RNA Flashcards
(95 cards)
1
Q
mainly seen in cytoplasm, usually 100-5000 bases
A
RNA
2
Q
mostly inside nucleus with millions of base pairs
A
DNA
3
Q
guanine content is not equal to cytosine and adenine is not equal to uracil
A
RNA
4
Q
easily destroyed by alkali
A
RNA
5
Q
alkali resistant
A
DNA
6
Q
[RNA types] Carries the genetic instructions of a gene from the nucleus to the ribosome in the cytoplasm
A
mRNA
7
Q
[RNA types] This constitutes about 2-5% of total RNA in the cell. They are generally degraded quickly
A
mRNA
8
Q
[RNA types] Eukaryotic mRNA contains a ____ and a ____ and is synthesized in the nucleus
A
cap structure and a poly(A) tail
9
Q
[RNA types] The cap consists of ______ attached to the hydroxyl group on the ribose at the 5’ end of the mRNA
A
methylated guanine triphosphate
10
Q
[RNA types] in the mRNA cap, the ____ in the guanine is methylated
A
N7
11
Q
[RNA types] in the mRNA cap, The _____ of the 1 and 2 ribose moieties of the mRNA may also be methylated
A
2’-hydroxyl groups
12
Q
[RNA types] The poly(A} tail contains up to ________ attached to the hydroxyl group at the 3’ end of the mRNA
A
200 adenine (A) nucleotides
13
Q
[RNA types] This constitutes about 80% of all RNA in the cell. Together with proteins, composes the ribosome, the organelles that are the site of protein synthesis. They are very stable.
A
Ribosomal RNA (rRNA)
14
Q
rRNA contains many loops and extensive base-pairing. rRNA molecules differ in their _________. They associate with proteins to form ribosomes
A
sedimentation coefficients (S)
15
Q
Prokaryotes have three types of rRNA:
A
16S, 23S, and SS rRNA
16
Q
Eukaryotes have four types of cytosolic rRNA:
A
18S, 28S, SS, and 5.8S rRNA
17
Q
A. The eukaryotic ribosomes have _____ different proteins
A
83
18
Q
eukaryotic mitochondrial ribosomes are similar to
A
prokaryotic ribosome
19
Q
[RNA types] They constitute about 15% of the total RNA in the cell. Brings the correct amino acid to the ribosome during translation. They are very stable
A
transfer RNA (tRNA)
20
Q
[RNA types] there are about ___ different tRNA species
A
60
21
Q
[RNA types] tRNA has a cloverleaf structure and contains _______. tRNA molecules are relatively small, containing about _______
A
modified nucleotides, 80 nucleotides
22
Q
In eukaryotic cells, many nucleotides in tRNA are ______
A
modified
23
Q
Modified nucleotides containing ____, ____, and ____ are present in most tRNAs.
A
pseudouridine (Ψ), dihydrouridine (D), and ribothymidine (T)
24
Q
in tRNA molecules, the first loop from the 5’ end, the D loop, contains
A
dihydrouridine
25
in tRNA molecules, the middle loop contains the ______, which base-pairs with the codon in mRNA
anticodon
26
in tRNA molecules, the third loop, the TΨC loop, contains both
ribothymidine and pseudouridine
27
in tRNA molecules, the _____ at the 3' end carries the amino acid
CCA sequence
28
RNAs involved in gene regulation and mRNA degradation
Small interfering RNA (siRNA), microRNA (miRNA) and small nuclear RNA (snRNA)
29
[gene expression] a DNA molecule is divided into functional units called
genes
30
[gene expression] During gene expression, the DNA is first copied into
RNA
31
[gene expression] The RNA can be ______ (transfer RNAs and ribosomal RNAs) or be the intermediate template for a protein that performs a function
directly functional
32
[gene expression] when RNA is said to be directly functional this means
it can act immediately as tRNAs or rRNAs
33
[gene expression] s the central dogma of
molecular biology
DNA -> RNA -> protein
34
[gene expression] One strand of the gene's DNA is copied into RNA
transcription
35
[gene expression] In eukaryotes, the RNA transcript must undergo _______ in order to become a mature messenger RNA (mRNA)
additional processing steps
36
[gene expression] The nucleotide sequence of the mRNA is decoded to specify the amino acid sequence of a polypeptide
translation
37
[gene expression] in translation, arranging of the polypeptide occurs inside a ribosome and requires
adapter molecules ( tRNAs)
38
[transcription] one strand of the DNA that makes up a gene and acts as a template for the synthesis of a matching (complementary) RNA strand
non-coding strand
39
[transcription] This RNA strand is the pre-mRNA
matching (complementary) RNA from the non-coding strand of DNA
40
[transcription] the action of synthesis of a matching complementary strand of RNA is through the enzyme
RNA polymerase
41
[transcription] The DNA opens up to form a bubble, and the lower strand serves as a template for the synthesis of a complementary RNA strand, called the
template strand
42
[transcription] Transcription of the template strand produces an mRNA that nearly
matches the ______ of DNA in sequence
coding strand
43
[transcription] in eukaryotes, caps are added to the ends of the pre-mRNA, and some pieces of it may be carefully removed in a process called ______ in order to become a mature mRNA
splicing
44
[transcription] Eukaryotic rRNA is produced by ______ as a 45S precursor
RNA polymerase I
45
[transcription] in eukaryotic rRNA, the 45S precursor is methylated and cleaved to form 3 of the rRNAs (___, ____, ____) that appear in ribosomes
18S, 28S, and 5.8S
46
[transcription] in eukaryotic rRNA, The 5S rRNA is produced from a separate gene by ______
RNA polymerase III
47
[transcription] in eukaryotes, the ______ is the site of rRNA production and ribosome assembly
nucleolus
48
[transcription] eukaryotic mRNA, produced by ______, is capped at the 5' end and has a poly{A) tail added at the 3' end
RNA polymerase Il
49
[transcription] ___ are segments that do not code for protein are removed, and exons (segments that produce the mature mRNA) are spliced together
introns
50
[transcription] Eukaryotic tRNA is produced by _____ as a precursor that is trimmed at the 5' and 3' ends. Introns are removed and exons are spliced together
RNA polymerase Ill
51
[transcription] Unusual nucleotides are produced in mature tRNA by _____, and a CCA
sequence is added at the 3' end
posttranscriptional modification of normal nucleotides
52
[transcription] In bacteria, the pre-mRNA can _______ as a messenger RNA, or mRNA. They don't have a nucleus, so they carry
out both transcription and translation in the cytosol
directly serve
53
[transcription] Bacteria do not contain nuclei, so transcription and translation occur ______
simultaneously
54
[transcription] A ______ produces mRNA, rRNA, and tRNA in bacteria
single RNA polymerase
55
[transcription] Bacterial transcripts (e.g., those from E. coli) do not contain _____
introns
56
[clinical corr] Compounds that inhibit _____ can be utilized as antibiotics
RNA synthesis
57
[clinical corr] These antibiotics ____ affect bacterial function and have minimal side effects in humans, and they are usually selected to treat bacterial infections
selectively
58
[clinical corr] inhibits the initiation of prokaryotic RNA synthesis, is used to treat tuberculosis
rifampicin
59
[clinical corr] derived from the poisonous mushroom Amanita phalloides, inhibits eukaryotic RNA polymerases, particularly polymerase II
α-Amanitin
60
[clinical corr] Ingestion of small amounts of α-Amanitin initially causes ______ but can rapidly result in death
gastrointestinal problems
61
messenger RNA (mRNA) is decoded in a ribosome, to produce a specific amino acid chain, or polypeptide.
translation
62
[translation] The polypeptide later folds into an ______ and performs its functions in the cell
active protein
63
[translation] The ribosome will facilitate
decoding by inducing the _______ of complementary tRNA anticodon sequences to mRNA codons.
binding
64
The _____ is the collection of codons that specify all the amino acids found in proteins.
genetic code
65
[genetic code] A codon is 1 sequence of three bases (triplet} in mRNA (______) that specifies (corresponds to) a particular amino acids
5' to 3'
66
[genetic code] During translation, the successive codons in an mRNA determine ______ add to the growing polypeptide chain
the sequence in which amino acids
67
[genetic code] Each of the 20 common amino acids has at least 1 codon; many amino acids have numerous codons.
degenerate (redundant)
68
[genetic code] each nucleotide is used only once, beginning with a start codon (AUG)
near the 5' end of the mRNA and ending with a termination (stop) codon (UGA. UAG, or UAA) near the 3' end
s non overlapping
69
[genetic code] there are no breaks or markers to distinguish one codon from the next
comma-less
70
[genetic code] The same codon specifies the same amino acid in almost all species studied;
however, some differences have been found in the codons used in mitochondria
nearly universal
71
[genetic code] Mitochondrion, has its own circular
DNA chromosome and protein biosynthetic apparatus
72
[genetic code] Only a small number of mitochondrial proteins are encoded by the
mitochondrial genome
73
[genetic code] The start codon ____ determines the reading frame. Subsequent nucleotides are read in sets or three,
sequentially following this codon
(AUG)
74
[effects of mutation on proteins] Mutations in DNA are_______ into mRNA and can thus cause changes in the encoded protein
transcribed
75
[effects of mutation on proteins] occur when one base in DNA is replaced by another, altering the codon in mRNA
Point mutations
76
[effects of mutation on proteins] type of point mutation that do not affect the amino acid sequence of a protein (e.g., CGA to CGG causes no change, since both codons specify arginine)
Silent mutations
77
[effects of mutation on proteins] type of point mutation that result in one amino acid being replaced by another (e.g., CGA to CCA causes
arginine to be replaced by proline)
Missense mutations
78
[effects of mutation on proteins] type of point mutation that result in a premature termination or the growing polypeptide chain (e.g., CGA to UGA causes arginine to be replaced by a stop codon)
Nonsense mutations
79
[effects of mutation on proteins] type of mutation that occur when a base or a number or bases are added to DNA. They can result in a protein with more amino acids than normal
insertions
80
[effects of mutation on proteins] type of mutation that occur when a base or a number of bases are removed from the DNA. They can result in a protein with fewer amino acids than normal
deletions
81
[effects of mutation on proteins] type of mutation that occur when the number of bases added or deleted is not a multiple of three. The reading frame is shifted so that completely different sets of codons are read beyond the point where the mutation starts
frameshift mutations
82
[clinical corr] results from a point mutation (GAG to GTG) that causes valine to replace
glutamate at position 6 in the β-globin chain
sickle cell anemia
83
[clinical corr] in sickle cell anemia, hydrophobic interactions between these valine residues on different hemoglobin molecules cause _______, which alters the shape of the red blood cells and results in hemolysis
polymerization of sickle cell hemoglobin (HbS)
84
[clinical corr] is due to a point mutation, also in position 6 of the β-globin chain, which
causes a lysine to replace glutamate at this position causing anemia
Hemoglobin C (HbC)
85
[clinical corr] a group of hemolytic anemias, mutations can affect all steps of RNA metabolism. This is also an imbalance in the synthesis of the globin proteins
Thalassemias
86
[clinical corr] type of thalassemia that is an excess of α subunits
a β-thalassemia
87
[clinical corr] type of thalassemia that is an excess of β subunits
α-thalassemia
88
translation proceeds in 3 phases, namely:
initiation, elongation, termination
89
[translation phase] The ribosome assembles around the target mRNA. The first tRNA is attached at the start codon
initiation
90
[translation phase] The last tRNA validated by the small ribosomal subunit (_______) transfers the amino acid it carries to the large ribosomal subunit which binds it to the one of the precedingly admitted tRNA (_____). The ribosome then moves to the next mRNA codon to continue the process
(_____________), creating an amino acid chain
elongation, accommodation, transpeptidation, translocation
91
[translation phase] When a stop codon is reached, the ribosome releases the polypeptide
termination
92
The process in cells by which an enzyme makes a copy of DNA from RNA
reverse transcription
93
Synthesis of DNA from an RNA temp late is catalyzed by reverse _______
transcriptase
94
Retroviruses contain RNA as their genetic material. The retroviral RNA serves as a ______ for the synthesis of DNA by reverse transcriptase
template
95
in viruses, the DNA that is generated from reverse transcription can be inserted into the _____ of the host cell and be expressed
genome (chromosomes)
