Bio Exam 1 Study Guide

Bio 181 Exam 1 Study Guide 1. Know what positive and negative feedback are and how they work (generally). - Negative feedback: Most common; returns to the correct set point→ ex) blood pressure,body temp - Positive: Special circumstances or disease; gets further from set point→ ex) Childbirth, ovulation 2. Know the difference between prokaryotes and eukaryotes. Which organisms are made of prokaryotic cells and which are made of eukaryotic cells. - Prokaryotic: Bacteria and archaea, circular chromosome O, no nucleus---> nucleoid region, no membrane-bound organelles, smaller in size. Eukaryotic: Protists, fungi, and animals. plant and animal cells. linear chromosomes X, have a nucleus, membrane-bound organelles, larger in size. Both Have: Cell membrane (plasma), phospholipid (bi-layer), cytosol (liquid jelly-ish substance inside cell), ribosomes (make proteins). 3. Know the characteristic of all living organisms. - Order, Ability to reproduce, Respond to the environment, energy processing, growth and development, regulation=homeostasis, evolutionary adaptation. 4. What things are important for a good experimental design? 5. Given an experiment be able to determine the hypothesis, control group, experimental group, constants, independent variable, and dependent variable. - Hypothesis: Possible explanation to observation - Control Group: Baseline, no changes - Experimental Group: Change one thing, variable - Independent Variable: Experimental variable, what researcher changes. - Dependent Variable: What you measure 6. Be able to convert within the metric system and from English to metric. 7. 8. - What are the 4 most abundant elements in living matter? Carbon, hydrogen, oxygen, and nitrogen make up 96% of living matter What does the atomic mass (mass number) and atomic number represent? Atomic mass: The number of protons and neutrons in the nucleus. the atom’s total mass, can be approximated by the mass numberAtomic Number: Number of protons in the nucleus. 9. How do you determine the number of protons, neutrons, and electrons in an element? - To determine the amount of protons, Look at the atomic number - To determine the number of neutrons, Mass#-Atomic #= # neutrons - To determine the number of electrons, same number as protons 10. What is an isotope? - Are two atoms of an element that differ in number of neutrons 11. Know what polar covalent bonds, nonpolar covalent bonds, ionic bonds, hydrogen bonds, and van der waals forces are. - Nonpolar covalent bond: The atoms share the electron equally - Polar Covalent bond: One atom is more electronegative, and the atoms are shared unequally - Ionic bonds: Attraction between a cation (+) and aion(-) transfer of electrons Atoms sometimes strip electrons from their bonding partners, EX)the transfer of an electron from sodium to chlorine. After the transfer of an electron, both atoms have charges. - Hydrogen Bonds: Forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom - Van der waals forces: Are attractions between molecules that are close together as a result of these charges 12. What is an ion? How are cations formed? How are anions formed? - Ion: A charged atom or molecule - Cations: Is a positively charged ion - Anions: Is a negatively charged ion 13. How many electrons are involved in a single bond, double bond, and triple bond? **Pay attention to electrons vs electron PAIRS** - A single covalent bond, or single bond, is the sharing of one pair of valence electrons - A double covalent bond, or double bond, is the sharing of two pairs of valence electrons - A triple bond is a chemical bond between two atoms involving six bonding electrons instead of the usual two in a covalent single bond 14. Be able to identify the products and reactants in a chemical reaction. - Reactants: The starting molecules of a chemical reaction - Products: The final molecules of a chemical reaction 15. For water be able to identify where the nonpolar covalent bonds are and where the hydrogen bonds are. 16. Know what specific heat is and how a high vs low specific heat determines how fast/slow a substance changes temperature. - Is the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1°C. 1 cal/g/°C - If we increase temperature, we increase kinetic energy (molecules move faster) - Water resists changing its temperature because of its high specific heat - The high specific heat of water minimizes temperature fluctuations to within limits that permit life 17. Why does ice float and why is this important? - Ice floats in liquid water because hydrogen bonds in ice are more “ordered,” making ice less dense than water 18. What is a calorie? - Energy available from the food - The amount of heat required to raise the temperature of 1 g of water by 1°C 19. What does hydrophobic mean? What types of substances are hydrophobic? - Hydrophobic: Hate water Ex) oil, fats 20. What does hydrophilic mean? What types of substances are hydrophilic? - Love water Ex) salt,sugar 21. If a positive substance is placed in water how do the water molecules arrange themselves? What if there is a negative substance? 22. What is the purpose of a buffer? - Resist changes in pH 23. What is pH? What is the pH of an acid? What is the pH of a base? Which has more hydrogen ions an acid or a base? - pH: The negative logarithm of H+ concentration - Acidic solutions have pH values less than 7 - Basic solutions have pH values greater than 7 - The solution is neither acidic or basic. An acid is a substance that donates hydrogen ions. Because of this, when an acid is dissolved in water, the balance between hydrogen ions and hydroxide ions is shifted. Now there are more hydrogen ions than hydroxide ions in the solution. 24. What is adhesion? What is cohesion? - Adhesion is an attraction between water and something, for example, between water and plant cell walls - Cohesion is the attraction of water molecules, it helps the transport of water against gravity in plants 25. What does it mean is a substance is an ORGANIC molecule? - Organic molecules are usually composed of carbon atoms in rings or long chains, to which are attached other atoms of such elements as hydrogen, oxygen, and nitrogen. - Carbon chains form the skeletons of most organic molecules, Carbon chains vary in length and shape - Hydrocarbons are organic molecules consisting of only carbon and hydrogen - Many organic molecules, such as fats, have hydrocarbon components - Hydrocarbons can undergo reactions that release a large amount of energy  26. What are isomers? Be able to identify structural isomers, cis/trans isomers, and enantiomers. - Isomer are compounds with the same molecular formula but different structural formula - Structural isomers have different arrangements - Cis-trans isomers have the same covalent bonds but differ in spatial arrangements - Enantiomers mirror images What is a dehydration reaction? What does it make? Taking out water molecule Monomers bond together What is a hydrolysis reaction? What does it break down? - When you add water molecule - polymers are disassembled 29. Carbohydrates a. The monomer (structure): Monosaccharides - Example→ Glucose, Fructose, Glucose b. Polymer: Disaccharides/polysaccharides - Example→ Starch (cellulose) = plants, Glycogen = animals, Chitin = arthropods c. What is a disaccharide: Is formed when a dehydration reaction joins two monosaccharides - Example→ Lactose, Sucrose, Maltose d. Glycosidic linkage: = covalent bond e. Functions of carbohydrate: - Serve as fuel and building material - Strengths plant cell walls - Stores glucose for energy - Strengthens exoskeletons and fungal cell walls f. The polymers (and characteristics of each polymer) i. Starch: Plants ii. Cellulose: Plants iii. Glycogen: Animals iv. Chitin: Animals and Fungi 30. Lipids: Hydrophobic→ due to non-polar hydro chains 27. 28. a. FATS Triglyceride: Glycerol (fats & oils) + 3 fatty acids, important energy source 1. Trans fat: Contribute more than saturated fats to cardiovascular disease 2. Saturated fat: Single bond, BAD, solid at room temperature, animal fat 3. Unsaturated fat: Have at least 1 double bond, liquid at room temperature, plant fat and oil, PRODUCES TRAN FAT (BAD 4 HEART) b. PHOSPHOLIPIDS - Two fatty acids and a phosphate group attached to glycerol - Cell membrane→ bilayer c. STEROIDS - Made from cholesterol→ 4 ring structure d. Functions of lipids - Component of cell membranes (cholesterol) - Signaling molecule that travel through the body (hormones) e. What 1 characteristic do all lipids share? - Does not include true polymers, they mix poorly, if at all, with water 31. Proteins a. The monomer (structure): Amino acid b. The polymer: Polypeptide = covalent bond i. Primary structure: Amino acid sequence ii. Secondary structure: Alpha helix oro B Pleated sheet iii. Tertiary structure: 3D iv. Quaternary structure: Combine many proteins c. Dipeptide bond: A dipeptide is a short protein consisting of only two amino acids linked together by one peptide bond. d. Functions of proteins - Speed up chemical reactions (enzymes) - Provide structural support (structural proteins) - Coordinate organismal responses (hormones) - Receive signals from outside cell (receptor proteins) - Function in cell movement (motor proteins) - Protect against cell disease (defensive proteins) 32. Nucleic Acids a. The monomer (structure): Nucleotide→ phosphate b. The 2 classes of nitrogen base and which bases belong to each class c. The polymer: DNA/RNA i. DNA: Sugar = deoxyribose, Nitrogenous bases = C, G, A, T, Usually double-stranded ii. RNA: Sugar = ribose, Nitrogenous bases = C, G, A, U, Usually single stranded iii. Differences in DNA and RNA - DNA: Two polynucleotides,double helix,thymine - RNA: Ribose, single stranded, uracil d. Functions of nucleic acids - Store, transmit and help express hereditary information. - DNA: Stores hereditary info - 33. 34. 35. 36. 37. RNA: Various functions in gene expression, including carrying instructions from DNA to ribosomes Know the structure of a prokaryotic cell: No nucleus, DNA in an unbound region called the nucleoid, No membrane-bound organelles, Cytoplasm bound by the plasma membrane Know the function of the organelles in the eukaryotic cell a. Nucleus: Nucleus contains most of the cell’s genes and is usually the most conspicuous organelle b. Nucleolus:Synthesizes RNA c. Ribosomes: Make proteins d. Rough ER: Has bound ribosomes, which secrete glycoproteins (proteins covalently bonded to carbohydrates)Distributes transport vesicles, secretory proteins surrounded by membranes, Is a membrane factory for the cell e. Smooth ER: Synthesizes lipids, Metabolizes carbohydrates, Detoxifies drugs and poisons, Stores calcium ions f. Lysosomes: Is a membranous sac of hydrolytic enzymes that can digest macromolecules, Lysosomal enzymes work best in the acidic environment inside the lysosome, Hydrolytic enzymes and lysosomal membranes are made by rough ER and then transferred to the Golgi apparatus for further processing. g. Vacuole: Storage, are large vesicles derived from the ER and Golgi apparatus, Vacuoles perform a variety of functions in different kinds of cells Food vacuoles are formed by phagocytosis Contractile vacuoles, found in many freshwater protists, pump excess water out of cells Central vacuoles, found in many mature plant cells, hold organic compounds and water h. Mitochondria: Cellular respiration to make *ATP*, found in plants and animals. i. Chloroplast: Found in plants and algae, are the sites of photosynthesis j. Centrosome:Microtubules grow out from a centrosome near the nucleus. In animal cells, the centrosome has a pair of centrioles, each with nine triplets of microtubules arranged in a ring Know the pathway a protein would take through the endomembrane system. The endomembrane system regulates protein traffic and performs metabolic functions in the cell Consists of: Nuclear envelope, Endoplasmic reticulum, Golgi apparatus, Lysosomes, Vacuoles, Plasma membrane What are plasmodesmata? What are tight junctions? What are desmosomes? What are gap junctions? - Plasmodesmata are channels that perforate plant cell walls, Through plasmodesmata, water and small solutes (and sometimes proteins and RNA) can pass from cell to cell - Tight Junctions are membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid - Desmosomes are (anchoring junctions) fasten cells together into strong sheets - Gap Junctions are (communicating junctions) provide cytoplasmic channels between adjacent cells Know the differences between plant and animal cells