?

Answer 11

Deoxyribonucleic acids (deoxyribose)
Ribonucleic acids (ribose)

Question 12

Where are ribose and deoxyribose found in?

Answer 12

Ribose (RNA)
Deoxyribose (DNA)

Question 13

What does the phosphate group in nucleotides contribute to?

Answer 13

Contributes to the overall negative charge

Question 14

DNA replication: How the helix unzips steps and what happens after

Answer 14

1. Doble helix separates as weak hydrogen bonds break in response to enzymes
2. New hydrogen bonds form between new complementary nucleotides and each strand of parental template to form new base pairs
3. Enzymes catalyze the formation of sugar phosphate bonds between sequential nucleotides on each resulting daughter strand

Question 15

How can a cell’s DNA be changed?

Answer 15

Mutations during replication, vertical transfer
Horizontal Gene transfer

Question 16

Mutation informatin

Answer 16

Permanent change in base sequence in DNA
Sometimes will cause a change in the product encoded by that gene

Question 17

Spontaneous mutations occur when?

Answer 17

In the absence of any mutation causing agents

Question 18

What are the types of mutations?

Answer 18

Spontaneous
Base
Nucleotide insertion/ deletion

Question 19

What are the types of base substitutions(mutation)

Answer 19

SIlent
Missense
Nonsense

Question 20

What’s a silent mutation?

Answer 20

Occurs when a change in sequence of nucleotide base but doesn’t change the function or amino acid

Question 21

Whats a missense mutation?

Answer 21

When a base substitution results in a change of amino acid

Question 22

What’s a nonsense mutation?

Answer 22

Base subsitutution results in a stop codon

Question 23

TYpe of nuleotide insertion/ deletion mutation?

Answer 23

Frameshift

Question 24

What’s a frameshift mutation?

Answer 24

INsertion or deletion of one or more nucleotide pairs

Question 25

What are mutagens?

Answer 25

Agents that directly or indirectly bring about mutations

Question 26

Whats the mutation rate?

Answer 26

Probability that a gene will mutate when a cell divides Usually a negative exponent as they are so rare

Question 27

What's genetic recombination

Answer 27

Exchange of genes between 2 DNA molecules to form new combinations of genes on a chromosome

Question 28

What happens if a cell picks up foreign DNA (genetic recombination)

Answer 28

Some of it can insert into cells chromosomes called crossing over Some of the genes carried by chromosomes are shuffled DNA is now recombined, meaning it has some of donors DNA

Question 29

What happens in horizontal gene transfer?

Answer 29

Donor cell gives a portion of its DNA to recipient cell

Question 30

What's the recombinant in horizontal gene transfer?

Answer 30

The recipient cell that incorperates donor DNA into its own DNA

Question 31

What are some ways genetic transfer can occur?

Answer 31

Plasmids and transposons / conjugation Transformation Transduction

Question 32

Plasmid facts

Answer 32

Self replicating Circular pieces of DNA 1 to 5% of size of chromosome Often code for proteins that enhance the pathogenicity of a bacterum

Question 33

Different types of plasmids?

Answer 33

F factor/ conjugative Virulence DISIMILATION Col Resistance factor

Question 34

F factor plasmid fact

Answer 34

Carries gene for sex pili and transfer of plasmid to another cell

Question 35

Virulence plasmid facts

Answer 35

Encode proteins that enhance pathogeniity

Question 36

Disimilation plasmds

Answer 36

Code for enzymes that trigger catabolism

Question 37

Col plasmids

Answer 37

Colicinogenic factor Production of colicins Colicins are proteins that have antibiotic activity and can kill other bacteria

Question 38

R factor

Answer 38

Carry genes that can their host resistence to antibiotics, heavt metak, or cellular toxins

Question 39

The 2 groups of R factor genes

Answer 39

Resistance transfer factor (genes for plasmid replication) R determinant group (resistence genes)

Question 40

Requirements for conjugation

Answer 40

Cell to cell contact Must be between opposite mating types F+ (has plasmid) F- (does not)

Question 41

Gram negative cells use what to comjugate?

Answer 41

Sex pilus

Question 42

Comjugation steps

Answer 42

Donor cell attaches to recipient with pilus Cells contact each other One strand of plasmid Dna transfers Recipient cell becomes F+

Question 43

Limits to conjugation?

Answer 43

No same cells allowed will connect Restriction enzymes