Biology 1121- Final Exam PDF

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Biology 1 ( Major Health Studies) Practice for Final Examination...

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BIOLOGY 1121 - Final Exam Which of the following proteins appear in some stages of the cell cycle and are degraded at other stages? a. kinases b. cyclins c. nucleotides d. phosphatases e. none of the above the concentrations of cyclins fluctuate throughout the cell cycle What is the sequence corresponding to the following electropherogram obtained by Sanger sequencing (green: A; red:T; black: G; blue: C)? a. CCGTTATGAAC b. GGCTTATGAAG c. CAACTATTGCC d. GGCAATAGTTG e. CCGTTATCAAC The process of _______________ cuts introns from the primary transcript and the final "processed" mRNA is produced. a. RNA cleaving b. RNA translocation c. RNA elongation d. RNA splicing Introns are removed from primary transcripts by cleavage at conserved sequences called splice sites. These sites are found at the 5′ and 3′ ends of introns. At which pH will the concentration of hydrogen ions be equal to the concentration of hydroxide ions? a. pH 1 b. pH 5 c. pH 7 d. pH 9 e. pH 14 in a neutral solution the hydrogen ion (H+) and the hydroxyl ion (OH−) concentrations are equal, and each is equal to 10−7. A pH of 7 is neutral.

G0 is: a. part of interphase b. the phase of the cell cycle where DNA replication occurs c. the phase of the cell cycle where two identical daughter cells are created d. a special "resting" phase in which cells are in a non cycling state e. a special phase where the number of chromosomes in a parent cell is reduced by half such that each daughter cell contains only one member of a pair of homologous chromosomes resting phase is a period in the cell cycle in which cells exist in a quiescent state. Which of the following can be described as 'a sequence that can be several thousand base pairs upstream or downstream of a eukaryotic promoter and which increases gene expression as much as 200-fold.'? a. CAAT box b. enhancer c. insulator d. TATA box Segment of DNA that is upstream, downstream, perhaps thousands of nucleotides away, or on another chromosome that influence the transcription of a specific gene Many of the extracellular signal molecules that regulate inflammation are released locally at the site of infection. What form of cell-to-cell signaling is being used? a. endocrine b. paracrine c. neuronal d. contact-dependent The eicosanoids are rapidly broken down and therefore act locally in autocrine or paracrine signaling pathways. They stimulate a variety of responses in their target cells, including blood platelet aggregation, inflammation, and smooth-muscle contraction Which of the following correctly matches an organelle with its function? a. mitochondrion - photosynthesis b. nucleus - cellular respiration c. ribosome - manufacture of lipids d. lysosome - movement e. central vacuole - storage Vesicles and vacuoles - Storage and transport

If the appropriate final electron acceptor is not present, the pyruvate that was formed at the end of glycolysis is reduced. Why? a. to form additional NADH b. to regenerate NAD+ c. to allow the now-reduced compound to enter the Krebs cycle d. to regenerate glucose If NAD+ is not present, glycolysis will not be able to continue. When oxygen is not present, pyruvate will undergo a process called fermentation. In the process of fermentation the NADH + H+ from glycolysis will be recycled back to NAD+ so that glycolysis can continue. What term is used to describe the process by which a segment of DNA is copied to produce a molecule of messenger RNA? a. reproduction b. replication c. translation d. transcription During transcription, only one strand of DNA is usually copied. This is called the template strand, and the RNA molecules produced are single-stranded messenger RNAs (mRNAs). The energy-requiring process by which small molecules are joined to form larger molecules is specifically called a. metabolism b. anabolism c. catabolism d. enzymatic reactions anabolic reactions involve the joining of smaller molecules into larger ones. ______ are chemicals or combinations of chemicals that take up excess hydrogen ions or hydroxide ions in order to keep the pH constant. a. acids b. bases c. salts d. buffers e. carbohydrates Buffers are chemicals that take up excess hydrogen or hydroxide ions and help hold the pH constant Only $3.99/month

The function of tRNA is to a. provide a site for polypeptide synthesis b. transport amino acids to the ribosome c. transcribe DNA d. transform DNA RNA that carries activated amino acids to the site of protein synthesis on the ribosome Complete the following sentences: "Primary active transport is dependent on __________. Secondary active transport is dependent on __________ created by __________. a. channel proteins, electrochemical gradient, carrier proteins b. electrochemical gradient, ATP, mitochondria c. electrochemical gradient, ATP, primary active transport d. ATP, electrochemical gradient, primary active transport e. carrier proteins, electrochemical gradient, channel protein Primary active transport moves ions across a membrane and creates a difference in charge across that membrane, which is directly dependent on ATP. Secondary active transport does not directly require ATP: instead, it is the movement of material due to the electrochemical gradient established by primary active transport Enzymes catalyse biochemical reactions by a. lowering the potential energy of the products b. separating inhibitors from products c. forming a complex with the products d. lowering the activation energy of the reaction e. providing energy to the reaction Enzymes are macromolecular biological catalysts. which accelerates chemical reactions. Catalysts lower the activation energy (energy required to start a reaction.) for reactions. The lower the activation energy for a reaction, the faster the rate. The methods of membrane transport that don't require protein channels or carriers are a. osmosis b. diffusion c. phagocytosis d. exocytosis e. all of the above simple diffusion is a form of diffusion that does not require the assistance of membrane proteins. Osmosis does not require a transport protein, but channel proteins are used to increase the rate at

which osmosis happens phagocytosis, a portion of the inward-facing surface of the plasma membrane becomes coated with a protein called clathrin, which stabilizes this section of the membrane. The lipid bi-layer is a. hydrophilic b. hydrophobic c. hydrophilic and hydrophobic d. depends on the surrounding medium All of the lipid molecules in cell membranes are amphipathic (or amphiphilic)—that is, they have a hydrophilic ("water-loving") or polar end and a hydrophobic ("water-fearing") or nonpolar end. Which of the following enzymes has proofreading activity? a. Ligase b. Helicase c. Topoisomerase d. DNA polymerase e. Peptidyl transferase proofreading, the DNA pol reads the newly added base before adding the next one, so a correction can be made. Complete the following sentences: "__________ connect the extracellular matrix with microfilaments. __________ connect intermediate filaments from adjacent cells." a. Cadherins, Integrins b. Connexins, Cadherins c. Integrins, Cadherins d. Integrins, Connexins e. Connexins, Integrins integrins link up to the microfilaments of the cytoskeleton. cadherins join two adjacent cells together Cellular organelles containing hydrolytic enzymes are called: a. peroxisomes b. lysosomes c. ribosomes d. mesosomes A lysosome is a membrane-bound organelle found in many animal cells. They are spherical vesicles that contain hydrolytic enzymes that can break down many kinds of biomolecules.

Which of the following terms correctly describes a compound featuring more than one double bond? a. saturated b. polyunsaturated c. monounsaturated d. disaturated A saturated compound contains only single covalent bond, while one featuring double bonds is termed unsaturated. The prefix 'mono' means 'one', so a monounsaturated compound contains only one double bond. The released energy obtained by oxidation of glucose is stored as a. a concentration gradient across a membrane b. ADP c. ATP d. NAD The released energy obtained by oxidation of glucose is stored as ATP. Only $3.99/month A(n)_______ is the movement of a segment of a chromosome from one chromosome to another nonhomologous chromosome a. inversion b. translocation c. deletion d. duplication translocations involve the movement of a chromosomal segment from one location in the chromosome to another. Which of the following is a reduced compound? a. CO2 b. O2 c. N2 d. NAD+ e. NADH NAD+ is reduced to NADH during both glycolysis and the citric acid cycle. Manufacturing recombinant DNA molecules involves cutting a gene from its normal location, inserting it into a circular piece of DNA from a bacterial cell, and then transferring the circle of

DNA to cells of another species. Which of the below describe the circular piece of DNA? a. restriction enzyme b. plasmid c. bacteriophage d. transposon Recombinant DNA technology enables individual fragments of DNA from any genome to be inserted into vector DNA molecules, such as plasmids, and individually amplified in bacteria. plasmids, which are shorter circular DNA molecules that may only contain one or a few genes What are epigenetic modifications? a. the addition of reversible changes to histone proteins and DNA b. the removal of nucleosomes from the DNA c. mutation of the DNA sequence d. the addition of more nucleosomes to the DNA Which enzyme is incorrectly matched to its function? a. RNA polymerase -- transcription b. aminoacyl-tRNA synthetase -- attaches an amino acid to a tRNA c. peptidyltransferase -- translation d. DNA ligase -- joins Okazaki fragments e. All of the above are paired correctly. RNA polymerase is the main transcription enzyme. aminoacyl-tRNA synthetase attaches the appropriate amino acid onto its corresponding tRNA. The peptidyl transferase forms peptide bonds between adjacent amino acids using tRNAs during the translation process of protein biosynthesis. DNA ligase I connects the Okazaki fragments. Eukaryotic mRNA transcripts are protected from modification by a. 5' caps b. 5' poly-A caps c. 3' caps d. 5'-3' poly tails

a special nucleotide "cap" to the 5′ end of the growing transcript. In addition to preventing degradation, factors involved in protein synthesis recognize the cap to help initiate translation by ribosomes.

Control of gene expression in eukaryotic cells occurs at which level(s)? a. only the transcriptional level b. epigenetic and transcriptional levels c. epigenetic, transcriptional, and translational levels d. epigenetic, transcriptional, posttranscriptional, translational, and posttranslational levels Gene expression is regulated at many levels (epigenetic, transcriptional, post-transcriptional, translational, and post-translational) Which of the following regions of RNAs are translated? a. 5' UTR b. exons c. introns d. 3' UTR e. poly-A Exons are coding sections of an RNA transcript, or the DNA encoding it, that are translated into protein. In protein-coding genes, the exons include both the protein-coding sequence and the 5′and 3′-untranslated regions (UTR). Which structure is found in plant cells but not animal cells? Check all that apply. a. Cell wall b. Chloroplast c. Plastid d. Central vacuole e. Lysosomes The plant cell has a cell wall, chloroplasts, plastids, and a central vacuole—structures not found in animal cells. Plant cells do not have lysosomes or centrosomes. The coding region of a gene is 102 nucleotides long, including both start and stop codons. Which of the following would be the most likely effect of a single nucleotide deletion at position 76 in the coding region? a. There would be no effect on the polypeptide. b. Only the active site would be affected. c. The entire amino acid sequence of the polypeptide would change. d. There would be changes in only the first 25 amino acids. e. There would be changes in only the last 8 amino acids. Complete the following sentence: "Meiosis results in genetic variation between gametes from the same individual due to genetic recombination in __________ and independent assortment of

homologous chromosomes in __________." a. prophase I, metaphase II b. metaphase I, metaphase II c. prophase I, metaphase I d. metaphase II, prophase I e. prophase II, metaphase II Recombination Occurs During the Prolonged Prophase of Meiosis I. Prophase I. Independent assortment in meiosis takes place in eukaryotes during metaphase I of meiotic division Complete the following sentences: "Replication forks from the same origin of replication extend __________. __________ DNA strand is used as template for the leading strand at one fork and for the lagging strand at the second fork. New DNA is synthesized from 5' to 3' on the __________." a. unidirectionally, A different, both the leading and lagging strands b. bidirectionally, The same, leading strand c. bidirectionally, The same, lagging strand d. unidirectionally, A different, leading strand e. bidirectionally, The same, both the leading and lagging strands Replication forks extend bi-directionally as replication continues. One strand, which is complementary to the parental DNA strand, is synthesized continuously toward the replication fork. Both the Okazaki fragments and the leading strand are synthesized in the 5′ → 3′ direction. Which of the following statement is true a. the two DNA strands are parallel and complementary b. the two DNA strands are anti parallel and non-complementary c. the two DNA strands are anti-parallel and complementary d. none of these Complementary base pairing of DNA. DNA has two strands in anti-parallel orientation. Which of the following statements is FALSE? a. carbohydrates are generally hydrophilic molecules. b. living things use carbohydrates for structure and for energy storage. c. carbohydrates are composed principally of carbon, hydrogen, and oxygen. d. none of the above - they are all true Carbohydrates are composed of carbon, hydrogen and oxygen in a 1:2:1 ratio. Carbohydrates, in particular glucose, are the main source of energy for nearly all living things Carbohydrates are generally considered as hydrophilic molecules

Gel electrophoresis separates DNA fragments according to their: a. base sequence b. size c. percentage of labelled nucleotides d. electrical charge Gel electrophoresis is a technique used to separate DNA fragments according to their size. When DNA replication starts a. the phosphodiester bonds between the adjacent nucleotides break b. the bonds between the nitrogen base and deoxyribose sugar break c. the leading strand produces Okazaki fragments d. the hydrogen bonds between the nucleotides of two strand break The first step of the DNA replication starts with the unzipping of the DNA i.e. the breaking of the hydrogen bonds present between them. Transcription is initiated when RNA polymerase binds to a. a promoter b. an initiator c. a transciptor d. a codon Transcription begins when RNA polymerase binds to a promoter sequence near the beginning of a gene (directly or through helper proteins). Complete the following chemical equation to make it balanced: glycerol + ___ → triacylglycerol + ___ a. 3 fatty acid, 3 H2O b. fatty acid, H2O c. 3 OH-, 3 H+ d. 3 H2O, 3 fatty acid e. fatty acid, 3 H2O Glycerol+fatty acid=triacylglycerol+water. joining of three fatty acids to a glycerol backbone in a dehydration reaction. Three molecules of water are released in the process....