(true or false) Specific transcription factors are not important for tissue-specific gene expression and for cell growth and differentiation
false
The polyadenylation reaction is an important regulatory step because:
- the length of the poly(a) tail modulates both mARNA stability and translations efficiency
- the poly(a) tail protects the mRNA from premature degradation by 3' exonucleases
RNA processing control includes all the following except
basal trancriptonal factors
(True) General transcription factors are needed for priming transcription
True
Why is the addition of the 5' cap structure critical?
an mRNA to be translated in the cytoplasm, is needed to protect the growing RNA chain from degradation in the nucleus by 5' exonucleases, the cap also helps the transcript bind to the ribosome during the protein synthesis
(True or False) RNA polymerase III synthesizes rRNAs involved in facilitating protein synthesis by the ribosome
False
Which of the following is an mRNA processing reaction?
Removal of introns from the heterogenous nuclear RNA
Which of the following sites on a gene is important for recognition of the beginning the ends of intron sequences?
splice sites GU and AG
Splicing of a newly synthesized RNA molecule to remove introns and join exons
Occurs in the nucleus and involves a complex of small nuclear RNA and protein molecules
What will be the sequence of the single-stranded RNA transcribed from the following segment of double-stranded DNA?
5'-TTGCACCTA-3'
3'-AACGTGGAT-5'
5'-UUGCACCUA-3'
Telomeres-
consist of repetitive DNA sequences found at the ends of chromosomes.
The nucleotide is composed of
a pentose sugar, a phosphate, and a base (G, C, A, T)
How many hydrogen bonds bind G and C and how many bind A and T?
3 hydrogen bonds bind G and C and 2 hydrogen bonds bind A and T
DNA is composed of the following bases-
adenine (A), guanine (G), cytosine (C), thymidine (T)
The nucleotides in each strand are linked by-
strong (covalent) chemical bonds
The nucleosome consists of
a complex of 8 histone proteins ( 2 molecules of each histone H2A, H2B, H3, and H4) with double-stranded DNA wound around it
Which of the following statements about histone proteins is correct?
Nuclear DNA associates with histone proteins to form chromatin
The phosphodiester bonds are bonds that form between
3'-OH groups of the deoxyribose sugar on one nucleotide with the 5' phosphate groups on the adjacent nucelotide
Chromatin consists of-
very long double-stranded DNA molecules, nearly an equal mass of rather small basic proteins termed histones, as well; as smaller amounts of nonhistone proteins and a small quantity of ribonucleic acid (RNA)
Modification of histone proteins by acetylation will-
increase the transcription of target genes
(true or false) DNA polymerases "read" a parental strand 5' to 3' and synthesize a complementary antiparallel new strand 3' to 5'
false
DNA replication occurs during the ____________ phase of the cell cycle
synthesis
__________ enzyme unwinds and breaks the hydrogen bonds between nucleotides of 2 DNA strands for DNA replication
DNA helicase
DNA primase-
adds RNA primer to DNA strand for replication
Exonuclease-
removes RNA primers from the lagging strand
Okazaki fragments-
are the DNA synthesized on the lagging strand
Single-stranded DNA binding proteins-
prevent premature annelaing of the single-stranded DNA to double-stranded DNA
___________ is an enzyme that catalyzes the sealing of nicks (breaks) remaining in the DNA polymerase fills the gaps left by RNA primers
DNA ligase
__________________ enzymes relieve torsional stress in DNA by inducing reversible single-stranded breaks in DNA
topoisomerases
(true or false) Telomerase shortening is recognized as and is a part of the normal aging process
false
(true or false) Telomerase adds a series of DNA repeats to the leading strand. This addition allows the lagging strand to be completed by DNA polymerase
false
mismatch repair-
correcting the mismatches of normal bases that fail to maintain normal waston-crick base pairing
base excision repair-
correct the spontaneous depurination and spontaneous deamination that happens to bases present in DNA
Nucleotide excision repair-
removes UV light-induced DNA damage as well as DNA damage from environmental chemicals
Double-stranded DNA repair-
correct the severed strands of DNA caused by ionizing radiation, oxidative free radicals, or chemotherapeutic agents
(true or false) non homologous end joining is more accurate in repairing severed DNA than homologous recombination.
false
(true or false) UCA conversion to CCA is a silent mutation
False (its missense)
(true or false) The A site binds an incoming aminoacyl-tRNA, The P site codon is occupied by peptidyl-tRNA, The E site is occupied by the empty tRNA
True
In a patient with cystic fibrosis caused by the F508 mutation, the mutant cystic fibrosis transmembrane conductance regulator (CFTR) protein folds incorrectly. The patient's cells modify this abnormal protein by attaching ubiquitin molecules to it. What is the fate of this modified CFTR protein?
It is degraded by the proteosome
The stop and initiation codons are?
Stop codons: UAG, UAA, UGA
Start codon: AUG
_________ is a dictionary that identifies the correspondence between a sequence of nucleotide bases and a sequence of amino acids
The genetic code
26S proteosome is a large complex of proteins made of a central core ___________ and a _______ regulatory particle and either end
20S, 19S
The carboxyterminal _____________ residue in ubiquitin binds to a _____________ residue in the protein to be degraded
glycine, lysine
_________________ is the first therapeutic proteasome inhibitor to be tested in
Bortezomib
Necrosis is-
cell death in response to tissue damage
Why does autophagosome fuse with a lysosome?
To form autolysosome and hydrolyse and degrade autophagosome content
Ubiquitination of proteins occurs through the following steps except-
The ubiquitin-regulatory enzyme (E1) to initially bind ubiquitin
Which of the following molecules marks a protein for degradation by a proteosome?
Ubiquitin
(true or false) Proteins with long half-lives are degraded by the proteosome
False
Short-lived proteins with half-life in seconds and minutes are degraded by utilizing-
ATP dependent protein degradation pathway by the proteosome
(true or false) Ubiquitination occurs by tagging a "bad" protein, This increases its likelihood of being degraded. Proteasomes don't necessarily need to identify a protein that has a ubiquitin tag in order to degrade it
False
Function of CDK 4 ?
progression past the restriction point at the G1/S boundary
Function of CDK2?
Initiation of DNA synthesis in early S phase
Function of CDK 1?
The transition from G2 to M
S phase cyclins include-
type E cyclins and cyclin A
What is prophase?
chromatin condenses into defined chromosomal structures called chromatids
What is prometaphase?
is when the spindle microtubules bind to kinetochores and chromosomes are pulled by the microtubules of the spindle
What is metaphase?
is when chromatids aligned at the equator of the spindle, halfway between the two poles
What is anaphase?
is when the mitotic poles are pushed further apart as a result of polar microtubules elongating
cyclin-dependent kinases are degraded by-
proteosome
G1 phase-
is generally both a growth phase and preparation time for DNA synthesis
G0 phase-
is a resting state
S phase-
is where DNA replication occurs
G2 phase-
is a time of preparation for the nuclear division of mitosis
All of the following are correct regarding interphase except-
Specialized protein complexes, called kinetochores, form, and associate with each chromatid
In mitosis, the parent cell divides to make _________ chromosomes in ________ phase of the _____________
92 chromosomes, synthesis, interphase
In meiosis, _________ haploid cells and each containing __________ chromosomes
4, 23
Why one cell undergo apoptosis will not affect neighboring cells? (weird ass wording)
Phagocytic cells release cytokines including interleukin-10 (IL-10) and transforming growth factor-B(TGF-B)
How long does necrosis take?
Days
The marker for senescence is-
senescence-associated beta-galactosidase enzyme activity (SA-B-gal)
Replicative senescence depends on-
The number of cell divisions and cell type
Which of the following characteristics of senescent cells in incorrect?
Can be induced into cell cycle
(remain metabolically viable, but can not enter the cell cycle under any condition)
Mitochondria of apoptotic cells release _________ but remain within the membrane blebs
cytochrome C
_____________ is a passive, pathological process induced by acute injury or disease
Necrosis
Why is mtDNA vulnerable to oxidative stress?
Due to the close proximity between the sites of ROS production and mtDNA
A population of cells is being grown in the laboratory and the total number of viable cells is observed to decrease. Analysis of Bax protein reveals an increase in its expression. Which of the following findings may be used to confirm that apoptosis is occurring in this cell population?
Phosphatidylserine on the outer membrane leaflet
______________ is an active, normal, physiological process that removes individual cells without damaging neighboring cells or inducing inflammation
Apoptosis
Zymogen becomes activated through __________ when they reach their proper sites of action
cleavage
Phosphorylation occurs on the hydroxyl groups of _______ or, less frequently, _________ residues in a protein
- serine, threonine
-tyrosine
Glycosylation involves the addition of __________ in ____________
carbohydrate/sugar, a target protein
________ and _________ residues of the a chains of collagen are extensively hydroxylated in the ER
proline & lysine
(true or false) Attachment of lipids, such as farnesyl groups, can help anchor proteins in membranes
True
The pancratic zymogen ________ becomes activated to ________ in the small intestine
- trypsinogen
-trypsin
Portions of the protein chain must be removed by specialized ____________ resulting in the release of an active molecule
endoproteases
The steady-state level of individual RNA species in a cell is determined by
Both the rate of decay and transcription
Transcription is inhibited in heterochromatin because
The DNA is packaged so tightly that it is inaccessible to the protein responsible for RNA transcription
Centromeres serve in all of the following except:
allow mitotic spindles to attach to the chromosome during cell division
separate the two arms of the chromosome
replicate DNA
replicate DNA
(true or false) Proteins that have a half-life of minutes to hours are coded by stable mRNA
False
Which of the following DNA sequences would have the highest melting temp.?
- CGCAACCATCCG
- CGCAATAATACA
- CGTAATAATACA
- CATAACAAATCA
- CGCAACCATCCG
(true or false) Spliceosome converts the primary transcript into mature mRNA
true
RNA processing control includes all of the following except-
- mRNA capping
- Poly(A) tail
- removal of introns
- basal transcriptional factors
basal transcriptional factors
Insertion of many extra glutamine residues results in
Huntingtons disease
(true or false) Specific transcription factors are not important for tissue-specific gene expression and for cell growth and differentiation
false
Which of the following sites on a gene is important for recognition of the beginning and the ends of intron sequences?
Splice sites GT and AG
The addition of the 5' cap structure is critical for all the following except
protects the mRNA from premature degradation by 3' exonucleases
Please complete the complementary DNA start of AGTCGTA
TCAGCAT
(true or false) The consensus sequence for promoters typically has the sequence TATA
true
(true or false) General transcription factors are needed for priming transcription
true
(true or false) A DNA molecule is composed of two parallel DNA strands
False
(true or false) DNA replication is unidirectional and starts in several different locations at once
False
(true or false) CAAT box sequences determine how frequently the transcription event occurs
True
__________________ synthesizes rRNAs involved in facilitating protein synthesis by the ribosome
RNA polymerase I
________________ is responsible for the synthesis of mRNA and miRNAs
RNA polymerase II
___________ catalyzes the synthesis of tRNAs
RNA polymerase III
The following sequence, when found in the 3' UTR, is a signal for early degradation
AUUUA
The positively charged amino acids help histones-
bind tightly to the negatively charged sugar-phosphate backbone of DNA
Telomeres serve to
protect the chromosome from degradation
Which of the following is an mRNA processing reaction
Removal of introns from the heterogenous nuclear RNA
Basal promoter sequences have-
The proximal component, generally the TATA box, directs RNA polymerase II to the correct site
A distal component specifies the frequency of initiation (CAAT and GC boxes)
Modification of histone proteins by acetylation will-
increase the transcription of target genes
All of the following are characteristics of the genetic code except-
overlapping
specificity
universality
degeneracy
overlapping
(true or false) DNA replication is a semiconservative process because each of the two daughter strands has half new DNA and half old DNA
true
The difference between leading and lagging DNA strands is-
Continuous (leading strand) vs. discontinuous (lagging strand)
The leading strand is the one in which 5' to 3' synthesis proceeds in the same direction as the replication fork movement.
The lagging strand is the one in which 5' to 3' synthesis proceeds in the direction opposite to the direction of the fork movement
_______ codes for proteins
mRNA
_______ catalyzes protein synthesis
rRNA
__________ brings amino acids to mRNA
tRNA
_______ regulates gene expression
miRNA
(true or false) DNA polymerases "read" a parental strand 5' to 3' and synthesize a complementary anti-parallel new strand 3' to 5'
False
Which of the following statements is false regarding transcription in eukaryotic cells?
Transcription takes place in the cytoplasm
The regulatory region consists of
both basal and regulated expression
Nucleotides bind other nucleotides on the other DNA strand by _______________ bonds
hydrogen
(true or false) 61 of the 68 codons code for the 20 common amino acids
false
Which of the following statements is correct?
- The amount of protein present in a cell depends on its rate of synthesis and rate of degradation
- Ribosomes are cytoplasmic organelles that are encapsulated by a single membrane
- Because the two strands of DNA are complementary, the mRNA of given gene can be synthesized using either strand as a template
- an mRNA may contain the sequence ATTGACCCCGGTCAA
The amount of protein present in a cell depends on its rate of synthesis and rate of degradation