Chapter 11

Question 1

How do you convert the mother DNA strand to mRNA?

Answer 1

C -> C
G -> G
A -> A
T -> U

Example on slide 2

Question 2

What are the steps from DNA to protein?

Answer 2

DNA
Transcription
RNA
Translation
Protein

Question 3

What is the common structure of nucleotides?

Answer 3

A phosphate group (or multiple) attached to a pentose on the right then the purine or pyrimidine base on top of the pentose

Picture on slide 3

Question 4

How can you determine the type of nucleus acid you are looking at (deoxyribose vs ribose) by the pentose?

Answer 4

If the pentose has two hydroxide groups on the bottom it’s ribose but if it has one hydroxide group and a hydrogen it is deoxyribose

Slide 5

Question 5

What bond links successive nucleotides in nucleic acids?

Answer 5

Phosphodiester bonds
Connect 3’ carbon from above pentose by a phosphate group to the 5’ carbon of pentose below

Slide 8 picture

Question 6

Who are Rosalind Franklin and Maurice Wilkins?

Answer 6

They obtained the x Ray diffraction data that showed that DNA is a helix

Question 7

What is similar about purines and pyrimidines?

Answer 7

# of purines = # of pyrimidines
A=T and G=C so A+G=T+C

When A-T bonded and G-C bonded, they have nearly identical geometry and are planar (flat)

They both form hydrogen bonds with eachother

Question 8

What’s the difference in hydrogen bond numbers of the purine pair (A-T) and pyrimidine pair (G-C)?
Which melts quicker?

Answer 8

A-T purines have 2 hydrogen bonds
G-C pyrimidines have 3 hydrogen bonds

Purines melt quicker since they only have 2 hydrogen bonds

Question 9

What is a palindrome?

Answer 9

A sequence of DNA that reads forward and backward the same way

Like “race car”

Question 10

What is the supercooling method of compacting DNA?

Answer 10

It is twisting of the double helix that produces a second order helix (superhelix)

Question 11

How is DNA pack in eukaryotic cells?

Answer 11

It is packed into nucleosomes that contain 8 histones
The histone core helps bond negatively charged DNA backbone so it winds around the core in 146 nucleotide pairs length
Including the linker it’s 200

Slide 16

Question 12

How are chromatids broken down into DNA?

Answer 12

2 chromatids
1 coil
1 rosette
1 loop
30nm fiber
“Beads on a string” form of chromatin
DNA

Slide 17

Question 13

What is denaturation?

What is it’s reversed process?

Answer 13

Denaturation- breaking of hydrogen bonds at high temps that cause the strands of DNA to unwinds and separate
Annealing is the reverse process

Question 14

How is the melting temperature of DNA determined (tm)?

Answer 14

The temperature at which 50% of the DNA is denatured

Question 15

What two scenarios can lead to Increase mutation rate in DNA?

Answer 15

Deamination of nitrogenous bases in DNA
Chemical modification of DNA by UV light

Slide 20
Slide 22

Question 16

What are the most important RNA functions in the cell?

Answer 16

1. mRNA transfers genetic information from the chromosome to the ribosomes
2. tRNA are adaptors for matching amino acids to the mRNA in protein synthesis
3. rRNA is structural component of ribosomes
4. RNA is a component of some enzymes that process other RNAs

Question 17

Does RNA for regular double helix like DNA?

Answer 17

Short stretches of double helix are common but not regularly it doesn’t

Eventually causes hair pins, internal loops, bulges, and single strands can lead to very complex rna structures
Slide 24-25

Question 18

What is DNA polymerase?

Answer 18

DNA polymerase synthesizes complementary strand on a single stranded DNA template and attaches nucleotides to the 3’ end of the growing strand

Question 19

What does DNA synthesis start with?

Answer 19

Single stranded DNA primer called oligonucleotide primer

Question 20

Who invented the first fast method of DNA sequencing and determined amino acid sequence of insulin?

Answer 20

Frederick Sanger

Question 21

What terminates the growing chain of DNA?

Answer 21

Adding 2’,3’-dideoxy-nucleotides terminates growing since they have no 3’ hydroxyl

Question 22

What are the 7 steps in DNA sequencing?

Answer 22

1. DNA template is denatured and primer is added to template by lowering temp
2. DNA polymerase, dNTPs, and ddNTPs labeled with dye are added
3. DNA synthesis process and terminated at points where ddNTP is incorporated
4. Double stranded DNA products are denatured to separate label stands
5. Labeled strands are separated by size
6. Each band is registered as it passes detector
7. Computer generates sequence of DNA template
   Slide 31