Week One Biochem Review Flashcard

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

Get instant access to
all materials

Become a Member