Biology. Exam 1 Study Guide

BIO 1401 – Principles of Biology Exam 1 Study Guide Chapter 3 1. Compare the properties of saturated and unsaturated fatty acids. a. Which has double bonds? Unsaturated fats b. Which is solid at room temperature? Saturated fats c. Which can pack more tightly together? Saturated fats 2. List 3 functions of lipids. Storage, signaling, and structural components for cell membranes 3. Compare starch, glycogen, and cellulose. a. How do they differ in structure? b. Where are they typically found? c. What is their function? The main function of starch, glycogen, and cellulose is that on hydrolysis they yield "Glucose" that is the source of the energy. d. What is their monomer? Starch is the polysaccharide carbohydrate formed by the monomer called alpha glucose. Beta glucose is the monomer for Cellulose. Alpha glucose is the monomer for glycogen. (sugar molecules) 4. Is DNA single- or double-stranded? What about RNA? DNA is double stranded, while RNA is single stranded 5. Describe the 4 levels of protein structure. hydrogen atom, a carboxyl group, an amino acid group, and a variable or R group. 6. How can a protein become denatured? The protein will lose its shape, which will then affect the protein’s ability to function. 7. List 3 functions of proteins. Storage, Transport, and Defense 8. What is it called when a peptide bond is broken? (i.e. shortening a protein) Hydrolysis 9. How do catalysts work? a. Can they make a reaction occur that would not otherwise happen? They can help speed up the reaction b. Do they undergo changes themselves? They do not undergo chemical changes. They help to reduce the activation energy required by a reaction. 10. How do catabolic and anabolic reactions differ? Catabolic pathways break down molecules into smaller molecules and release energy. Anabolic pathways synthesize complex molecules from simpler ones. 11. Where does an allosteric regulator bind? What about a competitive inhibitor? The regulator binds to a site other than the active site (allosteric site). Competitive inhibition is reversible, the inhibitor is similar to the substrate, but no reaction occurs. 12. How does an allosteric inhibitor prevent a substrate from binding to an enzyme? The substrate can still bind to the enzyme, but the inhibitor changes the shape of the enzyme so it is no longer in an optimal position to catalyze the reaction. Chapter 4 1. What is the function of the cell membrane? They separate the internal environment from the external environment, giving cells or cell compartments the ability to regulate their internal composition 2. What types of proteins can be found in the cell membrane? Integral membrane proteins: at least partly embedded in phospholipid bilayer. Hydrophobic regions interact with membrane interior; hydrophilic regions interact with the aqueous environment. Anchored membrane proteins: covalently attached to fatty acids or other lipid groups 3. What portion(s) of the cell membrane is/are hydrophobic? Hydrophilic? Hydrophobic regions interact with the membrane interior, while hydrophilic regions interact with the aqueous environment. 4. How do passive and active transport differ? Passive transport does not require energy, substances diffuse down a concentration gradient. Active transport requires energy and the assistance of specialized membrane proteins. 5. What moves in diffusion – solute or solvent? Is movement from high to low concentration, or low to high concentration? In diffusion, a both moves. The movement is from high to low concentration. 6. What types of molecules can diffuse more easily through simple diffusion? In simple diffusion, small, nonpolar lipid -soluble molecules can diffuse more easily through simple diffusion. 7. What moves in osmosis? Does it move from high to low concentration, or low to high? In osmosis, there is a net movement of water from a region of lower solute concentration to a region of higher solute concentration. 8. Contrast isotonic, hypotonic, and hypertonic. Isotonic- solutions have equal solute concentrations, Hypotonic-lower solute concentration, Hypertonic-higher solute concentration a. What happens when a red blood is placed in a hypertonic solution? b. What happens if it is placed in a hypotonic solution? 9. What are aquaporins? Channels for movement of water 10. What molecule powers active transport? 11. Compare and contrast exocytosis, endocytosis, pinocytosis, and phagocytosis. cell takes in water-pinocytosis, takes in molecules-endocytosis, takes in food-phagocytosis, moves materials out of cell-exocytosis a. Are molecules moving into or out of the cell? b. What type of molecules are being moved? 12. List 2 functions of the cytoskeleton. Supports and maintains cell shape and moves organelles and other particles within the cell 13. What is the function of the rough endoplasmic reticulum (RER)? What type of cell would have an abundance of RER? What about smooth ER? Rough ER- has many ribosomes; as proteins are synthesized, they enter the Rough ER lumen where they are modified and transported to other areas. Smooth ER- lipid synthesis, detoxification of small molecules, storage of calcium ions for muscle contractions. Chapter 5 1. What is the main energy currency in cells? ATP 2. What monomer is broken down during aerobic metabolism? 3. Name the 4 stages of aerobic metabolism. a. Where in the cell does each stage occur? b. What is/are the main product(s) of each? 4. How does fermentation differ from aerobic metabolism? One of the most striking differences though between fermentation and aerobic respiration is the end product. Fermentation process yields only 2 ATP while the other produces 38 ATP. 5. What molecule is the final electron acceptor in oxidative phosphorylation? a. What molecule does it form? 6. What is gluconeogenesis? citric acid cycle and glycolysis intermediates are reduced to form glucose. 7. What are 2 pathways in photosynthesis called? a. Where do they occur? b. What is the end-product of each? c. How do they interact? 8. What happens to a receptor molecule when it absorbs a photon? 9. What 2 pigments are primarily responsible for absorbing light energy in photosynthesis? 10. What mechanism is similar in both aerobic metabolism in animals and photosynthesis in plants? 11. What is the name of the enzyme that catalyzes carbon fixation in the Calvin cycle? 12. How do autotrophs and heterotrophs differ in the way they acquire chemical energy? Chapter 6 (6.1 and 6.2 only) 1. What is a ligand? the chemical signal that binds to the receptor and cascade of events leads to a response 2. Why don’t all cells in an organism respond to a particular ligand?Binding of ligands to receptor protein is very specific. Signals can be targeted to specific groups of cells.The same signals may be detected by different receptors on different cells. Cells without a receptor for a ligand will not be able to detect the signal. 3. Compare juxtacrine, paracrine, autocrine, and endocrine signaling. Specifically, where is the target cell in relation to the signaling cell? Juxtacrine- requires direct contact between the two cells, Paracrine- diffuse to and affect nearby cells, Autocrine- This signaling affects the same cells and release them, Endocrine- Hormones are transported long distances by bulk flow 4. What type of molecule is the signal in endocrine signaling? 5. What are the 2 types of cell receptors? Intracellular receptors: located inside a cell; ligands are small or nonpolar (hydrophobic) and can diffuse across the cell membrane. They respond to hydrophobic ligand molecules that are able to travel across the plasma membrane. Membrane receptors: located on the cell surface; ligands are large or polar and can’t cross the lipid bilayer. Also have a cytosolic region that initiates signal transduction. Chapter 7 1. Is mitosis considered sexual or asexual reproduction? What about meiosis? Mitosis is considered asexual reproduction, and meiosis is considered sexual reproduction. 2. What is the result of mitosis? a. How many cells result? 2 b. Are the cells diploid or haploid? Haploid c. Are the cells genetically similar or different compared to each other and the parent cell? Similar 3. What must take place for a zygote to form? Fertilization- two haploid gametes fuse to form a zygote 4. What are the 4 phases of the cell cycle? a. What process occurs in each phase? G1: cells carry out normal functions. G0 is an arrested state. Cells remain in this state until receiving cell division signals. S phase: DNA is replicated G2: cell prepares for mitosisM phase: mitosis and cytokinesis. b. In which phase does a cell spend most of its time? G1 Phase 5. Name and describe what happens during each of the phases of mitosis. Prophase—first stage of mitosis: Chromosomes condense Protein structures called kinetochores appear on each side of the centromere. Centrosomes orient at both ends of the cell; consist of a pair of centrioles—they are the “poles” toward which chromosomes move during segregation. Prometaphase: spindle is fully formed, nuclear envelope breaks down and chromatids attach to the kinetochore microtubules. Metaphase: the chromosomes line up on the spindle at the midline of the cell (the metaphase plate). Anaphase: centromeres divide and sister chromatids separate; daughter chromosomes move toward the poles. Telophase: nuclear envelopes form; spindle breaks down and chromosomes become less compact. Cytokinesis: In animal cells, a contractile ring of actin and myosin microfilaments pinches the cell membrane in. In plant cells, vesicles from the Golgi apparatus appear along the plane of cell division and fuse to form a new cell membrane. Contents of vesicles contribute to forming the new cell wall. 6. Which structure forms to aid in plant cell cytokinesis? Microtubules 7. What is chromatin made up of? Chromosomes are compacted by being wrapped around histones and other proteins to form chromatin. 8. Compare and contrast necrosis and apoptosis: In necrosis, the cell is damaged or starved for oxygen or nutrients. The cell swells and bursts. Cell contents are released to the extracellular environment and can cause inflammation. When an organism dies, all of its cells will soon succumb to this kind of death. Apoptosis is genetically programmed cell death; reasons for apoptosis: Cell is not functioning properly, e.g., cells are replaced as they age or if damaged. The cell is no longer needed (e.g., the connective tissue between the fingers of a fetus) Infection: death of the cell prevents the infection from spreading. a. Which occurs when cells are damaged or lack nutrients? Necrosis b. Which causes inflammation? Necrosis c. Which is another term for programmed cell death? Apoptosis 9. What is the result of meiosis? Four Haploid Cells that are not genetically identical a. How many cells result? Four b. Are the cells diploid or haploid? Haploid c. Are the cells genetically similar or different compared to each other and the parent cell? Not genetically identical 10. What 2 events increase genetic diversity during meiosis? Crossing over Chapter 8 1. What is the name of the first generation of offspring produced from a parental cross? 2. Contrast genotype and phenotype. Can environment affect phenotype? 3. If we want to know the genotype of an individual with a dominant phenotype, what known genotype would we cross it with to find out? (homozygous dominant, homozygous recessive, or heterozygous) 4. What is linkage? 5. How are pedigrees helpful in studying health? 6. Are genetic mutations always harmful? Why or why not? 7. What is the wild type allele? 8. What does it mean when an individual is hemizygous? 9. Can a male (XY) affected by an X-linked recessive trait pass this trait on to his daughters? What about his sons? 10. What is pleiotropy? 11. What is epistasis? 12. Which of the following is a discrete trait? Which is a quantitative trait? i. fin color in tuna fish ii. tail feather length in male peacocks iii. presence of dewclaws in puppies iv. number of petals on a rose Quantitative Chapter 10 1. What is the sequence of events in gene expression? Transcription- information from a DNA sequence is copied to a complementary RNA sequence. Translation- RNA sequence is used to synthesize the amino acid sequence of a polypeptide 2. What type of protein binds upstream to help RNA polymerase determine which genes are expressed? Other proteins (sigma factors and transcription factors) bind “upstream”from the initiation site and helpRNA polymerase bind and determine which genes are expressed. 3. How are exons and introns different? Which is removed from the final mRNA? Eukaryotes: each gene has its own promoter and most have noncoding sequences called introns. Transcribed regions are exons. Introns and exons both appear in the primary mRNA transcript (pre-mRNA); introns are removed from the final mRNA. 4. At what structure does translation occur? Ribosomes 5. What are the 3 steps in translation? Initiation ("beginning"): in this stage, the ribosome gets together with the mRNA and the first tRNA so translation can begin. Elongation ("middle"): in this stage, amino acids are brought to the ribosome by tRNAs and linked together to form a chain. Termination ("end"): in the last stage, the finished polypeptide is released to go and do its job in the cell. 6. Where can a polypeptide go after it crosses into the RER? It may be retained in the lumen, sent to other regions in the endomembrane system, or be secreted from the cell.