UCI Bio 93 Final Exam Questions with 100% Correct Answers | Verified | Updated 2024, Exams of Nursing

Download UCI Bio 93 Final Exam Questions with 100% Correct Answers | Verified | Updated 2024 and more Exams Nursing in PDF only on Docsity! UCI Bio 93 Final Exam Questions with 100% Correct Answers | Verified | Updated 2024 What are the four most common elements in living matter? - Correct Answer-Hydrogen, Oxygen, Nitrogen, and Carbon -- make up 96% of all living matter. Properties of Acids - Correct Answer-Donate H+ to a solution, accept electrons, and have a pH of <7 What happens in the S phase of the cell cycle? - Correct Answer-DNA Synthesis What happens in the G1 phase of the cell cycle? - Correct Answer-Growth -- cell contents are duplicated. What happens in the G2 phase of the cell cycle? - Correct Answer-More growth and preparation for division. What happens in the M phase of the cell cycle? - Correct Answer-Mitosis (and cytokinesis -- division of the cell). pg. 1 professoraxe l What are the subphases of mitosis? - Correct Answer- Prophase, Pre-metaphase, Metaphase, Anaphase, and Telophase. How many checkpoints are there in the cell cycle? - Correct Answer-3 -- G1 checkpoint, G2 checkpoint, and the M checkpoint. What is a Karyotype? - Correct Answer-A layout of Metaphase chromosomes matched with their homologous pairs. What is a diploid cell? - Correct Answer-A cell with 46 chromosomes -- somatic cells. What is a haploid cell? - Correct Answer-A cell with 23 chromosomes -- sex cells. What does the mesoderm give rise to? - Correct Answer-the notochord (similar to a spinal chord). pg. 2 professoraxe l What happens in prophase 2 of meiosis? - Correct Answer-A new spindle forms around the chromosomes. What happens in metaphase 2 of meiosis? - Correct Answer- Metaphase 2 chromosomes line up at the equator. What happens in anaphase 2 of meiosis? - Correct Answer- Centromeres divide chromatids move to opposite poles of the cells. What happens during telophase 2 of meiosis? - Correct Answer-A nuclear envelope forms around each set of chromosomes and the cytoplasm divides. What makes meiosis a unique form of cell division - Correct Answer-Synapsis and crossing over -- occurs in prophase 1, pairing up of homologous chromosomes, homologous chromosomes cross over and exchange corresponding genetic information (the DNA exchanged contain the same genes, but may have different alleles). pg. 5 professoraxe l How does meiosis increase genetic variability? - Correct Answer-Independent assortment (meiosis 1 -- homologous chromosomes separate independently), crossing over (genetic recombination, prophase 1), and random fertilization (any egg can join with any sperm -- most effective way to obtain genetic variability). What is the law of segregation? - Correct Answer-Alleles coding for the same trait separate independently during gamete formation. What is non-disjunction? - Correct Answer-When homologous chromosomes or sister chromatids do not separate properly. What is a character? - Correct Answer-An observable heritable feature that may vary among individuals. Ex: flower color. What is a trait? - Correct Answer-One of two or more detectable variants in a genetic character. Ex: purple flower color/white flower color. What does the blending theory state? Is this true? - Correct Answer-The offspring is a blend of both parents (ex: a tall pg. 6 professoraxe l mom giraffe + a short dad giraffe = a medium height giraffe). This is not true because if so, every single offspring would look the same. What does particulate inheritance state? Is this true? - Correct Answer-Different traits are inherited in separate distinct units (genes) (ex: F1 and F2 generations). This is always true because of not every offspring looks the exact same (has the exact same genetics). What is an allele? - Correct Answer-An alternate form of a gene (ex: the gene that determines hair color). What does the Law of Segregation state? - Correct Answer- The Law of Segregation states that two alleles in a pair segregate into different gametes. (this deals with separation of homologous pairs in Meiosis 1 producing haploid daughter cells after Meiosis 1). What does Independent Assortment state? - Correct Answer- Each pair of alleles assort/segregate separately from each other during gamete formation. AKA no gene linkage. pg. 7 professoraxe l Most likely phenotype = immediate phenotype and the least likely phenotype = the extreme phenotype. Shaped like a bell curve -- immediate in middle with high peak and extreme on both ends. What can impact the phenotype of an organism? - Correct Answer-Environment (ex: hydrangeas -- the acidity of the soil determines their color no matter their alleles), diet, epigenetics, etc. Is albinism dominant or recessive? - Correct Answer-recessive. Is Achondroplasia (dwarfism) dominant or recessive? - Correct Answer-dominant. Is Huntington's disease dominant or recessive? - Correct Answer-dominant. What did Thomas Hunt Morgan study/discover? - Correct Answer-Morgan studied drosophila (fruit flies) and their eye color. He discovered that certain genes such as fly eye color are on specific chromosomes (ex: the X chromosome). This proved that genes are located on specific chromosomes. pg. 10 professoraxe l What is a wild type? - Correct Answer-A normal, unaffected phenotype. What is a parental phenotype? - Correct Answer-Phenotype of parent generation. What is a non-parental phenotype? - Correct Answer-Different phenotype from parents. What are recombinant offspring? - Correct Answer-Offspring that have a non-parental phenotype. What is a recombinant frequency? - Correct Answer-How often do you produce a recombinant offspring. When are 2 genes considered "linked"? - Correct Answer-If they are inherited together (located near each other on the same chromosome). When will genes assort independently? - Correct Answer-If they are far apart on a chromosome -- not linked. pg. 11 professoraxe l A large % of offspring will have what phenotype? - Correct Answer-The parental phenotype. A small % of offspring will have what type of phenotype and why? - Correct Answer-they will have the non-parental phenotype because linkage can break. What causes gene linkage to break? - Correct Answer-The crossing over at chiasmata during prophase 1. What are the purpose of recombination frequencies? - Correct Answer-They are used to map the placement of genes on a single chromosome. This map is called a "linkage map". What does a larger recombination frequency mean? - Correct Answer-The genes are farther apart. What does a smaller recombination frequency mean? - Correct Answer-The genes are close together. pg. 12 professoraxe l both transcription and translation are involved in gene expression. What is the structure of chromatin? - Correct Answer-DNA + histones (proteins in chromatin that help compact DNA) complex in the nucleus. What are euchromatin? - Correct Answer-Euchromatin are loosely packed and easier to access (increased transcription). What are heterochromatin? - Correct Answer- Heterochromatin are highly packed and hard to express (reduced transcription) ex: telomeres and centromeres. Why is it hard for heterochromatin to be expressed? - Correct Answer-Because the proteins associated with transcription have a hard time accessing the DNA due to the DNA being densely packed. What is histone acetylation? What is its purpose? - Correct Answer-A process that adds acetyl groups to the positively charged lysines on histone tails. The purpose is to loosed the chromatin and allow for transcription to begin. pg. 15 professoraxe l What is DNA Methylation? - Correct Answer-A process that inactivates DNA through the addition of methyl groups. Used in genomic imprinting. This information is then passed down to future generations. This process also reduces transcription. What do activator proteins do? - Correct Answer-Bind to an enhancer and promote transcription. What do suppressor proteins do? - Correct Answer-Block transcription. How do activator proteins work? - Correct Answer-They have two domains (regions). One binds to DNA, the other activates DNA. What are the 3 steps to activator proteins beginning transcription? - Correct Answer-1.) the activator binds to the enhancer. 2.) DNA bending protein binds and transcription factors bind to a promoter. 3.) formation of active transcription initiation complex. pg. 16 professoraxe l What is the end result of gene regulation at the initiation of transcription? - Correct Answer-Depending on which combination of activators are around the enhancer and interacting with it, certain cell types will form (liver cell, lung cell, etc.). What are 3 ways genes are regulated during translation? - Correct Answer-Alternative RNA splicing, mRNA degradation, and blocking of initiation of translation. What happens in alternative RNA splicing? - Correct Answer- The splicing out of keeping different eons. What happens in mRNA degradation? - Correct Answer-Via shortening the poly A tail/removing the 5' cap, the mRNA gets degraded by nuclease. What happens in the blocking of initiation of translation? - Correct Answer-Via regulatory proteins binding to the 5' UTR, which prevents ribosomes from attaching. pg. 17 professoraxe l What is MyoD and what does it do? - Correct Answer-MyoD is a master regulatory gene that produces proteins that commit the cell to becoming a muscle cell. The MoD gene is transcribed and translated into a transcription factor that binds to itself and enhancers of other muscle specific genes. What do maternal effect genes do? - Correct Answer-Code for cytoplasmic determinants in the unfertilized egg that create the body axis. COME FROM THE MOM. What does the bicoid gene do? - Correct Answer-affects the formation of a head. If mom has no bicoid, then the embryo has no head. What is the primary significance of a concentration gradient for maternal effect genes? - Correct Answer-It determines the polarity (orientation) of the body. Helps organize the body axes. What are the four steps in embryonic development? - Correct Answer-Fertilization, cleavage, morphogenesis (gastrulation & organogenesis). pg. 20 professoraxe l What happens in fertilization? - Correct Answer-The sperm meets the egg and their nuclei combine going from haploid to diploid. What happens in cleavage? - Correct Answer-Rapid cell division without growth. Purpose: to create a multicellular embryo. What are blastomeres? - Correct Answer-The name of smaller cells which the division of one large cell created. What is a blastula? - Correct Answer-A ball of cells with a fluid filled cavity called a blastocoel. Which pole has more yolk? - Correct Answer-Vegetal pole (bottom half). Which pole has less yolk? - Correct Answer-Animal pole (top half). What process is going on during cleavage? - Correct Answer- Mitosis -- the cell is not growing in size, it is simply taking one big cell and dividing it into smaller cells via mitosis. pg. 21 professoraxe l What happens in morphogenesis? - Correct Answer-A two step process by which cells occupy their correct location. What two processes occur during morphogenesis? - Correct Answer-Gastrulation and organogenesis. What happens during gastrulation? - Correct Answer-The movement of cells from the blastula surface to the interior of the embryo. Begins when a group of cells on the dorsal side of the blastula invaginate (cells move outside in) it continues moving inside via involution. This movement forms a crease called the dorsal lip. Cells that move inside become the endoderm (inner layer) and mesoderm (middle layer). Cells on the embryo surface become the ectoderm (outer layer). What happens in organogenesis? - Correct Answer-The process which various regions of the germ layers (mesoderm, ectoderm, and endoderm) develop into organs. What forms from the mesoderm? - Correct Answer-the notochord. pg. 22 professoraxe l Does brain cancer involve neurons? - Correct Answer-No, because neurons cannot divide, and tumors are resulted from uncontrolled cell division. Neurons contain _________ that open or close in response to stimuli. - Correct Answer-voltage gated ion channels. What is resting potential? - Correct Answer-When the neuron is not sending any signals (-70mV) Concentration of K+ is ________________ inside the cell. - Correct Answer-greater. Concentration of Na+ is ____________________ outside the cell. - Correct Answer-greater. What happens in depolarization? - Correct Answer-Gated Na+ channels open to let Na+ inside the cell, which makes the inside of the cell less negative. What is the threshold required in order to create an action potential? - Correct Answer--50mV pg. 25 professoraxe l What is an action potential? - Correct Answer-A signal that carries information along the axon. Produces an all or nothing response. The _____________ of action potentials reflects the _______________ of a stimulus. - Correct Answer-Frequency, strength. Action potentials can travel _______________ distances and only in ___________________ direction. - Correct Answer- long, one. What is a refractory period? - Correct Answer-After an action potential, a second action potential cannot be immediately initiated due to temporary inactivation of the Na+ channels. What happens in repolarization? - Correct Answer-The falling phase of action potential that occurs when the gated Na+ channels close while the gated K+ channels are open so that K+ can leave. pg. 26 professoraxe l What happens in hyperpolarization? - Correct Answer-Gated K+ channels close. What is a catabolic reaction? - Correct Answer-One that releases energy. What is an anabolic reaction? - Correct Answer-One that requires energy. Is DNA replication a catabolic or anabolic process? - Correct Answer-Anabolic, because it builds a pathway and requires energy to do so. The delta G of an endergonic reaction should be __________ than zero. What is this called? - Correct Answer-Greater than 0. Nonspontaneous because it consumes/requires energy. The delta G of an exergonic reaction should be ________ than zero. What is this called? - Correct Answer-Less. Spontaneous because it releases energy. Less energy = _______ stable. - Correct Answer-more. pg. 27 professoraxe l What does the helicase do? - Correct Answer-Separates the double helix by breaking the Hydrogen bonds between the nitrogenous bases. What does the Single Stranded Binding Protein (SSBP) do? - Correct Answer-Binds to the single strand to stabilize it. Without this protein, the DNA would reanneal, and the strands must be separated in order to be replicated. What does the topoisomerase do? - Correct Answer-Relieves pressure of overwinding ahead of the replication fork by breaking, flipping, and reconnecting the DNA strands. This can also be used in chemotherapy to kill cancerous cells. What does DNA polymerase 3 do? - Correct Answer-Elongates DNA at the replication fork using a template and a primer (5- 10 bases long) on the 3' end What does a primase do? - Correct Answer-Synthesises a short RNA primer using the parent DNA as a template. pg. 30 professoraxe l What direction does the leading strand move? - Correct Answer-the same direction as the replication fork. Only one primer is needed. Proceeds continuously. What direction does the lagging strand move? - Correct Answer-the opposite direction of the fork. Multiple primers are needed. Proceeds discontinuously as is synthesized as multiple fragments (Okazaki fragments). What does DNA polymerase 1 do? - Correct Answer-Replaces the RNA primer with DNA. What does DNA ligase do? - Correct Answer-Covalently joins the Okazaki fragments together between the sugar phosphate backbone after the RNA has been replaced with DNA. What does DNA polymerase do? - Correct Answer-Proofreads newly synthesized DNA and replaces incorrect nucleotides. What does RNA polymerase 2 do? - Correct Answer-Untwists the DNA strand and transcribes the DNA into mRNA at a promoter. pg. 31 professoraxe l What does a promoter do? - Correct Answer-A specific DNA sequence that signals RNA polymerase to bind to it (ex: TATA box). What is a transcription unit? - Correct Answer-The DNA that's transcribed. What are transcription factors? - Correct Answer-Help RNA polymerase bind to the promoter/initiate transcription. What is the transcription initiation complex? - Correct Answer-The name given once RNA polymerase 2 and the transcription factors bind to the promoter. This completes the initiation process. What does nuclease do? - Correct Answer-Cuts out damaged DNA (from the environment, diet, behaviors - smoking, etc.) What are telomeres and what are their purpose? - Correct Answer-Special nucleotide sequences that are found at the ends of chromosomes for eukaryotes. They prevent important coding DNA sequences from being degraded after every pg. 32 professoraxe l What are the 3 step of translation? - Correct Answer- initiation, elongation, and termination. What happens in initiation in translation? - Correct Answer- The small ribosomal subunit will bind to the mRNA strand -- an initiator tRNA brings methionine to the AUG codon in the P-site. This process uses GTP instead of ATP. To match the correct tRNA to the correct amino acid, an enzyme called aminoacyl tRNA synthetase is used. The large ribosomal subunit comes in, and the initiation complex is complete. What happens in elongation in translation? - Correct Answer- The next tRNA, carrying the next amino acid to be added to the polypeptide chain, enters the A site of the complex. A peptide bond is formed between the Amino Acid in the P site and the new Amino Acid in the A site. Then, translocation occurs, in which the tRNA in the A site moves to the P site, and the tRNA in the P site moves to the E site. Finally, the tRNA in the E site is ejected and the polypeptide chain is in the P site. What happens in termination in translation? - Correct Answer- The ribosome will eventually arrive at a stop codon on the DNA. There is no tRNA that can bind to this codon. A release factor will enter the A side, and promote hydrolysis of the pg. 35 professoraxe l polypeptide chain from the tRNA in the P site. The ribosomal subunits and the other components dissociate. As a result, a free polypeptide chain is released. Is a lipid a polymer? - Correct Answer-No, because they are formed from 2 different types of subunits. What bonds are formed to turn monosaccharides into carbohydrates? - Correct Answer-Glycosidic linkages. What bonds are formed to turn amino acids into proteins? - Correct Answer-polypeptide bonds. What bonds are formed to turn nucleotides into nucleic acids? - Correct Answer-hydrogen bonds. What are saturated fats? - Correct Answer-Viscous fats found in animal products (solid at room temperature ex: butter). They are fatty acids with no CC double bond which mean that they are more closely packed and therefore harder to digest. What are unsaturated fats? - Correct Answer-Fluid fats found in plant based products. They have CC double bonds which pg. 36 professoraxe l leads to a kink in the structure, thus allowing it to be more fluid leading to easier digestion. What do buffers do? - Correct Answer-Resist change in pH. Phospholipids have a ___________ head and a _________ tail. - Correct Answer-Hydrophilic, Hydrophobic. This allows for selective permeability when forming the phospholipid bilayer. What is a eukaryotic cell? - Correct Answer-An animal, plant, protist, or fungi cell that has a nucleus, organelles, and linear DNA. What is a prokaryotic cell? - Correct Answer-A bacteria or archaea cell that has a nucleoid and circular DNA. What do eukaryotes and prokaryotes both have? - Correct Answer-Cells, a cell membrane, and ribosomes. How are polymers formed? - Correct Answer-Dehydration -- the removal of a water molecule to allow the monomers to covalently bond. pg. 37 professoraxe l molecules inside the cell. Phagocytosis, pinocytosis, receptor mediated endocytosis. What does exocytosis do? - Correct Answer-Vesicles releases molecules outside the cell. What happens in phagocyotsis? - Correct Answer- Pseudopodium surround food to generate a food vacuole. What happens in pinocytosis? - Correct Answer-A portion of the plasma membrane pinches off to bring in different molecules (non specific). What happens in receptor mediated endocytosis? - Correct Answer-Receptors pick up ligands and then send a signal to pinch off and create a coated vesicle (specific mechanism). Ex: LDL -- low density lipoproteins -- LDL binds to receptors on the membrane and causes endocytosis to occur. What is the cytoskeleton? What functions does it provide? - Correct Answer-A network of fibers throughout the cytoplasm. They provide structural support, hold down pg. 40 professoraxe l internal cellular components and organelles, and provide movement. What are the three types of structural elements of the cytoskeleton? - Correct Answer-Microfilaments, microtubules, and intermediate filaments. What type of bonds connect lipids? - Correct Answer-Ester linkages. What does non-disjunction in meiosis 1 look like? - Correct Answer-n+1 n+1 n-1 n-1 What does non-disjunction in meiosis 2? - Correct Answer-n+1 n-1 n n pg. 41 professoraxe l