Fundamentals of Molecular Biology, Exams of Genetics

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A benefit of alternate splicing of introns out of mRNAs is that Select one: A. it increases the number of proteins that the genome encodes. B. it maximizes the number of introns. C. it lowers the risk of infection. D. it speeds transcription. - correct answer- - A A nucleotide consists of Select one: A. one deoxyribose sugar, one nitrogenous base, and one phosphate group. B. three DNA bases. C. three sugars for every phosphate. D. three phosphates for every sugar. - correct answer- - A A somatic mutation Select one: A. occurs only in microbes. B. affects all cells of an individual. C. is expressed only in embryos. D. affects a particular subset of cells. - correct answer- - D

A point mutation alters Select one: A. a chromosome tip. B. only a purine. C. a single base. D. a centromere. - correct answer- - C Which of the following descriptions of genetic information flow best illustrates the central dogma of biology? Select one: A. DNA to RNA to protein B. protein to RNA to DNA C. protein to DNA to protein D. RNA to DNA to protein - correct answer- - A Mutations are more likely to occur in repeated DNA sequences because Select one: A. the repeats hold onto the replication enzymes, causing base mismatches. B. the repeats attract and bind to mutagens, increasing the mutation rate. C. these bases are unstable. D. bases in the strand can form base pairs, generating loops that interfere with replication and repair enzymes. - correct answer- - D DNA in the nucleus winds around proteins called Select one: A. ribosomes.

B. karyosomes. C. proteasomes. D. histones. - correct answer- - D Select the type of chromosomal abnormality that results in a balanced chromosome. Select one: A. Robertsonian translocation B. Deletion C. Duplication D. Inversion - correct answer- - D The nitrogenous bases adenine and thymine are Select one: A. a purine and a pyrimidine, respectively. B. a pyrimidine and a purine, respectively. C. both purines. D. both pyrimidines. - correct answer- - A A chromosome with two arms of about equal length is called Select one: A. metacentric. B. telocentric. C. paracentric. D. acrocentric. - correct answer- - A The enzyme that synthesizes messenger RNA from a DNA template is

Select one: A. reverse transcriptase. B. RNA polymerase. C. DNA polymerase. D. ligase. - correct answer- - B The chromosome shorthand ________ is used to designate a normal male. Select one: A. 46, XX B. 45, X C. 47, XXY D. 46, XY - correct answer- - D Purines and pyrimidines refer to the ________ of the DNA molecules. Select one: A. hydrogen bonds B. nitrogenous bases C. sugar-phosphate backbone D. histones E. nucleus - correct answer- - B In DNA, cytosine binds with Select one: A. adenine. B. thymine. C. uracil.

D. guanine. - correct answer- - D Which chemical is not a part of DNA? Select one: A. cytosine B. ribose C. phosphate D. nitrogen - correct answer- - B The nitrogenous base that is in RNA but not in DNA is Select one: A. thymine. B. thiamine. C. urea. D. uracil. - correct answer- - D Which of the following is a transition mutation? Select one: A. A to G B. GG to AA C. A to T D. ACC to CCC - correct answer- - A Which choice is the correct sequence from smallest to largest? Select one: A. Protein, polypeptide, peptide, amino acid

B. Amino acid, peptide, polypeptide, protein C. Peptide, polypeptide, amino acid, protein D. Amino acid, DNA, peptide, gene - correct answer- - B Cells replicate DNA Select one: A. only when a person is stressed. B. all the time. C. during the S phase of the cell cycle. D. during the M phase of the cell cycle. - correct answer- - C ________ are illustrations that show chromosome arm and major regions. Select one: A. Polygrams B. Chromatograms C. Anagrams D. Ideograms - correct answer- - D Pseudogenes Select one: A. may be transcribed but not translated. B. are not transcribed. C. may be transcribed and translated. D. are rare in the human genome. - correct answer- - A Which type of mutation substitutes one amino acid for another?

Select one: A. antisense B. missense C. sense D. nonsense - correct answer- - B A cell that has three copies of every chromosome is Select one: A. aneuploid. B. triploid. C. tetraploid. D. euploid. - correct answer- - B Erwin Chargaff showed that DNA that has 30% adenine has ________ thymine. Select one: A. 60% B. 30% C. 20% D. 40% - correct answer- - B Which of these is not found in RNA? Select one: A. purines B. ribose C. deoxyribose D. phosphate - correct answer- - C

During transcription Select one: A. RNA is synthesized from DNA. B. protein is synthesized from DNA. C. protein is synthesized from amino acids. D. DNA is replicated. - correct answer- - A The probability of cancer development in the general population is one in ________ people. Select one: A. two B. five C. four D. three - correct answer- - D Tiny fat bubbles used to deliver genes are Select one: A. liposomes. B. phospholipids. C. cholesterols. D. plasmids. - correct answer- - A An organism that carries DNA from other species is termed Select one: A. translocated. B. transverted.

C. transgenic. D. transformed. - correct answer- - C Proteins isolated from bacteria and used in recombinant DNA technology to cut DNA at specific sequences are Select one: A. plasmids. B. methylating enzymes. C. restriction enzymes. D. bacteriophage enzymes. - correct answer- - C The simplest type of antibody consists of Select one: A. 2 polypeptide chains, one large and one small. B. 4 polypeptide chains, two heavy and two light. C. a single folded polypeptide chain. D. 4 polypeptide chains of about equal size. - correct answer- - B In normal differentiated somatic cells, telomerase Select one: A. is not expressed and telomere tips erode with each division. B. adds material to the ends of chromosomes with each cell division. C. repairs double strand breaks in DNA. D. removes telomere tips with each division. - correct answer- - A Major histocompatiblity complex (MHC) genes account for about ________ percent of the genetic influence on immunity.

Select one: A. 40 B. 20 C. 30 D. 50 - correct answer- - D Transgenic organisms carry the transgene in Select one: A. the cell in which it was originally introduced. B. gametes only. C. somatic cells only. D. every cell. - correct answer- - D Mutations that enable cancer cells to grow and divide faster than other normal cells are known as ________ mutations. Select one: A. passenger B. driver C. benign D. gateway - correct answer- - B A ________ mutation does not cause or propel a cancer's growth and spread. Select one: A. somatic B. passenger C. germline

D. driver - correct answer- - B Cytotoxic T cells target Select one: A. B cells and macrophages. B. bacterial cells and fungal cells. C. skin cells and blood cells. D. cancer cells and virally infected cells. - correct answer- - D A cancer's spread is called Select one: A. malignancy. B. microstasis. C. carcinogenesis. D. metastasis. - correct answer- - D Inflammation helps to fight infection by Select one: A. creating an environment in the body that is hostile to pathogens. B. producing collectins, cytokines, and red blood cells. C. producing antibodies that kill viruses and bacteria. D. limiting the number of phagocytes at the infection site. - correct answer- - A The requirements for patenting of an invention involving DNA in the U.S. are that it should be Select one:

A. helpful and affordable. B. new, useful, and not obvious to an expert in the field. C. new, useful, and predicted by experts in the field. D. obvious, and no one should have previously been able to accomplish it. - correct answer- - B The term used to describe the fact that cancer cells have lost the specializations of the cells from which they descend is Select one: A. angiogenic. B. oncogenic. C. dedifferentiated. D. heritable. - correct answer- - C Recombinant DNA technology is used to Select one: A. make RNA in the cell nucleus. B. make more copies of DNA polymerase. C. copy protein into RNA. D. create many copies of a specific piece of DNA. - correct answer- - D Which type of white blood cell secretes specific antibodies? Select one: A. B cell B. Erythrocyte C. Cytokine D. T cell - correct answer- - A

Identifying combinations of ________ alleles is useful in tissue typing, establishing identity, and estimating disease risk. Select one: A. HLA B. erythrocyte C. HIV D. antibody - correct answer- - A The cause of p53-related cancers is Select one: A. continual expression of the telomerase gene, which keeps cells dividing. B. deletion of cell cycle checkpoint genes. C. fetal cells that remain in a child or adult, dividing too frequently. D. failure to repair damaged DNA, allowing the cell to continue dividing. - correct answer- - D A gene expression microarray has Select one: A. an entire genome of DNA, cut into hundreds of pieces, attached to a small plastic or glass square. B. amino acids attached to a small plastic or glass square. C. short pieces of DNA of known sequence attached to a small plastic or glass square. D. short pieces of RNA of known sequence attached to a small plastic or glass square. - correct answer- - C

The new approach to type blood, by identifying the instructions for the cell-surface antigens, is Select one: A. genotyping. B. gene therapy. C. serology. D. phenotyping. - correct answer- - A Which genome editing tool is most versatile and easy to use? Select one: A. Homologous recombination B. Zinc finger nuclease technology C. CRISRP-Cas9 system D. TALEN technology - correct answer- - C The first drug produced using recombinant DNA technology was Select one: A. streptokinase. B. insulin. C. tissue plasminogen activator. D. erythropoietin. - correct answer- - B Helper T cells secrete Select one: A. immunoglobulins. B. cytokines.

C. antigens. D. antibodies. - correct answer- - B A molecule that consists of a piece of DNA from one organism combined with the DNA from a member of another species is called Select one: A. bioengineered DNA. B. homogenic DNA. C. recombinant DNA. D. restricted DNA. - correct answer- - C A(n) ________ is a type of cancer-causing gene that promotes cancer by activating cell division at an inappropriate time or place. Select one: A. oncogene B. tumor suppressor gene C. DNA repair gene D. teratoma - correct answer- - A To create a multicellular eukaryotic transgenic organism, a researcher Select one: A. injects a gene of interest into a somatic cell. B. introduces foreign DNA into somatic cells in culture and transplants them. C. introduces foreign DNA into a fertilized ovum. D. injects a gene of interest into several somatic cells. - correct answer- - C Cancer cells

Select one: A. are dedifferentiated. B. divide uncontrollably and then die. C. are impossible to grow in culture. D. are particularly sensitive to extracellular signals. - correct answer- - A Cancer does not typically follow a Mendelian pattern of inheritance because it is usually caused by Select one: A. two gene variants, one dominant and one recessive, and no environmental input. B. genes that cause death before birth. C. specific combinations of alleles and an environmental factor. D. specific combinations of an environmental factor and one dominant gene variant. - correct answer- - C Restriction enzymes are useful in creating recombinant DNA molecules because they Select one: A. are used to encapsulate and transport foreign DNA into cells of the target organism. B. generate "sticky ends" by cutting at the same sequence in any DNA source. C. stimulate DNA amplification so that the desired cells or their products can be scaled up. D. are found only in human cells, where they naturally mend broken DNA strands. - correct answer- - B All of the following are cytokines except Select one: A. interferons. B. collectins.

C. interleukins. D. tumor necrosis factor. - correct answer- - B A ________ mutation is one that is present in every cell of an individual, including gametes. Select one: A. sporadic B. benign C. germline D. somatic - correct answer- - C A cancer stem cell can divide to give rise to Select one: A. tumor cells, abnormal daughter cells, normal cells, and more cancer stem cells. B. more cancer stem cells only. C. healthy stem cells and normally differentiated cells. D. invasive cells and metastatic malignant cells. - correct answer- - A The three basic characteristics of adaptive immunity are Select one: A. prevention, protection, and memory. B. suppression, activation, and transference. C. specificity, diversity, and memory. D. generality, diversity, and retention. - correct answer- - C In a few sentences, summarize Darwin's theory of natural selection. - correct answer- - Natural selection posited that more offspring were produced than an environment could actually support. Survival in a crowded environment would lead to struggle within a population, so the offspring that inherited the most desirable traits for a certain

environment would ultimately survive. Over time, variations would evolve in offspring that would make them more adaptive, and ultimately over time, new species could evolve. Name 2 types of animal models that are used for genetics research. Describe one trait that each model possesses that makes it a useful genetic tool. - correct answer- - Mouse- similar genome to human, easy to breed Fruit fly- extremely cheap, short life, easy to breed, small genome Worms- inexpensive, simple nervous system, easy to use, short life span Zebrafish- transparent larvae and embryo How does preformation differ from epigenesis? - correct answer- - Preformation postulated that a fertilized egg contained a miniaturized version of a tiny human, called a homunculus. Epigenesis directly contradicted that theory by stating that a fertilized egg undergoes a series of developmental events that eventually form a human. What type of plants did Gregor Mendel use in his famous experiments? - correct answer- - pea plants The chromosomal theory of inheritance states that: - correct answer- - Genes, contributed from each parent, are carried on chromosomes. True or False: Nucleotides are the basic building blocks that make up DNA. Correct! - correct answer- - true Explain how the use of biotechnology has contributed to modern agriculture. - correct answer- - Transgenic plants have been engineered to resist insects and harsh environments, grow bigger and more prolifically, or to enhance nutrition.

True or False: The theory of spontaneous generation posits that living things can spontaneously generate from nonliving things. Correct! - correct answer- - true Natural selection posits that organisms that have the most advantageous characteristics will survive their environment. Do humans have the same selective pressures for natural selection that their animal counterparts do? Are humans still evolving? - correct answer- - Modern humans have overcome the survival barriers that most animals face. They (typically) do not face harsh environments or predators because of their ability to shelter; they do not need to hunt or gather for food because there are markets; they have equipment and clothing to help them to be strong, to climb, etc. So, humans do not face the same selective pressures that other animals do for survival. That being said, they do continue to evolve. Genetic mutations occur within populations that may be slightly advantageous to a certain lifestyle (eg evolving the ability to digest milk even into adulthood), and these mutations may be selected for within a population. So, evolution occurs even though it is no longer a true "natural selection" for survival. Cell theory was introduced by: - correct answer- - Matthias Schleiden and Theodor Schwann Charles Darwin's publication on evolution is called: - correct answer- - the origin of species Propose examples of certain traits that could benefit a mammal that lives in a mountainous environment. - correct answer- - The ability to climb easily, have good balance, blend in with the colors of mountains (snow or rocks), to deal with low oxygen levels, and to find food on rough terrain are traits that would benefit a mountain animal. Answers may vary. The _________hypothesized that heredity and development depend on the passing of genetic information via _______that are contained within chromosomes. - correct answer- - Chromosomal theory of inheritance; genes

The number of total chromosomes in a normal human chromosome set is____. Chromosomes exist in matched numbers of____. - correct answer- - 46; ______ genes are the "normal" genes, such as the red eye color in the fruit fly. A mutation of a gene is referred to as an ______. - correct answer- - wild type;allele How many nucleotides make up DNA? In which combinations do they pair? - correct answer- - 4; A-T and G-C Corn and soybeans are 90% transgenic crops. What does this mean? - correct answer- - A transgenic crop has had advantageous traits introduced via recombinant DNA technology. The FDA-approved ATryn used to treat blood clots, was derived from genetically engineered

• correct answer- - goats A ________is carrier DNA in which a gene can be inserted using specific ________. - correct answer- - vector;restriction enzymes Which two scientists won the Nobel Prize for their model of the double-stranded DNA helix? - correct answer- - james watson and francis crick True or False: Proteins are responsible for carrying the genetic information within organisms. - correct answer- - false Which of the following statements is correct? - correct answer- - Dominance and recessiveness are not linked to the sex chromosomes. True or False: A dominant gene will always cause the expression of a dominant phenotype in any genetic cross. - correct answer- - false

People with sickle-cell disease can become very sick under what conditions? - correct answer- - high altitudes A homozygous long-haired cat is bred to a homozygous short-haired cat. Assuming that the gene for long hair is completely dominant, what are the chances of the F1 offspring being long-haired? - correct answer- - 100% A dog breeder is looking to cross a long-haired female dog with a short-haired male dog. The gene for hair length has incomplete dominance. By crossing the F1 offspring, what percentage of the F2 generation are predicted to be short-haired? - correct answer- - A 1:2:1 ratio predicts 25% of the offspring to be homozygous short-haired. Consider 3 genes that assort independently in squirrels. A gene for brown color is dominant (D), a gene for a bushy tail is dominant (B), and a gene for reflux after eating acorns is recessive (a). Use the product law to predict the likelihood of producing a squirrel (from parents that are heterozygous for each trait individually) that is brown, bushy-tailed, and has reflux from all those acorns. - correct answer- - (3/4) x (3/4) x (1/4) = 9/64 probability of this squirrel being brown, bushy-tailed, and having reflux. Two individuals with widow's peaks have a child with a straight hairline. A. Is the gene for a widow's peak likely dominant or recessive? B. Could you predict the genotype of the parents, assuming there is no codominance? C. If the child with the straight hairline someday marries a person with a widow's peak, can you predict for certain whether their offspring will have a widow's peak? - correct answer- - Dominant (WW or Ww) would produce a widow's peak. Because both parents have widow's peaks, only a homozygous recessive (ww) would result in the opposing phenotype of a straight hairline. B. The parents are likely heterozygous for a widow's peak (Ww) to pass along a ww genotype.

C. You cannot predict for certain, because the other parent could be heterozygous (Ww) or homozygous (WW) for a widow's peak, and either phenotype (Ww or ww) could be produced. Alternate forms of a gene are termed: - correct answer- - alleles A karyotype is a snapshot of the ______ within the cell. _______ cells are isolated and stained so that a trained geneticist can organize them into __________ chromosomes to detect genetic abnormalities. - correct answer- - chromosomes; white blood; homologous or paired True or False: A normal chromosome set always has paired X and Y chromosomes. - correct answer- - false The phenotype for sickle-cell anemia is distortion of the ______ in afflicted people. This results in depletion of ______ in the blood and poses a significant risk to the patients at high_____. Sickle-cell anemia is caused by ______ mutation(s) in the protein sequence. - correct answer- - red blood cells; oxygen; altitude;one Why did Mendel choose the pea plant as his genetics model? Correct! - correct answer- - it was self fertilizer In a cross, the original generation is known as the ______ generation and the first generation of their offspring is known as the ______ generation. - correct answer- - p1 or parental; f1 Which of Mendel's hypotheses needs a correction? Make the correction. Genetic characters are controlled by unit factors existing in pairs in individual organisms. When two unlike unit factors responsible for a single characteristic are present in a single individual, one unit factor is said to be dominant to the other, which is said to be recessive.

During the formation of gametes, the paired unit factors separate, or segregate, randomly so that each gamete receives one or the other with equal likelihood. During gamete formation, segregating pairs of unit factors assort in pairs. - correct answer-

• 4. During gamete formation, segregating pairs of unit factors assort independently to each other. True or False: A change in genotype does not always affect a change in phenotype. - correct answer- - true A mutation in which gene is responsible for a large number of breast cancers? - correct answer- - BRCA1 The minimum amount of gene product needed to meet a normal phenotypic expression in an individual is known as: - correct answer- - the threshold effect True or False: In codominance, two alleles are fully expressed regardless of the sex of the organism. - correct answer- - true The O phenotype in ABO genotyping possesses how many antigens on the surface of red blood cells? - correct answer- - 0 True or False: Chromosomes are uncondensed and diffuse for only a short time during the cell cycle. You Answered - correct answer- - false Which of the following is correct? - correct answer- - sister chromatids are held together by cohesin The longest of the stages during mitosis is:

Correct! - correct answer- - prophase The genetic flow of material between organisms is NOT dependent on which of these criteria? - correct answer- - independent assortment of the genes DNA is condensed within the nucleus (cellular compartment) by coiling around ____(1)____ proteins. Modification of these ____(2)____charged proteins alters them to become either neutral or negatively charged. Thus, the interaction with ____(3)____charged DNA is interrupted, and the interactions loosen. - correct answer- - histone;positively;negatively Which of the following is true about anaphase? - correct answer- - chromatids undergo disjunction to travel to opposite poles A chiasma is a point during meiosis at which the non-homologous sister chromatids: - correct answer- - intertwine Which of the following statements is correct? - correct answer- - The Y chromosome is the driving determinant for sex of an offspring. Genes that are part of the same chromosome are said to be ________. - correct answer- - linked Consider genes A, B, and C, which are located on a chromosome in that order. If genes A and B cross over 40% of the time, and genes B and C cross over 30% of the time, what is the probability of a double crossover between A B and C? - correct answer- - (0.4) * (0.3) = 0.12, 12% chance of this crossover The (1) chromosome and specifically the (2) gene on that chromosome, appear to determine the sex of a human. - correct answer- - y;SRY

Klinefelter syndrome is a disorder of the (1) sex chromosome and displays a genotype of (2). - correct answer- - male;XXY Indicate whether each of the following statements is True or False. G0 is an actively dividing cell cycle phase. False Cells enter G0 when the environmental conditions are not ideal for survival. True Cells in G0 do not undergo active replication. True When conditions become normal, cells may go back into the cell cycle. True - correct answer- - false;true;true;true A fertilized egg that is the result of fusion of two gametes is called a ________. - correct answer- - zygote The primary male gamete is the (1) and the primary (2) gamete is the oocyte. - correct answer- - sperm;female Which of the following criteria must be met in order to successfully map genes? - correct answer- - There must be a distinct phenotype for all genes since genotypes cannot be observed. True or False: At fertilization, the phenotype of a male or female is immediately evident. - correct answer- - false When cells become quiescent during G0, they are: Correct! - correct answer- - resting The X and Y sex chromosomes are known as _______ chromosomes. - correct answer- - heteromorphic