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DNA Flashcards

(96 cards)

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1
Q

What did Watson and Crick do?

A

introduced an elegant double-helical model for the structure of deoxyribonucleic acid, or DNA

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2
Q

What did TH Morgan discover?

A

-genes are stored in chromosomes inside cell nuclei.
- the two components of chromosomes—DNA and protein—became candidates for the genetic material

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3
Q

What did Hershey and Chase discover?

A

concluded that DNA, not protein, was the genetic material

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4
Q

What did Rosalind Franklin discover?

A
  • discovery of the structure of DNA
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5
Q

Chargaff’s Rules

A
  • The base composition of DNA varies between species
  • In any species the number of A and T bases is equal and the number of G and C bases is equa
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6
Q

Why do purines always bond with pyrimidines?

A

the distance between them is good

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7
Q

Purine and Purine cannot bind because

A

they are too wide

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8
Q

Pyrimidine cannot bind to Pyrimidine because

A

they are too narrow

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9
Q

Why do adenine and cytosine not bind together?

A

because of different number of hydrogen bonds

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10
Q

How do bonds between G and C and A and T differ?

A

G and C is stronger as they have 3 bonds

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11
Q

Semiconservative Model

A

In this model, the two strands of DNA unwind from each other, and each acts as a template for synthesis of a new, complementary strand.

This results in two DNA molecules with one original strand and one new strand.

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12
Q

Helicase

A

an enzyme that unwinds and separates the two strands of the DNA double helix

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13
Q

Topiomerase

A

relieve the pressure during the uncoiling of DNA by breaking one back bone and bringing it back together

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14
Q

Primase

A

initiate the addition of new nitrogen-containing bases to the single-stranded DNA that was brought about by the actions of helicase

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15
Q

DNA polymerase

A

to add new nucleotides to the 3’ end of a growing chain.

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16
Q

Lagging Strand

A

The strand that opens in the 3’ to 5’ direction towards the replication fork

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17
Q

Okazai Fragment

A

the short lengths of DNA that are produced by the discontinuous replication of the lagging strand.

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18
Q

DNA ligase

A

oining of DNA strands together by catalyzing the formation of a phosphodiester bond.

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19
Q

RNA primer

A

tells DNA polymerase where to start

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20
Q

Transcription

A

Making an mRNA copy of DNA

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21
Q

What is the only time the cell cannot make new RNA?

A

Mitosis

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22
Q

Mismatch Repair

A

DNA polymerases proofread newly made DNA, replacing any incorrect nucleotides

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23
Q

nucleotide excision repair

A

a nuclease cuts out and replaces damaged stretches of DNA

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24
Q

Telomeres

A

special nucleotide sequences at ends that are eaten away and contribute to aging

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25
Telomerase
catalyzes the lengthening of telomeres in germ cells
26
Immortal Cell Line
cell that has active telomerase that can replace caps and be endlessly replicated
27
What is the organization from DNA to Chromsomes
1. DNA 2. Histone 3. Nucleosome 4.Chromatin 5. Chromosome small to thick
28
Heterochromatin
tightly packed chromatin that we cannot use
29
Euchromatin
loosley packed chromatin that we use
30
Nucleosome
basic unit of DNA packaging
31
Transformation
a process by which foreign genetic material is taken up by a cell
32
Transduction
moving dna from one cell to another using a virus
33
Conjugation
the process by which one bacterium transfers genetic material to another through direct contact
34
Translation
the synthesis of a polypeptide using information in mRNA
35
Rough ER
site of ribosomes making proteins
36
Where does transcription take place in humans and bacteria
nucleus and cytoplasm ; bacteria do not have a nucleus
37
Where does translation take place
ribosomes
38
Introns
a segment of a DNA or RNA molecule which does not code for proteins and interrupts the sequence of genes.
39
Exons
a segment of a DNA or RNA molecule containing information coding for a protein or peptide sequence.
40
How many amino acids?
20
41
Codons
three nucleotides that code for a single amino acid ; these are on mRNA
42
Relationship with codons and amino acid
codons can code for the same amino acid
43
start codon
AUG
44
stop codons
UAA, UGA, UAG
45
Frameshift Mutations
adding one or subtracting one codon
46
Initiation
occurs when the enzyme RNA polymerase binds to a region of a gene called the promoter. the mRNA strand enters the ribosome, allowing tRNA to attach at a region called the start codon.
47
Elongation
the stage when the RNA strand gets longer, thanks to the addition of new nucleotides.
48
TATA Box
indicates to RNA where promoter site is
49
Promoter Region
where the start point for RNA replication is ; binding point for rna polymerase
50
How fast is transcription
40 nucleotides per second
51
What three things does the nucleus need before snding off rnA
1 - 5' cap 2- poly a tail 3-introns
52
poly A tails
dictates how much RNA can be used
53
Splicisome
used to splice RNA
54
alternative splicing
a cellular process in which exons from the same gene are joined in different combinations, leading to different, but related, mRNA transcripts.
55
Transcription Unit
stretch of DNA that is transcribed
56
What does tRNA do chemically?
binds to an amino acid and contains anticodon segments
57
What does tRNA do functionally
the tRNA “reads” the mRNA and “translates” it into a sequence of amino acids.
58
Amincoacyl-tRNA-synthetase
enzyme matches tRNA and amino acid
59
Ribosomal RNA
makes up rna
60
Translation - process of building RNA in ribosome - has three stations. What are they?
A for attachment P for polypeptide elongation E- exit
61
Feedback Inhibition
regulatory mechanism in which the activity of the first enzyme in a metabolic pathway is inhibited by the end product of that pathway.
62
Operon
A functional unit of DNA containing a cluster of genes under the control of a single promoter, including the operator and promoter regions.
63
Promoter
The DNA sequence where RNA polymerase binds to initiate transcription.
64
Activator
A protein that increases gene transcription by binding to the promoter or enhancer region.
65
Repressor
A protein that inhibits gene transcription by binding to the operator region.
66
Corepressor
A molecule that cooperates with a repressor protein to inhibit gene transcription. Added to repressor to activate. These turn genes off.
67
Inducer
deactivate repressor/ not the same as activators
68
Inducible Operon
An operon whose transcription is activated in response to a specific inducer molecule. - usually turned off
68
Histone Acetylation
The addition of acetyl groups to histone proteins, often associated with an open chromatin structure and increased gene transcription. -
68
DNA Methylation
The addition of methyl groups to DNA molecules, which can result in the repression of gene transcription
69
Repressible Operon
An operon whose transcription is inhibited in response to a specific corepressor molecule. - usually turned on
70
Cloning Vector
A DNA molecule capable of carrying foreign DNA into a cell and replicating there. (Eg: bacterial plasmid)
71
Restriction Enzymes
Enzymes that cut DNA molecules at specific locations; used in making recombinant DNA.
72
Why are restriction enzymes important?
Discovery of restriction enzymes facilitated gene cloning and genetic engineering by enabling precise cutting of DNA molecules.
73
Sticky Ends
: Sticky ends refer to the single-stranded overhangs created by the staggered cuts made by restriction enzymes on DNA molecules. These overhangs have unpaired nucleotides
74
Gel Electrophoresis
a method for rapidly analyzing and comparing genomes by separating macromolecules (nucleic acids or proteins) based on their rate of movement through a polymer gel in an electrical field. The rate of movement depends on size, electrical charge, and other physical properties.
75
Noncoding RNA
Noncoding RNA refers to RNA molecules that do not encode proteins but play crucial roles in various cellular processes, including gene regulation.
76
miRNA (MicroRNA)
Small, single-stranded RNA molecules that bind to complementary sequences in mRNA molecules.
77
miRNA Formation
Derived from longer RNA precursors that fold back on themselves to form short, double-stranded hairpin structures.
78
Dicer Enzyme
Cuts each hairpin into short, double-stranded fragments (about 22 nucleotide pairs).
79
RNA Interference (RNAi)
The phenomenon of inhibiting gene expression by RNA molecules.
80
siRNA (Small Interfering RNA)
Similar in size and function to miRNAs, generated by similar mechanisms in eukaryotic cells.
81
RNAi Mechanism
Injecting double-stranded RNA molecules into a cell can turn off the expression of a gene with the same sequence as the RNA.
82
Epigenetic Inheritance
The inheritance of traits by mechanisms not directly involving changes in the nucleotide sequence.
83
Epigenetic Variations
Epigenetic variations may contribute to differences between identical twins in acquiring genetically based diseases, such as schizophrenia, despite having identical genomes.
84
DNA Methylations and Cancer
Alterations in normal patterns of DNA methylation are observed in some cancers, associated with inappropriate gene expression.
85
Oncogenes
Genes that, when mutated or overexpressed, can contribute to the development of cancer.
86
Protoncogenes
Normal cellular genes that can become oncogenes when mutated or overexpressed.
87
Ras GENES
A family of genes that code for proteins involved in cell signaling; mutations in Ras genes are commonly found in cancers.
88
Acetyl
double bond of oxygens
89
PCR STEPS
Denaturation: heat up to 70 Annealing : cool down Extension : heat up again
90
Polymerase Chain Reaction
making copies of dna with machine
91
DNA Cloning
- done with plasmid so bacteria
92
electroporation
applying an electrical pulse to create temporary holes in plasma membranes
93
Reverse transcriptase-polymerase chain
useful for comparing
94
CRISPR- CAS 9
uses RNA to get to replace targeted genes in adults

Biology (20 decks)

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