Genetics Chapter 7 + 8 Test Flashcards
1
Q
What are the ends of linear chromosomes called? Why are bits of the ends lost with each cycle?
A
Telomeres, bits are lost bc do not replicate as easy the middle of cells
2
Q
Lengths of telomeres decrease as we age. The effects of aging within cells is known as _______.
A
senescence
3
Q
What is central dogma?
A
Central dogma describes how information flows in a cell.
4
Q
The first step of information flow is transcription. What is transcription?
A
Process of copying gene (DNA) into a short mRNA sequence
5
Q
What is the main enzyme involved in transcription? This enzyme uses single-stranded DNA to synthesize a complementary strand of ________.
A
RNA polymerase. Complementary strand of RNA
6
Q
RNA polymerase reads DNA in the ____ to ____ direction. But, it builds an RNA strand in the _____ to _____ direction, adding each new nucleotide to the _____ end of the strand.
A
3’ to 5’ . It builds RNA 5’ to 3’, new nucleotides added to the 3’ end
7
Q
Since only one strand of DNA can be transcribed, choose the one that starts w __ ______ (hint: its a number and 3 letters)
A
3’ TAC
8
Q
mRNA is the intermediary between ____ and ________. From ribosomes, it is translated into _________.
A
DNA, ribosomes, protein
9
Q
Translation is responsible for building a protein’s _______ structure. It assembles _____ _____ using the nucleotide sequence of _____.
A
primary, amino acids, mRNA
10
Q
Every three nucleotides is called a _____. The codon chart is specific to ______.
A
codon, mRNA
11
Q
What region does RNA polymerase bind to on DNA?
A
Promoter region
12
Q
How do DNA and RNA compare location wise?
A
DNA: nucleus RNA: nucleus and cytosol
13
Q
The promoter region is high in the bases adenine and thymine.
A
Adenine and thymine only have two H bonds.
14
Q
What does RNA polymerase do?
A
It unwinds and unzips DNA and transcription begins
15
Q
The start of the bases on DNA is 3’ TAC. Therefore, the first 3 bases of RNA are __ _____.
A
5’ AUG
16
Q
The product of transcription is always ________ RNA. It is ______ length to a gene.
A
immature, equal
17
Q
Immature RNA (aka _______) will undergo which two modifications?
A
- Splicing
- Addition of a cap and tail
18
Q
What is splicing of pre-mRNA? What are the regions that are removed called? The regions that stay?
A
Splicing is when regions of the pre-mRNA are cut out. The regions that stay are called exons, those that stay are called introns.
19
Q
An active __________ forms when the enzymes _______ bind to an intron and loop it out.
A
splicesome, SnRNPs
20
Q
When two _______ are spliced together to form mRNA, the cleaved ______ and _______ are released.
A
exons, introns, snRNPs
21
Q
mRNA can be spliced in many different ways. This is known as ____________ ________.
A
alternative splicing
22
Q
After splicing, a ______ and ______ are added to mRNA
A
cap and tail
23
Q
A cap contains 7 ________ nucleotides and is added to the ____ end. It aids in the bonding to a _______ and gives mRNA ________.
A
guanine, 5, ribosome, direction
24
Q
A tail is added to the ____ end of mRNA. It consists of approximately _____ adenine nucleotides, known as a Poly A Tail.
A
3 end, 200
25
Both the cap and tail extend the life of mRNA is the cytosol. Why?
The pre-mRNA needs to last long enough to be translated by the ribosomes before it is recycled.
26
The translation of a new mature mRNA into a protein is accomplished by a \_\_\_\_\_\_\_\_\_. It is a _____ and protein hybrid, and composed of 2 subunits. What are they known as?
ribosome, RNA
27
Ribosomes bind to the RNA _________ initiation sequence and build a new _________ in the ___ to ___ direction.
translation, polypeptide, 5' to 3'
28
The first amino acid on the polypeptide chain has a free amino group, it is called the ____ terminal. The last amino acid has a free acid group, it is called the ____ terminal.
N terminal, C terminal,
29
Transfer RNA is the adaptor between the three bases of ______ and its corresponding ______ \_\_\_\_\_.
codon, amino acid
30
tRNAs are only 70 to ____ base pairs long and have a signature _______ pattern.
90, cloverleaf
31
Each tRNA has 3 bases that make up its \_\_\_\_\_\_. These bases pair w the three bases of codon on the mRNA sequence during _________ (translation/transcription)
anticodon, translation
32
Each tRNA has an amino acid attached to its ___ end. The aminoacyl RNA _________ are used to charge the tRNA w the proper ______ acid.
3', synthetases, amino
33
The third base of an anticodon is called the ________ position. What does it do?
wobble position, it forms base pairs w several different nucleotides
34
In eukaryotes, ribosomes bind to the 5' cap, then move down the mRNA until they reach the first ______ (three letter codon)
AUG
35
A ribosome has two sites for tRNAs, called ____ and \_\_\_\_. The initial tRNA with attached amino acid enters at the ____ site.
P and A, P is the first
36
Corresponding to the next codon that makes up mRNA, a new tRNA enters SECOND at the ____ site.
A
37
What catalyzes the transfer of the amino acid from the A to the P site? What kind of bond is formed?
A ribosome! Polypeptide bond is formed
38
The tRNA at which site holds the polypeptide chain? New tRNA binds to which site?
P holds the polypeptide chain. New tRNA binds to the A site.
39
\_\_\_\_\_\_\_\_\_\_\_ is when a ribosome reaches a _____ codon. No more tRNA binds, instead proteins called ________ \_\_\_\_\_\_\_ bind and the polypeptide chain is completed. What still continues past the stop codon?
Termination, stop, release factors, mRNA
40
What does rRNA stand for? What does it do?
ribosomal RNA, binds with proteins to form ribosomes
41
What is an operon?
A cluster or series of related genes
42
What is the lac operon? What is it responsible for?
Cluster of genes responsible for the metabolism (breakdown) of lactose
43
Operons have a promoter and an operator region. What is the function of each?
Promoters PROMOTE transcription
Operators BLOCK transcription
43
Operons have a promoter and an operator region. What is the function of each?
Promoters PROMOTE transcription
Operators BLOCK transcription
44
What happens at the promoter region?
RNA polymerase binds and transcribes the operon
45
What happens at the operator region?
Repressor and maybe a co-repressor binds and blocks transcription
46
When is the Lac operon gene is "on"?
It turns on when lactase is present in the cell. Some lactase binds to the lac repressor
47
When the Lac operon turn "off"?
When lactase is not present in the cell (no metabolism needs to happen). Lac repressor binds to the operator, blocking transcription.
48
3 _______ required for this reaction are coded for by which 3 genes?
enzymes, 3 genes are Lac Z, Lac Y and Lac A
49
What does the trp operon do? How many genes code for the 5 enzymes needed to regulate this reaction? What are they?
Makes the amino acid tryptophan. 5 genes are needed to code for the 5 enzymes. They are Trp A-E
50
When is the Trp operon turned on? When is it turned on?
Trp turned on when tryptophan is absent in the cell, and turned off when trp is present
51
When lactase is present, some of it binds to the \_\_\_\_\_\_\_\_\_\_, (acts as an \_\_\_\_\_\_\_\_\_). It does not bind to the operator. ____ \_\_\_\_\_\_\_\_\_ binds to the promoter, allowing transcription to happen.
represser, inducer, RNA polymerase
52
Unlike lac, when RNA polymerase binds to the promoter in the trp operon, the repressor is automatically \_\_\_\_\_\_\_\_. It does not need an \_\_\_\_\_\_\_\_.
Inactive, inducer
53
To stop making trp, what needs to bind to the inactive trp represser to make it active?
A tryptophan corepressor
54
What is genetic engineering?
The science of altering/ cloning genes to make a new trait or biological substance. It involves removing the gene of one organism and placing it into another
55
Restriction enzymes are found in \_\_\_\_\_\_\_\_. They cut ______ DNA into smaller pieces.
bacteria, viral
56
Restriction enzymes _____ at specific locations. They cut at __________ sequences.
cut, palindromic
57
Restriction enzymes cut up viral DNA. Why isn't bacterial DNA also cut up?
It is methylated (contains methyl groups, CH3)
58
Restriction enzymes are named for the organism from which they were first isolated. Ex. ______ is isolated from E. coli strain RY13. Eco is the _______ and ______ is the species. R is the the strain. 1 means it was the first \_\_\_\_\_\_.
EcoR1, genus, coli, enzyme
59
Restriction _____ are also known as palindromic sequences. They posses two-fold ________ symmetry (same forward and back)
site, rotational
60
DNA digestion (also known as DNA \_\_\_\_\_\_\_\_\_) is done with a series of restriction \_\_\_\_\_\_\_\_. DNA fragments are separated by ______ during ____ \_\_\_\_\_\_\_\_\_\_\_\_\_\_.
fragmentation, enzymes, size, gel electrophoresis
61
What does endonuclease cleavage do to a piece of DNA?
Cuts a polynucleotide chain by separating nucleotides other than the two end ones.
62
What are restriction maps used for?
To characterize and unknown DNA
63
All bacteria have ___ chromosome. It is circular and made up of approx ____ million base pairs and _____ genes.
1, 4 million base pairs, 1000 genes
64
A plasmid is a small piece of DNA in the shape of a \_\_\_\_\_\_, found in SOME bacteria. Usually, plasmid genes produce genes that give the bacteria _______ to an antibiotic.
circle, immunity
65
for ex, the amp'r gene gives immunity to the antibiotic \_\_\_\_\_\_\_
the tet'r gene gives bacteria immunity to the antibiotic \_\_\_\_\_\_\_\_.
ampicilin, tetracyline
66
Gel ___________ is a tool for plasmid mapping.
1. Restric enzymes cleave _______ into smaller fragments
2. DNA segments are located into ____ of the gel at the _______ end. The gel floats in a _______ solution.
3. When an electric current is passed through the gel, segments move toward the _______ charged cathode.
4. ______ DNA move faster than large.
electrophoresis,
1. DNA
2. wells, negative, buffer
3. positively
4. smaller
67
To have matching ______ ends, a bacterial plasmid and piece of _____ must have been cut with the same _________ enzyme. The _______ and DNA are joined by DNA _____ and inserted into a bacteria. The structure is called a _________ \_\_\_\_\_\_\_.
sticky, DNA, restriction, plasmid, ligase, recombinant plasmid
68
Bacteria take up a __________ plasmid by means of a ______ shock. We cannot see the plasmid, so how do we know which bacteria were transformed and which were not?
recombinant, heat. Place ALL bacteria into a petri dish with agar gel and ampicillin. Ampicillin kills the non-resistant bacteria.
69
What gene allows the plasmid to survive antibiotics? Each surviving bacterium gives rise to a group of new bacteria, all with the same \_\_\_\_\_\_\_\_. What is this called?
The antibiotic resistance gene. plasmid, colony
70
Once a colony with the correct plasmid has been found, we can give them a ________ signal to make a target \_\_\_\_\_\_. Churning out large amounts of protein, they are similar to \_\_\_\_\_\_\_.
chemical, protein, mini factories
71
Once the protein is produced, bacterial cells can be ______ open to _______ it. Since the cell has other contents, we must ______ the protein using _________ techniques.
split, release, purify, biochemical
72
What are the two types of immune genes? What are they immune to?
amp^r gene: immune to the antibiotic ampicillin
tet^r gene: immune to the antibiotic tetracycline
73
What does PCR stand for? It is an automated process developed by Kerry Mullis that does what?
PCR: Polymerase Chain Reaction
Purpose: amplify or clone DNA
74
What are 3 applications of PCR?
1. Amplify small amount of DNA at crime scene, to create a DNA "finger print"
2. Parental testing
3. Cancer gene research
75
What are the 4 materials required for PCR?
1. DNA sample
2. Free nucleotides (A,C,T,G)
3. DNA primers (short, single-strand DNA)
4. TAQ polymerase (used to cool DNA to prevent denaturation)
76
Explain the 3 main steps of PCR
1. \_\_\_\_\_\_\_\_\_\_\_: Heat DNA fragment to 94C and denature into _______ strands.
2. \_\_\_\_\_\_\_\_\_\_\_: Cool the mixture to 50-65 C to ______ to ______ to the ends of their complementary strands. TAQ synthesizes the new strand
3. \_\_\_\_\_\_\_\_\_\_: Heat to 72 for DNA _______ to extend primers using free-floating nucleotides
1. **Denaturation**: Heat DNA fragment to 94C and denature into **single** strands.
2. **Annealing:** Cool the mixture to 50-65 C to **anneal** the **primers** to the ends of their complementary strands. TAQ synthesizes the new strand
3. **Elongation**: Heat to 72 for DNA **polymerase** to extend primers using free-floating nucleotides
77
What does VNTR stands for? How is it used to distinguish between individuals.
VNTR stands for **Variable Number of Tandem Repeat.** VNTR is a single strand of DNA where there is a tandem reset sequence. There are different numbers of repeats between individuals.
78
VNTR can be classified as mini or micro satellite. What is the difference?
mini: each repeat is 10 nucleotides
micro: each repeat is 2-5 nucleotides
79
VNTR does not undergo the two Ts. What are they?
They are not transcribed or translated
80
What does RFLP stand for? What is it used to create?
RFLP stands for “restriction fragment length polymorphism” it used to create a DNA fingerprint
81
Describe RFLP
1. DNA is fragmented by ________ enzymes
2. DNA fragments are separated by agarose gel \_\_\_\_\_\_\_\_\_\_
3. DNA fragments are denatured to single _____ using an ________ solution.
4. DNA is transferred to _______ paper by applying pressure.
5. ________ probe complementary to DNA attaches
6. Autoradiography exposes the film to form an _______ of the DNA
1. DNA is fragmented by restriction enzymes
2. DNA fragments are separated by agarose gel electrophoresis
3. DNA fragments are denatured to single strands using an alkaline solution.
4. DNA is transferred to nitrocellulose paper by applying pressure.
5. Radioactive probe complementary to DNA attaches
6. Autoradiography exposes the film to form an image of the DNA
82
Sanger DiDeoxy DNA Sequencing uses ____________ to stop replication.
Di-nucleotides
83
How do dideoxynucleotides stop DNA replication?
Dideooxynucleotides lack the C3-OH group required by DNA polymerase to add the next nucleotide
Phosphodiester bond cannot be made
84
If this DNA strand was placed in a test tube with 4 normal nucleotides and dideoxycytosine, how many fragments are produced?
TCGAAAAGAT
3 potential strands!
1. AGC
2. AGCTTTTC
3. ACFTTTTCTA (normal)
85
What is the difference between regular Sanger dideoxynucleotide sequencing and automated?
the products are labeled with flurosecnt dye rather than radioactive markers. it is excited by lasers. sequencing determined by a computer
86
what is sequencing?
the order of nucleotides
