Biology Unit 2 Study Guide
Biology Unit 2 Study Guide Bio 190
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This 9 page Study Guide was uploaded by Anna Stidham on Tuesday February 9, 2016. The Study Guide belongs to Bio 190 at Towson University taught by Joseph Velenovsky in Fall 2015. Since its upload, it has received 18 views. For similar materials see Intro Biology for Health Professions in Biology at Towson University.
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Date Created: 02/09/16
Bio Unit 2 Exam Study Guide Essay- structures of a protein The primary structure of a protein is the linear sequence of amino acids; The secondary structure of a protein is Alpha helical region(s) & beta pleated sheet(s), both of which are held together through hydrogen bonds; The tertiary structure of a protein is the three dimensional shape formed by the interactions between R groups; The quaternary structure of a protein is an association of multiple polypeptides Primary- upon denaturation it stays intact; linear sequence of amino acids Secondary- backbone of a protein; Alpha helixes- fibrous proteins have more; beta pleated sheets- globular proteins; held together by Hydrogen bonds Tertiary- 3D shape that determines function of protein; interactions of R groups are important and h bonds happen between them. Di sulfide bonds are covalent bonds that are very important and hold the whole structure together Quaternary- 2 or more polypeptide chains make one macromolecule; can be the same polypeptides or different ones Denaturation- Salt and pH break up R groups which breaks tertiary structure and that creates function so it makes it all fall apart Salt- Na+ Cl- ; dissociate into ions and sodium and chlorine will compete for R groups bond. This ill break apart R group’s interactions with one another pH- OH- and H+ will compete for R group bonds and will break up R groups interactions Temperature- vibrates and breaks apart stuff Short answers: Receptor-mediated endocytosis Very highly selective. Receptors for certain solutes, only works for certain thing, receptors ill bind to solute and it will trigger clathrin coated pit that buds off and formed coated vesicle. 3 steps: Receptor binding, formation of pit, vesicle buds off and goes where it needs to go Example: cholestrol Signal Transduction (get diagram of them and explain) Way for cells to talk; signaling cell will exocytosis (export) signal molecule that binds to protein that is receptor for molecule that signal relay proteins to propagate signals. Can make transcription factor and make a new protein Hyperactive ras relay protein- growth factor ordinarily proteins get secreted; but ras relay protein takes over (no growth factor, no cell talk) hyperactive sends its own signal (growth shouldn’t be happening), proteins made when no signal said it should in the first place- cancer P53- tumor suppressor gene- growth inhibiting factor should stop growth but nonfunctional transcription factor doesn’t signal transcription of protein that should stop growth. Osmosis Passive transport of water across a selectively permeable membrane. Water molecules readily pass through the cell membrane even though they are polar because of protein channels called ‘ aquaporins. Water diffuses until the solute to water concentration is equal on both sides. Tonicity Hypertonic: Inside- LS, HW and outside-HS, LW and so water moves out, shrivel Hypotonic: Inside- HS, LW and outside- HW, LS and so water moves into cell, burst Covalent bonds - are the strongest, two atoms chare one or more pairs of electrons Nonpolar: atoms exert an equal pull on the electrons, the electrons are shared equally Polar: Unequal sharing of electrons; negatively charged electrons get pulled closer to the more electronegative atom an it makes that atom partially negative and the other atom partially positive. Chemistry extent: be able to draw water, determine between covalent polar v nonpolar Polar- hydrophilic Nonpolar- hydrophobic Functional groups Proteins, carbs, lipids All dehydration reactions and hydrolysis Carbs- Glucose and Fructose are sugar monomers or monosaccharides Maltose- G+G; Sucrose- G+F, hydrophilic or soluble in water Polysaccharide (all made of glucose): starch (storage in plants; unbranched; Amylase breaks it down), glycogen (storage in animals; branched in liver and muscles); cellulose (structural in plants for their wall; cellulose breaks it down; we don’t have but cows and termites have bacteria that break it down; highly branched and bonds switch off top to bottom) Proteins- Made of amino acids R groups determine what amino acid it is Polar R groups- either bc its charged or because of an OH- group Lipid- no monomer, hydrophobic Fatty acid- three tails and glycerol Saturated- all hydrogens Unsaturated- kink (poly- many kinks in one tail) Fatty acid Steroid (cholesterol) Phospholipid- 2 fatty acid tails Hydrophilic (polar) head, hydrophobic tail choline, glycerol, phosphate group, 2 fatty tails Diffusion: tendency for particles of any kind to spread out evenly in an available space; molecules in a fluid are constantly in motion and they collide with each other and bounce off others and spread into open space. If the membrane is permeable to a molecule—the molecule can easily pass through membrane Equilibrium: when the number of molecules moving in one direction is equal to the number of molecules moving in the opposite direction. Concentration Gradient: substances tend to move from areas of high concentration (where a ton of molecules are) to areas of less concentration (where fewer are) Passive Transport- diffusion across a membrane that requires no energy (O and 2 CO 2iffuse easily) Facilitated Diffusion- passage of a substance through a specific transport protein across a biological membrane down its concentration gradient. Transport proteins help substances that do not diffuse freely across membrane, without them certain substances wouldn’t be able to cross membrane or would take too long & wouldn’t be useful; t.proteins are specific for the substance they help No energy is used because it is a type of passive transport and works with the concentration gradient Polar molecules and ions use facilitated diffusion Aquaporin- the transport protein that helps move water across membrane b/c water is polar Active Transport- energy (ATP) must be expended to move a solute against its concentration gradient (toward the side where the solute is more concentrated) 1. Solute Binding- solute on the cytoplasmic side of the plasma membrane attaches to a specific binding site on the transport protein 2. Phosphate Attaching (Phosporylation)- ATP transfers one of its phosphate groups to the transport protein 3. Transport- Protein changes shape in such a way that the solute goes through and is released on the other side of the membrane 4. Protein reversion- Phosphate group detaches and transport protein returns to its original shape Exocytosis- export bulky materials ex. Proteins and polysaccharides Transport vesicle filled with macromolecules buds from Golgi goes to plasma membrane then vesicles fuse with membrane and vesicle’s contents spill out of cell. Tears are when salty solutions get exported through exocytosis. Endocytosis- cell takes in large molecules Depression in the plasma membrane pinches in and forms a vesicle enclosing material that had been outside the cell Three kinds: Phagocytosis: “cellular eating”, cell engulfs a particle by wrapping extensions called pseudopodia around it and packaging it within a membrane-enclosed sac large enough to be called a vacuole Pinocytosis- “cellular drinking”, cell gulps droplets of fluid into tiny vesicles; not specific (any and all solutes dissolved in the droplets) Receptor-mediated endocytosis- highly selective; receptor proteins for specific molecules are embedded in regions of the membrane that are lined by a layer of coat proteins; take cholesterol from blood for synthesis of membranes and steroids Signal Transduction pathway- a series of molecular changes that converts a signal on a target cell’s surface to a specific response inside the cell 1. Signaling cell secretes a signaling molecule 2. This molecule binds to a receptor protein embedded in the target cell’s plasma membrane 3. The binding activates the first in a series of relay proteins within the target cell 4. The last relay molecule in the series activates a transcription factor 5. The factor triggers transcription of a specific gene 6. Translation of the mRNA produces a protein KNOW ALL CELL PARTS Endomembrane System Nuclear Envelope- has two membranes that keep nucleus together; traffic cop of nucleus ER- Smooth- making of lipids; rich in ovaries and testes bc they make hormones (steroids), and livers bc it detoxifies drugs and alc, and stores calcium ions in muscle and nerve cells Rough- makes phospholipids that help plasma membrane grow bc vesicles go off and add to them, bound (on rER or membrane) or secreted by cell. Golgi- Comes to receiving end and adds to membrane of Golgi, contents move through, and then modification (glycosylation or phosphorylation), buds off and vesicles is made from membrane of Golgi Lysosome- They digest everything. They bind to vacuoles and digest it all and can recycle things to organic parts Plasma Membrane forms a flexible boundary between the living cell and its surroundings Phospholipid hydrophilic heads face into the cell exposed to the aqueous solutions on both sides of the membrane and out of the cell while hydrophobic tails point inward mingling together and shielding from water Nonpolar Molecules (O ,2CO )2easily move across membrane Ions and Polar Molecules need help getting across. Some proteins form channels so the polar molecules can get through the membrane Vacuole- big vesicles Not in system but part of cell: Ribosomes: Make proteins can be free in cytoplasm or bound to rER or nuclear envelope Mitochondria- energy processing Chloroplast- photosynthesis Cytoskeleton- protein fibers; support and structure; need motor proteins Microfilaments: thinnest, globular, form 3d network that supports cell bc they don’t have cell walls Intermediate Filaments: made of fibrous, supercoil, anchor organelles ex. Nucleus, permanent Microtubules: mainly globular, act like train tracks for organelles to move along like lysosomes Extracellular Matrix- forms tissues and helps protect cell; main component is glycoprotein Integrins: transmit signals between ECM and cytoskeleton Junctions Tight- prevents leakage, knit together by proteins Anchor- strength and stability, intermediate filaments, stretch or mechanical stress Gap- communicating Plants: cell wall made of cellulose and plasmodesmata that prevents isolation and keeps open channels of water, nutrients, and helps chemical signals go from one cell to another Plants do not have lysosomes- they use contractile vacuoles to digest and to keep things that you don’t want in other parts of the cell like plant pigment and antiherbivore compounds like nicotine or caffeine The small size of cells relates to the need to exchange materials across the plasma membrane Cell must be large enough to house enough DNA, protein molecules, and structures to survive and reproduce Large cells have more surface area than small cells, but much less surface area relative to their volume Bonus: What level of protein structure determines function?; What level of protein structure is considered the backbone of a protein?; What is a polypeptide? Tertiary; Secondary; A linear chain of amino acids What are transmembrane proteins? Transmembrane proteins typically have regions of what two classifications of amino acids? Where are the different classifications found within the protein? What part of the amino acid determines its classification? Chitin- exoskeleton of insects and crustaceans Endosymbiotic theory- mitochondria and chloroplast very close to prokaryotes Single circular chromosome, ribosomes, and reproduce by splitting Made their way into eukaryotic cells and stayed bc aerobic environment. These structures helped use oxygen to make energy
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