Molecular Genetics (Unit 3) - chapter 7 Flashcards
(155 cards)
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
2
Q
He found that people with alkaptonuria excrete a particular chemical in their _____.
A
urine
3
Q
He hypothesized that people with this disorder were not ________
A
able to break down this chemical
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
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
6
Q
One Gene-One Polypeptide Hypothesis
-Each gene codes for the synthesis of one ______
A
polypeptide
7
Q
-Different polypeptides can be combined to form more _________
A
complex proteins
8
Q
-Can form (3)
A
hormones, enzymes, antibodies etc.
8
Q
the fundamental principle of molecular genetics, which states that genetic information flows from DNA to RNA to Proteins
A
Central Dogma
9
Q
The Central Dogma Includes (3)
A
Transcription, Translation,
and Folding
10
Q
information in DNA is copied into RNA
A
Transcription
11
Q
RNA can exit the nucleus and enter the _____
A
cytosol
12
Q
RNA acts as a copy of the instructions
contained in DNA that can be transported outside of the ______
A
nucleus
13
Q
RNA can then be used to build ______
A
proteins
13
Q
_______ information contained within RNA
is used to build proteins
A
Translation
14
Q
___ contains instructions coding for a specific amino acid sequence
Involves the use of ______
A
RNA
Ribosomes
14
Q
changing shape of an amino acid chain
into a functioning protein
A
Folding
14
Q
_______ chains must fold properly in order
to become functioning proteins
A
Amino acid
14
Q
RNA:
______ Stranded
A
single
14
Q
RNA:
Adenine pairs with _______
A
Uracil (A-U not A-T)
15
Q
RNA:
Contains _______ instead of deoxyribose sugar in DNA
A
Ribose sugar
16
Q
Three major types of RNA include
A
-Messenger RNA (mRNA),
-Transfer RNA
(tRNA)
-Ribosomal RNA (rRNA)
17
Q
translated by
ribosomes into a protein
A
Messenger RNA (mRNA)
18
Q
Used to move the information from DNA to the ribosome where it can be translated
A
Messenger RNA (mRNA)
19
Varies in length depending on the length of the gene being copied
Messenger RNA (mRNA)
20
a carrier molecule that
binds to a specific
amino acid and adds
the amino acid to the
growing polypeptide
chain
Transfer RNA (tRNA)
21
tRNA Transfers amino
acids to ______ to
help build proteins
ribosomes
22
RNA molecules used
with proteins to make up ribosomes
Ribosomal RNA (rRNA)
23
DNA strand is called the
Template Strand
23
enzyme that reads DNA and
creates a complimentary strand of RNA
RNA Polymerase
23
Major component of ribosomes
Ribosomal RNA (rRNA)
23
Allow mRNA and tRNA to bind to ribosome
Ribosomal RNA (rRNA)
23
RNA is created _’ to _’
5’ to 3’
23
Initial RNA strand has to be _____ before it
can become ____ and is called pre-mRNA or
Precursor mRNA
modified
mRNA
23
The RNA alphabet consists of:
A U C G
23
specific coding relationship
between bases and the amino acids they code
for
Genetic Code
23
The DNA alphabet consists of:
A T C G
24
three base pairs that code for an individual amino acid
Codon
25
used to initiate translation
(methionine)
Start Codon (AUG)
25
used stop translation (UAA,UAG or UGA)
Stop Codon
26
The same ______ specify the same ______ in all living things (there are a few exceptions)
codons
amino acids
27
This demonstrates the fact that DNA evolved ____ in our evolution and remained relatively ____
throughout our history
early
unchanged
27
Transcription involves three main steps:
Initiation
Elongation
Termination
27
promoter sequence of DNA initiates RNA replication
Initiation
28
RNA molecule is made by
adding nucleotides
Elongation
28
RNA molecule is released once
it reaches a termination sequence
Termination
29
Enzyme_______ binds to DNA
at a _______ (a DNA sequence that lies just before a gene)
RNA Polymerase
Promoter
29
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)
TATA box
Thymine and Adenine
30
RNA is made in the __🡪 __ Direction (follows DNA from 3’🡪 5’) using _______
5’🡪 3’
template strand
30
Strand not used = _________
coding strand
31
Newly synthesised mRNA is the _____ as the coding strand (with exception of T/U)
same
32
_______ unwinds DNA and adds nucleotides to build an RNA strand
RNA Polymerase
33
This allows _______ of a gene to be _______
multiple copies
made simultaneously
33
RNA transcription
____ when _______ reaches a
termination sequence
stops
RNA polymerase
33
Once one RNA polymerase molecule has ________________ another can ________________
passed the beginning of a gene
attach and make another copy of the same gene
34
a section of bases at the
end of a gene that stops
RNA transcription
Termination Sequence
35
The recently made RNA needs to be modified before it can be used to help make _____
proteins
36
a chain of adenine added to the 3’ end of the RNA
Poly A Tail
37
seven guanine bases attached to the beginning of the RNA strand
5’ Cap
38
protects from _____ digestion during translation
enzyme
39
Acts as an attachment site for ____ to initiate translation
ribosomes
40
If transcribed, protein
would ________
fold improperly
40
Parts of mRNA in
Eukaryotes (_____) are
not transcribed—do not
code for proteins
introns
40
a non-coding sequence of DNA or RNA
Intron
41
Prokaryotes have no
introns (T/F)
TRUE
42
Introns need to be removed from RNA--_______
Introns stay in the _____
spliceosomes
nucleus
43
a sequence of DNA/RNA that has coding regions of a gene
Exon
43
Exons exit the _____
nucleus
44
_____ in RNA need to be connected by removing
introns
Exons
44
Spliceosomes cut off _____ and attaches the ___ together
intron loop
RNA
45
proteins that bind to introns and signals them for removal
Small Ribonucloproteins (snRNP’s)
46
snRNP’s bind to introns and form an ______
intron loop
46
enzyme that removes introns
from RNA
Spliceosome
47
a process that produces different mRNA’s from pre mRNA
Alternative Splicing
47
Allows for more than one ________ to be made from a single gene
polypeptide
47
Ex. Humans have _____ genes but can make ______ different proteins!
20,000
100,000
47
central dogma DNA to RNA is:
Transcription
47
central dogma RNA to protien is:
Translation
47
RNA molecules used with proteins to make up ribosomes is:
Ribosomal RNA (rRNA)
48
rRNA Allow mRNA and tRNA to bind for _______
translation
48
Recap Codons
Every __ nucleotides
on mRNA
3
49
The way the codons are
arranged in groups of
three is called the
________
reading frame
50
Three Steps of Translation
Initiation
Elongation
Termination
51
Initiation:
Ribosomal subunits
bind to mRNA at ___
cap
5`
52
Goal of translation:
to turn post-transcriptional
mRNA code into an
amino acid sequence
53
Initiation:
Binds to start codon:
_____
AUG
54
in Initiation: AUG
This always codes for
the amino acid
_______
methionine
55
Elongation:
Ribosomes move along the
mRNA in __🡪___ direction
5`🡪3
56
Elongation:
Reads _____ nucleotides at a
time—reads codons
three
57
Elongation:
Each ____ carries one specific
______ and delivers the
appropriate, corresponding
amino acid to the ribosomes to
build polypeptides
tRNA
anticodon
57
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
Aminoacyl
Peptidyl
Exit
58
_______ brings methionine to P-site
First tRNA
59
________ brings next amino acid to A-site
Second tRNA
60
________ formed between amino acids
Peptide bond
61
tRNA with met. now in in ____
E-site
61
Ribosome shifts over one codon; moving _______
first tRNA
62
Next tRNA will always enter _____
A-site
62
Process _____ until stop _____
repeats
codon
63
Termination:
_______ causes translation to terminate
Stop codon
64
Release factors cause the complex to dissassociate
releasing the _____ and ______
mRNA and ribosomes
65
______ folding then occurs and the cell further modifies it
for use
Protein
66
Controlling Gene Expression:
Not all _______ are required by all cells at all times
proteins
67
Cells regulate _______ in response to their own life cycles and environmental
conditions
gene expression
68
Ex – insulin only required when:
blood glucose levels are high
69
Gene expression in prokaryotes is regulated in response to the concentration of two
molecules:
lactose and tryptophan
70
Some genes are always required – called
____________ ex hemoglobin
housekeeping genes
71
Both of these responses are examples of:
negative feedback control
72
The Lac Operon:
To regulate the expression of genes required for _______ metabolism, prokaryotes use what is known as the _________
lactose
operon model
72
The lac operon consists of:
Promoter
Operator
Coding regions for the enzymes thatmetabolize lactose
72
The ___ operon is a cluster of three genes that
code for the proteins involved in the metabolism of lactose
lac
73
Upstream from the operon is a gene that codes
for a ______ protein
repressor
73
This allows ________ to bind to
the promoter and
transcribe the genes
RNA polymerase
74
In the presence of
______ the lactose
molecule itself binds
to the _______
protein.
lactose
repressor
74
When lactose is
_____ from the cells
environment, the
___________
binds to the operator
of the lac operon,
blocking transcription
absent
active lac repressor
74
The trp Operon:
_______ is an amino acid which is an important
component to many proteins.
Tryptophan
75
76
Prokaryotes can synthesis tryptophan directly or
_____________
through their environment
77
The trp operon has the same components as the
lac operon, but ________ acts in a different
manner to regulate gene expression
repressor protein
77
There is a ________ is a signal molecule
that binds to a repressor protein to control gene
expression
corepressor protein
78
When tryptophan is
absent, the trp
repressor is _____
inactive
79
When tryptophan is
______ in the cell’s
environment, the
amino acid binds to
and activates the trp
repressor.
present
79
changes in DNA sequence
Genetic Mutation
80
Genetic mutation May be caused by:
Radiation
Chemicals
Replication Errors
81
Genetic mutation Can change the _____ and _____ of a genome
structure and function
82
Keep in mind that mutations are _____ all bad
not
83
There are three basic categories of mutations:
Mutations with POSITIVE effects
Mutations with NEGATIVE effects
Mutations that do not cause any discernible changes
83
_______ have driven our evolution
Mutations
83
Do not affect large portions of DNA
Small-Scale Mutations
84
Small-Scale Mutations Involve the following types of mutations:
Substitution
Insertion
Deletion
Inversion
84
replacement of one base pair by another
Substitution
84
addition of a base pair or larger coding region
Insertion
85
removal of a base pair or larger
coding region
Deletion
86
bases switch positions
Inversion
87
Substitution Mutations:
________ - a mutation that changes a single amino acid in the coding sequence
Missense Mutation
88
Substitution Mutations:
________ – a mutation that results in a premature stop codon
Nonsense Mutation
89
Substitution Mutations:
________ – a mutation that does not alter the resulting amino acid sequence
Silent Mutation
90
a shift in the reading frame
resulting in multiple missense/nonsense effects
Frameshift Mutation
91
frame shift mutation May occur from an ______ or ______ of a base pair
insertion or deletion
92
Large-Scale Mutations
_______ - the movement of entire genes/sequences of DNA from one chromosome
to another
Translocation
93
__________ Can remove entire coding regions
Large Scale Deletions
94
Ex of ______: Deletion of Dystrophin gene causes muscular dystrophy
Large Scale Deletions
95
Large Scale _______:
The addition/duplication of large regions of DNA
Insertions
96
Large Scale Insertions:
Leads to a large number of the ______
Provides opportunities for new genes to _____
same gene
evolve
97
________ – caused by
environmental effects
Induced Mutations
97
Causes of Genetic Mutations:
_______ - caused by errors in DNA replication
Spontaneous Mutations
98
______ – an environmental agent
that directly alters the DNA within a cell
Mutagen
99
_______ – bonds to
nucleotides and negatively
affects replication
Benzene
100
Chemical Mutagens:
_________ – linked
to various forms of cancer
101
______ – inserts
itself between strands of
DNA and causes errors in
replication
Ethidium Bromide
102
Ultraviolet radiation may cause damage to DNA
and cause ________
skin cancer
102
_______ radiation may cause mutations
Electromagnetic
102
________/_______ can break bonds within DNA
molecules and cause cancer/super powers
X-Rays/Gamma Rays
103
________ are
passed on while negative
mutations are generally
lost quickly (species can’t
breed if they are dead)
Beneficial mutations
103
______ are responsible
for the variety of life we
see today
Mutations
104
The majority of mutations
are _____ (in non-coding
regions of DNA)
neutral
