Chapter 10 Flashcards
1
Q
DNA and RNA are _____ acids
A
nucleic
2
Q
DNA polynucleotide
A
a nucleotide polymer (chain)
3
Q
1 of the 2 strands of DNA is a..
A
DNA polynucleotide
4
Q
A nucleotide is composed of a..
A
- nitrogenous base
- 5 carbon sugar
- phosphate group
5
Q
The nucloeotides are joined to one another by a..
A
sugar phosphate backbone
6
Q
4 different nitrogen-conatining bases
A
- adenine
- cytosine
- adenine
- guanine
7
Q
2 pyrimidines
A
thymine and cytosine
8
Q
2 purines
A
adenine and guanine
9
Q
RNA uses the sugar ____ instead of _____ like DNA
A
ribose; deoxyribose
10
Q
RNA has the nitrogenous base _____ instead of ____
A
uracil; thymine
11
Q
Watson and Crick determined
A
double helical structure of DNA
12
Q
Complementary base pairing
A
- A pairs with T
- G pairs with C
13
Q
DNA molecule consists of..
A
2 complementary polynucleotides
14
Q
DNA replication follows a..
A
semiconservative model
15
Q
Semiconservative model of DNA replication
A
- 2 DNA strands separate and untwist
- each stand is used as a pattern to produce a complementary strand (base pairing)
16
Q
Each new DNA helix after replication has…
A
one old strand with one new strand
17
Q
Watson and Crick noted that the structure of DNA suggests..
A
a possible copying mechanism
18
Q
Copying mechanism of DNA uses..
A
semi-conservative replication by applying base pair rules, A=T, G=C
19
Q
DNA replication begins…
A
at origin of replication
20
Q
DNA replication proceeds in..
A
both direction creating replication bubbles
21
Q
Daughter strand grows in..
A
5’ to 3’
22
Q
Daughter strands _______ until the fuse with..
A
elongate; strand in adjacent bubbles
23
Q
During replication parental strands…
A
open up
24
Q
DNA polymerase is an
A
enzyme links DNA nucleotides to the growing daughter strand
25
DNA polymerase's job
proofreads to ensure copied cells carry genetic info
26
One daughter strand is..
synthesized in pieces
27
Okazaki fragments are linked by...
DNA ligase enzyme
28
What repairs damaged DNA
DNA polymerase, DNA ligase and other proteins
29
Genotype
organisms genetic make up, heritable info contained in its DNA
30
Phenotype
organisms physical trait
31
DNA genotype is expressed as..
proteins
32
Proteins provide a ______ ___ for phenotypic traits
molecular basis
33
The molecular chain of command is from
- DNA in the nucleus to RNA
| - RNA in the cytoplasm to protein
34
Transcription
is the synthesis of RNA under the direction of DNA
35
Translation
is the synthesis of proteins under the direction of RNA
36
Order to get DNA to protein
DNA- transcription- RNA- (from nucleus to cytoplasm) translation- protein
37
The sequence of nucleotides in DNA provides
a code for constructing a protein
38
Protein construction requires a ..
conversion of a nucleotide sequence to an amino acid sequence
39
Transcription rewrites the..
DNA code into RNA using the same nucleotide "language"
40
Translation involves..
switching from the nucleotide "language" to the amino acid "language"
41
The flow of info from gene to protein is based on a
triplet code
42
Codons
Series of non overlapping 3 base 'words'
43
Genetic instructions for the amino acid sequence of a polypeptide chain are written in..
DNA and RNA as a series of codons
44
Each amino acid is specified by a..
codon
45
How many codons are possible from the 4 nucleotides
64
46
Some amino acids have...
more than 1 possible codon
47
Genetic code is...
a set of rules that relate codons in RNA to amino acids in proteins
48
_ nucleotides specify _ amino acid
3;1
49
__ codons correspond to amino acids
61
50
_ stop codons signal end of translation
3
51
The one start codon is __ and also codes for...
AUG; methionine
52
4 things the genetic code is..
- redundant
- unambiguous
- w/o punctuation
- nearly universal
53
How the genetic code is redundant
more than 1 codon for some amino acids
54
How the genetic code is unambiguous
any codon for one amino acid does not code for any other amino acid
55
How the genetic code is without punctuation
codons are adjacent to each other with no gaps in between
56
How the genetic code is nearly universal
the genetic code is shared by organisms from the simplest bacteria to the most complex plants and animals
57
RNA nucleotides are linked by the transcription enzyme..
RNA polymerase
58
What marks where transcription begins and ends
specific sequences of nucleotides along the DNA
59
Promotor
the 'start transcribing' signal is a nucleotide sequence
60
Transcription begins with..
initiation, as the RNA polymerase attaches to the promotor
61
During second phase of transcription..
elongation where the RNA grows longer
62
As the RNA peels away..
the DNA strands rejoin
63
3 phases of transcription
- initiation
- elongation
- termination
64
During termination in transcription
the RNA polymerase reaches a terminator
65
Terminator
sequence of bases in the DNA template which signals end of the gene
66
Finally in transcription
the polymerase molecule now ditches from the RNA molecule and the gene
67
RNA transcript is processed before..
leaving the nucleus as messenger RNA
68
RNA splicing..
cuts and pastes
69
Non coding regions
introns
70
Coding regions
exons
71
____ removed leaving the ____ that are spliced together
introns; exons
72
G nucleotide is added as a..
cap
73
Long chain of A nucleotides added as a .
tail
74
As a spliced product mRNA is..
exported from the nucleus into cytoplasm
75
Transfer RNA
molecules function as a language interpreter
76
How tRNA is a language interpreter
converting the genetic message of mRNA into the language of proteins
77
tRNA molecules perform this interpreter task by..
- picking up the appropriate amino acids
| - using a anticodon to recognize appropriate codons in mRNA
78
Anticodon
complementary to codon triplet on mRNA and is single stranded RNA
79
tRNA is ....
partially double stranded
80
Anticodon uses..
base pair rules
81
Ribosomes
large and small subunits that coordinate the functioning of mRNA and tRNA
82
Ribosomes catalyze...
the synthesis of polypeptides
83
Ribosomes are the binding site for..
mRNA and tRNA
84
2 binding sites for tRNA
- A site
| - P site
85
Initiation in translation brings together..
- mRNA
- a tRNA bearing the first amino acid
- 2 subunits of a ribosome
86
Initiation in translation occurs in __ steps
2
87
1st step in initiation in translation
mRNA molecule binds to a small ribosomal subunit and the first tRNA binds to mRNA at the start codon
88
The first tRNA has the anticodon...
UAC
89
2nd step in initiation in translation
a large ribosomal subunit joins the small subunit allowing the ribosome to function
90
The first tRNA occupies the.. ______ which will..
P site; hold the growing peptide chain
91
The _____ is available to receive the next tRNA
A site
92
Codon recognition
the anticodon of incoming tRNA carrying its amino acid, pairs with mRNA codon on A site
93
Peptide bond formation
polypeptide transferred from P to A site, ribosome catalyzes bond formation
94
Translocation
spent tRNA leaves P site tRNA with new peptide bond moves from A to P site and process repeats
95
Elongation continues until the termination stage of translation when..
- the ribosome reaches a stop codon
- the completed polypeptide is freed from last tRNA
- ribosome splits back into separate subunits
96
3 stages of translation
- initiation
- elongation
- termination
97
Mutation
any change in DNA nucleotide sequence
98
Mutations may be _____ or _______
large regions of chromosome; a single nucleotide pair
99
Mutation often detrimental but can be...
beneficial and allows for genetic diversity or may create new alleles w/ benefits
100
Mutations within a gene can be divided into..
2 general categories
101
1st category of mutations
base substitutions involve the replacement of one nucleotide with another
102
Base substitutions may..
- be a silent mutation
- be a missense mutation
- be a nonsense mutation
- lead to a base substitution that produces an improved protein that enhances the success of the mutant organism
103
Silent mutation
base substitution that have no effect at all
104
Missense mutation
base substitution that change the amino acid coding which produces a different amino acid
105
Nonsense mutation
base substitutions may change an amino acid into a stop codon
106
2nd category of mutations
mutations can result in deletions or insertions
107
Mutagenesis
production of mutations
108
Mutations can be caused by
- spontaneous errors that occur during DNA replication or recombination
- mutagens
109
Mutagens include
- high energy radiation such as X rays
| - chemicals
110
UV radiation causes..
skin cancer
111
How does UV radiations cause skin cancer
DNA absorbs UV radiation, results in thymine dimer which distorts DNA which causes mutation of genes
112
Tanning beds increase skin cancer risk by
75%
113
Nucleotide excision repair (NER)
repairs thymine dimers and uses 30 diff enzymes and proteins
114
Unprepared thymine dimers lead to..
mutation
115
Mutations allow bacteria to..
resist antibiotics
116
Antibiotics
drugs that kill infectious microorganisms
117
Overuse of antibiotics have..
driven evolution in bacteria
