BIOLOGY MCQ FOR MEDICAL ENTRANCE EXAM

1) The first phase of photosynthesis, a series of reactions that requires the absorption of photons, is referred to as the _______ phase. a. reduction b. dark reactions c. carbon fixation d. light reactions (or photophosphorylation) e. None of the above 2) Which of the following is the revised, balanced equation for the generation of sugar from sunlight, water, and CO2? a. 6 CO2 + 6 H2O ® C6H12O6 + O2 b. 6 CO2 + 12 H2O ® C6H12O6 + 6 O2 + 6 H2O c. 6 CO2 + 6 H2O ® C6H12O6 + 6 O2 d. 12 CO2 + 12 H2O ® 2 C6H12O6 + 2 O2 e. None of the above 3) Which of the following occurs during the light-independent reactions of photosynthesis? a. Water is converted into hydrogen and water. b. CO2 is converted into sugars. c. Chlorophyll acts as an enzyme. d. Nothing occurs; the plant rests in the dark. e. None of the above 4) When a photon interacts with molecules such as those within chloroplasts, the photons may a. bounce off the molecules, having no effect. b. pass through the molecules, having no effect. c. be absorbed by the molecules. d. Both a and c e. All of the above 5) How do red and blue light differ from one another? a. They differ in intensity. b. They have a different number of photons in each quantum. c. Their wavelengths are different. d. They differ in duration. e. Red is radiant, whereas blue is electromagnetic. 6) A molecule has an absorption spectrum that shows maximum absorption within the wavelengths of visible light. This molecule is a. a reducing agent. b. a quantum. c. a photon. d. electromagnetic radiation. e. a pigment. 7) The photosynthetic pigment chlorophyll a absorbs a. infrared light. b. orange-red and blue light. c. X rays. d. gamma rays. e. white light. 8) Plants are green because a. Major & minor pigments absorb all necessary wavelengths of visible light and reflect green light b. Thylakoids transmit green light c. Thylakoids energized chlorophyll a to emit green light d. Plants possess green pigment natually e. Chlorophylls a/b absorb green light 9) A graph that plots the rate at which CO2 is converted to glucose versus the wavelength of light illuminating a leaf is called a. a Planck equation. b. an absorption spectrum. c. enzyme kinetics. d. an electromagnetic spectrum. e. an action spectrum. 10) During cyclic photophosphorylation, the energy to produce ATP is provided by a. heat. b. NADPH. c. ground-state chlorophyll. d. the redox reactions of the electron transport chain. e. the Calvin–Benson cycle. 11) Photophosphorylation provides the Calvin–Benson cycle with a. protons and electrons. b. CO2 and glucose. c. water and photons. d. light and chlorophyll. e. ATP and NADPH. 12) The main purpose of photosynthesis is to a. consume CO2. b. produce ATP. c. convert light energy to chemical energy. d. produce starch. e. generate water 13) Which of the following best represent the components that are necessary for photosynthesis to take place? a. Mitochondria, accessory pigments, visible light, water, and CO2 b. Chloroplasts, accessory pigments, visible light, water, and CO2 c. Mitochondria, chlorophyll, visible light, water, and O2 d. Chloroplasts, chlorophyll, visible light, water, and CO2 e. Chlorophyll, accessory pigments, visible light, water, and ATPs 14) Chlorophyll is suited for the capture of light energy because a. certain wavelengths of light raise it to an excited state. b. in its excited state chlorophyll gives off electrons. c. chlorophyll’s structure allows it to attach to thylakoid membranes. d. A & B e. All of the above 15) Plants give off O2 because a. O2 results from the incorporation of CO2 into sugars. b. They do not respire; they photosynthesize. c. water is the initial proton donor, leaving O2 as a photosynthetic by-product. d. oxygen is the initial proton donor, leaving CO2 as a photosynthetic by-product e. All of the above 16) In both photosynthesis and respiration, _______ synthesis is coupled to the diffusion of protons across a membrane. a. O2 b. CO2 c. H2O d. NADP+ e. ATP 17) _________ generates 2 daughter cells & _________ generates gametes a. mitosis & meiosis b. meiosis & mitosis c. genotype & phenotype d. phenotype & genotype e. cytokinesis, binary fission 18) Prokaryotes divide by ______ & Eukaryotes divide by ___________ a. Meiosis/Mitosis & Transformation b. Meiosis/Mitosis & Conjugation c. Transduction & Mitosis/Meiosis d. Binary fission & Mitosis/Meiosis e. Mitosis/Meiosis & Binary fission 19) List IN ORDER four events occur before, during, & after cell division: A. DNA is segregated and distributed to the new cells B. A signal to reproduce is received C. Cell membrane (& cell wall in some organisms) is formed via cytokinesis between the 2 new cells D. Replication of DNA & vital cell components a. A à Bà Cà D b. A à Cà Dà B c. C àAà Bà D d. A à Cà Bà D e. B à Dà Aà C 20) Mitosis can be divided into the following orderly phases: a. prophase, anaphase, metaphase, telophase b. prophase, telophase, metaphase, anaphase c. prophase, metaphase, anaphase, telophase d. metaphase, prophase, anaphase, telophase e. metaphase, telophase, prophase, anaphase 21) In sexually reproducing organisms, the diploid phase of the life cycle begins at a. spore formation b. gamete formation c. meiosis d. mitosis e. fertilization 22) A haploid cell is a cell a. in which the genes are arranged haphazardly b. containing only one copy of each chromosome c. that has resulted from the process of mitosis d. with twice the number of chromosomes of a diploid cell e. None of the above 23) Sexual reproduction increases genetic variability through a. the exchange of genetic information between male and female gametes during meiosis I b. the random separation of homologous chromosomes c. the union of male and female gametes d. crossing over, independent assortment, and random fertilization e. random assortment of male and female chromosomes 24) Diploid cells of the fruit fly Drosophila have ten chromosomes. How many chromosomes does a Drosophila gamete have? a. One b. Two c. Five d. Ten e. Twenty 25) The members of a homologous pair of chromosomes a. are identical in size and appearance b. contain identical genetic information c. separate to opposite poles of the cell during mitosis d. are found only in haploid cells e. are present only after the S phase 26) Individual chromosomes can be recognized by length, position of centromere, and banding patterns by applying a. x-ray crystallography b. cross breeding c. mutagenesis d. karyotyping e. homologous recombination 27) ______ is when cells are damaged by nutrients or oxygen starvation and ______ is when cells are genetically programmed to die because they are no longer needed. a. apoptosis / necrosis b. necrosis / apoptosis c. apoptosis / neurotoxin d. neurotoxin / apoptosis e. polyploidy / hexaploidy 28) Who is the father of classical genetics: a. Watson b. Crick c. Mendel d. Morgan e. Darwin 29) Mendel concluded that each pea has two units for each character, and each gamete contains one unit. Mendel’s “unit” is now referred to as a(n) a. gene b. character c. allele d. transcription factor e. trait 30) If a trait not expressed in the F1 generation reappears in the F2 generation, the inheritance of the trait in question is an example of a. codominance b. dominance and recessiveness c. incomplete dominance d. epistasis e. a sex-linked trait 31) The physical appearance of a character is called a. the genotype b. the phenotype c. an allele d. a trait e. a gene 32) Different forms of a gene are called a. traits b. phenotypes c. genotypes d. alleles e. character 33) The site on the chromosome occupied by a gene is called a(n) a. allele b. region c. locus d. type e. phenotype 34) Human male has _______ different types of chromosomes a. 23 b. 24 c. 46 d. 48 e. 92 35) In Griffith’s experiments, when heat-killed S strain pneumococci were injected into a mouse along with live R strain pneumococci, a. DNA from the live R was taken up by the heat-killed S, converting the latter to R and killing the mouse b. DNA from the heat-killed S was taken up by the live R, converting the latter to S and killing the mouse c. proteins released from the heat-killed S killed the mouse d. RNA from the heat-killed S was translated into proteins that killed the mouse e. there was no result 36) In order to show that DNA is the “transforming principle,” Avery, MacLeod, and McCarty showed that DNA could transform nonvirulent strains of pneumococcus. Their hypothesis was strengthened by their demonstration that a. enzymes that destroy proteins also destroy transforming activity b. enzymes that destroy nucleic acids also destroy transforming activity c. enzymes that destroy complex carbohydrates also destroy transforming activity d. the transforming activity is destroyed by boiling e. other strains of bacteria also can be transformed successfully 37) The Hershey–Chase experiment a. proved that DNA replication is semiconservative b. used 32P to label protein c. used 35S to label DNA d. helped prove that DNA is the genetic molecule e. Both b and c 38) Which of the following molecules functions to transfer information from one generation to the next in eukaryotes? a. DNA b. mRNA c. tRNA d. Proteins e. Lipids 39) Evidence indicating that DNA replication was semiconservative came from a. DNA staining techniques b. DNA sequencing c. density gradient studies using “heavy” nucleotides d. viral infection methods e. x-ray crystallography 40) In DNA polymerization, a. DNA polymerases add deoxyribonucleotides only to the 3’; end of a growing strand. b. the 3’ end of the primer contains a free 3’-hydroxyl group. c. the strand grows from the 3’ end to the 5’ end. d. Both a and b. e. Both b and c. 28) Which of the following statements does not summarize the molecular architecture of the DNA molecule? a. The sugar-phosphate ‘backbones’ of the polynucleotide chains coil within the inside of the helix b. It is a double-stranded helix c. It has a uniform diameter d. It is right-handed (that is, it twists to the right, as do the threads on most screws) e. It is antiparallel (the two strands run in opposite directions) 29) One strand of DNA has the sequence 5'-ATTCCG-3'. The complementary strand for this is a. 5'-TAAGGC-3' b. 5'-ATTCCG-3' c. 5'-ACCTTA-3' d. 5'-CGGAAT-3' e. 5'-GCCTTA-3' 30) Griffith’s experiment with pneumococcus demonstrated that a. smooth bacteria can survive heating b. DNA, not protein, is the genetic molecule c. materials from dead organisms can affect and change living organisms d. nonliving viruses can change living cells e. None of the above 31) The rules formulated by Erwin Chargaff state that a. A = T and G = C in any molecule of DNA b. A = C and G = T in any molecule of DNA c. A = G and C = T in any molecule of DNA d. A = U and G = C in any molecule of RNA e. DNA and RNA are made up of the same four nitro­genous bases 32) A deoxyribose nucleotide (or DNA) is a a. deoxyribose plus a nitrogenous base b. sugar and a phosphate c. deoxyribose plus a nitrogenous base and a phosphate d. ribose plus a nitrogenous base e. nitrogenous base bonded at the 5’ end to a sugar–phosphate backbone 33) Information sources used by Watson and Crick to determine the structure of DNA included a. electron micrographs of individual DNA molecules b. light micrographs of bacteriophage particles c. light micrographs of individual bacteria chromosomes d. nuclear magnetic resonance analysis of DNA e. X-ray crystallography of double-stranded DNA 34) If a double-stranded DNA molecule contains 30 percent T, it must contain _______ percent G. a. 20 b. 30 c. 40 d. 50 e. 60 35) The force of _______ holds DNA together in a double helix. a. the twist b. covalent bonds c. ionic bonds d. Van der Waals e. hydrogen bonds 36) The structure of DNA explains which three major properties of genes? a. They contain information, direct the synthesis of proteins, and are contained in the cell nucleus b. They contain nitrogenous bases, direct the synthesis of RNA, and are contained in the cell nucleus c. They replicate exactly, are contained in the cell nucleus, and direct the synthesis of cellular proteins d. They encode the organism’s phenotype, are passed on from one generation to the next, and contain nitrogenous bases e. They contain information, replicate exactly, and can change to produce a mutation 37) At the end of DNA replication, two DNA molecules are produced, each one consisting of a parental DNA strand and a new DNA strand. This process is known as a. semiconservative replication b. conservative replication c. dispersive replication d. fission e. the transforming principle e. the genetic code is ambiguous but not degenerate 38) Okazaki’s fragments: a. generate from the leading strand during replication b. generate from lagging strand during replication c. generate from the leading strand during transcription d. generate from the lagging strand during transcription e. none of the above