BIOL 416 FINAL EXAM (OLD EXAM Qs)
A covalent bond between two atoms is formed as a result of the ______________. (a) sharing of electrons. (b) loss of electrons from both atoms. (c) loss of a proton from one atom. (d) transfer of electrons from one atom to the other.
A
By definition, prokaryotic cells do not possess __________. (a) a nucleus. (b) replication machinery. (c) ribosomes. (d) membrane bilayers.
A
Which of the following elements is Most abundant in living organisms? (a) hydrogen (b) carbon (c) oxygen (d) nitrogen
A
Which of the following statement is false. (a) Comparing the relative number of chromosome pairs is a good way to determine whether two species are closely related. (b) Chromosomes exist at different levels of condensation, depending on the stage of the cell cycle. (c) Eukaryotic chromosomes contain many different sites where DNA replication can be initiated. (d) The centromere is a specialized DNA sequence where microtubules from the mitotic spindle attach to the chromosome so that duplicate copies move to opposite ends of the dividing cell.
A
Which of the following statements about DNA damage and repair is false? (a) The DNA polymerase that has nuclease activity is less accurate in DNA replication than the DNA polymerase that does not have nuclease activity. (b) Proofreading mechanism of DNA polymerase increase accuracy of DNA replication by 100-fold. (c) Nucleotide excision repair can recover mismatched base pair in DNA strand. (d) Depurination is naturally happen in cells and it removes Purine base from DNA.
A
Which of the following statements about miRNAs is false? (a) miRNA can not regulate translation efficiency of mRNA. (b) miRNAs are transcribed in the nucleus from genomic DNA. (c) Initial transcripts containing miRNAs form hairpin structure by base pairing. (d) miRNAs reduce stability of mRNA in cytoplasm.
A
Which of the following statements about transcriptional regulators is false? (a) Transcriptional regulators usually interact with the sugar-phosphate backbone on the outside of the double helix to determine where to bind on the DNA helix. (b) Transcriptional regulators will form hydrogen bonds, ionic bonds, and hydrophobic interactions with DNA. (c) Eukaryotic transcriptional regulators could affect gene expression from a far distant from transcription initiation sequence. (d) The binding of transcriptional regulators generally does not disrupt the hydrogen bonds that hold the double helix together.
A
Which of the following transporter use energy from ATP hydrolysis for its transport reaction? (a) Na+/K+ pomp (b) Na+/Glucose symport (c) voltage gated Cá+ channel (d) Bacteriorhodopsin
A
You discover that the underlying cause of a disease is a protein that is now less stable than the non-disease-causing version of the protein. This change is most likely to be due to ________. (a) a mutation within an exon. (b) a mutation within the regulatory DNA of a gene. (c) a mutation within introns. (d) a mutation within UTR region of the gene.
A
Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell. Which of the following ions is the most abundant inside a typical mammalian cell? (a) Na+ (b) K+ (c) Cá+ (d) Cl-
B
Chemical reactions carried out by living systems depend on the ability of some organisms to capture and use atoms from nonliving sources in the environment. The specific subset of these reactions that break down nutrients in food can be described as _____________. (a) metabolic. (b) catabolic. (c) anabolic. (d) biosynthetic.
B
Which of the following statements about RNA splicing is false? (a) Conventional introns are not found in bacterial genes. (b) Spliceosome contains DNAs and proteins. (c) Small RNA molecules in the nucleus are necessary to perform the splicing reactions for the removal of introns. (d) Alternative splicing increases variation of mRNA from an initial transcript.
B
Which of the following statements about iPS cells is false? (a) iPS cells are created by adding a combination of transcription regulators to a fibroblast. (b) iPS cells created from mouse cells can differentiate into almost any human cell type. (c) Stimulation by extracellular signal molecules causes iPS cells to differentiate. (d) During the de-differentiation process to become an iPS, the fibroblast will undergo changes to its gene expression profile.
B
Which of the following statements about nucleosomes is true? (a) Nucleosomes activate transcription when bound to the promoter. (b) When DNA packed within nucleosomes, the general transcription factors and transcriptional regulators can not bind to their binding sequence if their binding sites are not located close to the end of nucleosomes or between the nucleosomes. (c) Histone acetyltransferases affect transcription by adding acetyl groups mainly to C-terminal tail of histones. (d) Histone deacetylases remove lysines from histone tails.
B
Telomeres serve as caps at the ends of linear chromosomes. Which of the following is not true regarding the replication of telomeric sequences? (a) The lagging-strand telomeres are not completely replicated by DNA polymerase. (b) Telomeres are made of repeating sequences. (c) No cells can extend telomere DNA. (d) Telomere length is reduced in most of cells in our body when cells divide.
C
The process of DNA replication requires that each of the parental DNA strands be used as a ___________________ to produce a duplicate of the opposing strand. (a) catalyst (b) competitor (c) template (d) copy
C
The sigma subunit (sigma factor) of bacterial RNA polymerase ___________________. (a) contains the catalytic activity of the polymerase. (b) remains part of the polymerase throughout transcription. (c) recognizes promoter sites in the DNA. (d) recognizes transcription termination sites in the DNA.
C
What type of macromolecule helps package DNA in eukaryotic chromosomes? (a) lipids (b) carbohydrates (c) proteins (d) RNA
C
In a DNA double helix, _____________________. (a) the two DNA strands are identical. (b) purines pair with purines. (c) thymine pairs with cytosine. (d) the two DNA strands run antiparallel.
D
Which of the following statement of Homology-directed repair (HDR) is false? (a) Homologous recombination mechanism is used for HDR. (b) HDR requires homologous DNA strand as a template. (c) When DNA damage repaired by HDR, there will be no error in DNA sequence. (d) HDR can happen at any stage in cell division.
D
Which of the following statement related to molecular chaperon is false? (a) They assist polypeptide folding by helping the folding process follow the most energetically favorable pathway. (b) Prions are molecular chaperon that can change folding of protein. (c) They can interact with unfolded polypeptides in a way that changes the final fold of the protein. (d) Stacked α-helix often observed in Prion-mediated changes in protein folding.
D
Which of the following statements about eukaryotic general transcription factor is false?? (a) It contains TBP. (b) It binds to RNA polymerase II. (c) It binds specific DNA sequence. (d) It binds more tightly when RNA polymerase II is phosphorylated.
D
Histone tails tend to interact with DNA tightly and this makes Nucleosome structure stable. What kind of bond between DNA and Histone tail contribute to this binding? How can the cell change this tight binding to allow nucleosome to move? (You may answer this by a few sentences.)
Ionic bond between positive charge on Histone tail (Lys and Arg) and negative charge on DNA backbone (Phosphate). Acetylation of Lys on Histone tail can neutralize the charge that allow Histone tail dissociates from DNA backbone.
When cells supply membrane lipid to plasma membrane, two enzymes are required to move lipid from one layer to another layer. What are the name of these two and how different are they?
Scrambalase on ER membrane and Flippase on Golgi membrane can flip-flop lipids. Scrambalase does not have specificity for lipase but Flippase flip-flop specific lipids. Thus, at Golgi membrane lipids will become asymmetrically distributed between layers.
Telomeres on each chromosome forms a structure called __________________. To form that structure a repetitive DNA sequence in telomeres and ___________ protein complex are essential. If that structure is lost, chromosomes can be fused by _______________________________________ repair mechanism at their telomeres. Telomerase expression in ________ cells also can prevent this telomere fusion because telomerase can extend telomere sequence.
T-loop, TRF2, NHEJ, STEM
Protein modification by ____________________ is used for regulating stability of proteins. Modified protein will be degraded by the protease called _____________________ .
Ubiquitin, Proteasome
Glycoproteins contribute to the carbohydrate layer on the surface of the cell. Which of the following is not true abut glycoproteins? (a) The carbohydrate chain on glycoproteins can be made in cytoplasmic side of Golgi. (b) They are also located in vesicles that transfer from Golgi apparatus to plasma membrane. (c) They are part of glycocalyx (carbohydrate layer of cell surface). (d) They can be recognized by lectins.
A
Membrane lipids are capable of many different types of movement. Which of these does not occur spontaneously in biological membranes? (a) switching between lipid layers (b) lateral movement (c) rotation (d) flexing of hydrocarbon chains
A
Methylation and acetylation are common changes made to histone H3, and the specific combination of these changes is sometimes referred to as the "histone code." Which of the following patterns will probably lead to gene silencing? (a) lysine 9 methylation (b) lysine 4 methylation and lysine 9 acetylation (c) lysine 14 acetylation (d) lysine 9 acetylation and lysine 14 acetylation
A
Modern eukaryotes depend on mitochondria to generate most of the cell's ATP. How many molecules of ATP can a single molecule of glucose generate in cell? (a) 30 (b) 2 (c) 20 (d) 36
A
Oxidation is a favorable process in an aerobic environment, which is the reason cells are able to derive energy from the oxidation of macromolecules. Once carbon has been oxidized to _______________, its most stable form, it can only cycle back into the organic portion of the carbon cycle through __________________. (a) CÓ, photosynthesis. (b) CH3, combustion. (c) CÓ, respiration. (d) CO, reduction.
A
Polypeptides are synthesized from amino acid building blocks. The condensation reaction between the growing polypeptide chain and the next amino acid to be added involves the loss of ________________. (a) a water molecule. (b) an amino group. (c) a carbon atom. (d) a carboxylic acid group.
A
Pumps are transporters that are able to harness energy provided by other components in the cells and drive the movement of solutes across membranes, against their concentration gradient. This type of transport is called _____________. (a) active transport. (b) free diffusion. (c) positive diffusion. (d) passive transport.
A
Specific regions of eukaryotic chromosomes contain sequence elements that are absolutely required for the proper transmission of genetic information from a mother cell to each daughter cell. Which of the following is not known to be one of these required elements in eukaryotes? (a) terminators of transcription (b) origins of replication (c) telomeres (d) centromeres
A
The chromosomes we typically see in images are isolated from mitotic cells. These mitotic chromosomes are in the most highly condensed form. Interphase cells contain chromosomes that are less densely packed and __________________________. (a) occupy discrete territories in the nucleus. (b) share the same nuclear territory as their homolog. (c) are restricted to the nucleolus. (d) are completely tangled with other chromosomes.
A
Which of the following does not occur before a eukaryotic mRNA is exported from the nucleus? (a) The ribosome binds to the mRNA. (b) The mRNA is polyadenylated at its 3′ end. (c) 7-methylguanosine is added at a 5′end of the mRNA. (d) RNA polymerase dissociates.
A
Which of the following molecules of RNA would you predict to be the most likely to fold into a specific structure as a result of intramolecular base-pairing? (a) 5′-CCCUAAAAAAAAAAAAAAAAUUUUUUUUUUUUUUUUAGGG-3′ (b) 5′-UGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUGUG-3′ (c) 5′-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA-3′ (d) 5′-GGAAAAGGAGAUGGGCAAGGGGAAAAGGAGAUGGGCAAGG-3′
A
DNA and RNA are different types of nucleic acid polymer. Which of the following is true of DNA but not true of RNA? (a) It can make hydrogen bond between bases. (b) It contains thymine. (c) It contains sugar. (d) It contains phosphate.
B
Select the peptide sequence that can form a single transmembrane domain. (a) VGHSLSIFTLNVISLRGIFVFFEL (b) ILVIMIVLVMLLLIMLAILFVHF (c) ILVFFILVMPAVLFWMLIALLVE (d) VTLHKNMFLTDYILENSMIIIILL
B
Steps 7 and 10 of glycolysis results in phosphorylation of substrate. Which of the following best describes the reaction occurred at step 7 and 10. (a) ATP is being hydrolyzed to phosphorylate the carbohydrate. (b) High-energy phosphate on carbon is transferred to ADP for the conversion of ADP to ATP. (c) Two successive phosphates are transferred, first to AMP, then to ADP, finally forming ATP. (d) The substrate is hydrolyzed using ATP as an energy source.
B
The information stored in the DNA sequences is used directly as a template to make ___________. (a) lipids. (b) RNA. (c) polypeptides. (d) carbohydrates.
B
The tryptophan operator ___________________________. (a) is an allosteric protein. (b) interacts to the tryptophan repressor when the repressor is bound to tryptophan. (c) is required for production of the mRNA encoded by the tryptophan operon. (d) is located far away from promoter of the tryptophan gene.
B
Two or three α helices can sometimes wrap around each other to form coiled-coils. The stable wrapping of one helix around another is typically driven by ________________ interactions. (a) hydrophilic (b) hydrophobic (c) van der Waals (d) ionic
B
Where does most new membrane synthesis take place in a eukaryotic cell? (a) in the Golgi apparatus (b) in the endoplasmic reticulum (c) in the plasma membrane (d) in the mitochondria
B
Which of the following DNA sequences is not commonly carried on a DNA-only transposon? (a) transposase gene (b) reverse transcriptase gene (c) recognition site for transposase (d) antibiotic-resistance gene
B
Which of the following monomer building blocks is necessary to assemble compartments inside of eukaryotic cells? (a) sugars (b) fatty acids (c) amino acids (d) nucleotides
B
Which of the following statement is true? (a) Enzymes will change its conformation before and after catalysis. (b) Enzymes lower the activation energy for a specific reaction. (c) Enzymes can not control direction or specificity of the reaction. (d) Enzymes can not make energetically unfavorable reaction.
B
Which of the following statements about the genetic code is correct? (a) All codons specify more than one amino acid. (b) The genetic code is redundant. (c) All amino acids are specified by more than one codon. (d) All codons specify an amino acid.
B
Which of the following statements is false? (a) Compartmentalization in eurakyotic cells could has benefit to make enzyme reaction efficiently. (b) All cytoplasmic proteins are static (not moving) in cytosol. (c) Antibody is used to visualize specific molecules in cells by using fluorescent microscope. (d) Genome size does not show correlation to complexity of organism.
B
Which of the following statements is false? (a) Synaptic vesicles containing Neurotransmitters will fuse to presynaptic membrane when Cá+ concentration increased. (b) Action potentials are usually mediated by voltage-gated Cá+ channels. (c) Voltage-gated Na+ channels become automatically inactivated shortly after opening, which ensures that the action potential cannot move backward along the axon. (d) Cl- channel can antagonize induction of action potential by changing membrane potential towards more negative.
B
Which of the following statements is true? (a) All rRNAs are transcribed in Nucleolus. (b) RNA polymerase I is mostly located at Nucleolus. (c) tRNAs are made in Nucleolus. (d) RNA polymerase II only transcribe protein-coding genes.
B
hich of the following statements is false? (a) CÓ and Ó can diffuse freely across the cell membranes. (b) The differences in permeability between artificial lipid bilayers and cell membranes arise from variations in phospholipid content. (c) Direction of passive transport of molecules across membrane is controlled by osmosis and electrochemical gradient. (d) Cells expend energy in the form of ATP hydrolysis to maintain ion concentrations that differ from those found outside the cell.
B
Although the chromatin structure of interphase and mitotic chromosomes is very compact, DNA-binding proteins and protein complexes must be able to gain access to the DNA molecule. Chromatin-remodeling complexes provide this access by __________________. (a) recruiting other enzymes. (b) modifying the N-terminal tails of core histones. (c) using the energy of ATP hydrolysis to move nucleosomes. (d) denaturing the DNA by interfering with hydrogen-bonding between base pairs.
C
At first glance, it may seem that living systems are able to defy the second law of thermodynamics, but cell does not defy it. Cells create organization from raw materials in the environment, they also contribute to disorder in the environment by releasing _____________. (a) water. (b) radiation. (c) heat. (d) proteins.
C
Based on the relationship between reaction rates and substrate concentration for an enzyme-catalyzed reaction discussed in class, what does the Km value indicate with respect to enzyme-substrate interactions? (a) the maximum rate of catalysis (b) the number of enzyme active sites (c) the enzyme-substrate binding affinity (d) the equilibrium rate of catalysis
C
Energy cannot be created or destroyed, but it can be converted into other types of energy. Cells use chemical energy in the form of activated carrier molecules to make energetically unfavorable reaction, which are often employed to join two molecules together in _____________ reactions. (a) oxidation (b) hydrolysis (c) condensation (d) reduction
C
Glycolysis generates more stored energy than it expends. What is the net number of activated carrier molecules produced in this process (number and type of molecules produced minus the number of those molecules used as input)? (a) 6 ATP, 2 NADH (b) 4 ATP, 4 NADH (c) 2 ATP, 2 NADH (d) 4 ATP, 2 NADH
C
In anaerobic conditions, skeletal muscle produces _____________. (a) lactate and CÓ. (b) ethanol and CÓ. (c) lactate only. (d) ethanol only.
C
Indicate whether the following statement is false. (a) Two carbons supplied to citric acid cycle as acetyl CoA are converted to CÓ in subsequent reaction cycle. (b) Acetyl CoA has high-energy thioester bond. (c) Oxygen is consumed during citric acid cycle. (d) The pyruvate dehydrogenase complex catalyzes three different, but linked, enzymatic reactions.
C
Many biological processes depend upon the number and type of noncovalent interactions between molecules. Which of the noncovalent interactions below will contribute most to form core of globular proteins in water? (a) ionic bond (b) hydrogen bonds (c) hydrophobic interactions (d) Van der Waals attractions
C
Mitochondria and chloroplast are considered as prokaryotic parasites of ancient eukaryotic cells. Which following evidence supports this notion? (a) does not contain any DNA. (b) composition of lipids forming their membrane structures is identical to eukaryotes. (c) some of their membrane integrated protein form β-barrel structure. (d) they contains ribosomes that are similar to eukaryotes.
C
Motor proteins use the energy in ATP to move along with their specific track, such as actin filaments and microtubules. Which of the following statement is false for motor proteins discussed in class? (a) DNA can serve as a track for motor protein moving along. (b) Motor protein's function is mediated by allostery. (c) A conformational change is not coupled to the binding of ATP. (d) A conformational change is linked to ATP hydrolysis.
C
Proteins are important architectural and catalytic components within the cell, helping to determine its chemistry, its shape, and its ability to respond to changes in the environment. Remarkably, all of the different proteins in a cell are made from the same 20 __________. By linking them in different sequences, the cell can make protein molecules with different conformations and surface chemistries, and therefore different functions. (a) nucleotides. (b) sugars. (c) amino acids. (d) fatty acids.
C
Select the option that best completes the following statement: Non-homologous end joining is a process by which a double-stranded DNA end is joined ___________________. (a) to a similar stretch of sequence on the complementary chromosome. (b) by using homologues recombination mechanism. (c) to the nearest available double-stranded DNA end. (d) after filling in any lost nucleotides, helping to maintain the integrity of the DNA sequence.
C
Which combination of atoms (elements) could form electrically polar covalent bond? (a) Carbon - Carbon. (b) Hydrogen- Carbon. (c) Nitrogen-Hydrogen. (d) Oxygen-Oxygen.
C
Which modifications on side chain is not observed on Lysine? (a) Acetylation (b) Ubiquitination (c) Phosphorylation (d) Methylation
C
Which of the following statement about viruses is false? (a) Some DNA viruses can affect cell division cycle of host cells. (b) Viral genome can be made of RNA or DNA. (c) Only RNA viral genomes can be integrated into host genome. (d) Retrotransposons most likely originated from an RNA virus.
C
Which of the following statement related to Cyclic AMP (cAMP) is false? (a) hydrogen bonds is a critical to make cAMP binding to protein (b) cAMP binding site could be predicted from primary sequence of the protein (c) Proteins that bind to cAMP have identical cAMP binding motif. (d) cAMP binding proteins can be distinct in their 3D structures
C
Which of the following statements about allostery is false? (a) Allosteric regulators are often products of other chemical reactions in the same biochemical pathway. (b) Allosteric regulation is not always used for negative regulation of enzyme activity. (c) Enzymes are the only types of proteins that are subject to allosteric regulation. (d) Modification on amino acids of protein can be resulted in allosteric regulation of the protein.
C
Which of the following statements about eukaryotic transcription regulators is false? (a) Ligand binding to transcription regulator could induce its translocation form cytoplasm to nucleus. (b) Transcription repressors bind to HDAC either directly or indirectly. (c) All transcription regulators are specified to either repress gene expression or activate gene expression. (d) DNA binding activity of transcription regulators can be regulated by allostery.
C
Which of the following statements is false? (a) Burning of sugar for complete oxidation will release same amount of energy to stepwise oxidation of sugar in cells (b) Addition of Malonate to inhibit Citric acid cycle proves the reaction is "Cycled". (c) Oxygen is required for completing glycolysis process (d) Some products during glycolysis can be used to produce amino acids
C
Which of the following statements is false? (a) Primase is needed to initiate DNA replication on both the leading strand and the lagging strand. (b) DNA helicase unwinds DNA to make single-stranded DNA for DNA synthesis. (c) DNA polymerase needs ATP hydrolysis to make condensation between nucleotides. (d) DNA polymerase can add deoxynucleotide to 3' end of RNA strand
C
Although all protein structures are unique, there are common structural building blocks that are referred to as regular secondary structures. Some proteins have α helices, some have β sheets, and still others have a combination of both. What makes it possible for proteins to have these common structural elements? (a) specific amino acid sequences (b) side-chain interactions (c) the hydrophobic-core interactions (d) hydrogen bonds along the protein backbone
D
Even though DNA polymerase has a proofreading function, it still introduces errors in the newly synthesized strand at a rate of 1 per 107 nucleotides. To what degree does the mismatch repair system decrease the error rate arising from DNA replication? (a) 2-fold (b) 5-fold (c) 10-fold (d) 100-fold
D
Human beings with the inherited disease xeroderma pigmentosum have serious problems with lesions on their skin and often develop skin cancer with repeated exposure to sunlight. What type of DNA damage is not being fixed in the cells of these individuals? (a) Deamination (b) Double strand break (c) Chemical damage (d) Thymine dimer
D
In the 1940s, proteins were thought to be the more likely molecules to house genetic information. What was the primary reason that DNA was not originally believed to be the genetic material? (a) DNA has a high density of negative charges. (b) Nucleotides were known to be a source of chemical energy for the cell. (c) Both protein and nucleic acids were found to be components of chromosomes. (d) DNA was found to contain only four different chemical building blocks.
D
Related to epigenetic regulation discussed in class, which of the following statements is false? (a) Methylation of DNA is one of the epigenetic regulation mechanisms. (b) If cells fail to copy histone H3k9 methylation during DNA replication, daughter cells may have different heterochromatin region on chromosomes from mother cells. (c) Histone code plays a important role in epigenetic regulation. (d) Epigenetic information of germ-line cells is identical to one of skin cells in each individual.
D
Several different classes of enzymes are needed for the catabolism of carbohydrates. Which of the following class of enzyme is not involved in glycolysis reactions? (a) Kinase (b) Mutase (c) Isomearase (d) Preotease
D
The complete set of information found in a given organism's DNA is called its ____________. (a) genetic code. (b) coding sequence. (c) gene. (d) genome.
D
The distinct characteristics of different cell types in a multicellular organisms result from the differential regulation of the _________________. (a) expression transcription regulators. (b) Histone codes on chromosomes. (c) modification of DNA by methylation. (d) all of above.
D
The lateral movement of transmembrane proteins can be restricted by several different mechanisms. Which mechanism best describes separating transmembrane proteins on the apical surface of the epithelial cells from their basal and lateral surfaces by limiting lateral movement of any transmembrane proteins? (a) proteins are tethered to the cell cortex (b) proteins are tethered to the extracellular matrix (c) proteins are tethered to the proteins on the surface of another cell (d) protein movement is limited by the presence of a diffusion barrier
D
The octameric histone core is composed of four different histone proteins, assembled in a stepwise manner. Once the core octamer has been formed, DNA wraps around it to form a nucleosome core particle. Which of the following histone proteins does not form part of the octameric core? (a) H4 (b) H2A (c) H3 (d) H1
D
The ribosome is important for catalyzing the formation of peptide bonds. Which of the following statements is true? (a) The number of rRNA molecules that make up a ribosome greatly exceeds the number of protein molecules found in the ribosome. (b) The large subunit of the ribosome binds to the mRNA first. (c) Ribosome binds only one tRNA at any give periods of translation reaction. (d) Energy required for polypeptide formation (condensation of an amino acid) is provided from aminoacyl-tRNA.
D
Transcription is similar to DNA replication in that ___________________. (a) an RNA transcript is synthesized discontinuously and the pieces are then joined together. (b) it uses the same enzyme as that used to synthesize RNA primers during DNA replication. (c) the newly synthesized RNA remains paired to the template DNA. (d) nucleotide polymerization occurs only in the 5′-to-3′ direction.
D
Which following results were determined by comparison of whole genome sequence of organisms? (a) gaining lactose tolerance is originated by point mutation. (b) evolutionary tree relation among primates. (c) conservation of exons among vertebrates. (d) All of above
D
Which of the following is not a general mechanism that cells use to maintain stable patterns of gene expression as cells divide? (a) reestablishment of parental histone modifications during/after DNA replication (b) faithful replication of DNA and separation of set of chromosomes as cells divide (c) inheritance of DNA methylation patterns when cells divide (d) none of above
D
Which of the following membrane lipids does not contain a fatty acid tail? (a) phosphatidylcholine (b) a glycolipid (c) phosphatidylserine (d) cholesterol.
D
Which of the following processes do not take place in the mitochondria? (a) citric acid cycle (b) conversion of pyruvate to activated acetyl groups (c) oxidation of fatty acids to acetyl CoA (d) formation of ethanol in yeast for anaerobic fermentation
D
Which of the following questions would not be answered by using karyotyping? (a) Is the individual genetically female or male? (b) Do any of the chromosomes contain pieces that belong to other chromosomes? (c) Does the individual have an extra chromosome? (d) Do any chromosomes contain point mutations (small changes in DNA sequence)?
D
Which of the following statement is false? (a) Current Hemoglobin gene structure represents genome rearrangement by gene duplication. (b) Exon shuffling could produce variation of proteins that have similar catalytic activity. (c) Transposons on introns can contribute to exon shuffling. (d) L1 element is major DNA-only transposon in human genome
D
Which of the following statements about DNA methylation in eukaryotes is false? (a) Appropriate inheritance of DNA methylation patterns is important to maintain cell fate. (b) DNA methylation involves a covalent modification of cytosine bases. (c) Methylation of DNA attracts specific binding proteins through hydrophobic bond. (d) Immediately after DNA replication, each daughter helix contains one methylated DNA strand, which corresponds to the newly synthesized strand.
D
Which of the following statements about the newly synthesized strand of a human chromosome is true? (a) It was synthesized from a single origin solely by continuous DNA synthesis. (b) It was synthesized from a single origin by a mixture of continuous and discontinuous DNA synthesis. (c) It was synthesized from multiple origins solely by discontinuous DNA synthesis. (d) It was synthesized from multiple origins by a mixture of continuous and discontinuous DNA synthesis.
D
Which of the following statements is true? (a) A mutation that arises in a mother's somatic cell often causes a disease in her daughter. (b) An inheritable mutation that causes a disease, such as breast cancer gene, is only observed in germ-line cells but not in somatic cells of the individual who has the desease. (c) In an evolutionary sense, a mutation on somatic cells plays important role in our evolution. (d) A mutation is passed on to offspring only if it is present in the germ-line cells.
D
Which one of the following statement is true? (a) Feedback inhibition is defined as a mechanism of down-regulating enzyme activity by the accumulation of a product earlier in the pathway. (b) If an enzyme's allosteric binding site is occupied, the enzyme always adopt an alternative conformation that is not optimal for catalysis. (c) Protein phosphorylation is another way to alter the conformation of an enzyme and serves exclusively as a mechanism to increase enzyme activity. (d) GTP-binding proteins typically have GTPase activity, and the hydrolysis of GTP transforms them to the "off" conformation.
D
Which one of the following statement of heterochromatin is true? (a) Only constitutive heterochromatin will be inherited when cells divide. (b) Heterochromatin region of chromosomes will not code any genes. (c) In human male, entire X-chromosomes will be converted to heterochromatin. (d) Specific DNA sequence could stop formation of heterochromatin.
D
Which statement is NOT true about protein structure? (a) Primary structure of the protein can be determined by DNA sequence of the gene coding that protein. (b) Proline can not be a part of secondary structures in the proteins. (c) Tertiary structure of protein mostly determined by noncovalent bonds. (d) Disufide bond is used only for making quaternary structure of the proteins
D
ΔG° indicates the change in the standard free energy as a reactant is converted to product. Given what you know about these values, which reaction below is the most favorable? (a) ADP + Pi → ATP ΔG° = +7.3 kcal/mole (b) glucose 1-phosphate → glucose 6-phosphate ΔG° = -1.7 kcal/mole (c) glucose + fructose → sucrose ΔG° = +5.5 kcal/mole (d) glucose → CÓ + H2O ΔG° = -686 kcal/mole
D
Genetic model organism greatly contributing discoveries of cellular functions. For example, fission yeast mutants (weē- and cdc25-) revealed the regulatory mechanism of _______ kinase that required for entry into mitosis. Also, fruit fly mutant named ___________________ contributed to discovery of EGF/Ras signal transduction pathway.
cdc2, sevenless
____ requires the use of two sets of filters. The first filter narrows the wavelength range that reaches the specimen and the second blocks out all wavelengths that pass back up to the eyepiece except for those emitted by the dye in the sample. ____ eliminate reflection and unfocused light from specimen by limiting light pass by pinhole aperture. ____ has the ability to resolve cellular components as small as 2 nm.
fluorescence, confocal, transmission electron
Phospholipid is a polar molecule which consists ____________________________ head and ________________________ tail made by fatty acid. When phospholipids are mixed in water, they can from lipid ________________that resemble membrane structure of cells.
hydrophilic, hydrophobic, bilayer
