nucleic acids and protein synthesis Flashcards

1
Q

what is the shape of DNA?

A

double helix - spiral staircase or twisted ladder

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

Who is given credit for understanding the shape of DNA?

A

James Watson and Francis Crick

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

What prize did Watson and Crick receive for understanding the structure of DNA? Who shared in the prize?

A

Nobel Prize - Maurice Wilkins shared in the prize

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

Why did Rosalind Franklin not share the Nobel Prize with Watson, Crick, and Wilkins?

A

can not earn the prize posthumously - prize is to further research

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

Who experimented with mice and pneumococcus bacteria, and what was discovered?

A

Frederick Griffith discovered bacterial transformation - DNA from one bacterium can enter another bacterium and function - This turned harmless rough bacteria into harmful smooth bacteria

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

Who extended Griffith’s research to find out what the transforming chemical was, and what did they do?

A

Avery, Macleod, and McCarty used enzymes to destroy various cellular chemicals. When DNA was destroyed, the transformation didn’t occur, so they determined that DNA was the transforming chemical.

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

Who discovered base pairing?

A

Erwin Chargaff

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

What bases pair together in DNA?

A

adenine pairs with thymine

guanine pairs with cytosine

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

What holds DNA base pairs together, and what is significant about this type of bond?

A

hydrogen bonds - weak bonds - can easily be unzipped for DNA to work

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

How many hydrogen bonds are found between A-T?

How many hydrogen bonds are found between G-C?

A

A-T is held together by 2 hydrogen bonds.

G-C is held together by 3 hydrogen bonds.

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

What monomers are the building blocks of nucleic acids?

A

nucleotides

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

What polymer is made of nucleotides?

A

polynucleotides

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

Who experimented with bacteriophages and radioactive markers to verify that DNA is the transforming chemical?

A

Alfred Hershey and Martha Chase

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

What did the Hershey and Chase mark the bacteriophages with, and why?

A

radioactive phosphorus marked the DNA
radioactive sulfur marked the proteins
They wanted to know if bacteriophages injected DNA or protein into their host.

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

What is a bacteriophage?

A

a virus that infects bacteria

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

What was the result of the Hershey Chase experiments?

A

They verified that DNA is the transforming material, the genetic code.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the three parts of a nucleotide?

A
  1. sugar
  2. phosphate
  3. nitrogen base
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What sugar is in DNA?

What sugar is in RNA?

A

DNA - deoxyribose

RNA -ribose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What bases are in DNA?

What bases are in RNA?

A

DNA - A, T, G, C

RNA - A, U, G, C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What part of DNA is the code portion?

A

nitrogen base pairs - rungs of DNA ladder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What part of DNA is the supporting backbone?

A

alternating sugars and phosphates - sides of ladder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What kind of bond holds the sugars and phosphates together?

A

covalent bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Who made X-ray images of DNA and saw that it was a helix?

A

Rosalind Franklin and Maurice Wilkins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why do we say the DNA strands are antiparallel?

A

One end starts with a phosphate - 5’

One end starts with a sugar - 3’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the significance of the 5' and 3' ends of DNA?
It always is copied from 5' to 3'.
26
What is the term for DNA making an exact copy of itself?
replication
27
Why is DNA replication necessary?
It happens before cell division so each daughter cell will have all the information by getting a complete set of DNA
28
What are the 4 steps in DNA replication?
1. DNA unwinds 2. DNA unzips 3. new bases are brought in 4. The new strands are proofread for mutations
29
What chemicals cause replication?
enzymes
30
What enzyme unzips DNA?
helicase
31
What enzyme builds the new DNA strand?
DNA polymerase
32
Why is proofreading necessary?
to catch and fix mutations so that the new cell has the proper instructions
33
Why do we call DNA replication semiconservative?
an old strand serves as a template for a new strand. We don't waste the old strand.
34
What are the protective caps on the chromosome ends? What is their significance?
telomeres - related to aging as they wear down
35
What is the difference between prokaryote replication and eukaryote replication?
prokaryotes have circular DNA and replicates from one point outwards in each direction until it meets up - 2 replication forks eukaryotes have linear DNA and many replication forks to complete the entire strand
36
Give 5 ways DNA and RNA are different.
1. different sugars - ribose in RNA and deoxyribose in DNA 2. different bases - T in DNA and U in RNA 3. DNA is the code, RNA is the worker that reads the code and builds protein 4. DNA has 2 strands while RNA has 1 strand 5. DNA stays in the nucleus while RNA leaves 6. DNA has 1 type and RNA has 3 forms 7. DNA is longer while RNA is in smaller pieces
37
What are the three types of RNA, and what is the shape and function of each?
1. messenger RNA - linear - reads DNA and takes message to ribosomes 2. transfer RNA - hairpin or key - brings amino acids to ribosome 3. ribosomal RNA - globular - builds ribosomes
38
What is the name of the process where mRNA reads DNA?
transcription
39
Why is transcription necessary, and where does it happen?
to take the code to the ribosomes so proteins can be made - happens in nucleus
40
What enzyme builds the RNA?
RNA polymerase
41
What is the term for protein synthesis?
translation
42
Where does translation occur?
ribosomes
43
What are the building blocks of proteins?
amino acids
44
How many amino acids are in the human body?
20
45
Why is the code called a triplet code?
It works 3 bases at a time
46
What are three bases on DNA or mRNA called?
codons
47
What are three bases on tRNA called?
anticodon
48
How many codons are there, and what is the significance of having more codons than amino acids?
64 codons - some codons code for the same amino acids
49
What amino acid is always the start of a polypeptide chain?
methionine
50
How does the RNA know when to stop reading the code? How many are there?
stop codons - 3
51
What is a chain of amino acids?
polypeptide
52
What do we say is happening when a protein is being made from a gene?
gene expression
53
What is a mistake in the DNA called?
mutation
54
What is the general term for factors that cause mutations?
mutagens
55
Give 3 examples of mutagens.
1. radiation 2. heat 3. cigarette tar 4. asbestos
56
What do we call a mutation that affects 1 or 2 bases?
point mutation
57
What do we call a deletion or addition mutation that affects the entire code from that point?
frameshift
58
Which is more dangerous to an organism, a mutation in a body (somatic) cell, or a mutation in a gamete (sex cell)? Why
gametes - every cell forms from a mistake
59
Are mutations always bad?
no - most have no effect, and some are actually an advantage
60
What happens when a piece of DNA is missing?
genetic information is lost
61
What stores information in a cell?
nucleic acids - DNA and RNA
62
If you have 15% adenine in DNA, what would be the percent thymine in the same DNA?
15%
63
If you have 15% ademine in DNA, what would be the percent guanine in the same DNA?
35%
64
Why don't ademines pair with guanines?
they are both purines - both long, and the rungs would be irregular size
65
What are purines? What are they like?
A and G - double rings
66
What are pyrimidines? What are they like?
T and C - single rings
67
What should the strands of DNA be like after replication?
identical
68
What is the other half of DNA if one half is ACT GGA
TGA CCT
69
What is RNA if it reads the following DNA segment: ATT GCA
UAA CGU
70
Use the genetic code to translate the following mRNA segment: UAC CGU
tyrosine - arginine
71
What are tyrosine and arginine?
amino acids
72
genes contain instructions for assembling what?
proteins
73
What is the central dogma of biology?
DNA - RNA - protein
74
What do we call the DNA in a cell that is not dividing? | What do we call the DNA in a cell that is dividing?
chromatin - not dividing | chromosomes - dividing
75
other than the nucleus of eukaryotes, where is some DNA found, and what is unusual about this DNA?
mitochondria - only passed through maternal side
76
What is the term for the entire set of DNA of an organism?
genome
77
How many bases are in the entire human genome?
3 billion bases
78
Where do we get our DNA? What process divides our DNA in half to make gametes (sex cells)
half from mom and half from dad - meiosis
79
Who originally discovered DNA? When?
Frederich Miecher - 1800s
80
Why did we not believe DNA could be the code? What did we believe would be the code?
too simple - We thought proteins would be the code.
81
How are cells specialized?
They express different genes and produce different proteins. RBCs make hemoglobin and pancreas cells produce insulin.