Week 5: Genetic Variation & Microbial Genetics

Question 1

nucleotides are made up of

Answer 1

5-carbon sugar, phosphate group, and nitrogenous base

Question 2

phosphate group always attaches to

Answer 2

number 5

Question 3

base is always attached to

Answer 3

number 1

Question 4

when nucleotides join together a bond forms between

Answer 4

the phosphate group and carbon 3 adjacent nucleotide

Question 5

nucleotides are read from

Answer 5

the 5’ end to the 3’ end

Question 6

anti parallel

Answer 6

one strand in the DNA molecule runs 5’-3’, the other 3’-5’

Question 7

chromosomes are made up of

Answer 7

DNA and specific DNA binding proteins that package the DNA neatly in the cell

Question 8

DNA replication begins at the

Answer 8

origin

Question 9

what enzyme binds at the origin and replication is initiated in
either direction along the circular chromosome

Answer 9

DNA polymerase

Question 10

how does DNA polymerase move

Answer 10

moves in one direction only. Adds nucleotides in a 5’-3’ direction, so it
adds nucleotides continuously to one daughter strand and in short segments on the
other that are fused together later in the process

Question 11

replication proceeds in

Answer 11

both directions from the origin using two replication forks

Question 12

gene expression involves two important processes

Answer 12

transcription and translation

Question 13

transcription is the process by which

Answer 13

a gene’s DNA is converted into a complementary RNA molecule

Question 14

transcription is an enzyme-mediated process led by the enzyme

Answer 14

RNA polymerase

Question 15

RNA polymerase attaches to a specific site on the DNA template

Answer 15

the promoter

Question 16

RNA polymerase synthesizes a complementary strand of

Answer 16

mRNA as it moves along the DNA template

Question 17

how does eukaryotic transcription differ from prokaryotes

Answer 17

RNA polymerase does not bind to the promotor directly, instead transcription factors bind the promotor and RNA polymerase recognizes these proteins

Question 18

introns

Answer 18

noncoding sequences of DNA within a gene

Question 19

exons

Answer 19

coding sequences of DNA within a gene

Question 20

introns are

removed from the mRNA molecule by

Answer 20

RNA splicing

Question 21

second step in gene expression is

Answer 21

translation; the mRNA is converted into a
specific amino acid sequence that forms a
specific protein

Question 22

Codons on the mRNA specify

Answer 22

which amino acid is added to a growing protein

Question 23

start codon

Answer 23

AUG

Question 24

stop codons

Answer 24

UAA, UAG, UGA

Question 25

first amino acid in protein synthesis

Answer 25

mathionine

Question 26

bacteria reproduce

Answer 26

asexually

Question 27

transformation (horizontal gene trasnfer)

Answer 27

Bacteria take up DNA from the environment; environmental DNA is usually a result of dead
bacteria releasing DNA in to the environment

Question 28

transduction

Answer 28

Bacteriophages (viruses that infect bacteria) transferring DNA from one bacterium to another

Question 29

conjugation

Answer 29

A donor bacterium transfers short DNA segments (usually plasmids) to another bacterium via
a sex pilus;

Question 30

transposons

Answer 30

‘jumping genes’ that can relocate to other parts of the genome, increasing genetic diversity

Question 31

reasons for mutation

Answer 31

• Spontaneous mutations
• Chemical mutagens and intercalating agents
• Free radicals
• Radiation

Question 32

neutra mutation

Answer 32

phenotype/ protein is

unchanged

Question 33

missense mutation

Answer 33

A different amino acid is substituted due to the mutation

• The phenotype is changed; can be positive or negative, or have little effect

Question 34

nonsense mutation

Answer 34

Translation terminates early due to a mutation that results in a stop codon where an amino
acid would have normally been
• Usually very harmful to the protein

Question 35

frameshift mutation

Answer 35

When a base is added or deleted mistakenly shifting the entire ‘reading frame’ of the mRNA
• Usually very harmful to the protein