1406 Final

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Northwest Vista College *

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1406

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Biology

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Jan 9, 2024

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docx

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Final Study Guide: Exams 1-3 1. What do we mean when we talk about hypothesis, theory, and law in science? science? Hypothesis = A tentative answer to a well-framed scientific question. It must be testable and falsifiable. Theory = Supported by a large body of evidence in comparison to a hypothesis. Examples: Cell theory and theory of evolution Laws describe what is expected to happen in a specific situation, doesn’t explain why or how. Examples : Laws of genetics and thermodynamics group = group that is not being given the treatment or change. independent variable= “the cause” Factor manipulated by the researchers. On the x-axis dependent variable = the response to the manipulated factor. Differs with experimental group- one variable, pos control- has the variable of interest. Neg control- doesn’t have variable of interest 2. How do you define a control group/experimental group? What other kinds of experiments can you do? control group = group that is not being given the treatment or change. Control group serves as a reference or a baseline= normal growth for the plant. Experimental groups = group that is being treated or changed. Other kinds is Observational experiments. 3. What kinds of data are qualitative? Quantitative? What kinds of experiments use inductive reasoning versus deductive reasoning? Qualitative = descriptions rather than measurements. Quantitative = recorded measurements, organized into tables and graphs 4. How are the following terms defined and related to each other: matter, element, atom, isotope, ion, compound, molecules? Matter- anything that takes up space and has mass, made up of elements  Element(sodium na) : can’t be broken down to another substance by a chemical reaction. Compounds: made of two or more elements in a specific ratio. (Sodium chloride NaCl). Atoms : smallest unit of matter that retains the properties of the element. Neutrons- no charge, Protons - +charge, Electrons - (-)charge Isotope - different atomic forms of the same element. Different # of neutrons. Atomic mass= different but atomic number the same. Ions- formed when an atom either gains or loses electron. 5. atomic particles/locations= Neutrons- no charge (inside nucleus), Protons - +charge (inside nucleus), Electrons - (-)charge (cloud around nucleus in electron shells) 9. What happens to the electrons in a covalent bond? A polar covalent bond? A nonpolar covalent bond? Ionic bond? Covalent bonds= involves sharing a pair of valence electrons “wants” a full valence shell (2 or 8 electrons). Nonpolar covalent : if two atoms have the same electronegativity, electrons are shared equally. Polar Covalent- More electronegative atoms “hold on” to electrons longer than less electronegative atoms Example: water. One end slightly neg and one end is slightly pos. Ionic Bonds- bonding that results from one atom losing electrons and another atom gaining electrons. 10. Describe what happens during a hydrogen bond in water. H2O is polar- o has a slight (-) charge and Hs have slight + charges (polar covalent bond) Hydrogen bond is

an attraction between an H bonded to a very electronegative atom and another atom with 1 pair of electrons. 11. What properties does water have that makes it such an important molecule for living things? Why does it have all these unique properties? Because it is polar and forms hydrogen bonds water exhibits special properties • Cohesion = water is very attracted to itself • Adhesion = water is also attracted to cell walls, glass, and other surfaces +high specific heat, high heat of vaporization, sweat is mostly h2o helps cool organism= evaporate cooling. Great solvent. “Like dissolves like” Hydrophilic= Molecules that are attracted to water. Hydrophobic = Molecules that repel water 12. Acids have pH 0 to 6.9 bases have pH 7.1 to 14 Acids have more H+ than water. Bases have less H+ than water and more OH-. pH is a measure of the H+ concentration. 13. What’s so special about carbon? Has four valence electrons so it can form four covalent bonds • Allows molecules to have many different shape 14. Complete the table Functional group Atoms Found in Molecules Hydroxyl OH Alcohol= polar, makes compounds more soluble in water. E.g. ethanol Carboxyl COOH Acts as an acid e.g. vinegar Amino NH2 Acts as base e.g. ammonia Sulfhydryl SH Rubber Phosphate PO4 ATP 14. What reaction is used to build polymers? Dehydration Synthesis- two monomers are joined by a covalent bond. 1 molecule of h2o released for each bond. Enzymes speed up this process. What reaction is used to break down polymers? Hydrolysis: “Lysis” means break open, reverse of dehydration reaction. Bond between two monomers is broken by adding h2o. Monomer is separated. Enzymes speed up this reaction too. 16. Why aren’t lipids polymers? They lack a monomer unit; What are the smaller molecules of fats, phospholipids, and steroids? Glycerol- small organic molecule with three hydroxyl (OH) groups. Fatty Acids- 4-36 most have 12-18. Steroids- another class of lipids- Basic 4 fused carbon rings. What molecule is involved in these reactions besides the monomers and polymers themselves 17. Fill in the table of macromolecules. Polymer Monomer Type of bond Function Carbohydrates Sugars- monosaccharide Polysaccharides- amylose, starch, and glycogen (CH 2 O) 12 ATP, cellular respiration to do conversion. Plants= store glucose as starches. Protein Polypeptides- Amino Acids 20 aa- 4 main Central carbon- hydrogen backbone, NH2 COOH, R group or side chain. Unique structure- unique function. Protein denature or unfold or lose it function. Nucleic Acid Two polymers: DNA and RNA Monomers- Double helix- held together by Build dna/rna sequences

Nucleotides covalent phosphodiester bonds. 19. What are the components of an amino acid? What makes each amino acid unique ? 20 different amino acids so 20 different side chains Side chains/R groups have different properties • Grouped according to properties: • non-polar (hydrophobic)• polar (hydrophilic)• acidic • basic Carboxylic acid (- charge) = acidic Amino group (+ charge) = basic PEPTIDE BOND • Result of a dehydration synthesis reaction between 2 amino acids • Covalent bond between the C of a carboxylic acid group and the N of an amino group 20. How many levels of protein structure are there? 3 levels of structure for all proteins. Some have a 4 th level. How are shape and function Primary structure: the chain of amino acids . Secondary structure can fold into two regular shapes: beta sheet or alpha helix • Tertiary structure is the 3D globular shape • Quaternary structure only occurs when the protein is made of more than one polypeptide chain What kinds of proteins have a fourth level of structure ? Hemoglobin PROTEIN FUNCTIONS • Enzymes = speed up reactions• Storage = storage of amino acids• Hormones = regulation of activities• Contractile and motor = movement• Defensive = antibodies• Transport = transport materials• Receptor = respond to stimuli• Structural = support 21. What are the components of a nucleotide? What are the differences and similarities between DNA and RNA? Nucleotides have three components: • Phosphate group • 5 carbon sugar, either deoxyribose (DNA) or ribose (RNA) • Nitrogenous base = adenine, cytosine, guanine, thymine (DNA) and uracil instead of thymine (RNA). DNA- sugar- deoxyribose, base=thymine, overall structure- double stranded. Function= genetic material. Location- nucleus only. RNA- sugar- ribose, base- uracil, overall structure- usually, single stranded, function- =copies genetic material, protein synthesis, location= nucleus & cytoplasm. Sugar triglyceride Nucleic Acid Amino Review for 2 and 3 1. The main function of cholesterol in the plasma membrane of some animals is to A) Make the membrane more rigid, allowing it to resist pressure from outside the cell. B) Help with the removal of hydrogen atoms from saturated phospholipids. C) Help with cell-cell Interactions by binding to receptors on neighboring cells

D) Allow the membrane to stay fluid more easily when the temperature changes. 2. The Image to the right is of some red blood cells that have been placed in a(n) A) hypertonic B) hypotonic C) isotonic D) supertonic solution. 3. At the right is an image of a plasma membrane and some molecules. Which of the molecules can rapidly cross the membrane easily? A) lipid B) water C) glucose D) hydrogen ion 4. Which of the following membrane activities requires energy from ATP? A) facilitated diffusion of chloride ions across the membrane through a chloride channel B) movement of sodium ions from a lower concentration in a mammalian cell to a higher concentration outside the cell? C) movement of carbon dioxide out of a paramecium (one celled organism) D) movement of glucose into a bacterial cell from a solution containing a higher concentration 5. Endocytosis moves materials…...a cell using…...? A) out of ... transport vesicles B) into ... transport vesicles C) into ... facilitated diffusion D) out of ... diffusion a cell using 6. The term "ligand" in cell biology refers to A) the target cell of a signal molecule B) the change in shape that occurs when a signaling molecule binds to its receptor C) the bond that forms between a signaling molecule and its receptor D) a small molecule that can bind in a specific manner to a receptor 7. Which of the following is NOT an example of a receptor in a cell signaling pathway? A) Ligand-gated ion channel B) G-protein coupled receptor C) Sodium-Potassium pump D) Enzyme-linked 8. Phosphorylating a protein means that A) an ATP molecule has been added to the protein B) an inorganic phosphate has been removed from the protein C) an inorganic phosphate has been added to the protein D) an ADP molecule has been added to the protein 9. Steroid hormone receptors in animals tend to be A) glycolipids rather than proteins. B) proteins in the cytoplasm. C) integral proteins D) peripheral proteins 10. Energy transformations always result in the loss of _______of the universe which increase…….? A) chemical energy; entropy B) light; enthalpy C) heat; entropy D) potential energy; ATP 11. The cellular process of breaking down larger molecules into smaller ones is defined as? A) metabolism B) catabolism C) anabolism D) catalysis 12. The type of energy that cells use to do work is A) ATP B) Kinetic C) ADP D) Glucose 13. Below is a graph showing the reaction rate of three different enzymes. The optimal pH for salivary amylase is A) 9 B) 7 C) 6 D) 2 14. A specific substrate is recognized by the…… of an enzyme. A) cofactor B) temperature C) bonds D) active site

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