AHHHHHHHHH
The highest frequency of recombination expected between these two genes is:
50%
Penicillin-resistant Staphylococcus aureus produces an enzyme, beta-lactamase, that hydrolyzes and inactivates penicillin. Using the data below estimate the Km of Β-lactamase.
6 um
Different breeds of horses exhibit significant differences in size. The genetic basis for size difference among horses is likely to result form:
Allelic variation in growth factor receptor genes
Which of the following statements does not describe benign tumors?
Benign tumors are never life threatening.
A biology student is sunbathing on "Beury Beach". UV radiation from the sun causes the development of several thymine dimers in the genome of a keratinocyte (skin cell). Which of the following groups of enzymes will remove the damaged nucleotide bases and restore the normal DNA structure?
DNA methyltransferase, Histone acetylase, Histone methyltransferase
Features that stabilize a messenger RNA in the cytoplasm are:
Intron & 5' 7-methyl guanosine cap
Which of the following is false, regarding the law of segregation?
It reveals the distance between two genes on a chromosome.
All of the following chromatin modifications lead to the transcriptional activity of a gene except:
Methylation of cytosine residues (5-methyl-cytosine) in the promoter of the gene
A list of weak acids with their pKa's is given below. Which will best ionize into its conjugate base? Acid pKa Boric acid 9.24 Citric acid 3.13 Formic acid 3.75 Oxalic acid 1.27 Succinic acid 4.21
Oxalic acid
A mutation in which of the following would result in an inability to shut down the fructose operon.
Repressor & Operator
The energy of activation in the presence of an enzyme is shown
Shorter one (C)
The difference in free energy between the reactants and the products is
The distance from reactants to products (D)
By using a dihybrid cross, Mendel studied the behavior of two different traits. In the F2 generation, these traits produced a phenotypic ratio of 9:3:3:1. Based on these results, Mendel stated that each pair of alleles segregates independently of other pairs of alleles during gamete formation. This statement is the basis of which genetic law?
The law of independent assortment
In the tryptophan operon, the trp repressor blocks transcription when it binds to
The operator
Homologous chromosomes, in the form of tetrads, are arranged on the metaphase plate.
The statement is true for meiosis I only
Homologous chromosomes synapse and crossing over occurs.
The statement is true for meiosis I only.
A reductional division halves the number of chromosome sets per cell from diploid to haploid
The statement is true for meiosis II only.
Four genetically varied haploid cells are produced.
The statement is true for meiosis II only.
The process is preceded by replication of the DNA
The statement is true for mitosis and meiosis I.
The pH of blood plasma is regulated by the rate of inhaling and exhaling. (T or F)
True
Determine the standard free energy (ΔG°) for the following coupling reactions. Is this coupled reaction exergonic or endergonic? W-X + ATP → Y-Z + ADP + Pi W-X → Y-Z ΔG° = -49.5 kJoules/mole ADP + Pi → ATP ΔG° = 30.5 kJoules/mole
-19 kJoules/mole, exergonic
Hemophilia is an X-inked disease. A man with hemophilia marries a normal woman who is not a carrier of the disease. They have a normal son and daughter. The probability that their next son will have hemophilia is:
0
The probability that the daughter described in question 55 (above) is a carrier of hemophilia is:
1
Arranges the descriptions below in an order that most logically illustrates a sequence of meiosis
1.) Formation of four new nuclei, each with half the chromosomes present in the parental nucleus 2.) Alignment of tetrads at the metaphase plate 3.) Separation of sister chromatids 4.) Separation of the homologues; no uncoupling of the centromere 5.) Synapsis; chromosomes moving to the middle of the cell in pairs 5,2,4,3,1
In a cross AaBbCc x AaBbCc, what is the probability of producing the genotype AABBCC? (Hint: Use a Punnett Square for each gene separately)
1/64
The probability that the daughter, II-3, is a carrier of the deafness allele is:
2/3
On a genetic linkage map, how many map units apart are the Y and T genes?
22.5%
What is the recombination frequency between the Y and T genes?
22.5%
A. Transcribe the DNA template, shown below, into a single primary messenger RNA. (Hint: Use the promoter region as a guide for transcription initiation.)
5'-(TATA)-GGGGCUAUGAAGUCUGCUCAGCAGCACGACGUCCGCAGCUGA-3'
In the crocus, the gene for plant height (T) and the gene for flower color (Y) are on the same chromosome. A tall yellow-flowered crocus (TTYY) was crossed with a short white-flowered crocus (ttyy) to product the F1 generation with the genotype TtYy. The F1 generation was backcrossed to the homozygous recessive plant (ttyy) to produce the following progeny: 75 TtYy 80 ttyy 25 Ttyy 20 ttYy If the genes for plant height (T) and flower color (Y) were not linked, how many of each phenotype would be expected?
50 TtYy: 50 ttyy: 50 Ttyy: 50 ttYy
⦁ The energy of activation (ΔGuncat) needed to convert reactants to products is 9.9 kJoules/mol. When the reaction is catalyzed by an enzyme that's activation energy (ΔGcat) is 3.6 kJoules/mol. The binding energy (ΔGB) of the reaction is
6.3 kJoules/mol
Use the Henderson-Hasselbalch equation to calculate the pH of a one-liter solution containing 0.09 moles of cacodylic acid and 0.9 moles of its conjugate base, cacodylate. The pKa of cacodylic acid is 6.27. pH = pKa + log [Proton acceptor]/ [Proton donor]
7.27
Between which two genes would you expect the highest frequency of recombination?
A and D
The most common mutation in people with the genetic disease cystic fibrosis is a deletion of 3 bases in the coding sequence of the CFTR gene. The result of this deletion is:
A missing amino acid in the polypeptide
Which of the following statements does not describe a mechanism that converts a proto-oncogene to an oncogene?
A proto-oncogene is translocated to another chromosome and is now regulated by a very active promoter.
During the elongation stage of translation, which site on the ribosome does an activated t-RNA first bind?
A site
As a biochemist in a pharmaceutical company, you are working to develop a drug that will stop the cell cycle in tumor cells. Which of the following factors should the drug target in order to halt the cell cycle?
All of the above ⦁ Cyclin dependent kinase ⦁ Cyclin ⦁ Mitotic spindle ⦁ Kinetochore
The translation complex includes all of the following except:
Aminoacyl-tRNA synthetase
The ABO blood group system.
Codominance
What is the role of Folate in its association with the enzyme?
Coenzyme
What is the role of Magnesium (Mg2+) in its association with the enzyme?
Cofactor
What would occur if the repressor of an inducible operon were muted so that it could not bind to the operator?
Continuous transcription of the operon's genes
A cell in a banana leaf has very high levels of NADPH in the stroma of the chloroplasts, and inadequate amounts of ATP to power the Calvin Cycle. The mechanism the cell will use to balance ATP and NADHP+ levels is
Cyclic electron flow
. All of the following are examples of tumor-suppressor proteins except:
Cyclin dependent kinase 2 (cdk2)
Trisomy 21 (Down's syndrome) can occur when two chromosomes 21 remain together during meiosis I in sperm or egg maturation. Which of the following statements is false regarding Down's syndrome?
Down's syndrome has the most sever phenotype of all known trisomy conditions.
A DNA sequence that can activate expression of a tissue-specific gene located 10,000 base pairs away is a(n):
Enhancer
DNA methylation and histone acetylation are examples of which of the following processes?
Epigenetic modification of cytosine and histones
The incidence of age-related diseases has decreased significantly in the 21st century
False
What type of mutation occurs when an error in DNA replication inserts two nucleotides into the coding region of a gene?
Frameshift
Mutation of the Ras G-protein can contribute to the development of a variety of cancers including lung, urinary bladder, and colon. Which of the following activities in the cancer-inducing Ras G-protein is lost due to mutation?
GTPase
Which of the following statements does not describe the flow of enzymes?
Glycogen synthesis is achieved through a series of exergonic reactions.
Violet (380-450) Blue (450- 500) Green (500- 550) Yellow (550 -600) Orange (600 650) Red (650-700) For questions 30 and 31 (below), please refer to the diagram above of the color spectrum of visible light. Additional information: chlorophylls a and b of green plants absorb between 425-475nm and 625-675nm. Compared to the corn plant with normal pigments, the growth and corn production of the mutant plant will be:
Greater growth and greater corn production than the normal plant.
A recent epidemic of influenza A killed hundreds of individuals in several countries. What molecular markers were used to identify this strain of influenza A?
Hemagglutinin and Neuraminidase
The phenotype of the heterozygote differs from the phenotypes of both homozygotes.
Incomplete dominance
Origins of genetic variation among offspring include all of the following except:
Independent segregation
Features that stabilize a messenger RNA in the cytoplasm include all of the following except:
Introns
A Lineweaver-Burk plot is used to accurately determine the Km and Vmax of an enzyme. Use the Lineweaver-burk plot shown below to determine the Km and Vmax values of Hexokinase, the enzyme that catalyzes the following chemical reaction.
Km = 0.33 mM, Vmax = 0.4 µM/sec
The rhinovirus infects the epithelial cells that line your respiratory tract. As mature virus is synthesized in the infected cells, the cells fill with virus particles until the cells burst (lysis). The newly replicated virus particles then infect surrounding cells and the cycle continues, producing the symptoms of the common cold that we all have enjoyed from time to time. The best defense(s) against rhinovirus infection is (are):
Leukocytes and lymphocytes
An enzyme increases the rate of a reaction by
Lowering the energy of activation (EA)
Which of the following is not a factor in the aging process?
Macrophage migration
Viruses are not considered living organisms because they cannot replicate their genomes or translate their mRNA independently. Components of the host cell that are required for the production of a mature DNA virus include al of the following except:
Major histocompatibility complex
In a yeast cell undergoing mitosis, several chromosomes are not yet attached to kinetochore microtubules. For this reason, the yeast cell halts its progress until all its chromosomes are associated with kinetochore microtubules. The yeast cell then resumes cell division. In which phase of mitosis did the yeast cell stall?
Metaphase
SU5416 is a cancer drug that interferes with the function of the vascular endothelial growth factor receptor (VEGF-R). Which of the following pathways does this drug directly inhibit?
Mitotic spindle formation
Acetylcholine is a neurotransmitter that binds to receptors that signals muscle contraction. After the signal for muscle contraction the enzyme acetylcholinesterase clears away excess acetylcholine breakdown into acetic acid and choline, thus terminating acetylcholine. Sarin is a chemical warfare "nerve agent" that functions as an inhibitor of acetylcholinesterase and preventing neuromuscular signals from transmitting between neurons from the central nervous system to muscle fibers. The action of Sarin is an example of:
Noncompetitive inhibition
The light reactions of photosynthesis yield three products. They are:
O2, NADPH, and ATP
A titration curve for acetic acid and its conjugate base, acetate, is attempted twice. A) A group of students attempted the same titration. The graph of each titration experiment is labeled. B) What is the reason for the lack of buffering in the students experiment?
OH- was added too rapidly
All of the following statements describe DNA synthesis except
Okazaki fragments are generated by leading strand synthesis
During the initiation stage of translation, which site on the ribosome does an activated Met-tRNA first bind?
P site
Cystic fibrosis affects the lungs, the pancreases, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections.
Pleiotropy
Traits that exhibit quantitative variation (skin color or height) and are under the control of several genes.
Polygenic inheritance
The region of a gene that binds to general transcription factors and RNA polymerase II is a(n):
Promoter
⦁ Angelman syndrome patients are profoundly impaired due to the absence of ubiquitin ligase in certain cells of the brain. Ubiquitin ligase attaches a ubiquitin molecule to old, damaged, or unnecessary cellular proteins, thus marking them for degradation. (Brain cell function is compromised in Angelman patients due to the failure to eliminate damaged cellular proteins.) Ubiquittinated proteins are eliminated by the:
Proteosome
Which of the following statements accurately describes eukaryotic gene expression?
RNA polymerase synthesizes mRNA in a 5' to 3' direction from the antisense strand of the DNA template.
A primary cause of aging are reactive oxygen species (ROS). The following statements describe ROS except:
ROS damage nuclear DNA at a rate 10-20 times higher than mitochondrial DNA
What would occur if the operator sequence is removed from the lac operon?
The operon would no longer be transcribed
All of the following statements about peptide bond formation are true except:
The peptide bond is catalyzed by a peptide synthetase
When proto-oncogenes mutate, they can become oncogenes. All of the following statements describe oncogenes and/or their oncoprotein products except:
The retinoblastoma protein (pRb) is an example of a tumor promoter.
The phenotype associated with any gene is a reflection of the molecular interactions of the protein product encoded by each allele. Based on that fact, which of the following statements is false?
The son of a man with dwarfism, an autosomal dominant disease, has 100% chance of also having dwarfism.
Chiasmata hold homologous chromosomes together
The statement is true for meiosis I only
A cell divides to produce two daughter cells that are genetically identical.
The statement is true for mitosis only.
Centromeres uncouple and chromatids are separated from each other.
The statement is true for mitosis only.
Important differences between the electron transport chain (ETC) in the chloroplasts of plant cells and the ETC in the mitochondria of animal cells include all of the following expect:
The structure and function of ATP synthase
A protein in muscle cells has an amino acid sequence that is 90% identical to a protein expressed only in neurons. Interestingly, both proteins are encoded by the same gene. How did this single gene give rise to slightly different proteins in two different cell types?
Tissue-specific splicing factors & Alternative mRNA splicing
. Energy is required for the enzyme to release the product.
True
Energy is released as the enzyme catalyzes the conversion of substrate to product.
True
Energy is released when weak chemical bonds form between acids within the catalytic cavity of the enzyme.
True
Energy is required for the enzyme to stress the chemical bonds.
True
⦁ The energy released from chemical bonds formed between the site of the enzyme
length of reactants the hill (B)
The Deadly Amanita mushroom (with a distressing resemblance to the delightful Morel) produces a toxin, -amanitin, that inhibits the activity of mammalian RNA polymerase II. What category of RNA is not transcribed when the Deadly Amanita is eaten? (Death occurs after 24-48 hours following great discomfort)
micro RNA & ⦁ Messenger RNA
The following statements describe the function of the p53 tumor suppressor except:
p53 slows down the rate of DNA replication by binding DNA polymerase.
. What is the buffering range of cacodylic acid (pKa = 6.27)?
pH 5.27 - 7.27
A mutation that inactivates the Ras GTPase activity is a dominant mutation.
true
The number of division a cell can undergo is limited by:
⦁ Cell age ⦁ Cell size ⦁ Telomere length ⦁ All of the above
Which of the following statements describes energy coupling?
⦁ Energy released from exergonic reactions used for endergonic reactions. ⦁ The intermediate molecule in energy coupling is adenosine triphosphate. ⦁ Energy coupling can occur through the phosphorylation of an enzyme endergonic reaction. ⦁ All of the above
Which of the following statements correctly describes malignant tumors?
⦁ Malignant tumors are metastatic. ⦁ Malignant tumor cells break away from the primary tumor, migrate through the vasculature, and establish secondary tumors. ⦁ Malignant tumors cells reactivate segments of the genome that encode proteins that initiate cell migration. ⦁ All of the above
Factors that are critical for the light reaction in plants are:
⦁ Photons (light energy) ⦁ Water (H2O) ⦁ A complex of Ca2+, Mn ions, and Mg2+ ⦁ All of the above
Mendel's law of independent assortment is demonstrated by:
⦁ The 9:3:3:1 ratio of phenotypes in an F2 generation. ⦁ The assortment of different traits into separate gametes. ⦁ The phenotypic ratio of a dihybrid cross ⦁ All of the above
Which of the following is true for alleles?
⦁ They can be identical or different for any given gene in a somatic cell. ⦁ They can be dominant or recessive. ⦁ They represent alternative forms of a gene. ⦁ All of the above
Violet (380-450) Blue (450- 500) Green (500- 550) Yellow (550 -600) Orange (600 650) Red (650-700) For questions 30 and 31 (below), please refer to the diagram above of the color spectrum of visible light. Additional information: chlorophylls a and b of green plants absorb between 425-475nm and 625-675nm. A corn plant is developed with a mutant chlorophyll a that absorbs light from 475-600nm, and a mutant chlorophyll b that absorbs light from 600-750nm. What color are the leaves and stalks of this corn plant?
⦁ Violet/Blue
Females with trisomy X are indistinguishable from women with the normal number of X chromosomes. The reason these women have a normal phenotype is:
⦁ X-inactivation ⦁ Xist RNA expression ⦁ Cytosine methylation ⦁ All of the above