Lecture 14- DNA Flashcards

1
Q

What is DNA composed of?

A

Nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are nucleotides composed of?

A

Nitrogenous base, pentose sugar (deoxyribose/ribose), & phosphate group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What was the significance of Griffith’s experiment?

A

Hypothesized transformation (experiment with mice and streptococcus pneumoniae)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How many common amino acids are there?

A

20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What was the significance of the experiments conducted by Avery, MacLeod, & McCarty?

A

Lysed smooth (S) cells → separated contents into biological macromolecules → tested each macromolecule for transforming ability → discovered that only DNA could transform

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What was the significance of the Hershey-Chase experiment?

A

Discovered that bacteriophages are composed of just DNA and protein (via radioactive tracers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the main classifications of nitrogenous bases?

A

Purines & pyrimidines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the difference between purines and pyrimidines?

A

Pyrimidines are composed of a single ring whereas purines are composed of two rings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which nitrogenous bases are considered purines?

A

Adenine & guanine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which nitrogenous bases are considered pyrimidines?

A

Thymine, cytosine, & uracil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What was the significance of Rosalind Franklin’s experiment?

A

Discovered the helical structure of DNA via x-ray crystallography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What was the significance of Erwin Chargaff’s experiment?

A

Discovered that there are approximately equal amounts of purines and pyrimidines in DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What was the significance of the discovery made by Watson & Crick?

A

Using Rosalind Franklin’s DNA model, Watson & Crick were able to explain how DNA could carry genetic information and how information could be replicated. Found that each rung in DNA is composed of a purine and a pyrimidine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What type of bond occurs between the sugar-phosphate backbone?

A

Phosphodiester linkages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What type of bond occurs between the nitrogenous bases?

A

Two hydrogen bonds between adenine and thymine & three hydrogen bonds between guanine and cytosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does dehydration synthesis occur to form bonds between the sugar-phosphate backbone?

A

Occurs between the free 3 hydroxyl (OH) & the free 5 phosphate

17
Q

Which nitrogenous bases pair with each other?

A

Adenine with thymine in DNA or uracil in RNA & cytosine with guanine (in both DNA/RNA)

18
Q

What does it mean that DNA replication follows a semi-conservative model?

A

A parental strand is used to synthesize a daughter strand

19
Q

What are the steps of transcription in order?

A

Initiation → elongation → termination

20
Q

Which event marks the start of transcription initiation?

A

Separation of strands & formation of replication bubble (origin of replication)

21
Q

How do single-stranded binding proteins (SSBPs) aid in DNA replication?

A

SSBPs keep DNA strands apart

22
Q

Relative to the replication bubble, in which direction does replication proceed?

A

Replication proceeds towards the replication forks

23
Q

Which protein is responsible for unwinding the DNA helix during replication?

24
Q

What is the function of topoisomerase?

A

Relaxes DNA helix (provides stability to unwound DNA)

25
What is the function of RNA primase?
Synthesize RNA primers which allow DNA polymerase to proceed with replication
26
What is the end result of transcription?
Pre-mRNA
27
How are DNA strands oriented relative to one another?
Antiparallel
28
What are the modifications pre-mRNA undergoes before it is considered a mature mRNA?
Introns snipped out by spliceosome and exons are joined together. Also a 3` poly-adenine tail and 5` guanosine cap are added to the ends of the mRNA
29
What is added to the growing molecule during the elongation stage of DNA replication?
Nucleoside triphosphates added → forms new phosphodiester bond → releases pyrophosphates
30
Which enzyme is responsible for combining DNA strands back together at the end of replication?
DNA ligase
31
What is the lagging strand composed of?
Okazaki fragments
32
stop