Biology - Transcription/ Translation

Question 1

Helicase

Answer 1

Breaks hydrogen bonds between complimentary bases, unzips DNA

Question 2

Primase

Answer 2

lays down RNA primers as helicase is moving away

Question 3

Ligase

Answer 3

glues Okazaki fragments together, seals the gaps

Question 4

DNA Polymerase

Answer 4

the main architect of DNA replication. Constructs a new DNA strand by adding nucleotides in a direction that runs from 5’ to 3’. Requires a primer to add nucleotides

Synthesizes a new strand of DNA. Nucleotides align opposite their partner and DNA Pol 3 joins them together.

Question 5

Lagging Strand Replication

Answer 5

DNA polymerase is compelled to work backwards, creating discontinuous Okazaki fragments

Question 6

SSB

Answer 6

Keeps strands separated, supercoiling needs to be controlled when replicating DNA

Question 7

anti-sense strand

Answer 7

the strand that is copied in translation

Question 8

sense strand

Answer 8

strand that doesn’t get copied, and then the codon strand copies this strand

Question 9

Linus Pauling

Answer 9

-Proposed a triple helix model for DNA. Although he was wrong, his research played a significant role in the exploration of molecular biology.

Question 10

Phoebus Levine

Answer 10

• Laid groundwork for understanding the structure and function of nucleic acids

Question 11

Erwin Chargaff

Answer 11

• Discovered that the percentage of adenine are equal to the amounts of thymine
  -Discovered that the percentage of cytosine is = to the amounts of guanine
  Suggested complimentary base pairings in DNA

Question 12

Rosaline Franklin

Answer 12

-Discovered the helical pattern of DNA and dimensions for helix.
- Her work was essential to the discovery of the double helix although she wasn’t recognized for a long time later

Question 13

Watson and Crick

Answer 13

Discovered the double helix structure of DNA which laid the foundation for understanding the mechanisms of heredity
- helped to understand genetics
- and molecular biology

Question 14

How is DNA rep. semi conservative?

Answer 14

When a new double stranded DNA molecule is formed:
- one strand is from the original template molecule (conserved)
- one strand is newly synthesized (non conservative)

Question 15

Outline how the results of the Meselson-Stahl experiment supported semi-conservative DNA replication.

Answer 15

Meselson and Stahl treated DNA with a heavier nitrogen isotope (15N) and then replicated in the presence of a lighter nitrogen isotope (14N) - so template DNA and newly synthesized DNA could be differentiated

Question 16

What is the purpose and process of PCR?

Answer 16

-Rapidly amplifies minute quantities of DNA
Involves a thermal cycler and 3 repeating steps;
1) Denaturation - DNA is heated to separate strands
2) Annealing - Primers are introduced to designate copying strands
3) Elongation - Taq polymerase synthesizes new strand

These steps double the amount of DNA, so a typical reaction of 30 cycles will produce over 1 billion copies of desire DNA sequence

Taq polymerase is heat resistant and so doesn’t denature during PCR

Question 17

Transcription

Answer 17

the process by which an RNA sequence is produced from a DNA template (a gene)

Question 18

sense strand

Answer 18

Is the strand that is NOT transcribed (this is identical to the RNA sequence, except U replace T)

Question 19

anti-sense strand

Answer 19

Is the strand that IS transcribed (this is complementary to the eventual RNA sequence)

Question 20

translation

Answer 20

is the process of protein synthesis, genetic information encoded by mRNA is translated into an amino acid sequence