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Week One Biochem Review
Review of Week One Biochemistry Powerpoint
86
Chemistry
Professional
09/19/2009

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Term
Our genetic code is made up of DNA and are expressed in the phenotype as a __________.
Definition
protein
Term
What are the four characteristics of our DNA?
Definition
Universal, unambiguous, redundant, non-overlapping & commaless
Term
The genetic code consists of bases, these bases comprise _________.
Definition
codons
Term
The four bases are:
Definition
A (adenine), T (thymine), C (cytosine), and G (guanine)
Term
Since there are four bases, there are ____ possible codons
Definition
64
Term
DNA molecule is a double-helix- __________ _________.
Definition
Rosalind Franklin
Term
Meselson and Stahl experiment showed replication of DNA to be ________________.
Definition
semiconservative
Term
___________ unwinds the strand.
Definition
helicase
Term
_____________ ___________ sets up for the RNA primer
Definition
RNA primase
Term
_______ ___________ _________adds nucleotides to the 3’ end of the RNA primer and elongates the DNA strand
Definition
DNA polymerase III
Term
_________ __________ ___ removes the old RNA primer and replaces it with DNA
Definition
DNA polymerase I
Term
________ _________ catalyzes the formation of the phosphodiester bond linking the Okazaki fragments
Definition
DNA ligase
Term
___________ __________ action causes the newly forming leading strandto grow in the 5’-to-3’ direction
Definition
DNA polymerase
Term
________ uses DNA polymerases to repeatedly replicate DNA in the test tube.
Definition
PCR (polymerase chain reaction)
Term
RNA differs from DNA in 3 ways:
Definition
1)it is single-stranded
2) its sugar molecule is ribose rather than deoxyribose
3) its fourth base is uracil rather than thymine
Term
Messenger RNA =
Definition
mRNA is the message or direction on how to make a protein
Term
Transfer RNA =
Definition
tRNA it matches up amino acids with the RNA message
Term
Ribosomal RNA=
Definition
rRNA used to bind the mRNA message
Term
recognition sequence: one or two recognition sequences of 50 - 70bp form what?
Definition
the TATA box
Term
TATA box (rich in thymine & adinine): ___ base pairs upstream from the_____ ______ for transcription
Definition
25; initiation site
Term
_________ __________ _________ ___ needs transcription factors to initiate transcription
Definition
Eukaryotic RNA polymerase II
Term
The protein ______ binds to the TATA box
Definition
TFIID
Term
Finally _____ ______________ ____ binds to the site
Definition
RNA polymerase II
Term
_____ is transcribed from the DNA template after the ________ __ ____ are exposed by unwinding of the double helix.
Definition
RNA;bases of DNA
Term
RNA polymerase reads the DNA template strand from __ to __ and produces the RNA transcript from __ to __.
Definition
3’ to 5’ ; 5' to 3'
Term
Nucleotides are added at the __ end of the growing RNA
Definition
3'
Term
One mRNA codon _____ indicates the starting point of translation, also codes for _____________.
Definition
AUG; methionine
Term
Three stop codons indicate the end of _________.
Definition
translation - UAA, UAG and UGA
Term
The other 60 codons code only for __________ ________ _________.
Definition
particular amino acids.
Term
_____ binds the correct amino acid; has an _______ complementary to the mRNA codon.
Definition
tRNA ; anticodon
Term
The _____________, a family of activating enzymes, attach specific amino acids to their appropriate tRNA’s, forming ________ tRNA’s.
Definition
aminoacyl-tRNA synthetases; charged
Term
The ribosome is composed of two units:
large subunit that consists of _____ different molecules of rRNA and ___ different ________ ________ .
small subunit of one ___ ________ and ___ different protein molecules
Definition
3; 45; protein molecules;rRNA molecule; 33
Term
An initiation complex consisting of an _______ _________ __________ _________ and a small ribosomal subunit bound to mRNA triggers the beginning of ____________.
Definition
amino acid-charged tRNA; translation
Term
On the large subunit of the ribosome there are ___ sites to which tRNA binds.
Definition
four
Term
T (transfer) site: where ___________.
Definition
tRNA first lands
Term
A (amino acid) site is where the tRNA anticodon binds to ___________.
Definition
binds to mRNA codon
Term
P (polypeptide) site is where the tRNA __________.
Definition
adds its amino acid to the growing poly peptide chain
Term
E (exit) site is where tRNA, without its ______ _______, resides before leaving the________ and going back to the cytosol to pick up another ________ _________.
Definition
amino acid; ribosome; amino acid
Term
Polypeptides grow from the __ terminus toward the __ terminus. The ribosome moves along the mRNA ___ codon at a time.
Definition
N to C; one
Term
The presence of a _____ ______ in the __ site of the ribosome causes translation to terminate
Definition
stop codon; A
Term
Signals contained in the amino acid sequences of proteins direct them to___________ ____________.
Definition
cellular destinations.
Term
Modifications of proteins after translation include:
Definition
proteolysis, glycosylation, and phosphorylation.
Term
Cells must regulate how they synthesize molecules to suit their:
Definition
condition, environment, and needs
Term
cells can control synthesis activity by
___________ or controlling the production
of _________.
Definition
regulating; enzymes
Term
cells can control synthesis activity by blocking __________ of the gene that codes for a protein.
Definition
transcription
Term
cells can control synthesis activity by _______ the ______ after it is made.
Definition
hydrolyze; mRNA
Term
cells can control synthesis activity by ________ __________ of mRNA at the ribosome.
Definition
preventing translation
Term
cells can control synthesis activity by __________ the protein after it was made
Definition
hydrolyzing
Term
Point mutations result from alterations in______ ________ ________ of DNA.
Definition
single base pairs
Term
What are some examples of point mutation?
Definition
silent, missense, nonsense, or frame-shift
Term
Chromosomal mutations involve _______ regions of a chromosome.
Definition
large
Term
What are some examples of chromosomal mutations>
Definition
deletions, duplications, inversions, or translocations
Term
Point mutations result from the _______ or _______ of one base for another in the DNA and as a result in the RNA
Definition
addition or subtraction;
Term
Some result in no change in amino acid because of the redundancy of the genetic code=
Definition
silent or synonymous mutation
Term
A ____________ mutation results in an amino acid change
Definition
missense
Term
____________ mutation results in no protein being made at all, they are disruptive.
Definition
nonsense
Term
____________ mutation results in no protein being made at all, they are disruptive.
Definition
nonsense
Term
A _________-__________ mutation, is when single base pairs may be inserted or deleted from DNA
Definition
frame-shift
Term
___________ remove part of the genetic material
Definition
deletions
Term
___________ mutations are homologous chromosomes brake at different positions and then reconnect to the wrong partners
Definition
Duplications
Term
_________ mutations are removal of a segment and its reinsertion into the same location but flipped.
Definition
Inversion
Term
___________ mutation is when a segment of DNA breaks off and is inserted into a different chromosome
Definition
translocation
Term
Spontaneous mutations occur because of instabilities in ______ or _____________.
Definition
DNA or chromosomes
Term
Induced mutations occur when an ________ __________ damages ____.
Definition
outside agent; DNA
Term
Some of these non-transcribed regions are ________, such as the telomeres; some regulate ______ ________; and some have no known use.
Definition
structural; gene expression
Term
____________ are 5-50bps are repeated side by side up to a million times.
Definition
Satellites
Term
________ are 12-100 bps long & are repeated several thousand times. Can be used as ______ _______ for identifying an individual because their numbers can vary
Definition
Minisatellites; genetic markers
Term
__________ are 1-5bps present in small clusters 10-50 copies. These have been used in sequencing the human genome
Definition
microsatellites
Term
___________ are repetitive sequences at the ends of chromosomes
Definition
telomeres
Term
Chromosome _________ occurs after each round of replication. This leads to ____ __________.
Definition
shortening; cell death
Term
The enzyme_____________ prevents the loss of telomeric ends
Definition
telomerase
Term
A ___ _______ is added to the 5’ end.
Definition
G cap, GTP
Term
A _______ __ _______ is added to the 3’ end
Definition
poly A tail
Term
_______ _____________ particle binds at the 5’ splice site and a second binds near the 3’ splice site
Definition
Small ribonucleoprotein (snRNP) particle
Term
____________ elements move about the genome
Definition
Transposable
Term
a _____________ consists of two transposable elements flanking another gene or genes. The entire transposon is copied and inserted as a unit.
Definition
transposon
Term
If the insertion takes place in a somatic cell, _________ may result
Definition
cancer
Term
If a transposon replicates not just itself but also an adjacent gene, the result may be _____ _____________.
Definition
gene duplication
Term
Transposons can result in:
Definition
cancer cells, gene duplication, genetic variability, new genes
Term
___________ _______ are instructions that specify the primary structures of a protein molecule (those that get transcribed into mRNA)
Definition
structural genes
Term
_________ are units of transcription; structural genes plus regulatory mechanisms.
Definition
operons
Term
__________ regions bind activator proteins that stimulate the transcription complex (promoter then binds RNA polymerase & transcription starts)
Definition
enhancer regions
Term
_________ -when attached to an operon, transcription shuts down
Definition
repressor
Term
__________ are negative regulatory regions; turn off transcription by binding to repressor
Definition
silencers
Term
___________ blocks RNA polymerase from binding & transcribing the structural genes, preventing synthesis of tryptophan pathway enzymes
Definition
tryptophan;
Term
When glucose levels are high:
Definition
1. RNA polymerase cannot bind efficiently
2. Structural genes are not transcribed. This is adaptive when the cell does not require an alternative energy source
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