Genetics Flashcards
(124 cards)
1
Q
T.H. Morgan 1908
A
Concluded genes are chromosomes.
2
Q
Frederick Griffith 1928
A
Worked with mice. Realized a transforming factor can change phenotype.
3
Q
Avery McCarthy and Macleod 1944
A
Purified DNA and proteins separately. Infected protien in bacteria had no effect but infected DNA did. So the transforming factor is DNA
4
Q
Who had first evidence that DNA was genetic material?
A
Avery McCarthy and Macleod
5
Q
Hershey and chase 1952
A
Worked with bacteriophage and put S35 in protien and P32 in DNA. Confirmed DNA is genetic material
6
Q
Chargaff 1947
A
Made rules. A=T
C=G.
7
Q
Watson and crick 1953
A
Developed double helix model of DNA
8
Q
Meselson and stahl 1958
A
Semi conservative replication
9
Q
Define central dogma
A
Flow of genetic material on cell
10
Q
Course of action of central dogma (protien synthesis order)
A
DNA replication is transcribed to RNA and translated to protien
11
Q
Purpose of DNA replication
A
Create a second copy of genetic material to be used in mitotic cell division
12
Q
Steps in DNA replication
A
Unwind the DNA molecule. Make new DNA strand. Rewind the DNA molecule
13
Q
Helicase
A
Splits H bonds between bases and unwinds them
14
Q
DNA polymerase 1
A
Digests rna primers and replaces them with DNA (lagging strand)
15
Q
DNA polymerase 3
A
Creates complimentary DNA strands in 5-3 direction. Adds dNTP’s to the 3’ end
16
Q
Ligase
A
Joins Okazaki fragments together
17
Q
How is the leading strand synthesized
A
Continuously in the 5’ to 3’ direction by DNA poly 3. Towards fork
18
Q
RNA primase
A
This enzymes adds NTP’s (rna primers) to be eaten up by DNA polymerase 1.
19
Q
Gyrase
A
Travels along DNA in front of fork relieving tension. Untangles DNA molecules before chromosomes can be replicated
20
Q
Okazaki fragments
A
This is what the lagging strand is made of. They are fragments between 1000 and 2000 nucleotides long. Grown in 5 to 3 direction away from the fork
21
Q
Leading strand
A
Grown continuously towards the replication fork in the 5 to 3 direction. DNA polymerase 3 is adding the dNTP’s
22
Q
Lagging strand
A
Replicating away from the replication fork in 5 to 3 direction. Grown discontinuously
23
Q
Purine
A
Class of bases that have a double ring structure ex guanine and and adenine
24
Q
Pyrimidine
A
Class of base with single ring structure. Thymine and cytosine are examples
25
Gel electrophoresis
Method of separating DNA using an electric field
26
How gel electrophoresis works
DNA is negative so it moves towards the positive end. Smaller pieces travel faster therefore go farther
27
What is gel electrophoresis used for?
Used in forensics and paternity testing
28
Using gel electrophoresis in forensics
Must be 13 enzymes that match the suspect to convict someone. Add enzymes to DNA and cuts in the same spots so we can match it
29
Polymerase chain reaction
Method for making many copies of specific segment of DNA
30
What do you need for pcr?
Template strand. Taq polymerase. dNTP's. Primer. And thermonuclear
31
What happens in pcr
Denature DNA at high temp then anneal to cool and hybridize primers and build the DNA
32
Taq polymerase
Used in pcr. It's it found in hot springs. And can stand the high heat without firing
33
Plasmid
Small circular section of DNA found in cytosol of bacteria. Replicates independently of chromosomal DNA
34
Vectors
DNA molecule used as a vehicle to transfer foreign genetic material into a cell
35
Why are vectors used?
It is put in a cell to use it to reproduce the substance multiple times bc it can reproduce without using the chromosomal DNA
36
Complementary base pairing
Chemical tendency of adenine to pair with thymine and cytosine to pair with guanine.
37
How many h bonds when a bonds with t
2
38
How many h bonds when c bonds with g?
3
39
Cell cenescence
Period in cells lifespan when it loses the ability to divide and grow. Referred to as cell aging
40
Hayflick limit
Total number of times a cell can divide
41
Telomerase
Enzyme that adds telomere sequences to the end of chromosomes
42
Roles of telomeres 4
1 help prevent chromosome ends from fusing to eachother. 2 percent DNA degradation from nucleases 3 help DNA repair and distinguishes between DNA breaks and chromosomal ends. 4 plays a role in knowing how many times a cell will divide.
43
Telomere
Repeated sequence of nucleotides
44
Why do we need telomeres
Bc DNA poly 1 can't replace the final rna primer on the stand and this would result in lost DNA but instead it breaks off the telomeres
45
How many times can a human cell divide
50 before hitting hayflick limit
46
Cells containing telomerase
Germ cells(gametes), stem cells, white blood cells and cancer cells
47
Cancer drugs are being developed to do what?
Inhibit binding site of telomerase. Or causes telomeres to fall offf the DNA
48
How many times is a telomere sequence repeated
500-5000 times
49
What does an operon consist of?
Structural genes. Promoter region. Operator region and regulatory gene. Y
50
Operans job
Save the cell energy and materials. Permit the cell to be responsive to its environment.
51
Lac operon
Cluster of genes that contains the DNA sequence to regulate the metabolism of lactose
52
Operator
Region in operon that regulatory factors bind to
53
Repressor protien
Protein that binds to operator to repress gene expression
54
Inducer
Signal molecule that triggers the expression of an operon gene
55
Corepressor
Signal molecule that binds to a regulatory protien to reduce the expression of an operon gene
56
Recombinant DNA technology
When DNA from two or more sources is combined to create a new DNA strand
57
Common uses of recombinant DNA
Make insulin in E. coli I
58
Sugar phosphate chains in DNA are..
Antiparallel strands
59
How are the sugars linked in DNA
Linked by phosphate groups attached to carbon 3 and 5 of the sugar.
60
Satellite DNA
5-300 base pairs long. Used in DNA profiling. Unclear of another purpose. No pattern. Different in everyone.
61
Spliceosome
Enzyme protien complex that removes introns from mRNA
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snRNP
Protien that binds to introns and signals them for removal
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Intron
Non coding sequence of DNA that is cut out using a spliceosome or else the mRNA would not make the protien correctly.
64
Exon
Sequence of DNA or RNA that codes for part of a gene. Important part
65
Poly(A) tail
Post transcriptional mod. Is a chain of 50-250 adenine molecules that are added to the 3' end of the pre-mRNA molecule to protect it from enzymes in cytosol.
66
5' cap
Post transcriptional mod. Sequence of 7 G's that is added to start of a pre-mRNA. Ribosomes recognize this and use it as a site of attachment
67
Alternative splicing
Process that produces different mRNa's from pre mRNA allowing more than one possible polypeptide to be made from a single gene
68
Pre m RNA
Initial rna transcription product. Has to be modified to mRNA strand. Then the mRNA exits the nucleus where ribosomes are found.
69
DNA transcribed in what direction
3'-5' polymerase adds nucleotides to 3' end of mRNA
70
Antisense
DNA template 3'-5' direction
71
mRNA is synthesized in what direction?
5'-3'
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tRNA
Similar to DNA on antisense. No T's. Just the base paring of it
73
Sense strand
Complimentary to antisense has same sequence of mRNA. Goes in 5'-3' direction. No real role
74
Reverse transcriptase
Viral enzyme that uses RNA as a template strand to synthesize complimentary DNA
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Retrovirus
Virus that uses reverse transcriptase for replication.
76
Example of retrovirus
HIV
77
How HIV works
HIV attaches to cell surface. Then virus enter cell using endocytosis. The viral DNA uses the enzyme and makes a double stranded DNA. Then it intergrates itself into the host DNA. Then Normal reproduction occurs and then the HIV leaves and it occurs again in a different cell
78
Transcription
First step in gene expression. When piece of DNA is copied into rna by rna polymerase.
79
Product of transcription in eukaryotes
Results in pre mRNA which must be modified to protect final mRNA from degradation and to remove introns.
80
Termination of transcription.
Nuclear proteins bind to polyuracil site and terminate transcription.
81
Elongation of transcription
Occurs slower than prokaryotes only 5-8 pairs per sec
82
Enzyme in transcription euk
Rna polymerase 2
83
Template strand
DNA strand copied into mRNA molecule during gene transcription
84
Promoter
Nucleotide sequence that lies just before a gene allows for the binding of rna polymerase
85
TATA box
Region of promoter that allows the binding of rna polymerase
86
Coding strand
DNA strand that isn't being copied but contains the same sequence as the new rna molecule
87
Transcription unit
Includes initiation wth a promoter, elongation then termination
88
Termination sequence
Sequence of bases at end of a gene that signals the rna polymerase to stop transcribing
89
Structure of atp
Three phosphates. Ribose. Adenine
90
Enzyme that carries the correct amino acid to tRNA
Aminoacyl tRNA synthetase. This places the correct amino acid onto the receptor arm of tRNA with the matching anticodon.
91
Role of gtp
In step 2. A gtp (like atp) is hydrolyzed to provide free energy for this step
92
Steps in translation
Initiation elongation and termination
93
Initiation steps
Small ribosomal sub unit binds to mRNA and scans until reaches start codon. Then large ribosomal sub unit binds on as well
94
Elongation
Binds to p site. Another tRNA and amino acid binds to a site and gtp gives off free e. Then bonds to tRNA in A site and P site becomes empty. Empty p exits and then the empty tRNA realeases from ribosomes
95
Termination
Occurs when A site arrives at stop codon.
96
Role of peptide love transferase
Enzyme that catalyze the forming of the bond with the amino acid on the tRNA in the A site
97
VNTRs
No coding repeating sequences of DNA that vary in length between individuals
98
Use of VNTR
Bio research forensics. DNA testing
99
LINE
Long interspersed nuclear elements. Repetitive DNA sequences approximately 6500 bp in length that are interspersed throughout the genome
100
SINE
Short interspersed nuclear elements. Repetitive DNA sequences about 500 bp in length and interspersed throughout genome.
101
Pseudogene
Sequence of DNA that is similar to an existing gene but does not code for proteins. Thought to be mutated versions of older genes
102
Restriction fragment
Fragment produced when a DNA strand is cut by a restriction enzyme.
103
Restriction enzyme
| Aka restriction endonuclease
Enzyme that cuts DNA at a specific location on a base sequence. Used in DNA fingerprinting
104
RFLP
Restriction fragment length polymorphism. When DNA sequence is cut up and th pieces are different in each person and can be used for DNA fingerprinting
105
Blunt end
Remains after restriction enzyme cut straight across a DNA strand. Hard to reconnect
106
Sticky end
Zigzag cut across DNA strand. Can form hydrogen bond easier and be reformed
107
Restriction endonuclease exising
Multiple enzymes will be put in with a DNA strand and it is cut in different places depending on if the receptor for the enzyme is there. Then used for DNA fingerprinting
108
RFLP
When DNA sequence is cut up and th pieces are different in each person and can be used for DNA fingerprinting
109
Blunt end
Remains after restriction enzyme cut straight across a DNA strand. Hard to reconnect
110
Sticky end
Zigzag cut across DNA strand. Can form hydrogen bond easier and be reformed
111
Restriction endonuclease exising
Multiple enzymes will be put in with a DNA strand and it is cut in different places depending on if the receptor for the enzyme is there. Then used for DNA fingerprinting
112
Induction of gene transcription
Activator binds to inducer and complex binds to activation sequence and activates target gene. When the inducer is removed it stops transcription
113
Transcriptional regulation
For a gene to be transcribed it needs to be partially unwound to expose promoter. In a type of regulation the promoter is exposed when an activator binds to a sequence that is upstream the promoter and signals for a remodelling.
114
Repression of gene transcription
A DNA binding repressor blocks the attachment of rna poly to promoter thus preventing transcription. Will also bind to mRNA and prevent translation to protien.
115
Point mutation
Change within a single nucleotide
116
Substitution
Sub of one base pair for another
117
Insertion
Addition of base pair (ss) or a large coding region (ls)
118
Deletion
Removal of base pair or large coding region
119
Inversion
2 adjacent base pairs trading places or reversal of a whole sequence
120
Missense
Mutation that changes a single amino acid in the coding region. Can be negative positive or have no effect
121
Nonsense
Mutation that results in pre mature stop codon
122
Silent mutation
Mutation that doesn't alter the resulting sequence of amino acids
123
Frameshift
Shift in reading frame resulting in multiple missense or nonsense effects
124
Translocation
Movement of entire genes or sequences of DNA from one chromosome to another
