Exam 2

Question 1

What is a gene? (Figuratively)

Answer 1

1. The functional unit of genetic information that specifies the structure of a protein.

Question 2

What is a gene? (Literally)

Answer 2

1. A segment of DNA coding a protein sequence

Question 3

Replication

Answer 3

DNA is copied

Question 4

Transcription

Answer 4

RNA molecule is synthesized from DNA template.

Question 5

Translation

Answer 5

Genetic information in mRNA is converted into protein sequences

Question 6

mRNA

Answer 6

messenger RNA

Question 7

tRNA

Answer 7

transfer RNA

Question 8

rRNA

Answer 8

ribosomal RNA

Question 9

Translation

Answer 9

Genetic information in mRNA is converted into protein sequence

Question 10

Genetic Code

Answer 10

3 bases = 1 amino acid

Question 11

5’–> 3’

Answer 11

1. Backbone- chain of alternating deoxyribose and phosphate

Question 12

Supercoiling

Answer 12

1. DNA twisted, torsion
2. Helical Pitch
3. DNA Gyrase
4. Topoisomerase I

Question 13

Helical Pitch

Answer 13

Number of base pair per turn

Question 14

Positive Supercoiling

Answer 14

1. coils on itself– righthanded supercoil
2. less base pairs creates stress
   * can eventually stop replication*

Question 15

Negative Supercoiling

Answer 15

1. Unwinding – lefthanded supercoil
2. more base pairs

Question 16

DNA Gyrase

Answer 16

Make negative supercoil (Topoisomerase II)
1. Chromosome Replication: easier to pull strands apart
2. Happens in transcription – aids

Question 17

Topoisomerase II

Answer 17

Topoisomerases that cut both strands of DNA helix simultaneously to mange DNA tangles and supercoils.

Question 18

Topoisomerase I

Answer 18

Relaxes negatively supercoiled DNA

Question 19

Replication Fork

Answer 19

1. Helicase pulls strands apart via ATP
2. Single Strand Binding Protein
3. RNA Primer
4. DNA Polymerase III

Question 20

Single Strand Binding Protein

Answer 20

Protein that prevents DNA from rejoining

Question 21

RNA Primer

Answer 21

Primase that allows polymerase something to grip

Question 22

DNA Polymerase III

Answer 22

Major elongation polymerase

Question 23

Leading Strand

Answer 23

Replicates IN to the replication fork; continuous long DNA Fragments

Question 24

Lagging Strand

Answer 24

Replications AWAY from the replication fork; discontinuous short DNA fragments; removes primers and DNA ligase “pastes” short” DNA fragments

Question 25

Errors of RNA in DNA

Answer 25

1. DNA Polymerase I: Degrades RNA; replaces with DNA ** leaves knicks**
2. DNA Ligase: Smooths kinks

Question 26

Correcting for Errors in Replication

Answer 26

1. DNA Polymerase III: High accuracy, 3’ exonuclease activity “backspace button”
2. Endonuclease can happen after DNA synthesis

Question 27

Bacterial Genetic Elements

Answer 27

1. Chromosome: long, usually one, usually circular double-stranded DNA
2. Plasmids
   Viral genomes

Question 28

Chromosomes

Answer 28

1. Very, very few introns
2. Group II (self-splicing)
3. Non-spliceosome introns

Question 29

Nucleic Acids

Answer 29

1. Relatively hydrophobic
2. Strands complimentary

Question 30

Plasmids

Answer 30

1. “Small” extrachromosomal DNA molecules
2. Linear plasmids = linear chromosomes
3. Plasmid- encoded genes usually not essential, advantage provided
   a. Antibiotic resistance
   b. Heavy metal resistance
   c. Virulence

Question 31

Restriction Modification System - Bacterial Immune Systems

Answer 31

1. Foreign DNA - Virus (not desired)
2. Restriction Endonuclease
   a. Endonuclease – cut DNA from inside
   b. Exonuclease– cut DNA from a free end
   *same forward and backward**

Question 32

Replication in Biotechnology

Answer 32

1. PCR:
   a. Taq
   b. Template DNA
   c. Deoxynucleotides
   d. Primers
2. Single Reaction Cycle
   a. Denaturation: 95 Celsius – Heating; separating DNA strands
   b. Annealing: 50 Celsius – Primers allow base pairing with complimentary
   c. Extension: 72 degrees Celsius – Added to 3’ end; synthesizes to DNA