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NBDE PART 1 BIOCHEM/PHYSIOLOGY > DNA/RNA > Flashcards

DNA/RNA Flashcards

(94 cards)

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1
Q

HIV/AIDS virus has the ability to produce __ from an __ molecule

A

DNA from mRNA

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2
Q

the enzyme HIV uses to make DNA from mRNA is called

A

reverse transcriptase

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3
Q

reverse transcriptase is a DNA/RNA polymerase?

A

it is a DNA polymerase = it makes DNA
it uses RNA as its template to make a DNA strand complementary to the viral RNA = cDNA that is incorporated into the host DNA

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4
Q

reverse transcriptase are found in viruses called

A

retroviruses

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5
Q

HIV causes __

A

AIDS

HIV ==> AIDS

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6
Q

the drug AZT used in HIV is a __ of reverse transcriptase

A

competitive inhibitor

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7
Q

reverse transcriptase is used in __ to obtain a copy of a gene form the mRNA

A

genetic engineering

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8
Q

ribosomes in prokaryotes are either free floating in the cytoplasm or __

A

attached to plasma membrane

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9
Q

ribosomes in eukaryotes are either free floating in the cytoplasm or __

A

attached to endoplasmic reticulum membrane =RER

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10
Q

ribosomes have _ activity

A

enzymatic. b/c they catalyze the formation of peptide bonds

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11
Q

T/F all protein synthesis begins on a FREE RIBOSOME

A

true!

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12
Q

if the protein is destined for secretion from cell, incorporation into plasma membrane or into a lysosome, it is transferred from the free ribosome to

A

a ribosome on the RER

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13
Q

The _s ribosome is site of translation = protein synthesis in bacterial cells and chloroplasts

A

70s - 2 subunits are the 50s and 30s

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14
Q

the _s ribosome is in eukaryotes

A

80s - 2 subunits are the 60s and 40s

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15
Q

genetic recombination experiments depend heavily upon which enzymes

A

dna ligases and restriction endonucleases

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16
Q

___ is a technique used to detect mutations in DNA and to identify DNA restriction fragments. it uses restriction enzymes and DNA probes

A

Southern blotting

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17
Q

DNA cloning is used in medicine to make recombinant DNA technology products like

A

human insulin = DM
anticoagulants = tissue plasminogen factor
erythropoietin for anemia
human growth hormone = dwarfism

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18
Q

the first organism used for DNA cloning was ____ and is still the most common host cell

A

E. Coli

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19
Q

plasmids, bacteriophages and cosmids are all

A

bacterial cloning vectors

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20
Q

DNA polymerase I function

A

fills in the gaps in duplexes by step wise addition of nucleotides to 3’end

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21
Q

exonucleases function

A

remove nucleases from 3’ of 5’ end depending on the specific one

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22
Q

a nuclease cleaves ___ bonds in a nucleic acid

A

phosphodiester bonds

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23
Q

nucleases that cleave internal phosphodiester bonds are called

A

endonucleases

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24
Q

nucleases that cleave external phosphodiester bonds at the 3’ or 5’ are called

A

exonucleases

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25
in dna replication rna intermediates are used for
primer for DNA polymerase ==> replaced by DNA later
26
DNA polymerase can only add nucleotides to an existing piece of _
nucleic acid = this is why the primer is needed
27
___ synthesizes RNA primer for DNA polymerase and does not need a primer chain
RNA polymerase
28
__ unwinds supercoiled DNA
topioisomerase
29
___ re forms the supercoiled structure once the replication fork has passed
DNA gyrase
30
1. ___ unwinds the HELIX | 2. __ unwinds supercoiled DNA
1. helicase = separating two annealed nucleic acid strands (i.e., DNA, RNA) 2. topoisomerase = DNA becomes overwound ahead of a replication fork. If left unabated, this tension would eventually halt DNA replication.
31
___relieve superhelical tension by creating a temporary break in one or both DNA strands. they do this and then ligate the strands back together. by doing this, they allow for the strands to quickly rotate to relieve (also known as 'relax') any tension that has been built up.
topoisomerases
32
___ separate the two strands of the DNA. in fact, if a helicase is unwinding the DNA, it will be creating superhelical tension in front of it. thus, helicases work best when there is a topoisomerase present at the same time to relive that tension.
helicases
33
only difference bw products of rna and dna hydrolysis are
ribose and uracil
34
DNA is double/single stranded
double ALWAYS
35
RNA is double or single stranded
single stranded ALWAYS
36
nitrogenous bases of DNA
ADENine GUANine THYMine Cytosine ==== not cysteine!!!!!
37
nucleoside vs nucleotide
``` Nucleotide = sugar (ribose/deoxyribose), phosphate, and nitrogenous base Nucleoside = sugar and base (NO PHOSPHATE) = to remember look at the word nucleoside = s for sugar and nucleo for base ```
38
a single base, sugar, phosphate is called a
nucelotide
39
individual nucleotides linked together to form
polynucleotide chain
40
phosphodiester bonds are bw
sugar and phosphates
41
the purines and pyrimidines are
nitrogenous bases
42
the sugars in DNA and RNA are hexose/pentoses
pentoses
43
the backbone of nucleic acids are made of
phosphate and pentose units with a purine/pyrimidine base attached
44
does the catabolism of a nucleotide produce ATP energy
no. | only lipids, proteins and carb catabolism do
45
do we get our purines and pyrimidines (nitrogenous bases) exogenously or endogenously
endogenously
46
ribonucleotides are synthesized first and then the 2-deoxyyribonucleotides. T/F
True
47
is uric acid soluble
poorly soluble in water. therefore it can cause kidney stones, and gout when it forms sodium urate in the joints
48
phosphodiester bonds link the _ of one sugar to the other
3'OH to a 5'OH
49
the variable part of the DNA is the
base sequences
50
when we write a base sequence, unless otherwise noted, it is written in which direction
5' ==>3' | 5'-ATCCG-3'
51
purine bases consumed in diet in form of DNA/RNA are mostly _
excreted in form of uric acid.
52
Xanthine oxidase catalyzes
formation of uric acid from purines
53
tetrahydrofolic acid (TFA) is used in
purine and pyrimidine synthesis.
54
tetrahydrofolic acid (TFA) used as a target for
antimetabolites = for cancer chemotrherapy
55
UV light effect in DNA
makes pyrimidine dimers = interfere with replication and transcription.
56
UV induced pyrimidine dimers are removed by
endonucleases = excise 12 bp fragments around the dimer
57
__ fills in the gaps after an endonuclease takes out bp and _ seals the seams
DNA polymerase I | DNA ligase seals or ligates
58
wobble effect means substitution of the __ nucleotide of a codon will have least effect on protein
3rd ex. Leucine codons are CUU CUA, CUC, CUG (only the 3rd one is different)
59
there are _# different triplet codons and only _amino acids = degeneracy of the genetic code
64 20 therefore some amino acids coded for by more than one codon
60
what 3 amino acids are the only ones that are coded by only ONE codon
methionine tryptophan selenocysteine Think I "met and tripped on selena"
61
all 17 other amino acids are coded by _ or more codons
2 or more
62
codons that specify the same amino acid are called
synonym
63
initiation codon is
AUG
64
AUG codes for
methionine
65
all proteins begin with
methionine (AUG)
66
termination codons are
``` UAA = you are an ass UGA = you go away UAG = you are gone ```
67
termination codons are aka
stop codons/nonsense codons
68
anticodons are located in
transfer tRNA = complementary to the codon for an amino acid in mRNA
69
tRNA and mRNA are
antiparallel
70
how many hydrogen bonds bw A and T? | C and G?
A and T = 2 | C and G = 3 (to remember, C is the 3rd letter of the alphabet)
71
Watson and crick deduced the _ of base pairing
specificity due to Hydrogen bonding and stearic factors
72
___law of thermodynamics - If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.
•Zeroth
73
__ law of thermodynamics - As temperature approaches absolute zero, the entropy of a system approaches a constant minimum.
. •Third
74
__law of thermodynamics - Energy can neither be created nor destroyed. It can only change forms. In any process, the total energy of the universe remains the same. For a thermodynamic cycle the net heat supplied to the system equals the net work done by the system
•First to remember: 1st law is energy (think E = mc2) second law is entropy (S) for second third law is temperature = T
75
__ law of thermodynamics - The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.
•Second
76
DNA double helix is held together by what 2 forces?
hydrogen bonding bw nitrogenous base pairs and base stacking interactions facilitated by phosphodiester bonds
77
the helix of DNA forms a major and minor groove. the _ groove is the binding region for many proteins that control the transcriptional activity of the DNA molecule
major
78
the weaker bonding bw A and T or U in RNA is used in transcription to aid in?
release of the newly formed RNA from the dna template
79
The AT base pair promotes helix stabilization in __ but not in __
in DNA but not in RNA
80
are purines or pyrimidines larger
purines (remember the shorter word is bigger)
81
the sum of the purine residues equals
the sum of the pyrimidine residues
82
the melting temperature is a function of the base composition with a higher __ content having a higher melting point
GC content
83
bases are hydrophobic/hydrophilic
phobic
84
the bases lay __ on top of each other
flat like pancake stack
85
the successive bases stacked on each other have __ interaction
van der Waals interactions
86
the strongest NON COVALENT forces in the double helix are the
van der Waals interactions! not the hydrogen bonds
87
dna is right/left handed helix
right handed
88
how many base pairs per turn in dna helix
10.4 bases per turn
89
the ribose phosphate portion of purine and pyrimidine nucleotides comes from
5-phophoribosyl-1-pyrophosphae (PRPP) which is synthesized from ATP and ribose 5 phosphate in the pentose phosphate pathway
90
which type of RNA is the least abundant in the cell: | mRNA, tRNA, or rRNA
mRNA
91
which type of RNA is the MOST abundant in the cell: | mRNA, tRNA, or rRNA
rRNA (ribosomal RNA) > tRNA > mRNA
92
is there any error checking in translation at the ribosome
no. individual enzymes are highly specific for ONE AMINO ACID = amino acyl-rRNA synthetase is the group of ligases (enzymes) that ensure that the correct amino acid is attached to the tRNA with the correct anticodon to be used.
93
__are the major component of ribosomes, which are the physical and chemical structures on which the protein molecules are assembled
rRNA
94
transcription will make what kind of RNA?
mRNA, tRNA and rRNA

NBDE PART 1 BIOCHEM/PHYSIOLOGY (43 decks)

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