Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

asd senior year > AP Bio Exam 4 > Flashcards

AP Bio Exam 4 Flashcards

1
Q

Who created the model of DNA?

A

James Watson and Francis Crick

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

Chargaff’s Rule

A

The base composition of DNA varies from one species to another

For each species, the percentages of A and T bases are roughly equal, as are those of G and C bases.

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

Rosalind Franklin

A

Took an X-ray diffraction image of DNA
The pattern implied that the helix was made up of two stands, contrary to the three strand model.

The diameter was the same every time

Concluded that the sugar-phosphate backbones were on the outside of the DNA molecule. (The phosphate groups negatively facing the aqueous surroundings, and the relatively hydrophobic nitrogenous bases were hidden in the interior)

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

Watson and Crick

A

Built DNA model that proved the:
Double helix theory
Chargaff’s rules
antiparallel arrangement
Purine and pyrimidine arrangement

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

Hershey and Chase

A

Used radioactive isotope of sulfur to tag protein in one batch of T2 and radioactive isotope of phosphorus to tag DNA in a second batch

The phages infected E. coli and the phosphorus stayed. The protein does not enter the cells.

CONCLUSION: DNA must hold the molecule carrying the genetic information that makes the cells produce more viral DNA and proteins.

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

Why are nucleic acids unique?

A

Their ability to replicate themselves from monomers

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

Transformation

A

A change in genotype and phenotype due to the assimilation of external DNA by a cell

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

Evidence that DNA can transform bacteria

A

Frederick Griffith mixed cell remains of killed pathogenic bacteria with living nonpathogenic bacteria. Some living cells became pathogenic and all offspring of pathogenic bacteria were also pathogenic.

Some DNA of the dead pathogenic cells cause this heritable change

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

Evidence that Viral DNA can program cells

A

Bacteriophage (viruses that infect bacteria) “T2” programs E. Coli into T2 making machines. Hershey and chase found that the DNA entered the bacteria but not the protein

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

Virus

A

DNA in a protective coat, often a protein. Infects a cell and takes over the cell’s metabolic machinery

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

Three components of a nucleotide monomer

A
  1. Nitrogenous base
  2. Phosphate Group
  3. A pentose sugar (deoxyribose)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Four nucleotide bases

A

Adenine, thymine, guanine, cytosine

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

Chargaff’s rules

A
  1. DNA base composition varies between species
  2. For each species, the percentage of A and T (and C and G) bases are roughly equal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are 5’ and 3’?

A

The carbon in the pentose that the phosphate group attaches to

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

Double helix

A

Presence of two strands

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

The sugar phosphate complex in nucleotides is the

A

“backbone” of the structure

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

What charge is DNA

A

Overall negative (because of the negative phosphate groups)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Antiparallel

A

Subunits of two sugar-phosphate backbones run in opposite directions

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

Purine

A

Two organic rings

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

Pyrimidine

A

One organic ring

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

Which bases are purines and which are pyrimidines?

A

Purine: Adenine and Guanine
Pyrimidines: Cytosine and Thymine

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

How many organic rings per nucleotide base pairs?

A

3
2 is too narrow and 4 is too wide in diameter of the helix

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

How many hydrogen bonds in each pairing?

A

A - T: Two
C - G: Three

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

Modern DNA sequencing techniques confirmed that

A

Nucleotide base pair ratios are exactly equal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Base principle of DNA replication

A
  1. Parental molecule is paired
  2. Pairs separate into two DNA strands
  3. Daughter strands pair complementary to both parental strands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Conservative Model of Replication

A

Two parental strands reassociate after acting as templates for new strands, restoring into a parental double helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Semiconservative Model

A

True model*
The two strands of parental molecule separate and each functions as a template for synthesis of a new complementary strand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Dispersive Model

A

Each strand of both daughter molecules contains a mixture of old and newly synthesized DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

When does DNA replication occur

A

S phase in Interphase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

T/F, DNA replication is slow but accurate

A

F: it is quick and accurate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Origins of replication

A

Where replication begins; short stretches of DNA that have specific sequence of nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How is a parent DNA separated?

A

Protein locate the specific sequence of the origins of replication and form bubbles which expand as daughter strands are synthesized from both directions of the strand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Replication fork

A

A Y-shaped region where the parental strands of DNA are being unwound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Helicase

A

Enzymes that untwist the double helix at the replication forks, separating the two parental strands and making them available as template strands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Single-strand binding proteins

A

Bind to the unpaired DNA strands, keeping them from re-pairing (stabilizing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Topoisomerase

A

Enzyme that helps relieve the strain of tighter twisting ahead of the replication fork. Done by breaking, swiveling and rejoining DNA strands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

RNA

A

The initial nucleotide chain that is produced during DNA synthesis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Primer

A

Initial RNA chain synthesized by a primase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Primase

A

Synthesizes an RNA primer at 5’ end of leading strand and at 5’ end of each Okazaki fragment of lagging strand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

How many nucleotides does a primer cover at a time?

A

5-10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

A new DNA strand will start from the ____ end of the RNA primer

A

3’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

DNA polymerase

A

Catalyze the synthesis of new DNA by adding nucleotides to the 3’ end of a preexisting chain

Attach incoming nucleotides and takes everything but pyrophosphate (two phosphates)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

How many DNA polymerases are discovered so far?

A

11, (but I and III are most important)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

DNA polymerase III

A

Adds a DNA nucleotide to the RNA primer and then continues adding DNA nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

DNA polymerase I

A

Removes RNA nucleotides of primer from 5’ end and replaces them with DNA nucleotides added to 3’ end of adjacent fragment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

DNA polymerase can only add nucleotides to the free ____ end of a primer or growing DNA stand

A

3’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Leading strand

A

DNA pol III remains at the replication fork and continues to the end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Lagging strand

A

When DNA pol III must work along the other template strand in the direction away from the replication fork

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Okazaki fragments

A

Series of fragments synthesized on the lagging strand
Okazaki fragments includes the primer until it is removed (by polymerase I) and replaced (by ligase) with DNA and brought together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

DNA Ligase

A

Joins the backbones of all the Okazaki fragments into a continuous DNA strand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Are hydrogen bonds or covalent weaker

A

hydrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

The overall negative charge of DNA means

A

It can only move in certain directions (and not across the membrane)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

RNA vs. DNA

A

RNA:
- Single stranded
- Uracil - A
- Wide purpose: DNA replication, translation, and transcription
- Ribose
- ATP is used

DNA:
- Double stranded
- Thymine - A
- Genetic information and regulation
- Deoxyribose
- dATP is used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

DNA replication quick facts

A
  • 17-18 different enzymes
  • Speedy and accurate
  • More known how its done in bacteria than eukaryote
  • Most of the process between prokaryotes and eukaryotes is similar
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What happens when a DNA polymerase finds an error when comparing the nucleotide to the template?

A

It removes the nucleotide and then resumes synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Mismatch pair

A

Evades the DNA polymerase proofread, and other enzymes remove and replace incorrect pair nucleotides resulted from replicatio errors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Describe how DNA damage after replication is fixed before they become mutation

A

They are corrected by about 170 DNA repair enzymes in humans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Nuclease

A

DNA cutting enzyme that cuts out damaged DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

After a nuclease cuts out damaged DNA, what fills it back in?

A

DNA polymerase and DNA ligase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Nucleotide excision repair

A

Enzymes detect damaged DNA, nuclease cuts the segment out, DNA polymerase fills in the missing nucleotide, and DNA ligase seals the free end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Thymine dimers

A

After covalently linking thymine bases that are adjacent on a DNA strand, causing the DNA to bycle ajd interfere with replication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Mutation

A

A permanent change in the DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Why does linear DNA becomes shorter and shorter?

A

Usual replication cannot complete the 5’ ends of daughter DNA strands. Most prokaryotes have circular DNA though

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Telomeres

A

Do not contain genes and located on the ends of eukaryotics chromosomal DNA molecules. Prevent shortening of linear DNA. Hold a crap ton of short nucleotide sequences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Two functions of telomeres

A
  1. Specific proteins in telomeric DNA prevent staggering ends of the daughter molecule from activating the cell’s system for monitoring DNA damage
  2. Acts as buffer zone that provides some protection against the organism’s genes shortening.

They don’t prevent erosion of genes at the ends, but postpone it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Shortening of telomeres contributes to

A

The aging of an organism overall and prevention of cancer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Telomerase

A

Catalyzes the lengthening of telomeres, restoring their original length.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

In a bacterium, the DNA is “supercoiled” and found in a region of the cell called
the

A

nucleoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Chromatin

A

A complex of DNA and protein, is found in the nucleus of eukaryotic
cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Heterochromatin vs. Euchromatin

A

Heterochromatins dense nature makes it largely inaccessible
to the machinery responsible for transcribing genetic information

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Heterochromatin

A

Irregular clumps of highly condensed chromatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Euchromatin

A

Less compacted, more dispersed chromatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

Gene expression

A

The process by which DNA directs the synthesis of proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

The one gene-one polypeptide rule is not entirely true. Why?

A
  1. Alternative splicing
  2. A few genes code for RNA molecules that have important functions in cells even though they are never translated into protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

Two stages of DNA expression

A

Transcription and Translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

Unique to RNA than DNA

A

Contains ribose instead of deoxyribose
Uracil instead of thymine
RNA molecule consists of a single strand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

Transcription

A

The synthesis of RNA using information in the DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

Molecules involved in transcription

A

messenger RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

Messenger RNA (mRNA)

A

carries a genetic message from the DNA to the protein-synthesizing machinery of the cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

Translation

A

The synthesis of a polypeptide using the information in the mRNA. mRNA nucleotide sequences are translated into amino acid sequences of a polypeptide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

Molecules involved in Translation

A

Transfer RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Location of translation

A

Ribosomes (help orderly linking of amino acids into polypeptide chains)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Difference in bacterial and eukaryote transcription and translation

A

Bacteria do not have nuclei, so nuclear membranes do not separate bacterial DNA and mRNA from ribosomes and the other protein synthesizing equipment.

So what? Lack of compartmentalization allows for translation to occur even when transcription is happening

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

Transfer RNA

A

Translates a series of codons along an mRNA molecule

Transfer an amino acid from the cytoplasmic pool of amino acids to a growing polypeptide in a ribosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

Transcription occurs in the

A

nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

mRNA must be transported from the ______ to the _______ for ______

A

nucleus, cytoplasm, translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Pre-mRNA

A

The initial version of mRNA that contains the primary transcript

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

Central Dogma

A

cells are governed by a cellular
chain of command
DNA -> RNA -> Protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

How many nucleotide bases and amino acids are there?

A

4 bases, 20 amino acids

90
Q

Why are enzymes translated from triplets of nucleotides?

A

It’s the smallest unit of uniform length that can code for all amino acids (20)
1: only 4
2: only 16
3: 64

91
Q

Triplet Code

A

The genetic instructions for a polypeptide chain are written in the DNA as a series of nonoverlapping, three nucleotide words in mRNA, which is then translated into a chain of amino acids

92
Q

Which strand does mRNA transcript?

A

Template strand. (3’ -> 5’)

it synthesizes an antiparellel strand

93
Q

Transcribe the following template strand

3’ACCAAACCGAGT5’

A

5’UGGUUUGGCUCA3’

94
Q

tRNA contains…

A
  • an amino acid at one end and at the other end has a
    nucleotide triplet that can base-pair with the complementary codon on
    mRNA

-a single RNA strand that is only about 80
nucleotides long

  • tRNA molecules can base-pair with themselves
95
Q

Codons

A

mRNA nucleotide triplets

96
Q

Anticodon

A

base pairs with an mRNA codon

97
Q

Coding Strand

A

The nontemplate DNA strand

98
Q

How many amino acids in a polypeptide will 300 nucleotide bases make?

A

100 amino acids

99
Q

_____ of the 64 codons code amino acids

A

61
The other three are termination codons

100
Q

Two functions of codon AUG

A
  1. Codes the amino acid methionine (Met)
  2. Functions as an initiation codon
101
Q

Stop (nonsense) Codons

A

UAA, UAG, UGA

102
Q

Polypeptide chains start with the _________ amino acid but _______

A

Methionine, but an enzyme may remove this starter amino acid later

103
Q

RNA polymerase

A

Pries the two strands of DNA apart and joins together RNA nucleotides complementary to the DNA template strand, thus elongating the RNA polynucleotide

104
Q

Promoter

A

The DNA sequence where RNA polymerase attaches and initiates transcription

105
Q

Terminator

A

In bacteria, the sequence that signals the end of transcription

106
Q

Direction of transcription

A

Downstream

107
Q

The promoter sequence in DNA is said to be _______ from the terminator

A

Upstream

108
Q

Transcription Unit

A

The stretch of DNA downstream from the promotor that is transcribed into an RNA molecule

109
Q

Bacteria vs Eukaryote RNA polymerase

A

Bacteria:
One type
Synthesizes mRNA and other types of RNA for protein synthesis (ex. Ribosomal RNA)

Eukaryotes:
Three Types
RNA polymerase II: used for pre-mRNA synthesis
Other two transcribe RNA molecules that are not translated into a protein

110
Q

Three stages of transcription and translation (both each)

A

Initiation, elongation, termination

111
Q

Start point

A

The nucleotide where RNA polymerase actually begins synthesis of mRNA

112
Q

Initiation

A

After RNA polymerase binds to the promoter, the DNA strands unwinds, and the polymerase initiates RNA synthesis at the start point on the template strand

113
Q

Elongation

A

The polymerase moves downstream, unwinding the DNA and elongating the RNA transcript 5’->3’

114
Q

Termination

A

Eventually the RNA transcript is released and the polymerase detaches from the DNA

115
Q

Transcription Factors

A

Mediate the binding of RNA polymerase and the initiation of transcription

116
Q

Transcription Initiation Complex

A

Transcription factors and RNA polymerase II bound to the promoter

Assembles on the promoter sequence at the upstream end of the gene

117
Q

TATA box

A

(TATAAA) A commonly included nucleotide sequence in eukaryotic promoters about 25 nucleotides upstream from the transcriptional starting point

118
Q

Example of the importance of protein-protein interaction in controlling eukaryotic transcription

A

Interaction between eukaryotic RNA polymerase II and transcription factors

119
Q

Transcription progresses at a rate of about 20 nucleotides per second in eukaryotes (TRUE or FALSE?)

A

FALSE; 40 nucleotides per second

120
Q

How bacteria terminates transcription

A

Transcription proceeds through a terminator sequence in the DNA

121
Q

How eukaryotes terminate transcription

A

RNA polymerase II transcribes a sequence on the DNA called the polyadenylation signal sequence which specifies a signal AAUAA in the pre-mRNA. Once detected it binds with certain proteins in the nucleus. 10-35 nucleotides downstream these proteins cut the RNA transcript free, releasing the pre-mRNA

122
Q

RNA processing

A

Both ends of the primary transcript are altered
5’ end first receives a 5’ cap x
3’ end receives a poly-A tail

123
Q

5’ Cap

A

A modified form of a guanine nucleotide added onto the 5’ end of pre-mRNA after transcription of the first 20-40 nucleotides

124
Q

poly-A tail

A

50-250 adenine nucleotides added onto the 3’ end of the pre-mRNA

125
Q

Functions of 5’ cap and poly-A tail

A
  1. Facilitate the export of the mature mRNA from the nucleus
  2. Protect the mRNA from degradation by hydrolytic enzymes
  3. Help ribosomes attach to the 5’ end of the mRNA once the mRNA reaches the cytoplasm
126
Q

Untranslated Regions (UTR)

A

Parts of the mRNA that will not be translated into protein, but have other functions, such as ribosome binding

127
Q

RNA splicing

A

Large portions of the pre-mRNA molecules are removed and the remaining portions are reconnected

128
Q

Introns

A

“Intruder”
The noncoding segments of nucleic acid that lie between coding regions

129
Q

Exons

A

“Expressed”
Translated into amino acid sequences

130
Q

Spliceosome

A

Large complex made of proteins and small RNAs that removes introns

131
Q

Ribozymes

A

RNA molecules that function as enzymes

ex. the RNA molecules in spliceosomes

132
Q

Introns can catalyze their own splicing (True or false)

A

True

133
Q

RNA splicing can occur without proteins, or even additional RNA
molecules (True or False)

A

True

134
Q

Alternative RNA splicing

A

Many genes are known to give rise to two or more different polypeptides depending on which segments are treated as exons during RNA processing

135
Q

Domains

A

Discrete structural and functional regions

136
Q

Two steps of accurate translation

A
  1. a correct match
    between a tRNA and an
    amino acid, done by the
    enzyme aminoacyl-tRNA
    synthetase
  2. a correct match
    between the tRNA anticodon
    and an mRNA codon
137
Q

Wobble

A

Flexible pairing at the third base
of a codon
- allows some tRNAs to bind to
more than one codon

138
Q

The two parts of the ribosome

A

Small and Large subunit

139
Q

rRNAs

A

Ribosomal RNAs

140
Q

Parts of the Small and Large Subunit of the ribosome

A

Small: mRNA binding site

Large: A site, P site, E site
A and P are tRNA binding sites, E is the exit

141
Q

Three stages of Translation

A
  1. Ribosome Association and Initiation of Translation
  2. Elongation of the Polypeptide Chain
  3. Termination of Translation
142
Q

Ribosome Association and Initiation of Translation

A

The initiation stage of translation brings together mRNA, a tRNA with the first amino acid, and the two
ribosomal subunits. A small ribosomal subunit binds with mRNA and a special initiator tRNA. Then the
small subunit moves along the mRNA until it reaches the start codon (AUG).

143
Q

Elongation of the Polypeptide Chain

A

During elongation, amino acids are added one by one to the previous amino acid at the
C-terminus of the growing chain

144
Q

Steps involving elongation factors

A
  1. Codon recognition
  2. Peptide bond formation
  3. Translocation
145
Q

Termination of translation

A
  1. Ribosome reaches a stop codon on mRNA
  2. Release factor promotes hydrolysis
  3. Ribosomal subunits and other components disassociate
146
Q

Two types of ribosomes in the cell and their function in producing proteins

A
  1. Free ribosomes: mostly synthesize proteins that function in the cytosol
  2. Bound ribosomes: make proteins of the endomembrane system and proteins that are
    secreted from the cell
147
Q

Polypeptide synthesis always begins in the

A

cytosol

148
Q

Synthesis finishes in the cytosol unless

A

the polypeptide signals the ribosome to attach to the ER

149
Q

signal peptide

A

Marking that indicates polypeptides destined for the ER or for secretion

150
Q

Exon shuffling

A

Introns increase the probability of crossing over between the exons of alleles of a gene

151
Q

The sequence of DNA nucleotides that codes for a eukaryotic polypeptide is usually not continuous but __________

A

split into segments

152
Q

Two ways metabolic pathways can be controlled

A
  1. adjust the activity of enzymes already present
  2. Adjust the production level of certain enzymes
153
Q

Operator

A

The on-off switch segment of DNA
Positioned within its promoter

Controls the access of RNA polymerase to the genes

154
Q

Operon

A

The operator, promoter, and the genes they control

155
Q

Trp operon

A

tryptophan (in e. coli)

156
Q

Repressor

A

Bonds to the operator and blocks attachment of RNA polymerase to the promoter, preventing transcription of the genes

157
Q

What is a repressor protein encoded by?

A

A regulatory gene

158
Q

Why are operons not switched off permanently when there are repressors?

A
  1. The binding of repressors to operators is reversible
  2. The repressor is an allosteric protein with two alternative shapes, active and inactive (it changes into active when it bonds)
159
Q

Corepressor

A

A small molecule that cooperates with a repressor protein to switch an operon off.

160
Q

Repressible operon

A

Transcription is usually on but can be inhibited

161
Q

Example of repressible operon

A

trp operon

162
Q

Inducible operon

A

Usually off but can be stimulated to be on when a specific small molecule interacts with a different regulatory protein

163
Q

Example of an inducible operon

A

lac operon

164
Q

Gene that catalyzes lactose metabolism

A

lacZ

165
Q

lacl

A

Regulatory gene located outside the lac operon, and codes for an allosteric repressor protein that can switch off the lac operon by binding to the lac operator

166
Q

Biggest difference between lac and trp operon

A

trp repressor protein is inactive by itself and requires tryptophan as a corepressor in order to bind to the operator

the lac repressor is active by itself, binding to the operator and switching the lac operon off

167
Q

Inducer

A

A specific small molecule that inactivates the repressor

168
Q

Inducer for lac operon

A

allolactose

169
Q

Inducible enzymes

A

Generally function in catabolic pathways, where synthesis is induced by a chemical signal

170
Q

Repressible enzymes

A

Generally function in anabolic pathways, which synthesize essential end products from raw materials

171
Q

Negative control of genes

A

operons are switched off by the active form of their respective repressor protein
(both trp and lac)

172
Q

Positive control of genes

A

A regulatory protein interacts directly with the genome to switch transcription on

173
Q

When glucose and lactose are both present in its environment…

A

E. Coli prefers to use glucose

174
Q

How does the E. Coli sense the glucose concentration and relay the information to the lac operon?

A

When cAMP binds to a cAMP receptor protein, the protein takes an active shape and can attach to the specific site at the upstream end of the lac promoter. Read the rest on page 367

175
Q

cAMP receptor protein (CRP)

A

An activator: A protein that binds to to DNA and stimulates transcription of a gene

176
Q

If the amount of glucose in the cell increases…

A

The cAMP concentration falls

177
Q

A typical human cell might express about

A

20% of its protein coding genes at any given time

178
Q

Differential gene expression

A

The expression of different genes by cells with the same genome

179
Q

DNA methylation

A

(Occurs in most plants, animals, and fungi)

Enzymes methylate DNA on certain bases, where it is passed down to daughter cells, causing genomic imprinting

180
Q

DNA methylation usually occurs on the base

A

Cytosine

181
Q

Epigenetic Inheritance

A

Inheritance of traits transmitted by mechanisms not involving the nucleotide sequence itself

Changes in the cell can be passed down to subsequent generations

182
Q

DNA methylation are permanent changes (True of False)

A

False, they are not changes to the DNA itself, but the chromatin

183
Q

Control elements

A

Segments of noncoding DNA that serve as binding sites for the protein called transcription factors, which bind to the control elements and regulate transcription

184
Q

Two types of transcription factors

A

General transcription factors, specific transcription factors

185
Q

General Transcription Factors

A

Act at the promoter of all genes

186
Q

Specific Transcription Factors

A

Bind to control elements that may be close to or farther away from the promoter

187
Q

Proximal control elements

A

Located close to the promoter

188
Q

Enhancers

A

Distal control elements
Thousands of nucleotides upstream or downstream of a gene or even within an intron

189
Q

Two types of structural domains that are commonly found in a large number of activator proteins

A
  1. DNA-binding domain
  2. Activation domains
190
Q

DNA binding proteins

A

A part of the protein’s three dimensional structure that binds to DNA

191
Q

Activation Domains

A

Bind other regulatory proteins or components of the transcription machinery, facilitating a series of protein-protein interactions that result in enhanced transcription of a given gene

192
Q

Transcription produces

A

mRNA

193
Q

Difference between eukaryote and Prokaryote gene expression

A

In eukaryotes, transcription is done in the nuclear envelope

194
Q

Reading frame

A

Correct grouping of nucleotides in order for specified polypeptide production

195
Q

RNA polymerases need a primer (true or false)

A

False

196
Q

Point mutations

A

chemical changes in just one or a few nucleotide pairs of a gene (in the DNA!)
ex.
- Nucleotide-pair substitutions
- One or more nucleotide-pair insertions or deletions

197
Q

nucleotide-pair substitution

A

replaces one nucleotide and its partner with another pair
of nucleotides

198
Q

Silent mutations

A

have no effect on the amino acid produced by a codon because of
redundancy in the genetic code

199
Q

Missense mutations

A

code for an amino acid, but not the correct amino acid

200
Q

Nonsense mutations

A

change an amino acid codon into a stop codon, nearly always
leading to a nonfunctional protein

201
Q

Mutagens

A

physical or chemical agents that can cause mutations

Spontaneous and induced
ex.
Spont: strand slippage
Induced: smoking

202
Q

What brings unity and diversity in genetic code?

A

Unity: all living things have DNA with nucleotides
Diversity: The sequences (code for amino acids which fold into a polypeptide) are different

203
Q

Main difference in eukaryote and prokaryote gene expression

A

Eukaryotes go through RNA processing

204
Q

These three mutations cause the other three

A

Point Mutations (substitution, insertion, deletion) cause a nonsense, silent or missense mutation

205
Q

Frame Shift Mutation

A

An insertion or deletion that alters the reading frame of the DNA

206
Q

What will a frame shift mutation lead to?

A

A long chain of missense mutations

207
Q

When glucose levels are scare

A

CAP (catabolite activator protein) acts as an activator of transcription

208
Q

CAP is activated by

A

binding with cyclic AMP (cAMP)

209
Q

Examples of noncoding RNAs

A

MicroRNAs
SiRNAs
Piwi-associated RNA

210
Q

MicroRNAs

A

small single-stranded RNA molecules that
can bind to complementary mRNA sequences. These can degrade the
mRNA or block its translation

211
Q

SiRNAs

A

Inhibits gene expression through a phenomenon called RNA interference

212
Q

Piwi-associated RNAs

A

induce formation of
heterochromatin

213
Q

How does recombinant DNA Technology work?

A

The plasmid of one bacterium is extracted, a gene of interest is extracted from a cell and put into the plasmid, and its all placed back into the bacterium

214
Q

What is the biggest outcome of recombinant DNA?

A

You can get a bunch of copies of the gene and a bunch of copies of the proteins it makes

215
Q

Plasmid technology

A
216
Q

Restriction Enzymes

A

Don’t really restrict, but cut DNA out at certain restriction sites. If the enzyme sees a palindrome, it will cut it to make “sticky ends”. The safely cut places can have new DNA inserted into it!

217
Q

Cloning Vector

A

DNA molecule that can carry foreign DNA into a host cell and replicate

218
Q

Conjugation

A

When two viruses send genes to each other if one needs a copy. ex. for resilience

219
Q

How do viruses infect?

A

Enters cell, injects DNA
DNA replicates
DNA, makes mRNA, makes protein coats
self assembly,
leaves cell

220
Q

Genomic Library

A

A bunch of copies of a certain plasmid, or phage

221
Q

cDNA

A

Reverse transcription
makes DNA out of mRNA

asd senior year (49 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions