Molecular Genetics (Unit 3) - chapter 7 Flashcards

1
Q

Archibald Garrod, in 1896, began studying ________ which is a condition where a person’s urine turns black on contact with air.

A

alkaptonuria

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2
Q

He found that people with alkaptonuria excrete a particular chemical in their _____.

A

urine

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3
Q

He hypothesized that people with this disorder were not ________

A

able to break down this chemical

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4
Q

Later research proved that people with
alkaptonuria have a_______ that codes for a defective enzyme that can no longer break down the ____________

A

mutated gene
amino acid tyrosine

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5
Q

Continual research into _____ and _____ prompted scientists to come up with a hypothesis that could explain the link between the two.

A

genes and proteins

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6
Q

One Gene-One Polypeptide Hypothesis

-Each gene codes for the synthesis of one ______

A

polypeptide

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7
Q

-Different polypeptides can be combined to form more _________

A

complex proteins

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8
Q

-Can form (3)

A

hormones, enzymes, antibodies etc.

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8
Q

the fundamental principle of molecular genetics, which states that genetic information flows from DNA to RNA to Proteins

A

Central Dogma

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9
Q

The Central Dogma Includes (3)

A

Transcription, Translation,
and Folding

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10
Q

information in DNA is copied into RNA

A

Transcription

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11
Q

RNA can exit the nucleus and enter the _____

A

cytosol

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12
Q

RNA acts as a copy of the instructions
contained in DNA that can be transported outside of the ______

A

nucleus

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13
Q

RNA can then be used to build ______

A

proteins

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13
Q

_______ information contained within RNA
is used to build proteins

A

Translation

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14
Q

___ contains instructions coding for a specific amino acid sequence

Involves the use of ______

A

RNA
Ribosomes

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14
Q

changing shape of an amino acid chain
into a functioning protein

A

Folding

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14
Q

_______ chains must fold properly in order
to become functioning proteins

A

Amino acid

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14
Q

RNA:

______ Stranded

A

single

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14
Q

RNA:

Adenine pairs with _______

A

Uracil (A-U not A-T)

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15
Q

RNA:

Contains _______ instead of deoxyribose sugar in DNA

A

Ribose sugar

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16
Q

Three major types of RNA include

A

-Messenger RNA (mRNA),
-Transfer RNA
(tRNA)
-Ribosomal RNA (rRNA)

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17
Q

translated by
ribosomes into a protein

A

Messenger RNA (mRNA)

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18
Q

Used to move the information from DNA to the ribosome where it can be translated

A

Messenger RNA (mRNA)

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19
Q

Varies in length depending on the length of the gene being copied

A

Messenger RNA (mRNA)

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20
Q

a carrier molecule that
binds to a specific
amino acid and adds
the amino acid to the
growing polypeptide
chain

A

Transfer RNA (tRNA)

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21
Q

tRNA Transfers amino
acids to ______ to
help build proteins

A

ribosomes

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22
Q

RNA molecules used
with proteins to make up ribosomes

A

Ribosomal RNA (rRNA)

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23
Q

DNA strand is called the

A

Template Strand

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23
Q

enzyme that reads DNA and
creates a complimentary strand of RNA

A

RNA Polymerase

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23
Q

Major component of ribosomes

A

Ribosomal RNA (rRNA)

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23
Q

Allow mRNA and tRNA to bind to ribosome

A

Ribosomal RNA (rRNA)

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23
Q

RNA is created _’ to _’

A

5’ to 3’

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23
Q

Initial RNA strand has to be _____ before it
can become ____ and is called pre-mRNA or
Precursor mRNA

A

modified
mRNA

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23
Q

The RNA alphabet consists of:

A

A U C G

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23
Q

specific coding relationship
between bases and the amino acids they code
for

A

Genetic Code

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23
Q

The DNA alphabet consists of:

A

A T C G

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24
Q

three base pairs that code for an individual amino acid

A

Codon

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25
Q

used to initiate translation
(methionine)

A

Start Codon (AUG)

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25
Q

used stop translation (UAA,UAG or UGA)

A

Stop Codon

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26
Q

The same ______ specify the same ______ in all living things (there are a few exceptions)

A

codons
amino acids

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27
Q

This demonstrates the fact that DNA evolved ____ in our evolution and remained relatively ____
throughout our history

A

early
unchanged

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27
Q

Transcription involves three main steps:

A

Initiation
Elongation
Termination

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27
Q

promoter sequence of DNA initiates RNA replication

A

Initiation

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28
Q

RNA molecule is made by
adding nucleotides

A

Elongation

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28
Q

RNA molecule is released once
it reaches a termination sequence

A

Termination

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29
Q

Enzyme_______ binds to DNA
at a _______ (a DNA sequence that lies just before a gene)

A

RNA Polymerase
Promoter

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29
Q

A key part of the Promoter is the _____ which is a sequence of DNA that contains _____ and _____ (These nucleotides make the DNA easier to unwind since they contain less hydrogen bonds)

A

TATA box
Thymine and Adenine

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30
Q

RNA is made in the __🡪 __ Direction (follows DNA from 3’🡪 5’) using _______

A

5’🡪 3’
template strand

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30
Q

Strand not used = _________

A

coding strand

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31
Q

Newly synthesised mRNA is the _____ as the coding strand (with exception of T/U)

A

same

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32
Q

_______ unwinds DNA and adds nucleotides to build an RNA strand

A

RNA Polymerase

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33
Q

This allows _______ of a gene to be _______

A

multiple copies
made simultaneously

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33
Q

RNA transcription
____ when _______ reaches a
termination sequence

A

stops
RNA polymerase

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33
Q

Once one RNA polymerase molecule has ________________ another can ________________

A

passed the beginning of a gene

attach and make another copy of the same gene

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34
Q

a section of bases at the
end of a gene that stops
RNA transcription

A

Termination Sequence

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35
Q

The recently made RNA needs to be modified before it can be used to help make _____

A

proteins

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36
Q

a chain of adenine added to the 3’ end of the RNA

A

Poly A Tail

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37
Q

seven guanine bases attached to the beginning of the RNA strand

A

5’ Cap

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38
Q

protects from _____ digestion during translation

A

enzyme

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39
Q

Acts as an attachment site for ____ to initiate translation

A

ribosomes

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40
Q

If transcribed, protein
would ________

A

fold improperly

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40
Q

Parts of mRNA in
Eukaryotes (_____) are
not transcribed—do not
code for proteins

A

introns

40
Q

a non-coding sequence of DNA or RNA

A

Intron

41
Q

Prokaryotes have no
introns (T/F)

A

TRUE

42
Q

Introns need to be removed from RNA–_______

Introns stay in the _____

A

spliceosomes

nucleus

43
Q

a sequence of DNA/RNA that has coding regions of a gene

A

Exon

43
Q

Exons exit the _____

A

nucleus

44
Q

_____ in RNA need to be connected by removing
introns

A

Exons

44
Q

Spliceosomes cut off _____ and attaches the ___ together

A

intron loop
RNA

45
Q

proteins that bind to introns and signals them for removal

A

Small Ribonucloproteins (snRNP’s)

46
Q

snRNP’s bind to introns and form an ______

A

intron loop

46
Q

enzyme that removes introns
from RNA

A

Spliceosome

47
Q

a process that produces different mRNA’s from pre mRNA

A

Alternative Splicing

47
Q

Allows for more than one ________ to be made from a single gene

A

polypeptide

47
Q

Ex. Humans have _____ genes but can make ______ different proteins!

A

20,000
100,000

47
Q

central dogma DNA to RNA is:

A

Transcription

47
Q

central dogma RNA to protien is:

A

Translation

47
Q

RNA molecules used with proteins to make up ribosomes is:

A

Ribosomal RNA (rRNA)

48
Q

rRNA Allow mRNA and tRNA to bind for _______

A

translation

48
Q

Recap Codons

Every __ nucleotides
on mRNA

A

3

49
Q

The way the codons are
arranged in groups of
three is called the
________

A

reading frame

50
Q

Three Steps of Translation

A

Initiation
Elongation
Termination

51
Q

Initiation:

Ribosomal subunits
bind to mRNA at ___
cap

A

5`

52
Q

Goal of translation:

A

to turn post-transcriptional
mRNA code into an
amino acid sequence

53
Q

Initiation:

Binds to start codon:
_____

A

AUG

54
Q

in Initiation: AUG

This always codes for
the amino acid
_______

A

methionine

55
Q

Elongation:

Ribosomes move along the
mRNA in __🡪___ direction

A

5`🡪3

56
Q

Elongation:

Reads _____ nucleotides at a
time—reads codons

A

three

57
Q

Elongation:

Each ____ carries one specific
______ and delivers the
appropriate, corresponding
amino acid to the ribosomes to
build polypeptides

A

tRNA
anticodon

57
Q

Elongation:

Ribosomes have three spots for tRNA to bind:

A Site: _______ site for aminoacyl tRNA to bind

P site: ______ site for peptide bonds to form

E site: _____ site, for tRNA to prepare to leave the complex

A

Aminoacyl
Peptidyl
Exit

58
Q

_______ brings methionine to P-site

A

First tRNA

59
Q

________ brings next amino acid to A-site

A

Second tRNA

60
Q

________ formed between amino acids

A

Peptide bond

61
Q

tRNA with met. now in in ____

A

E-site

61
Q

Ribosome shifts over one codon; moving _______

A

first tRNA

62
Q

Next tRNA will always enter _____

A

A-site

62
Q

Process _____ until stop _____

A

repeats
codon

63
Q

Termination:
_______ causes translation to terminate

A

Stop codon

64
Q

Release factors cause the complex to dissassociate
releasing the _____ and ______

A

mRNA and ribosomes

65
Q

______ folding then occurs and the cell further modifies it
for use

A

Protein

66
Q

Controlling Gene Expression:

Not all _______ are required by all cells at all times

A

proteins

67
Q

Cells regulate _______ in response to their own life cycles and environmental
conditions

A

gene expression

68
Q

Ex – insulin only required when:

A

blood glucose levels are high

69
Q

Gene expression in prokaryotes is regulated in response to the concentration of two
molecules:

A

lactose and tryptophan

70
Q

Some genes are always required – called
____________ ex hemoglobin

A

housekeeping genes

71
Q

Both of these responses are examples of:

A

negative feedback control

72
Q

The Lac Operon:

To regulate the expression of genes required for _______ metabolism, prokaryotes use what is known as the _________

A

lactose
operon model

72
Q

The lac operon consists of:

A

Promoter
Operator
Coding regions for the enzymes thatmetabolize lactose

72
Q

The ___ operon is a cluster of three genes that
code for the proteins involved in the metabolism of lactose

A

lac

73
Q

Upstream from the operon is a gene that codes
for a ______ protein

A

repressor

73
Q

This allows ________ to bind to
the promoter and
transcribe the genes

A

RNA polymerase

74
Q

In the presence of
______ the lactose
molecule itself binds
to the _______
protein.

A

lactose
repressor

74
Q

When lactose is
_____ from the cells
environment, the
___________
binds to the operator
of the lac operon,
blocking transcription

A

absent
active lac repressor

74
Q

The trp Operon:

_______ is an amino acid which is an important
component to many proteins.

A

Tryptophan

75
Q
A
76
Q

Prokaryotes can synthesis tryptophan directly or
_____________

A

through their environment

77
Q

The trp operon has the same components as the
lac operon, but ________ acts in a different
manner to regulate gene expression

A

repressor protein

77
Q

There is a ________ is a signal molecule
that binds to a repressor protein to control gene
expression

A

corepressor protein

78
Q

When tryptophan is
absent, the trp
repressor is _____

A

inactive

79
Q

When tryptophan is
______ in the cell’s
environment, the
amino acid binds to
and activates the trp
repressor.

A

present

79
Q

changes in DNA sequence

A

Genetic Mutation

80
Q

Genetic mutation May be caused by:

A

Radiation
Chemicals
Replication Errors

81
Q

Genetic mutation Can change the _____ and _____ of a genome

A

structure and function

82
Q

Keep in mind that mutations are _____ all bad

A

not

83
Q

There are three basic categories of mutations:

A

Mutations with POSITIVE effects

Mutations with NEGATIVE effects

Mutations that do not cause any discernible changes

83
Q

_______ have driven our evolution

A

Mutations

83
Q

Do not affect large portions of DNA

A

Small-Scale Mutations

84
Q

Small-Scale Mutations Involve the following types of mutations:

A

Substitution
Insertion
Deletion
Inversion

84
Q

replacement of one base pair by another

A

Substitution

84
Q

addition of a base pair or larger coding region

A

Insertion

85
Q

removal of a base pair or larger
coding region

A

Deletion

86
Q

bases switch positions

A

Inversion

87
Q

Substitution Mutations:

________ - a mutation that changes a single amino acid in the coding sequence

A

Missense Mutation

88
Q

Substitution Mutations:

________ – a mutation that results in a premature stop codon

A

Nonsense Mutation

89
Q

Substitution Mutations:

________ – a mutation that does not alter the resulting amino acid sequence

A

Silent Mutation

90
Q

a shift in the reading frame
resulting in multiple missense/nonsense effects

A

Frameshift Mutation

91
Q

frame shift mutation May occur from an ______ or ______ of a base pair

A

insertion or deletion

92
Q

Large-Scale Mutations

_______ - the movement of entire genes/sequences of DNA from one chromosome
to another

A

Translocation

93
Q

__________ Can remove entire coding regions

A

Large Scale Deletions

94
Q

Ex of ______: Deletion of Dystrophin gene causes muscular dystrophy

A

Large Scale Deletions

95
Q

Large Scale _______:

The addition/duplication of large regions of DNA

A

Insertions

96
Q

Large Scale Insertions:

Leads to a large number of the ______

Provides opportunities for new genes to _____

A

same gene

evolve

97
Q

________ – caused by
environmental effects

A

Induced Mutations

97
Q

Causes of Genetic Mutations:

_______ - caused by errors in DNA replication

A

Spontaneous Mutations

98
Q

______ – an environmental agent
that directly alters the DNA within a cell

A

Mutagen

99
Q

_______ – bonds to
nucleotides and negatively
affects replication

A

Benzene

100
Q

Chemical Mutagens:

_________ – linked
to various forms of cancer

A
101
Q

______ – inserts
itself between strands of
DNA and causes errors in
replication

A

Ethidium Bromide

102
Q

Ultraviolet radiation may cause damage to DNA
and cause ________

A

skin cancer

102
Q

_______ radiation may cause mutations

A

Electromagnetic

102
Q

________/_______ can break bonds within DNA
molecules and cause cancer/super powers

A

X-Rays/Gamma Rays

103
Q

________ are
passed on while negative
mutations are generally
lost quickly (species can’t
breed if they are dead)

A

Beneficial mutations

103
Q

______ are responsible
for the variety of life we
see today

A

Mutations

104
Q

The majority of mutations
are _____ (in non-coding
regions of DNA)

A

neutral