The Chemical Nature of the Cell Flashcards

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1
Q

T-A pairs have ___ hydrogen bonds

A

two

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2
Q

G-C pairs have ____ hydrogen bonds

A

three

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3
Q

DNA has ______ sugar

A

deoxyribose (no oxygen)

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4
Q

The strands in DNA run _____

A

antiparallel (opposite direction)

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5
Q

in RNA, _____ replaces thymine

A

uracil

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6
Q

RNA has _____ sugar

A

ribose (with an OH)

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7
Q

a _______ linkage connects the 5’ phosphate group and the 3’ OH group of adjoining nucleotides

A

phosphodiester

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8
Q

what is the DNA backbone made up of

A

deoxyribose sugars, linked by phosphate

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9
Q

what is the DNA backbone linked with

A

phosphate

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10
Q

what are the bases in DNA

A

A,T,G,C

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11
Q

what type of end does DNA have

A

5’

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12
Q

How many strands does DNA have

A

2

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13
Q

What are the bases in RNA

A

A<u></u>

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14
Q

What type of end does RNA have

A

triphosphate

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15
Q

how many strands does RNA have

A

one

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16
Q

what is eukaryotic genome organization

A

how we go from double stranded DNA to a metaphase chromosome

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17
Q

what are the steps in eukaryotic genome organization

A

DNA duplex - Nucleosome- chromatin- coil- condensed chromatid

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18
Q

greater than 80% of all colon cancers are caused by mutations in which gene

A

APC

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19
Q

RNA is ____ to the non-template strand, and ____ to the template strand

A

similar (with U instead of T)

complimentary

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20
Q

(expressed/not expressed)

Introns

A

not expressed

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21
Q

(expressed/not expressed)

exons

A

expressed

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22
Q

which way does the template strand run

A

3’-5’

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23
Q

how many different amino acids are there

A

20

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24
Q

how many codon are there for the 20 amino acids

A

64

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25
Q

what percentage of DNA actually codes for protein

A

3-5%

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26
Q

RNA has a _____ group on the 2’-carbon atom of its sugar component

A

hydroxyl

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27
Q

DNA has a _____ on its sugar component

A

hydrogen

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28
Q

(more/less)

RNA is ____ reactive than DNA

A

more

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29
Q

How does RNA form secondary structures

A

RNA fods to form secondary structures because of the hydrogen bonding between complementary bases on the same strand

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30
Q

What is ribosomal RNA

A

structural and functional component of the ribosome

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31
Q

what is messenger RNA

A

carried genetic code for proteins

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32
Q

what is transfer RNA

A

helps incorporate amino acids into polypeptide chain

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33
Q

describe the synthesis of an RNA molecule

A
  • from a DNA template (3’-5’)

- the transcribed strand is the template strand

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34
Q

describe the transcription unit of RNa

A

includes a promoter RNA coding sequence, and a terminator

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35
Q

RNA synthesis is ____ and _____ to the template strand

A

complimentary, antiparallel

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36
Q

where are new nucleotides added during RNA synthesis

A

they are added to the 3’-OH group of the growing RNA

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37
Q

which way does transcription proceed

A

5’-3’ (left to right)

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38
Q

does RNA synthesis require a primer to be initiated

A

no

39
Q

what is a consensus sequence

A

sequences that possess considerable similarity between different species

40
Q

where does transcription occur (eukaryotes)

A

in the cytoplasm

41
Q

how many genes er mRNA transcript

A

typically 1

42
Q

how many spaces are there between codons

A

none

43
Q

each nucleotide is part of ___ codon(s)

A

1

44
Q

what is meant by “the genetic code is degenerate”

A

most amino acids are specified by more than one codon

45
Q

what is meant by “the genetic code is (nearly) universal”

A

with minor exceptions, each codon has the same meaning in all organisms

46
Q

What is the ribosomal complex composed of

A

many proteins and ribosomal RNA
a small and a large subunit
three binding sites for tRNA

47
Q

what are the three binding sites for tRNA

A

APE

aminoacyl, peptdyl, exit

48
Q

How many tRNAs are there

A

there is a unique tRNA for each codon, so technically there should be 64 tRNAs but not all of them are used equally

49
Q

what do aminoacyl tRNA syntheses bind to

A

each aminoacyl tRNA syntheses bind to one UNCHARGED tRNA and its corresponding amino acid

50
Q

there is a specific ____ for each amino acid

A

enzyme

51
Q

where do enzymes attach the amino acids to

A

the enzyme attaches the amino acid to the 3’ end of the tRNA

52
Q

what is the process of getting a charged tRNA

A

free amino acid and an uncharges tRNA get blinded together by an aminoacyl tRNA synthase

53
Q

which amino acid does translation always begin with

A

met (aug)

54
Q

which way is the polypeptide synthesized

A

the polypeptide is synthesized from the amino end to the carboxyl end

55
Q

which amino acid is on the amino end of the polypeptide?

A

met (because the amino side is synthesized first and Met is the first one synthesized)

56
Q

describe translation initiation

A

the initiator aug codon is recognized and met is establishes as the first amino acid in the polypeptide chain

57
Q

describe translation elongation

A

elongation is when successive amino acids are added one by one to the growing amino acid polypeptide chain

58
Q

describe translation termination

A

termination is where the addition of amino acids stop and the completed stands is released from the ribosome

59
Q

initiation of translation requires a number of ____

A

initiation factors

60
Q

where do the initiation factors required for the initiation of translation bind

A

the initiation factors for the initiation of translation bind to the mRNA

61
Q

where specifically do the initiation factors for translation bind to on the mRNA

A

one group of initiation factors binds to the 5’ cap, others bring up a tRNA charged with met

62
Q

what type of bond holds together the polypeptide chain of amino acids

A

peptide bonds

63
Q

what do elongation factors do

A

elongation factors are bound to GTP molecules, and then they break their high-energy bonds to provide energy for the elongation if the polypeptide

64
Q

what are the stop codons

A

UAA
UAG
UGA

65
Q

what happens when a stop codon is encountered

A

a protein release factor binds to the A site of the ribosome

66
Q

When the protein release factor binds to the A site of the ribosome, what happens

A

this causes the bind connecting the polypeptide to the tRNA to break creating the carboxyl/terminus o the polypeptide. completes the chain

67
Q

what is translation

A

the process in which the sequence of bases in messenger RNA specifies the order of successive amino acids in a newly synthesized protein

68
Q

what is a protein

A

proteins are linear polymers of amino acids that form three-dimensional structures with specific functions

69
Q

how do proteins evolve

A

proteins evolve through mutation and selection and by combining functional units

70
Q

what determines a proteins function and structure

A

the exact order of amino acids in a protein determines the proteins function and shape

71
Q

what does the structure fo amino acids have

A

amino acids differ in their side chins; they consist of a central carbon atom connected by covalent bonds to four different chemical groups (ammino, carboxyl, hydrogen, and a variable side chain)

72
Q

what are hydrophobic amino acids

A

amino acids that do not interact with water

73
Q

amino acids are linked together to form ____ by ______

A

amino acids are linked together to form proteins by peptide bonds

74
Q

describe the process of bonding with peptide bonds

A

in forming peptide bonds the carboxyl group of one amino acids reacts with the amino group of the nest amino acid, and a molecule of water is released.

75
Q

what is a polypeptide

A

a polymer of amino acids connected by peptide bonds

76
Q

what is a primary structure

A

the sequence of amino acids in a protein

it determines the folds

77
Q

what is a secondary structure

A

formed by interactions between stretches of amino cids

78
Q

what is a tertiary structure

A

the overall 3D shape of the polypeptide. formed by long-range interactions between secondary structures

79
Q

what is a quaternary structure

A

several individual polypeptides that interact with each other

80
Q

what are ribosomes

A

complex structures of RNA and protein that bind with mRNA and are the site of translation

81
Q

where does transcription take place

A

in the nucleus

82
Q

where does translation take place

A

in the cytoplasm

83
Q

what are the cellular components needed for translation

A

messenger RNA, initiation factors, elongation factors, release factors, aminoacyl tRNA synthase, transfer RNA, and a ribosome (ribosomal RNA and ribosomal protein)

84
Q

each non-overlapping group of _____ adjacent nucleotides constitutes a codon

A

each non-overlapping group of THREE adjacent nucleotides constituted a codon

85
Q

each codon codes for a _____ in the poly peptide chain

A

each codon codes for a single amino acid in the polypeptide chain

86
Q

what is tRNA

A

small rna molecules of 70-90 nucleotides (clover leaf structure)

87
Q

each tRNA has the sequence ___ at the 3’ end

A

CAA

88
Q

what is the anticodon

A
  • the three bases in the anticodon loop (bottom loop of the clover-leaf structure)
  • these three bases are the three that undergo base pairing with the corresponding codon
89
Q

the _______ of the caA is the attachment site for amino acids that correspond to the anticodon

A

the 3’ hydroxyl of the A is the attachment site foe the amino acids that correspond to the anticodon

90
Q

what does aminoacyl tRNA synthase do

A
  • the aminoacyl TRNA synthase enzyme connects specific amino acids to specific tRNA molecules
  • directly responsible for actually translating the codon sequence in a nucleic acid to a specific amino acid in a polypeptide chain
91
Q

how many aminoacyl tRNA syntheses are there

A

most organisms have one for each amino acid

92
Q

how does aminoacyl tRNA synthase work

A

the enzyme binds to multiple sites on any tRNA that has an anticodon corresponding to the amino acid, and it catalyzes formation of the covalent bond between the amino acids and the tRNA

93
Q

what is an uncharges tRNA

A

a TRNA that has no amino acid attached

94
Q

what is a charges tRNA

A

a tRNA that has an amino acid attached