Exam 5

Question 1

In which direction is DNA usually read? (5’ or 3’ first?)

Answer 1

5’ to 3’

Question 2

What is a telomere?

Answer 2

The region at the ends of a eukaryotic chromosome, consisting of short repeated sequences of nucleotides.

Question 3

The bond between which DNA base pair is strongest? A-T or C-G

Answer 3

C-G

Question 4

What is the central dogma of biology?

Answer 4

DNA codes for RNA, which codes for protein. DNA does not code for protein directly.

Question 5

What is transcription?

Answer 5

Making an RNA sequence based on DNA

Question 6

What is translation?

Answer 6

Making a protein according to an mRNA sequence

Question 7

What is the coding strand of DNA used for?

Answer 7

Nothing directly. Only the template strand is used.

Question 8

What is a phosphodiester bond?

Answer 8

A bond between phosphate & hydroxyl used to hold together adjacent nucleotides on the same strand

Question 9

What type of bonds hold base pairs together?

Answer 9

Hydrogen bonds

Question 10

What is semiconservative replication?

Answer 10

DNA replication where each new double helix has 1 strand from the original DNA (the template strand) & 1 newly synthesized strand

Question 11

What does DNA helicase do?

Answer 11

Unwinds the double helix

Question 12

What are the steps of replicating the lagging strand of DNA?

Answer 12

DNA primase applies an RNA primer at the beginning of each Okazaki Fragment. DNA polymerase III can then synthesize the DNA until the next RNA primer. Then, the primer at the beginning is replaced with DNA by DNA polymerase I. That DNA must be connected to the DNA from DNA polymerase III by ligase.

Question 13

What is an Okazaki fragment?

Answer 13

A short sequence of DNA between RNA primers on the lagging strand of DNA being replicated

Question 14

What are Chargoff’s rules?

Answer 14

A pairs with T.
C pairs with G.

Question 15

What is the role of mRNA?

Answer 15

messenger RNA is created based on DNA in transcription, then the mRNA leaves the nucleus to code for proteins in the ER.

Question 16

What does tRNA do?

Answer 16

transfer RNA is an adapter between amino acids & mRNA. It holds an amino acid & has the anticodon sequence corresponding to that amino acid so that it can bond to the correct mRNA codon.

Question 17

What is SRP RNA used for?

Answer 17

It is useful in the synthesis of polypeptides on the rough ER.

Question 18

What does rRNA mean?

Answer 18

ribosomal RNA