BSCI105 Exam 1 Review
BSCI105 Exam 1 Review Bsci105
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This 8 page Study Guide was uploaded by Jordan Kotler on Sunday February 14, 2016. The Study Guide belongs to Bsci105 at University of Maryland taught by Dr. Alewall in Summer 2015. Since its upload, it has received 101 views. For similar materials see Intro to biological sciences in Biological Sciences at University of Maryland.
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Date Created: 02/14/16
BSCI105 Exam 1 Review **This study guide does not guarantee any grades, but outlines all of chapters 16 as presented through class lectures** Ch. 1: Evolution, Biology, and Scientific Inquiry ● Evolution the process of change over time ● Levels of organization: molecule → organelle → cell → tissue → organ/organ systems → organisms → populations → communities → ecosystems → biosphere ● Emergent properties due to arrangement and interactions between parts as complexity increases ● Systems biology exploring system by viewing interactions between parts ● Structure determines function!!!! ex. hummingbird wings, flat leaf vs bulky one ● Eukaryotes: membranebound organelles, complex DNA, more complex cells ● Prokaryotes: no membranes, no true nucleus, DNA is circular loop ○ Bacteria and archaea ● Chromosomes hold DNA and RNA in chromosomes (more about this in later chapters) ● Producers make food from light, consumers eat it ● Energy flows 1 way through; nutrients are cycled and recycled ● Natural selection (understand the concepts) Ch. 2: The Chemical Context of Life ● Matter anything that takes up space and has mass ● Element a substance that cannot be broken down anymore ○ 92 elements; 25% are essential ○ O, C, H, N make up 96% of living matter ● Compound a substance consisting of 2+ elements in a fixed ratio ● Trace elements required by an organism in only minute quantities ● Atom the smallest unit of matter that has properties of the element ○ Protons (+), neutrons (0), electrons () ○ Protons and neutrons are in nucleus; electrons form cloud around it in shells ■ P/N weigh 1.7x 10^24 gram = 1 dalton, electrons = 1/2000 of a dalton ● atomic mass = # of protons (also the # of electrons (11 for each) ● mass number = sum of protons + neutrons = 23 ● mass # atomic # = number of neutrons = 2311 = 12 ● Isotopes atom of a given element with a different number of neutrons = weighs more or less than the regular atom ○ Radioactive isotope less stable with a different number of neutrons so it radioactively decays ■ Halflife: time it takes to be ½ amount it started as ■ Energy ability to do work ● Potential energy energy the matter possesses due to its location ○ Electrons have PE due to distance from nucleus ● Electron shells: PE flows from least (closest to nucleus) to most (valence shells) ○ Complete valence shell = stable and unreactive = inert ● Electronegativity increases as you move up (valence shell is closer to nucleus) and left to right (as # protons increases → positive charge) ● More electronegative = more the atom pulls shared electrons toward itself ● Orbital 3D space where an electron is 90% of the time ○ First shell: 1s orbital ○ 2nd shell: 2s, three 2p orbitals ○ Each orbital holds 2 electrons ● First shell (closest to nucleus) holds 2 electrons ● Second shell holds up to 8 electrons (4 orbitals) ● Chemical bonds attractions between atoms ● Covalent strong; sharing of valence electrons ● Ionic strong; 2 oppositelycharged atoms → the more charged atom takes electron(s) from lesscharged atom ○ Positive charge = cation ○ Negative charge = anion ○ Make ionic compounds aka SALTS ■ ex. Na+Cl ● Molecule 2+ atoms held together by a bond ● Weak bonds ○ Hydrogen: between H and an electronegative atom; sharing of electrons ○ van der Waals interactions: everchanging regions of +/ charge that help atoms to stick together ● Molecular shape determines function (form = function) ● Chemical reactions: making and breaking of chemical bonds ○ Reactant + reactant → products ■ ex. 2H2 + O2 → 2H2O ■ Reactions are reversible!! ○ Chemical equilibrium forwards and reverse rxn occur at the same rate; no effect on net concentrations of reactants/products Ch. 3: Water and Life ● Polar: partial charge ● Polar covalent bond: valence electrons are shared due to uneven bond ● Properties of water ○ Cohesion bonding to other water molecules due to hydrogen bonding ○ Adhesion bonding to other molecules via hydrogen bonds b/w cell walls ○ Surface tension difficult to breaking surface ○ High specific heat hard to change the temperature of water ○ High heat of vaporization high heat required for vaporization ○ Universal solvent due to versatile feature due to polarity of water ● Solution homogenous mix of 2+ substances ● Solvent the dissolving agent ● Solute the dissolved substance ● Hydration shell H2O molecules that surround solute ions ○ When NaCl is added to water, it splits into Na & Cl surrounded by water mol. ● Acids: release protons (+), accept H+ ions, pH < 7 ● Bases: absorb protons (+), reduce hydrogen ion concentration, pH between 7 and 14 ● Hydrophobic repels water due to nonionic, nonpolar bonds; cannot form hydrogen bonds (ex. oil) ● Hydrophilic attracts water (ex. cotton → water adheres to cellulose fibers of cotton) ● Buffers minimizes change by accepting or donating H+ if it is in excess or too little of it Ch. 4 Carbon and the Diversity of Life ● Carbon has 4 valence electrons and can form 4 covalent bonds ● Usually bonds with H, N, or O ● Ex. Methane: 1 carbon, 4 single bonds with 4 hydrogens ● 4 structures of carbon skeletons: ○ Length: could be a chain of 2 carbons or 4 or 8 etc ○ Branching: carbons could be in a straight chain, a “T” shape, etc. ○ Double bond position: could be C = C C or C C = C ○ Rings: could form a ring of carbons (double or single bonds) ● Isomers compounds with the same number of atoms of same elements but different structures and properties ○ Structural: differ in covalent arrangements ○ Cistrans: differ in spatial arrangements due to flexible bonds ○ Enantiomers: isomers that are mirror images, differ in shape due to asymmetrical carbon ● Functional groups: chemical groups involved in rxns ○ Hydroxyl ○ Carbonyl ○ Carboxyl ○ Amino ○ Sulfhydryl ○ Phosphate ○ Methyl Group Info Example Hydroxyl (OH) Polar, forms hydrogen bonds Ethanol with water Carbonyl ( C=O) Ketone (carbonyl within Ketone (acetone)/aldehyde skeleton) or aldehyde (propanol) (outside) (O=C in center makes it a ketone) Carboxyl (COOH) Acts as acid and donates H+ Acetic acid bc of polar bond b/w O & H (the C = O and COH) Amino (NH2) Acts as base, accepts H+ Sulfhydryl (SH/HS) Thiol, 2 SH groups can react and form a crosslink Phosphate (OPO3, charge) Charge = 1 inside phosphate chain, 2 on end of chain Methyl (CH3) Affects gene expression when bound to DNA, affects shape/function of sex hormones Ch. 5: Macromolecules ● Definition: big molecules; include lipids, carbohydrates, proteins, and nucleic acids Carbohydrates Lipids mix poorly if at all w/H2O Sugar like mono & polysaccharides Made of glycerol (alcohol with 3 carbons) + Monomers connected by g lycosidic linkage fatty acid (carboxyl group + carbon chain) connected through dehydration rxn (H20 Joined by ester linkages removed) /separated by hydrolysis (H2O Saturated fats: solid at room temperature, added) straight single bonds, pack together tightly Monomer is monosaccharide; polymer is Unsaturated fats: liquid at room temperature, polysaccharide double bonds allow kinks = movement Make carbonyl and hydroxyl groups Phospholipids: hydrophilic (phosphate) Size of carbon skeleton differs head/hydrophobic tail (2 fatty acids) Spatial arrangement around asymmetric carbons differ Energy carbs: glycogen Structural carbs: cellulose, chitin Proteins Nucleic Acids Monomer: amino acids Monomer: deoxyribose or ribose AA → polypeptide → protein (folded polypep) Polymer: polynucleotides Primary structure: sequence of AA in Nucleic acids linked byhosphodiester polypeptide; peptide bonds linkage phosphate links to nitrogen base Secondary : Regular, repeated coiling/folding Made of nitrogen base + pentose + of polypep chain; alpha/beta helices; phosphate group hydrogen bonds b/w carbonyl + amino groups DNA: makes RNA: makes proteins Tertiary: 3D, irregular folding; noncovalent Purine: 6ring carbon/nitrogen fused with bonds between R groups 5ring; larger, adenine/guanine Structure determines function Pyrimidine: Smaller, 6ring carbon of C/N, Flexible, small, in constant motion cytosine/thymine/uracil Folding: chaperonin (promote correct folding), 5’/3’ end cause antiparallel arrangement; 3’ prion (misfolded protein, can cause other had hydroxyl group and 3carbon; 5’ has misfolded protein) phosphate and 5carbon Ch. 6: A Tour of the Cell ● Ways to observe cells ○ Light microscope: can’t always see cells ○ Electron microscope: can see some specimens ○ Scanning EM: study of the entire cell surface ○ Transmission EM: studies internal structure of cells ○ Cell fractionation: takes cells apart to identify individual organelle function Prokaryotes Both Eukaryotes Ex: bacteria and archaea Cytosol DNA in nucleus; is a double DNA in nucleoid, which has no Chromosomes helix membrane Ribosomes Nucleus and organelles are Cytoplasm holds organelles Plasma membrane membranebound Organelles are not membrane Tend to be bigger than bound prokaryotic cells; multicellular DNA is circular, only 1 (plasmid) Animals, plants ● Size influences function ● As size increases, volume and surface area also increase ● Volume grows faster than surface area ● Larger organisms have more cells, NOT bigger cells Organelle Where? Function Nucleus Eukaryotes Holds genes Nuclear envelope Eukaryotes Separates contents of nucleus from rest of cell DNA Pro/euk Made of chromosomes, carry genetic information Nucleolus Eukaryotes Where DNA makes RNA Ribosomes Both Made of RNA + protein, bound to ER or free in cytosol Endomembrane system Eukaryotes Synthesis/transport of proteins, movement of lipids, detoxification of poisons Endoplasmic reticulum Eukaryotes Smooth : no ribosomes, make lipids like sex hormones, metabolize carbs, detoxify alcohol, store ● Rough has calcium ions ribosomes, smooth Rough: wraps secretory proteins in transport vesicles does not (often glycoproteins), makes membranes and phospholipids Golgi apparatus Eukaryotes Shipping and receiving center: made of stacks of cisternae (flattened membranous stacks) Cis side: near ER, receiving side Trans side: sending side, forms vesicles from it Lysosomes Eukaryotes Membranous sac of hydrolytic enxymes, need acidic environment, function is intercellular digestion (phagocytosis), renews itself Vacuoles Eukaryotes Membranebound vesicles Food vac: lysosomes in it digest food Contractile: pumps excess water out of cel Central: plant cells, holds excess compounds Mitochondria Animal cells Where cellular respiration occurs; has 2 membranes that are both phospholipid bilyars and has some DNA; ATP made here Inner layer is folded and called cristae Chloroplasts Plant cells 2 membranes, has stacks of thylakoids (full of stoma fluid with DNA and ribosomes) called granum Where photosynthesis occurs Peroxisomes Eukaryotes Transfer H to O and create H2O2; break down fatty acids, detoxify alochol and other poisons Cytoskeleton: Both Support, motility, regulation Microtubules (part of CS) Pro and eu Made of tubulin dimers; shape and support Grow from centrosomes, make flagella and cilia Microfilaments (part of CS) Pro and eu Made of actin fibers, bear tension to support shape, myosin proteins for motility Intermediate filaments (CS) Pro and eu Shape and position of cells, hold nucleus in place ex. keratin Cell wall Plant cells Protection, shape, regulates water uptake Extracellular matrix Animal cells Made of glycoproteins, like collagen, fibronectin, or integrins Middle lamella Animal cells Layer of sticky polysaccharides between animal cells Plasmodesmata Plant cells Channels between cell walls Intercellular junctions Plant and Animal: tight junction, desmosome, gap junction animal
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