BIO 110-003 Exam 1 Study Guide CH. 2-5
BIO 110-003 Exam 1 Study Guide CH. 2-5 BIOL 110
University of Louisiana at Lafayette
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This 32 page Study Guide was uploaded by Kaylen Harrison on Sunday September 11, 2016. The Study Guide belongs to BIOL 110 at University of Louisiana at Lafayette taught by Patricia L. Mire-Watson in Fall 2016. Since its upload, it has received 113 views.
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Study Guide Exam 1 Kaylen Harrison Ch 2: Inorganic chemicals of life 1.Describe the locations, charges, and relative masses of the 3 types of particles that make -up atoms. • Protons o Located In the nucleus o + Positive charge of an atom o Are bigger in size than electrons o Protons are in equal weight to the neutrons • neutrons o Located in the nucleus of an atom o Are neutral --not charged o Are in equal weight to the protons o About the same size as the protons o What are they for ? o To serve as a buffer--to allow the protons to be able to hang out with them. Its in the middle o Neutrons are in equal weight to the protons • Protons and neutrons are nearly equal in mass. o Equal to about 1 • Electrons o Outside the nucleus of an atom o Negative charge of an atom o are in the electro negative cloud o Basically weigh nothing in comparison to neutrons and protons 2.Define atom, atomic number, atomic mass, isotope, molecule, element, and compound. • Atom o The smallest functional units of matter that form all chemical substances and that cann ot be further broken down into other substances by ordinary chemical or physical means o Are normally neutral. o Usually have the same number of protons and electrons . o Atoms pull electrons towards it which is called electronegativity o It pulls electrons b/c it is its happiest when its outer shell is full o They are always wanting to fill their outer shell so they tend to always want to interact with other atoms o If an atoms outer shell isn't full and another atom's shell isn't full, then they can share electrons with each other o Some atoms want to share electrons, some don’t, and some will only share with certain atoms and this affects how molecules interact o All atoms don’t have the same electronegativity b/c it depends on the need of the atom and the size relative to the other one o If the atom's electronegativity are the same, the two atoms will pull equally on each other o The atom with the higher electronegativity is the one with the most electrons orbiting around it • Atomic mass o Atomic mass scale indicates a n atom’s mass relative to the mass of other atoms o The mass is made by adding up # of protons and neutrons o The more protons and neutrons that atom has, the larger the mass o We disregard the mass of electrons because they basically weigh nothing in compariso n to protons and neutrons o Unit: Da(Daltonn) • Atomic number o # of protons in an atom • Isotope o Atoms that are of the same type but have different #'s of neutrons o That’s why the numbers don’t come out as whole numbers o The average is weighted ---the average reflects how abundant an atom is in nature o Ex. If 12C and 14C were averaged and they have equal weight, you would get 13, but that isn't the atomic mass of carbon. Its 12.0107, but that tells us that the 12 has more weight. So there is more carbon 12 in nature than there is carbon 14. • Molecule o Two or more atoms that bond together • Element o The substance that each atom forms o Has it own characteristics o Has its own genetic structure • Compound o An element made up of 2 or more atoms o Ex. Water 3.What is the octet rule? How is it significant? • Goal: o To fill their outer shell with 8 electrons • Hydrogen is an exception b/c it is such a little bitty atom so it only has 1 electron and 1 proton and that electron is in the very first shell which is its only shell and that shell is full at 2 so it is happy when it has two • Important b/c it tells us if whether or not the atom is already stable • Tells us if whether or not atoms will want to bond with other atoms • If their outer shell are already full, they don’t want to bond at all • Who they will bond with depends on how many electrons it needs to fill that outer shell 4.Compare and contrast polar and nonpolar covalent bonds. Explain the role of electronegativity in each. • Non-polar covalent bonds o Equal electronegativity • Polar covalent bond o Different electronegativities o The stronger one has more electrons o If a molecule has a polar covalent bond, it is called a polar molecule o Ex. Water is polar 5.Describe hydrogen bonds and their importance in b iology. • Hydrogen bonds o Occurs between water molecules having polar covalent bonds (between polar molecules) o Represented as dashed or dotted lines o Collectively, can form strong bond overall o Holds two strands together o Individually, weak bonds can form and break easily o Substrate and enzyme bonding o Not a covalent bond, no linking, just partial attractions between molecules that have different charge distributions around them which are polar molecules o Called hydrogen b/c a lot of the times, hydrogen will be involved in it o When they are close enough together they create this bond o Always involves hydrogen and oxygen o These bonds are also in DNA. They pull the two strands of DNA together. o The time that the DNA strand has to pull away is during replication so it’s a good thing that these bonds are weak b/c if they were so strong it would be difficult to allow the DNA strand to unzip o Hydrogen bonds form when the water molecules are in certain distances apart and once they form they will keep the water molecules that same distance apart o They hydrogen bonds hold the molecules at the same distance apart in the solid and in liquid state of water o This crystal formation forces the molecules to stay where they are o • Ionic bonds o If the bigger atom gets EXTREMELY bigger than the other atom then they no longer share the electron and it takes it away. Now they are no longer neutral and one atom is completely negative and the other atom is completely positive. And they will be attracted to each other b/c negative and positives attract and that’s called ionic bonds. 6.Using table salt as an example, describe the formation of ions, ionic bonds and the effect of water on these. • Formation of ions: o Ions are formed when atoms lose or gain electrons in order to fulfill the octet rule and have full outer valence electron shells. When they lose electrons, their charges become positive and are named cations. When they gain electrons, their charges become negative and they are called anions. • Ionic bond o When the electronegativities are in the molecule are very different. The much bigger atom (one with more electrons) completely steals the electron from the other . o So if one atom just steals an electron why do they even stay by each other ?? o They are attracted to each other b/c they are oppositely charged. • Table salt as an example: o Salt is NaCl o Sodium has 11 electrons and loses 1electron so now it’s a sodium ion with a net positive charge(cation). o Chlorine has 7 electrons in its outer most shell, it gains an electron to fill its outer shell and now has a negative charge (anion). o And an ionic bond is when a cation and an anion binds together, so when Na and Cl binds together, that creates table salt through an ionic bond. § Fig. 2.12 7.Distinguish between hydrophilic, hyd rophobic and amphipathic substances. Give examples of each. • Hydrophilic ("water loving") o Substances that like to interact with water o Readily dissolve in water o anything that is polar or ionic o Ex. § Salt--NaCl • Hydrophobic ("water -fearing") o Do not dissolve in water o Non polar o Ex. o Polar and hydrogen ---hydrocarbon o Oil • Amphipathic o Both hydrophobic and hydrophilic o Have both polar or ionized regions at one or more sites and nonpolar region at other sites o Ex. o Propionic acid o Phospholipid 8.Would a 1 M solution of NaCl and a 1 M solution of HCl contain the same number of grams of each compound? Moles? Molecules? Explain. • They do not have the same number of grams, but have the same number of moles. And I think they don’t have the same number of molecules. • Moles o 1M solution of NaCL =1m NaCl o 1M solution of HCl=1m HCl • To find Grams o Add Molecular masses together o NaCl § Na(23)+Cl(35)=58 o HCl § H(1)+Cl(35)=36 9. Sketch 3 adjacent water molecules in ice. Indicate each atom, polar covalent bond, and hydrogen bond. Fig. 2.18 10.Discuss how the structure of water allows it to perform important functions in living things. • Waters hydrogen bonds allow it to exist in all 3 states • The changes between these states such as solid, liquid, and g as states of H20 involve an input or release of energy. • The difference between a gas and a liquid of the same substance is the energy • Also… o Participates in chemical reactions o Hydrolysis or dehydration § Hydrolysis • The breakdown of a compound due to the re action of water • Ex. Breaking down a polymer into a monomer § Dehydration/ condensation • Chemical reaction that involves the loss of a water molecule from the reacting molecule o Helps you cool off o When you sweat you have water that gets formed on the surf ace of you skin and when the water evaporates it changes into a gas. In order to change into a gas it has to be able to break the hydrogen bonds that are in the water. Because there are these hydrogen bonds there its going to take heat to break those hydro gen bonds enough so that it can change into a gas o Because water can dissolve a lot of substances it can also remove a lot of toxic wastes on our bodies o Water interacts well with polar substances and b/c of this ability there are types of reactions that can occur in water 11.Differentiate between acids and bases. Give an example of each. • Acids o A substances that releases hydrogen ions o Strong acids release more hydrogen ions than a weak acid o Ex. Human stomach fluid § Your stomach is so acidic b/c it he lps begin the digestive process and kills a lot of bacteria that we taken in when we eat § • Bases o Lower the H+ concentration o Some relasee OH- and others bind H+ o Take hydrogen ions away from the solution and can do it by directly bonding the hydrogen ions to the cell or releasing OH- ions into the solution o Releasing OH- ions into the solution would motor the hydrogen ions b/c its going to bind the hydrogen ions. So OH will bind to hydrogen ions § Ex. Bleach • 12.Define pH. Why is maintaining pH important to living systems? • pH=-log10 [H ]+ • The meausre of the hydrogen ions binding to the OH -'s • The measure of the concentration of hydrogen ions in a solution • Acidic solutions= pH of 6 or below • pH 7 =neutral ---[H+]=10^-7 M (same as 1x10^-7)=.0000001-----this is smaller compared to 1 x 10^-5M=.00001=pH5 (this one has more hydrogen ions so is more acidic ) o In order for cells to remain alive they have to have a pH of around 7 o • Alkaline solutions=pH 7 or above Pure water ionizes slightly into H+ and OH -. It will have a [H+]=10^-7M • • Scale runs from 0-14 • The pH of a solution can affect: o Shapes and functions of molecules o Rates of many chemical reactions o The ability of two molecules to bind to each other o The ability of ions or molecules to dissolve in water o Substances that are either acids or bases can change the pH of a solution when they're in a living things. Therefore, the pH can affect many things in living things that have to happen o Cells have to be careful about their pH o They have to maintain a certain range o r can't function o Acids and bases are going to be in cells and in organisms and they are necessary for chemical reactions to occur 13.Describe how a buffer works to maintain pH. Give an example found in living systems. • If too many Hydrogen ions it takes up some, if too little, releases hydrogen ions • Homeostasis • Buffers o Solutions that help to keep a constant pH • Minimize fluctuations in the pH of solutions o Are usually weak acids and bases o Living things such as ourselves have buffers o If the solution gets too acidic the substance can take those hydrogen ions out of it ----this is base work o If the solution is too basic, we give back those hydrogens --this is acid work o We have buffers in our blood and our body uses it to keep our pH at around 7 o Organisms usually tolerate only small changes in pH • Ex. § In the blood if pH rises too high, carbonic acid (weak acid) will release H+ and form bicarbonate (which lowers pH). If pH gets too low, bicarbonate (weak base) will bind H+ and form carbonic acid (which raises pH). + • H 2O 3-----> H + HCO ^- Ch. 3: Organic Molecules 14. What is an organic molecule? What’s special about carbon? • Organic molecule: o Molecules that make up all living things on our planet o All organic molecules are based on carbon • Carbon o Carbon has 4 electrons in its outer shell o So carbon will need 4 electrons to be stable according to the octet rule o So a single part of it can form up to 4 covalent bonds o Its bonds that it can create are more complex than a molecule forming just one bon d o Carbon can form either single or double covalent bonds o Depending on who carbon is bonded to, carbon can form either polar or non polar bonds • Polar=un equal electronegativities § Can dissolve in water § Ex. Hydrocarbons • Non-polar=equal electronegativiti es § Cant dissolve in water § Can form non-polar bonds when its bonded to hydrogen 15. Describe the reactions used to form polymers from monomers and to form monomers from polymers. • When adding hydrogen , hydrolysis ---breaking down polymers to monom ers • Taking away hydrogen, dehydration ---putting together monomers to create polymers 16. List the 4 types of organic molecules 1. Carbohydrates 2. Lipids 3. Nucleic Acids 4. Proteins • Many organic molecules exist or have isomers • Water isn't an organic molecules b /c it does not contain carbon 17. In general, carbohydrate monomers have carbon:hydrogen:oxygen in what ratio? • Cn(H2O)n • 1:2:1 18. Distinguish between monosaccharides, disaccharides, and polysaccharides. Give examples of each. • Fig 3.5 • Monosaccharides --single sugars • If contain 5 carbons=pentose • 6 carbons =hexose (glucose) • Use glucose for energy • Glucose gets broken down to make ATP which is energy • When looking at a simple sugar can draw it as a linear or ring structure • when draw in linear array start with the carbon and the double bond with the oxygen on it • Number the carbons down from there • When put it into water it wont stay linear but will change into a ring figure • When drawing ring structure, numbering starts to the right of oxygen • Ex. § Glucose C 6 O12 6 • hexose § Ribose C 5 O 10 5 • pentose § Deoxyribose C H5O 10 4 • pentose § Cellulose • Our body can't break it down • Disaccharide • Carbohydrates composed of two monosaccharides • Two monosaccharides bonded together • In order to make this happen, a new covalent bond h as to be formed • This reaction is called dehydration/ condensation which will join these monosaccharides together • Joined by dehydration or condensation reaction • Broken apart by hydrolysis • Ex. § Sucrose § Maltose § Lactose • Polysaccharide --multiple sugars • Many monosaccharides linked together to form long polymers • Ex. § Energy storage-starch, glycogen § Structural role-cellulose, chitin, glycosaminoglycans 19. Distinguish between hexoses and pentoses and give 2 examples of each. • Pentoses o 5 carbons • Ex. § Ribose C H O 5 10 5 § Deoxyribose C 5 O 10 4 • Hexoses o 6 carbons • Ex. § Glucose C 6 O12 6 § Cellulose 20. What are isomers? Draw 4 stereoisomers of glucose. • Isomers o Molecules that have the same molecular formula, but if you draw out the molecules they are not going to be identical. They have different structures and characteristics o Some organic molecules form isomers • Structural isomers § Have all the same atoms and the same numbers so the chemical formula is the same but the atoms will not be bonded to the same other atoms • Stereoisomers § Same atoms bonded to each other, but different positioning • Cis-trans isomers • May have very different chemical properties from each other, most notably their stability and sensitivity to heat and light • Cis • Double bonds on the same side • Trans • Bonds on opposite sides • Enantiomers • Pair of molecules that are mirror images of each other • Glucose exists as stereoisomers • α- and β-glucose • glucose and galactose • Enantiomers of glucose • D- and L- glucose Fig 3.5 21. What is the defining feature of lipids? • Lipids: o Composed of predominantly of hydrogen and carbon atoms o Defining feature of lipids is that they are non -polar and so they are insoluble in water o Are non-polar b/c they have equal electronegativities o Don’t like water b/c they are non polar and water is polar 22. Distinguish between saturated and unsaturated fatty acids. • Saturated fatty acids o All carbons are linked by single covalent bonds o Carbons are full of hydrocarbons o They have as many hydrogens bonded to them as possible o Solid at room temp • Ex § Cream § Cheese § butter • Unsaturated o Your body can break down and is healthy o Liquid at room temp o Healthier for your b ody o Are normally in a cis o Oils • Ex. Plant oil 23. Why are fats important? • Fats(tryglycerides) are important for energy storage • Stores more energy than carbohydrates so really good for storing energy Can provide cushioning and insulation • o Cushioning is important • That’s why we have fat around our organs • But too much fat isn't good, and too little isn't good either 24. Draw a phospholipid and label the parts. Label the hydrophilic and hydrophobic areas. • Amphipathic molecule o Phosphate region-polar, hydrophilic o Fatty acid chain-non polar, hydrophobic Fig. 3.11 25. Describe steroids and give examples. • Steroids o 4 interconnected rings of carbon atoms o Usually not water soluble • Cholesterol --Fig. 3.12 • Estrogen § Female hormone • Testosterone § Male hormone 26. Name the 4 components that all amino acids have in common. How do the amino acids differ? 1. Carbon 2. R -groups (side chain) a. General destination for an amino acid side chain 3. Amino group a. Positively charged at neutral pH(7) b. Positive b/c gained a proton 4. Carboxyl group a. Negatively charged at neutral pH i. Negative b/c it loss a proton • Amino acids differ by their side chains • Amino Acids: o Amino acids are joined by dehydration/ condensation reactions o Forms polypeptides o Proteins are made up 1 or more polypeptides o Broken apart by hydrolysis 27. The 20 amino acids can be group into 3 categories based on similar properties. What are the categories? What is the significance of this? 1. Non-polar 2. Polar and charged 3. Polar and uncharged • The structures of the side chains are critical features of protein structure and function • The arrangement and chemical features of the side chain cause proteins to fold and adopt their three-dimensional shapes • When identifying: o For charged look for either a plus or minus o Acidics are negatively charged o Bases positively charged o Polar: look for OH and bond between carbon & oxygen 28. What is primary structure of proteins? What type of bonds hold this structure together? Primary structure: • o The linear sequence of amino acid, from beginning to end o Are determined by genes o Peptide bonds hold them together o How DNA codes proteins 29. Describe the 2 types of secondary structure in proteins. What type of bond holds these structures together? • Fig. 3.15 • Secondary Structure o Certain sequences of amino acids form hydrogen bonds that cause the region to fold into a spiral ( ) or sheet (β pleated sheet) α helix 1. α helices a. The polypeptide backbone forms a repeating helical structure that is stabilized by hydrogen bonds along the length o the backbone b. Like curly hair 2. β pleated sheets a. Regions of the polypeptide backbone lie par allel to each other. b. Zig zags • Hydrogen bonds hold these together 30. Explain tertiary structure and how it is maintained in proteins. • Fig. 3.15 • Tertiary structure o Secondary structures and random coiled regions fold into a three -dimensional shape o In many proteins this is sometimes there final level of structure and that’s all they need for some 31. Do all proteins have quaternary structure? Explain. • Quaternary structure o 2 or more polypeptides bonded to form a functional protein o When proteins co nsist of one or more polypeptides o The individual polypeptides are called protein subunits • Ex. Hemoglobin protein • No b/c o Quaternary structures only arise when a protein is made up of two or more polypeptide chains 32. Describe the 5 factors that promot e protein folding. Fig. 3.17 • Hydrogen bonds o the large number of weak hydrogen bonds within a polypeptide and between polypeptides adds up to a collectively strong force that promotes protein folding and stability. o A critical determinant of protein secon dary structure and also is important in tertiary and quaternary structure. Ionic bonds and other polar interactions o Some amino acid side chains are positively or negatively charged. Positively charged side chains may bind to ionic amino acids. Ionic bond s and polar interactions are particularly important in tertiary and quaternary structures. • Hydrophobic effects o Some amino acids are non polar. As a protein folds, the hydrophobic amino acids are likely to be found in the center of the protein, minimizing contact with water. As mentioned, some proteins have stretches of nonpolar acids anchor them in the hydrophobic portion of membranes. The hydrophobic effect plays a major role in tertiary and quaternary structures. • Van der Waals forces o Atoms within molecules have temporary weak attractions for each other if they are an optimal distance apart. This weak attraction is termed the van der Waals force . If two atoms are too close together, their electron clouds will repel each other. If they are far apart, the van der Waals dispersion forces will diminish. The van der Waals dispersion forces are important in determining tertiary structures. • Disulfide bridges (disulfide bond) o Two sulfides that come together o The linking of two amino acid side chains together (-S-S-). Disulfide bridges are covalent bonds that can occur within a polypeptide or between different polypeptides. Though other forces are usually more important in protein folding, the covalent nature of disulfide bridges can help to stabilize the struc ture of a protein. 33. Why would increases in temperature or changes in pH denature (change the shape) of proteins? • A protein consists of amino acids. Some of these amino acids are polar, having positively charged sides and negatively charged sides. A cha nge in PH means a change in the amount of H+ atoms. These hydrogen atoms are positively charged, and attract the negative side of the polar amino acids. So a change in the pH changes the stability of a protein structure and can causes its denaturation. 34. What are the 3 components of nucleotides? Fig. 3.21 1. A phosphate group a. 1 phosphorous atom joined to 4 oxygen atoms 2. A pentose (five-carbon) sugar a. either ribose or deoxyribose 3. A nitrogenous base a. A single or double ring of carbon and nitrogen atoms 35. Compare and contrast DNA and RNA. RNA DNA Deoxyribonucleic acid Ribonucleic acid Deoxyribose Ribose Thymine (T) Uracil (U) Adenine (A), guanine (G), cytosine ( C) used in both DNA and RNA 2 strands- double helix Single strand mostly One form Several forms • Fig 3.22 & 3.23 • Base pairs • A-T • G-C Ch 4 36. State the cell theory. • All living things are composed of one or more cells • Cells are the smallest unit of living organisms o Smallest unit that defines LIFE • New cells come only from pre -existing cells by cell division o Cells come from other cells o In order to have a cell produced, you have to have a pre -existing cell 37. Explain why cells are necessarily small. • surface_-to-volume ratio: decreases as cells get bigger • Fig. 4.8 • Outside of cell = cell membrane/ plasma membrane • Inside cell = cytoplasm • How much material it can exchange depends on how much space there is • There are cells that are very, very long, but they are also very skinny • Fig. 4.1 • Can see most cells under a light microscope(first microscope invented) 38. How do light and electron microscopy differ? • Light microscope • Uses light for illumination • Resolution 0.2µm ( micrometers) • Electron microscopy • Uses an electron beam • Resolution 2nm (nanometers) 39. Draw and label parts of a typical bacterial cell, an animal cell, and a plant cell. • Bacterial cell: ---Fig 4.4 • What is it made up of? • Plasma membrane-barrier • All cells have to have it • Cytoplasm-contained inside plasma membrane • Nucleoid -region where genetic material found • Has to have ribosomes • Ribosomes are involved in protein synthesis (make proteins ) • No cell can survive w/o making proteins • Doesn’t have a nucleus but have genetic material ----DNA • The area where the DNA is and where the nucleus would be if it had a membrane around it is called a nucleoid • Oid=means like • Nucleoid=like a nucleus • b/c where the DNA is • There's an abundant supply of them • Bacteria has many structures • Cell wall • Support and protection • Glycocalyx • Traps water, protection • Appendages on a prokaryotic cell: • Pil • Use bacteria to attach to a substrate • Allow bacteria to stick together and stick to other stuff • Flagella • Use for movement • Animal Cell--Fig. 4.5 • Cell wall (plasma membrane) • Membrane that controls movement of substances into and out of the cell; site of cell signaling • Cytosol • Gel in between the organelles • Site of many metabolic passageways • Golgi apparatus • Site of modification, sorting, and secretion of lipids • Peroxisome • Site where hydrogen peroxide and other harmful molecules are broken down • Cytoskeleton • Protein filament that provide shape and aid in movement • Mitochondrion • Site of ATP synthesis • Smooth ER: • Site of detoxification and lipid synthesis • Rough ER: • Site of protein sorting and secretion • Are covered in ribosomes • Centrosome • Site where microtubules grow and centrioles are found • Nuclear pore • Passageway for molecules into and out of the nucleus • Nucleus • Area where most of the genetic material is organized and expressed • Nuclear envelope • Double membrane that encloses the nucleus • Lysosome • Site where macromolecules are degraded • Ribosome • Site of polypeptide synthesis • Nucleolus • Site for ribosome subunit assembly • Chromatin • A complex of protein and DNA • Plant cell --Fig. 4.7 • Nucleus • Area where most of the genetic material is organized and expressed. Nuclear envelope • • Double membrane that enclose the nucleus • Central vacuole • Site that provides storage; regulation of cell volume • Cytosol • Gel in between the organelles • Site of many pathways • Mitochondrion • Site of ATP synthesis • Chloroplast • Site of photosynthesis • Cytoskeleton • Protein filaments that provide shape and aid in movement • Golgi apparatus • Site of modification, sorting, and secretion of lipids and proteins • Peroxisome • Site where hydrogen peroxide and other harmful molecules are broken down • Cell Wall • Structure that provides cell support • Plasma membrane • Membrane that controls the movement of substances in and out of the cell; site of cell signaling • Rough ER • Site of protein sorting and secretion • Smooth ER • Site of detoxification and lipid synthesis • Ribosome • Site of polypeptide synthesis • Nuclear pore • Passageway for molecules into and out of the nucleus • Nucleolus • Site for ribosome subunit assembly • Chromatin • A complex of protein and DNA 40. How do cells with identical DNA have different proteomes? • Proteome: the complete protein composition of a cell or organism • b/c the set of proteins in one cell type is not the same as that made in a different cell type • Gene regulation, amount of protein, amino acid sequence of a particular protein and protein modification can influence a cell's proteome • Proteomes in healthy cells are different from the proteomes of cancerous c ells 41. Describe important processes that occur in the cytosol. • Cytosol • Gel in between the organelles • Site of many metabolic pathways • The region of the eukaryotic cell that is outside the membrane -bound organelles but inside the plasma membrane • Includes everything inside the plasma membrane • Cytosol • Endomembrane system • Semiautonomous organelles • Synthesis and breakdown of molecules occur in the cytosol • Metabolism • Cytosol is the central coordinating region for many metabolic activities of eukaryotic cells • The sum of the chemical reactions by which cells produce the materials and utilize the energy necessary to sustain life • Each step in a metabolic pathway is catalyzed by a specific enzyme • A protein that accelerates the rate of a chemical reaction • Catabolism • The breakdown of a molecule into smaller components • These pathways are needed by the cell to utilize energy and also to generate molecules that provide the building blocks to construct macromolecule s • Anabolism • The synthesis of molecules and macromolecules • Ex. Polysaccharides are made by linking sugar molecules 42. Make a table comparing the 3 types of cytoskeletal filaments. Include the names, sizes, protein compositions and functions. Table 4.1 • Actin filaments (microfilaments) --smallest/thinnest o Long, thin fibers o 7 nm o Have plus and minus ends o Play key role in cell shape and strength o Tend to be highly concentrated near the plasma membrane o In many cells, it supports the plasma membrane and provide shape and strength to the cell • Intermediate o 10nm o Found in many cells but not all animal cells o These filament proteins bind to each other in a staggered array to form a twisted, ropelike structure o Function as tension bearing fibers that maintai n shape and rigidity o Keratins for intermediate filaments in skin, intestinal, and kidney cells • Microtubules ---biggest o 25nm wide o Composed of protein subunits called α- and β- tubulin o The assembly of a tubulin to form a microtubule results in a structure with a plus end and a minus end o Microtubules grow only at the plus end, but can shorten at either the plus or minus end. o Are important for the sorting of chromosomes during cell division o Important for cell shape and organization o Act as passage ways for things to come in and out of the cell 43. List parts of the "endo"membrane system. Why is "endo" in quotes? • 4.14 • Endo =inside • A system b/c they either directly or indirectly connected to each other or pass materials via vesicles • Network of membranes enclosing the nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles • Also includes plasma membrane • The nuclear envelope is part of the endomembrane system, but the interior of the nucleus is not. 44. Describe the nuclear envelope. • 4.15 Double-membrane enclosing nucleus • o It has a inner and outer membrane o Outer membrane is continuous with the endoplasmic reticulum membrane • Has nuclear pores providing passageways • Materials within the nucleus are no t apart of the endo membrane system • DNA is in the nucleus & wants to protect its material, but things need to get in and out of the nucleus and that’s proteins • Proteins need to come in • NRNA needs to come out • And there are pores that will allow this pass ageway o Fig. 4.15--Nuclear Pores • Made up of a lot of different proteins • The inner nuclear membrane is lined with chromatin (DNA combined w/ protein) • Genome o All of the DNA • Nucleolus o Where ribosomes are made 50. What is the function of the nucleus? • Primary function o Protection o Organization o Replication o Expression of the genetic material • Nucleolus o Assembles ribosome subunits o Prominent region in the nucleus of non -dividing cells • Chromosomes o Where genetic material is stored o Individual molecules composed of DNA and protein (chromatin) o 46 chromosomes in our cells 51. Compare and contrast the 2 kinds of ER. • Endoplasmic Reticulum ---Fig. 4.17 • Endoplasmic= inside the cytoplasm • Reticulum=a branching network of something o A network of folded membranes o Folded membranes form tunnels that are filled w/ fluid • Rough ER o Studded w/ ribosomes o Those black rocks are ribosomes • Ribosomes are involved in making proteins o Protein synthesis and sorting of proteins o Continuous with the outer nuclear membrane • Smooth ER o Lacks ribosomes o Responsible for detox, carbohydrate metabolism (the burning of carbs), calcium balance, synthesis and modification of lipids (fats) 52. Describe the structure and function of the Golgi, lysosomes, vacuole s, mitochondria, chloroplasts and peroxisomes. • Golgi apparatus (golgi body/ golgi complex/ or just Golgi) ---Fig 4.18 o Stack of flattened, membrane -bounded compartments, which are not continuous w/ the ER o Vesicles transport materials between stacks o 3 overlapping functions: • Secretion (spit out of the cell) • Processing • Protein Sorting • Lysosomes o Nicknamed suicide sacks b/c if they all burst open at the same time, the cell would commit suicide o Contain acid hydrolases that perform hydrolysis(breaking down polymers(monomers that get stuck together by covalent bonds ) into monomers ) of proteins carbohydrates, nucleic acids, and lipids • Ex. • Lipids • Polymers of fatty acids • Nucleic acids • Nucleotides • Polypeptide • Make up proteins o Autophagy: recycling of worn -out organelles through endocytosis • Vacuoles ("empty space") --looks empty under microscopes but not actually ----Fig 4.20 o In plants--central vacuole • Central vacuoles in plants are for storage and support • Contractile vacuoles in protists are for expelling excess water • phagocytic vacuoles in protists and white blood cells for degradation o In animals - but are much smaller than those in the plant cell • Stores materials inside the cell • Supports the cell o Contain fluid and sometimes even solid substances • Mitochondria --4.24 o Outer and inner membrane • Intermembrane space and mitochondrial matrix o Primary role is to make ATP o Store energy • Chloroplasts o Enclosed in a double membrane o Has internal thylakoid membra ne system that forms flattened compartments o These compartments stake on each other to form grana o The stroma is located inside the inner membrane but outside the thylakoid membrane • Thylakoid membranes • Contain integral membrane proteins which play an impor tant role in light harvesting and the light -dependent reaction of photosynthesis o The center of photosynthesis in a cell o The only organelle in the cell that gives the cell green pigment • Third membrane is green o Thylakoid=green pancake o Granum=stack of green pancakes o Stroma=syrup on green pancakes 53. List the semiautonomous organelles. Why are they called that? • Can grow and divide to reproduce, but not completely autonomous b/c they rely on other parts of the cell for internal components • Ex. o Mitochondria & chloroplast can divide to reproduce Ch. 5 54. Describe the fluid-mosaic model of the plasma membrane. • Mosaic of lipid, protein, and carbohydrate molecules • Exhibits properties that resemble a fluid b/c lipids and proteins can move relative to each other 55. How are the phospholipids arranged in t he plasma membrane? Why? • Hydrophobic tails pointed towards each other on the inside. • Phospholipids bilayer o Both heads are on the outside layer b/c they are polar and hydrophilic. o The tails are in the inside b/c they are non polar and hydrophobic
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