Lecture 3B Flashcards
(158 cards)
1
Q
The flow of genetic information
A
DNA –> RNA –> PROTEIN
2
Q
origin of replication site
A
DNA replication begins at a point in the DNA molecule called
3
Q
DNA replication begins at a point in the DNA molecule called
A
origin of replication site
4
Q
RNA primer
A
short sequence of RNA nucleotides,
complementary to a small, initial section of the DNA strand prepared for replication
5
Q
short sequence of RNA nucleotides,
complementary to a small, initial section of the DNA strand prepared for replication
A
RNA primer
6
Q
assembles an RNA primer at the origin
of replication site
A
Enzyme primase
7
Q
Enzyme primase
A
assembles an RNA primer at the origin
of replication site
8
Q
DNA polymerase
A
then adds nucleotides to the RNA
primer, thus, begins the process of constructing new complementary strand of DNA.
9
Q
then adds nucleotides to the RNA
primer, thus, begins the process of constructing new complementary strand of DNA.
A
DNA polymerase
10
Q
RNA primer
A
__ is then enzymatically removed and replaced by nucleotide replacement enzyme called DNA polymerase 1 with an
appropriate DNA sequence of the DNA nucleotides
11
Q
__ is then enzymatically removed and replaced by nucleotide replacement enzyme called DNA polymerase 1 with an
appropriate DNA sequence of the DNA nucleotides
A
RNA primer
12
Q
RNA primer is then enzymatically removed and replaced by nucleotide replacement enzyme called _____ with an appropriate DNA sequence of the DNA nucleotides
A
DNA polymerase 1
13
Q
DNA polymerase 1
A
nucleotide replacement enzyme is called __ which is the replacement from the removal of RNA primer
14
Q
DNA polymerase
A
enzyme complex that engages the separated portion of the molecule and initiates the process of replication.
15
Q
enzyme complex that engages the separated portion of the molecule and initiates the process of replication.
A
DNA polymerase
16
Q
DNA polymerase
A
can only add new DNA nucleotides to a preexisting
chain of molecules
17
Q
can only add new DNA nucleotides to a preexisting
chain of molecules
A
DNA polymerase
18
Q
DNA polymerase can only add new DNA nucleotides to
A
a preexisting chain of molecules
19
Q
a preexisting chain of molecules
A
DNA polymerase can only add new DNA nucleotides to
20
Q
Because the two complementary strands of the DNA molecule are oriented in opposite directions and the DNA polymerase can only accommodate replication in one direction,
A
two different mechanisms for copying the strands of DNA are employed
21
Q
why is two different mechanisms for copying the strands of DNA are employed
A
Because the two complementary strands of the DNA molecule are oriented in opposite directions and the DNA polymerase can only accommodate replication in one direction,
22
Q
LEADING STRAND
A
continuous replication
23
Q
continuous replication
A
LEADING STRAND
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Q
LAGGING STRAND
A
backward formation and in short DNA fragments
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backward formation and in short DNA fragments
LAGGING STRAND
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OKAZAKI FRAGMENTS
are series of short DNA
fragments, and each requires a separate RNA primer
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are series of short DNA
fragments, and each requires a separate RNA primer
OKAZAKI FRAGMENTS
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REPLICATION
process by which the original DNA is used as a template for the production of a new complementary DNA strand
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process by which the original DNA is used as a template for the production of a new complementary DNA strand
REPLICATION
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REPLICATION begins in
nucleus when enzyme HELICASE breaks the HYDROGEN bonds between the two strands of DNA, unwinding the double helix DNA into two single strands that serve as template for the replication of DNA
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resulting structure of replication
REPLICATION FORK.
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REPLICATION FORK.
resulting structure of replication
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_____ is the process by which the original DNA is used as a template for the production of a new complementary DNA strand. It begins in the nucleus when an enzyme _____ breaks the _______ bonds between the two strands of DNA, unwinding the double helix DNA into two single strands that serve as template for the replication of DNA. The resulting structure is called the _______.
Replication
Helicase
Hydrogen
Replication Fork
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formed from its 5’ to its 3’
LEADING strand
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LEADING strand
formed from its 5’ to its 3’
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The LEADING strand is formed from its 5’ to its 3’ strand by the enzyme
DNA POLYMERASE I
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DNA POLYMERASE I
form the leading strand from 5' to 3'
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This enzyme adds nucleotide units to leading strand
DNA POLYMERASE I
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DNA POLYMERASE I
This enzyme adds nucleotide units to leading strand
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Nucleotides contain ____, ____, and ____
phosphate, bases, sugars
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phosphate, bases, sugars
component of nucleotides
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LAGGING strand
formed backward from its 3’ to its 5’.
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formed backward from its 3’ to its 5’
LAGGING strand
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It does not form continuously; instead it forms in pieces known as OKAZAKI fragments.
LAGGING strand
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lagging strand forms in pieces known as
OKAZAKI fragments
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OKAZAKI fragments
lagging strand forms in pieces known as
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RNA PRIMASE adds a structure known as ____, short sequence of RNA nucleotides, complementary to a small, initial section of the DNA strand prepared for replication, to the lagging strand.
RNA PRIMER
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RNA PRIMER
short sequence of RNA nucleotides, complementary to a small, initial section of the DNA strand prepared for replication, to the lagging strand.
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lays down a new DNA in lagging strand
DNA polymerase 3
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DNA polymerase 3
lays down a new DNA in lagging strand
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The ____ is formed from its 5’ to its 3’ strand by the enzyme ____. This enzyme adds nucleotide units to leading strand. Nucleotides contain ____, ____, and ____. The other strand known as the ____ is formed backward from its 3’ to its 5’. It does not form continuously like the leading strand; instead it forms in pieces known as ____. ____ adds a structure known as ____, short sequence of RNA nucleotides, complementary to a small, initial section of the DNA strand prepared for replication, to the lagging strand. DNA polymerase 3 lays down a new DNA in lagging strand. This process is repeated as new DNA is added to the strand.
LEADING strand
DNA POLYMERASE I
PHOSPHATE, BASES, and SUGARS
LAGGING strand
OKAZAKI fragments
RNA PRIMASE
RNA PRIMER
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Another type of DNA polymerase known as ____ replaces the RNA primers in the lagging strand with DNA
DNA POLYMERASE I
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DNA POLYMERASE I
replaces the RNA primers in the lagging strand with DNA.
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Finally, the enzyme ____ links the OKAZAKI fragments, thus the lagging strand is completely replicated
DNA LIGASE
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Finally, the enzyme DNA LIGASE links the ____, thus the lagging strand is completely replicated
OKAZAKI fragments
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OKAZAKI fragments
Finally, the enzyme DNA LIGASE links this, thus the lagging strand is completely replicated
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GENES
a sequence of nucleotides in DNA that code for a particular protein
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a sequence of nucleotides in DNA that code for a particular protein
GENES
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PROTEINS
drive cellular processes, determine physical characteristics, and manifest genetic disorders by their absence or presence
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drive cellular processes, determine physical characteristics, and manifest genetic disorders by their absence or presence
PROTEINS
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protein synthesis occurs in ____ located in the cytoplasm
RIBOSOMES
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protein synthesis occurs in ribosomes located in the ____
CYTOPLASM
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____ occurs in ribosomes located in the cytoplasm
protein synthesis
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How does a ribosome synthesize the protein required if it does not have access to DNA?
Through an intermediate substance known as mRNA...
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transcription
Information is faithfully copied from DNA into mRNA by a process called
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Information is faithfully copied from DNA into mRNA by a process called
transcription
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Ribosomes use the mRNA as a blueprint to synthesize proteins composed of amino acid by a process called
translation
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In translation, ____ use the mRNA as a blueprint to synthesize proteins composed of amino acid
RIBOSOMES
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In translation, ribosomes use the ____ as a blueprint to synthesize proteins composed of amino acid
mRNA
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In translation, ribosomes use the mRNA as ____
as a blueprint to synthesize proteins composed of amino acid
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three types of RNA
mRNS
rRNA
tRNA
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mRNA function
“blueprint” for building a protein
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“site” where the proteins are made
rRNA
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rRNA function
“site” where the proteins are made
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“vehicle” delivering the proper amino acid to the site of protein synthesis
tRNA
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tRNA function
“vehicle” delivering the proper amino acid to the site of protein synthesis
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in transcription: INITIATION, ____ binds to a segment of DNA and opens up the double helix
RNA polymerase
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in transcription: INITIATION, RNA polymerase... (function)
binds to a segment of DNA and opens up the double helix
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in transcription: INITIATION, ___ then recognizes the promoter region which is a sequence of DNA rich in A and T bases (TATA box)
found only on one strand of the DNA
RNA POLYMERASE
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in transcription: INITIATION, RNA POLYMERASE then recognizes the promoter region which is a ____
a sequence of DNA rich in A and T bases (TATA box) found only on one strand of the DNA
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However, an RNA polymerase cannot ____. Another protein, a TRANSCRIPTION FACTOR
that recognizes the TATA, binds to the DNA before the
RNA polymerase can do so.
cannot recognize the
TATA box and other landmarks of the promoter region
on its own.
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However, an RNA polymerase cannot recognize the
TATA box and other landmarks of the promoter region
on its own. Another protein, a ____ that recognizes the TATA, binds to the DNA before the
RNA polymerase can do so.
TRANSCRIPTION FACTOR
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However, an RNA polymerase cannot recognize the
TATA box and other landmarks of the promoter region
on its own. Another protein, a TRANSCRIPTION FACTOR
that recognizes the TATA, ___.
binds to the DNA before the
RNA polymerase can do so.
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RNA polymerase uses only one of the strands of DNA
as a template for mRNA synthesis. (what process)
TRANSCRIPTION: 2. ELONGATION
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RNA polymerases can add nucleotides only to the 3’ end
of a DNA sequence. (what process)
TRANSCRIPTION: 2. ELONGATION
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Thus, an RNA molecule elongates in the 5’ to 3’ direction (what process)
TRANSCRIPTION: 2. ELONGATION
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in TRANSCRIPTION: 2. ELONGATION, ____ uses only one of the strands of DNA as a template for mRNA synthesis
RNA POLYMERASE
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in TRANSCRIPTION: 2. ELONGATION, RNA polymerase uses only ____
as a template for mRNA synthesis.
one of the strands of DNA
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in TRANSCRIPTION: 2. ELONGATION, RNA polymerase uses only one of the strands of DNA as a ____
template for mRNA synthesis.
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in TRANSCRIPTION: 2. ELONGATION, ____can add nucleotides only to the 3’ end
of a DNA sequence.
RNA POLYMERASE
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in TRANSCRIPTION: 2. ELONGATION, RNA polymerases can add nucleotides only to the _____
3’ end of a DNA sequence
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in TRANSCRIPTION: 2. ELONGATION, an ____ elongates in the 5’ to 3’ direction
RNA MOLECULE
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in TRANSCRIPTION: 2. ELONGATION, RNA molecule ____
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As the RNA polymerase molecule passes, the DNA helix
re-forms. Synthesis continues until the end of a gene is
reached where RNA polymerase recognizes a terminator sequence. (what process)
TRANSCRIPTION: 3. TERMINATION
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in TRANSCRIPTION: 3. TERMINATION, As the RNA polymerase molecule ____, the DNA helix ____. Synthesis continues until the end of a gene is reached where RNA polymerase recognizes a terminator sequence.
passess, re-forms
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in TRANSCRIPTION: 3. TERMINATION, As the ____ passes, the ____ re-forms. Synthesis continues until the end of a gene is reached where RNA polymerase recognizes a terminator sequence.
RNA polymerase molecule, DNA helix
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in TRANSCRIPTION: 3. TERMINATION, As the RNA polymerase molecule passes, the DNA helix re-forms. ____ continues until the end of a gene is reached where RNA polymerase recognizes a terminator sequence.
synthesis
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in TRANSCRIPTION: 3. TERMINATION, As the RNA polymerase molecule passes, the DNA helix re-forms. synthesis continues until ____ where RNA polymerase recognizes a terminator sequence.
the end of a gene is reached
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in TRANSCRIPTION: 3. TERMINATION, As the RNA polymerase molecule passes, the DNA helix re-forms. synthesis continues until the end of a gene is reached where ____
RNA polymerase recognizes a terminator sequence
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Once the RNA polymerase leaves the promoter region, a
new RNA polymerase can bind there to begin a new
mRNA transcript. (what process)
TRANSCRIPTION
102
Since prokaryotes lack a membrane bound nucleus
translation can begin even before the mRNA dissociates.
However, the pre-mRNA from eukaryotic cells needs
some modification before it leaves the nucleus. (what process)
TRANSCRIPTION
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in TRANSCRIPTION, Once the RNA polymerase leaves the promoter region, a
____
a new RNA polymerase can bind there to begin a new mRNA transcript
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in TRANSCRIPTION, Since prokaryotes lack a membrane bound, ____.
However, the pre-mRNA from eukaryotic cells needs
some modification before it leaves the nucleus
nucleus translation can begin even before the mRNA dissociates
105
in TRANSCRIPTION, Since prokaryotes lack a membrane bound, nucleus
translation can begin even before the mRNA dissociates.
However, the pre-mRNA from eukaryotic cells needs
____
some modification before it leaves the nucleus
106
In eukaryotes, the mRNA released at the end of
transcription is called
pre-mRNA
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pre-mRNA
In eukaryotes, the mRNA released at the end of
transcription
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undergoes several changes before it is exported out of the nucleus to protect it from the
cytoplasmic environment
Pre-mRNA
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Pre-mRNA undergoes several changes before it is
exported out of the nucleus because???
to protect it from the
cytoplasmic environment
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Processing of mRNA
The 5’ end of the pre-mRNA is capped with a modified form of the G nucleotide. At the 3’ end, an enzyme in the nucleus adds the poly A tail, a long series of A nucleotides
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The entire gene (introns and exons) are transcribed by
the RNA polymerase
mRNA Splicing
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The initial pre-mRNA contains introns that are removed
from the pre-mRNA by spliceosomes while the exons
are spliced together
mRNA Splicing
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Introns are cut OUT – mRNA
mRNA Splicing
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In mRNA splicing, The initial pre-mRNA contains introns that are removed from the pre-mRNA by ___ while the exons
are spliced together
spliceosomes
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After transcription mRNA exits the nucleus via nuclear
pores and ribosomes bind to mRNA(what process)
Translation
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Ribosomes synthesize different proteins by reading the
coding sequence on mRNA (what process)
Translation
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The mRNA is read in triplets of nucleotides each of which encodes an amino acid (what process)
Translation
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in translation, After transcription mRNA ____ via nuclear pores and ribosomes bind to mRNA
exits the nucleus
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in translation, After transcription mRNA exits the nucleus via ____ and ribosomes bind to mRNA
nuclear pores
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in translation, After transcription mRNA exits the nucleus via nuclear pores and ribosomes ____
bind to RNA
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in translation, Ribosomes synthesize different proteins by ____
reading the coding sequence on mRNA
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The ribosome alone cannot synthesize the polypeptide
chain
Transfer RNA (tRNA)
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The correct amino acids must be delivered to the
polypeptide building site
Transfer RNA (tRNA)
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Three-lobed like cloverleaf due to base pairing between
complementary nucleotides on different regions of each tRNA molecule causing it to
fold
Transfer RNA (tRNA)
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At the end of one lobe of tRNA, a sequence of three
bases called the anticodon recognizes and is
complementary to the codon of the mRNA
Transfer RNA (tRNA)
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The anticodon sequence is written in the 3’ to 5’
direction.
Transfer RNA (tRNA)
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in translation, The ribosome alone cannot synthesize the polypeptide chain (T or F)
True
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in translation, The ribosome alone can synthesize the polypeptide chain (T or F)
False
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in translation, The correct amino acids must be delivered to the ____
polypeptide building site
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three-lobed like “cloverleaf” due to base pairing between complementary nucleotides on different regions of each tRNA molecule causing it to fold (T or F)
true
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three-lobed like “cloverleaf” due to base pairing between supplementary nucleotides on different regions of each tRNA molecule causing it to fold (T or F)
false
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three-lobed like “cloverleaf” due to base pairing between complementary nucleotides on different regions of each mRNA molecule causing it to fold (T or F)
false
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three-lobed like “cloverleaf” due to base pairing between complementary nucleotides on different regions of each tRNA molecule causing it to bend (T or F)
false
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At the end of one lobe of tRNA, a sequence of three bases called the ____ recognizes and is complementary to the codon of the mRNA.
ANTICODON
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At the end of one lobe of tRNA, a sequence of three bases called the anticodon ____
recognizes and is complementary to the codon of the mRNA.
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At the 3’ end of the strand is an attachment site for the
corresponding amino acid specified by the mRNA codon
Transfer RNA (tRNA)
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There are 64 possible codon combinations, but the
cytoplasm only holds about 35-45 different tRNAs.
Wobble in the Genetic Code
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This leaves some anti-codons pairing with more than
one codon creating a more lenient compliment in the
third position
Wobble in the Genetic Code
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Redundancy of amino acid codons – wobble position
hypothesis
Wobble in the Genetic Code
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Redundancy of amino acid codons
wobble position hypothesis
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There are ____ possible codon combinations, but the
cytoplasm only holds about ____ different tRNAs
64, 35-45
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site of protein synthesis
Ribosomes
143
a complex that contains a cluster of different kinds of
proteins and rRNA which are linear strands of RNA
Ribosomes
144
has binding sites for the mRNA transcript and the amino acid-tRNA molecules
Ribosomes
145
Each active ribosome has 3 different binding sites for
tRNA molecules:
P (peptide) site
A (acceptor) site
E (exit) site
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P (peptide) site
holds one amino acidtRNA
and the growing chain of amino acids
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holds one amino acidtRNA
and the growing chain of amino acids
P (peptide) site
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holds the tRNA bringing the next amino acid to be added to the chain
A (acceptor) site
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A (acceptor) site
holds the tRNA bringing the next amino acid to be added to the chain
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releases the tRNA molecules back into the cytoplasm
E (exit) site,
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E (exit) site,
releases the tRNA molecules back into the cytoplasm
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Translocation of the ribosome exposes a stop codon in
the A site. Stop codons do not code for an amino acid,
there are no corresponding tRNAs
Termination of Protein Synthesis
153
A protein called a release factor binds to the exposed A
site causing the polypeptide to separate from the
remaining tRNA molecule
Termination of Protein Synthesis
154
Ribosome falls of the mRNA and translation stops.
Termination of Protein Synthesis
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____ of the ribosome exposes a stop codon in the A site. Stop codons do not code for an amino acid, there are no corresponding tRNAs
TRANSLOCATION
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TRANSLOCATION of the ribosome exposes a stop codon in the ____. Stop codons do not code for an amino acid, there are no corresponding tRNAs
A SITE
157
A protein called a ____ binds to the exposed A site causing the polypeptide to separate from the remaining tRNA molecule
release factor
158
binds to the exposed A
site causing the polypeptide to separate from the
remaining tRNA molecule
release factor
