Chapter 14 Flashcards

1
Q

The DNA inherited by an organism leads to specific traits by dictating ___ and of _____ involved in ____.

A

the synthesis of proteins, RNA molecules, protein synthesis

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2
Q

proteins are?

A

the link between genotype and phenotype

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3
Q

gene expression

A

process by which DNA directs protein synthesis

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4
Q

2 stages of gene expression

A

transcription and translation

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5
Q

metabolic pathway

A

cells synthesize and degrade molecules in a series of steps

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6
Q

Beadle and Tatum began studying the haploid bread mold ____ because it would be____?

A

Neurospora crassa, easier to detect recessive mutations

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7
Q

Beadle and Tatum generated ___, each of which was ___.

A

nutritional mutants, unable to synthesize a particular essential nutrient

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8
Q

For Neurospora one set of mutants all required ___ for ___.

A

arginine, growth

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9
Q

Some proteins are not ___, so researches revised the ____ hypothesis to ___.

A

enzymes, one gene-one enzyme, one gene-one protein

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10
Q

Beadle and Tatum’s hypothesis is now restarted as the ___ hypothesis.

A

one gene-one polypeptide

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11
Q

____ is the bridge between __ and ___ synthesis.

A

RNA, protein, DNA

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12
Q

2 stages of getting DNA to protein

A

transcription and translation

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13
Q

Transcription

A

synthesis of RNA using info in DNA

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14
Q

Transcription produces?

A

mRNA

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15
Q

Translation

A

synthesis of a polypeptide using info in mRNA

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16
Q

Sites of translation

A

Ribosomes

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17
Q

In eukaryotes, the nuclear envelope separates?

A

transcription from translation

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18
Q

Eukaryotic RNA transcriptions are modified through ___ to yield __

A

RNA processing, mRNA

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19
Q

Primary transcript

A

initial RNA transcript from any gene prior to processing

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20
Q

Central dogma

A

concept that cells are governed by a cellular chain of command

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21
Q

There are only ___ nucleotides bases to specify ___ amino acids

A

4, 20

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22
Q

The flow of info from ___ to ___ is based on __

A

gene, protein, triplet code

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23
Q

triplet code

A

a series of nonoverlapping three-nucleotide words of mRNA

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24
Q

The words from mRNA are then translated into?

A

a chain of amino acids forming a polypeptide

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25
During transcription, the template strand?
provides a template for ordering the sequence of complementary nucleotides in an RNA transcript
26
codons
mRNA triplets
27
codons are read in the ___ direction.
5'-3'
28
coding strand
nontemplate DNA strand
29
The genetic code is __
redundant
30
redundant
more than one codon may specify a particular amino acid
31
No codon specify ___
more than one amino acid
32
Codons must be read in the correct ___ in order for the ___.
reading frame, specified polypeptide to be produced
33
The genetic code is nearly ____?
universal
34
Genes can be ___ and ___ after being transplanted from ___ .
transcribed, translated, one species to another
35
A language shared by all living things must have?
been operating in the common ancestor of all present-day organisms
36
What is the first stage of gene expression?
transcription
37
RNA polymerase
pries the DNA strands apart and joins together complementary RNA nucleotides
38
RNA polymerase assemble polynucleotides only in the ___ direction
5'-3'
39
Promoter
DNA sequence where RNA polymerase attaches
40
terminator
In bacteria, the sequence signaling the end of transcription
41
transcription unit
stretch of DNA that is transcribed
42
3 stages of transcription
-Initiation -Elongation -Termination
43
Promoters signal the transcriptional ___ and usually extend __.
start point, several dozen nucleotide pairs upstream of the start point
44
Transcription factors
mediate the binding of RNA polymerase and the initiation of transcription
45
transcription inition complex
complicated assembly of transcription factors and RNA polymerase ll bound to a promoter
46
TATA Box
promoter DNA sequence
47
TATA Box is crucial in forming ___
the initiation complex in eukaryotes
48
In bacteria, the polymerase stops ___ at the end of the ___ and the ___.
transcription, terminator, mRNA can be translated without further modification
49
Enzymes in the eukaryotic nucleus modify __ before the __.
pre-mRNA, genetic messages are dispatched to the cytoplasm
50
pre-mRNA
RNA processing
51
5' end of pre-mRNA receives
a modified G nucleotide 5' cap
52
3' end of pre-mRNA recieves
poly-A tail
53
modifications to mRNA ends helps facilitate?
the export of mRNA to the cytoplasm
54
RNA splicing
large portions of the RNA molecules are removed and remaining portions are reconnected
55
introns
noncoding regions
56
exons are usually?
translated into amino acid sequences
57
In the process of splicing, introns are ___ and the exons __
cut out of the molecule, are joined together
58
alternative RNA splicing
exons from the same gene are joined in different combinations, leading to different, but related, mRNA transcripts
59
Spliceosomes consist of?
proteins and small RNA's
60
Ribozymes
RNA molecules that function as enzymes
61
transfer RNA
helps translate an mRNA message into protein
62
tRNA's transfer __ to the ___ in a ___
amino acids, growing strand, ribosome
63
Each tRNA enables the translation of___
a particular mRNA codon into a certain amino acid
64
In 3D, tRNA is ___ shaped
L
65
tRNA has one end which contains the ___ and the other end an __
anticodon, amino acid
66
anticodon
recognizes a specific codon on mRNA
67
There are no introns in?
bacteria
68
2 steps of accurate translation
-correct match between tRNA and amino acid done by aminoacyl-tRNA synthetase. -Correct match between the tRNA anticodon and an mRNA codon.
69
wobble
flexible pairing at the third base of a codon
70
Ribosomes facilitate specific ___ during ___.
coupling of tRNA anticodons with mRNA, protein synthesis
71
The large and small proteins are made of?
proteins and ribosomal RNA's
72
P site
holds the tRNA that carries the growing polypeptide chain
73
A site
holds the TRNA that carries the next amino acid to be added to the chain
74
E site
exit site where discharged tRNAs leave the ribosome
75
Energy is provided in the translation process by?
GTP
76
A start codon is important because
it establishes the reading frame for the mRNA
77
During elongation, amino acids are added ___ to the previous ___ at the ___
one by one, amino acid, C-terminus
78
Termination occurs when?
a stop codon in mRNA reaches the A site of the ribosome
79
The release factor at the A site causes?
the addition of a water molecule instead of an amino acid
80
During synthesis, a polypeptide chain spontaneously?
coils and folds into its 3D shape
81
Proteins may also require?
post translation modifications before doing their jobs
82
Bound ribosomes make?
proteins of the endomembrane system and proteins that are secreted from the cell.
83
Polypeptide synthesis always begins in the?
cytosol
84
Polypeptides destined for the ER or for secretion are marked by a ___ which ___
signal peptide, targets the protein to the ER
85
Signal-recognition particle binds to?
signal peptide
86
Once a ribosome is far enough past the start codon, another ribosome
can attach to the mRNA
87
Bacteria and eukaryotes can also transcribe multiple
mRNA's from the same gene
88
mutations
changes in the genetic material of a cell
89
point mutations
chemical changes in just one nucleotide pairs of a gene
90
The change of a single nucleotide in a DNA template strand can lead to?
production of abnormal protein
91
If a point mutation occurs in a gamete, it may be?
transmitted to offspring
92
2 categories of small-scale mutations within a gene
-single nucleotide-pair substitutions -nucleotide-pair insertions or deletions
93
nucleotide pairs substitution
replaces one nucleotide and its partner with another pair of nucleotides
94
silent mutations
have no effect on amino acid due to redundancy in genetic code
95
missense mutations
change one amino acid to another
96
nonsense mutations
change an amino acid codon into a stop codon, leading to nonfunctional protein
97
insertions/deletions
additions or losses of nucleotide pairs in a gene
98
Insertions or deletions have a ____ effect on the resulting __
disastrous effect, protein more often than substitutions do
99
insertions or deletions of nucleotides may alter the ___ producing a ___
reading frame, frame shift mutation
100
mutagens
physical or chemical agents that can cause mutations
101
Most carcinogens are?
mutagenic
102
we consider a gene as a DNA sequence that
codes for a specific polypeptide chain
103
A gene can be defined as a region of DNA that can be expressed to?
produce a final functional product, either a polypeptide or an RNA molecule