Lecture 7 DNA

Question 1

What is DNA’s full name

Answer 1

Deoxyribonucleic Acid

Question 2

What are the monomer building block of DNA CALLED

Answer 2

deoxyribonucleotides

Question 3

What is DNA composed of

Answer 3

– 5-carbon sugar deoxyribose
– a nitrogenous base
– a phosphate group

Question 4

Name the four nitrogenous bases found in DNA

Answer 4

– Adenine (A)
– Guanine (G)
– Cytosine (C)
– Thymine (T)

Question 5

Does DNA consist or one or two complementary stands

Answer 5

Two

Question 6

Are DNA complementary stands single or double stranded

Answer 6

Double stranded

Question 7

What does Adenine pair with

Answer 7

Thymine

Question 8

What does Guanine pair with

Answer 8

Cytosine

Question 9

Name the 4 stages of DNA replication

Answer 9

• Initiation
• Elongation
• Proofreading
• Termination

Question 10

DNA polymerase can add free nucleotides to only where

Answer 10

the 3’ end of the newly-forming strand.

Question 11

DNA polymerase can add a nucleotide only to what pre-existing group

Answer 11

3’-OH group

Question 12

Name the two stages of Gene expression

Answer 12

•Transcription
•Translation

Question 13

Describe Transcription

Answer 13

• Initiated at the promoter region upstream of the gene
• RNA polymerase copies the DNA and produces an RNA transcript (mRNA)

Question 14

Describe Translation

Answer 14

• mRNA is decoded by ribosomes and tRNA molecules to specify
• the exact sequence of amino acids in a protein

Question 15

How many adjacent nucleotides encode a particular amino acid

Answer 15

A set of 3

Question 16

What is the genetic code called

Answer 16

Codon

Question 17

What affects RNA polymerase

Answer 17

Rifampicin

Question 18

What affects ribosome and protein synthesis

Answer 18

Macrolides (erythromycin), Kanamycin,
Tetracycline

Question 19

Mutations in the antibiotic target can lead to what

Answer 19

Bacterial resistance

Question 20

What targets DNA Gyrase

Answer 20

Ciprofoxacin

Question 21

What does the enzyme Gyrase do

Answer 21

unwinds bacterial DNA during replication.

Question 22

What does Ciprofoxacin prevent

Answer 22

Cell division

Question 23

What type of antibiotic is Ciprofoxacin

Answer 23

Quinolone antibiotic

Question 24

Name the 3 plasmid genes

Answer 24

– Antibiotic resistance genes (often multiple)
– Virulence genes (e.g. toxins)
– Metabolic genes

Question 25

What is the most common source of genetic variation

Answer 25

Mutations

Question 26

Name the three types of mutations

Answer 26

– Substitution – Deletion – Insertion

Question 27

What is the Asparagine codon called

Answer 27

•AAC •Faulty protein •Missense mutation

Question 28

What is the stop codon called

Answer 28

•UAG .•Incomplete protein •Nonsense mutation

Question 29

What is the Tyrosine codon called

Answer 29

•UAU •Normal Protein •Silent mutation

Question 30

What is the second Tyrosine codon called

Answer 30

•5’UAC •Normal protein •Wild type

Question 31

Example of physical mutagen

Answer 31

Radiation

Question 32

Example of chemical mutagenesis

Answer 32

– Base analogues – Intercalating agents – Metals - ROS

Question 33

Example of biological mutagen agents

Answer 33

•Viruses •Transposon

Question 34

What is genetic exchange

Answer 34

Modes of genetic transfer between bacterial cells

Question 35

Example of naturally competent bacteria

Answer 35

Streptococcus pneumoniae

Question 36

What does conjugation describe

Answer 36

Plasmid transfer between bacterial cells

Question 37

What does conjugation require

Answer 37

•cell-to-cell contact & can occur between different bacterial species •even between G+ve and G-ve

Question 38

In conjugation where do plasmids replicate

Answer 38

replicate in the donor cell prior to transfer into the recipient cell

Question 39

What is Transduction

Answer 39

DNA transfer between bacteria via infection with a bacteriophage

Question 40

What infect the bacterial cell and replicate in Transduction

Answer 40

Phage

Question 41

What does Transduction involve the incorporation of

Answer 41

Phage DNA into phage capsids (heads)

Question 42

What are Transposons

Answer 42

DNA sequences that can ‘jump’ within the bacterial genome and from the genome to plasmids within the same cell

Question 43

What do Transposons often contain

Answer 43

Antibiotic resistance genes

Question 44

Example of a mutation

Answer 44

Drug resistance in Tuberculosis

Question 45

Example of Transformation/Transposition

Answer 45

Penicillin resistant gonorrhea

Question 46

Example of conjugation

Answer 46

Multi resistance shigella