Transcription and Translation

Question 1

Topoisomerase

Answer 1

“unwinding” enzyme which unwinds DNA’s double helix in preparation for transcription

Question 2

Helicase

Answer 2

“unzipping” enzyme which unzips the DNA into two separate strands in preparation for translation

Question 3

Primase

Answer 3

enzyme which lays down RNA primer to help signal DNA polymerase where to start

Question 4

DNA Polymerase

Answer 4

“builder” enzyme which copies over DNA into mRNA; this enzyme can only work in the direction of 5’ –> 3’ (phosphate end –> hydroxyl end), requiring extra help to work the other way

Question 5

Ligase

Answer 5

“gluing” enzyme that glues Okazaki fragments together

Question 6

Okazaki Fragment

Answer 6

name for a fragment of mRNA built by DNA polymerase in the 3’ –> 5’ direction

Question 7

Lagging Strand

Answer 7

strand of DNA which is more difficult for DNA polymerase to transcribe into mRNA because it goes from the 3’ end –> 5’ end

Question 8

Steps of Transcription

Answer 8

1. Initiation (transcription factors attach to TATA box, RNA polymerase begins transcribing mRNA)
2. Elongation (builds RNA transcript)
3. Termination (reaches final point)

Question 9

Steps of RNA Processing (eukaryotes only)

Answer 9

1. Adds 5’ Cap (allows mRNA to leave nucleus)
2. Adds poly-A tail (allows mRNA to leave nucleus)
3. RNA Splicing (removes introns and joins exons using snRPS)

Question 10

Steps of Translation

Answer 10

1. Initiation (small subunit of ribosome looks for AUG codon, large ribosomal subunit attaches at the EPA site)
2. Elongation (codon recognition –> peptide bonding of amino acids via anticodon tRNA attachment)
3. Termination (hits stop codon)

Question 11

Retroviruses

Answer 11

viruses which use the enzyme reverse transcriptase to copy their RNA into DNA as a provirus, which create mRNA and ultimately hijack the translation process to build more viruses.

Question 12

Three models of DNA replication

Answer 12

1. Conservative Model (original DNA is fully copied without any changes to the original DNA strand)
2. Semi-Conservative Model (original DNA is 1/2 the same and 1/2 different; this is the widely accepted model)
3. Dispersive Model (original DNA strand is copied randomly, creating two mixed DNA strands)

Question 13

Point Mutation

Answer 13

gene is swapped out

Question 14

Insertion

Answer 14

Extra base is added into the codons, resulting in a longer, altered amino acid chain

Question 15

Nonsense

Answer 15

Early stop codon

Question 16

Missense

Answer 16

Change in amino aicd results from change in codon/base

Question 17

Silent Mutation

Answer 17

Change in codon does not change amino acid

Question 18

Down Syndrome

Answer 18

Disease resulting from nondisjunction

Question 19

Tay Sachs

Answer 19

Autosomal recessive disease that leads to early death

Question 20

Hunington’s Disease

Answer 20

autosomal dominant disease with a late onset

Question 21

Sickle Cell Anemia

Answer 21

autosomal recessive disease