BIOL 190 Unit 2 Test Review Sheet
BIOL 190 Unit 2 Test Review Sheet BIOL 190
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This 21 page Study Guide was uploaded by Elyse Jenkins on Friday October 7, 2016. The Study Guide belongs to BIOL 190 at Towson University taught by Angela M. Cox in Fall 2016. Since its upload, it has received 45 views. For similar materials see Introductory Biology for Health Professions in Science at Towson University.
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Date Created: 10/07/16
BIOL 190 Professor Angela M. Cox Unit Exam #2 Test Review Sheet Lecture 1 (9/20/16) – Chemistry Matter o What everything is made of o Atoms – Tiny pieces of matter o Elements – Different kinds of atoms Hydrogen, oxygen, carbon o Compounds – Two (or more) kinds of atoms stuck together Water, Methane o Anything that occupies space and has mass States of matter: Solid, liquid, gas o Composed of elements 92 occurring elements 25 essential to life Oxygen, carbon, hydrogen, nitrogen Calcium, phosphorus, potassium, sulfur, sodium, chlorine, magnesium 14 trace elements o Elements combine to form compounds Compounds have different characteristics than their elements o Atoms made of protons (+), neutrons, and electrons (-) Protons and neutrons in nucleus Atoms o Smallest unit of matter that till retains the properties of an element o Composed of subatomic particles Proton – Single unit of positive charge Electron – Single unit of negative charge Neutron - Neutral o Protons and neutrons in nucleus – Have nearly identical mass (Daltons) o Electrons – Circle around the nucleus o Element symbol – Internationally recognized symbol for an element o Atomic # - # of protons o Mass # - # of protons and neutrons o Mass # – Atomic # = # of neutrons Molecule o A combination of atoms o Held together with covalent bonds o Similarities All have C and H This makes them organic molecules Chemical Bonding o Electrons determine how an atom bonds Electrons are organized into orbitals Atoms combine to obtain a full outer orbital Stable (happy) – 8 electrons (except for 2 H) Atoms can gain, lose, or share electrons (whatever it takes to get to a stable state) Covalent Bonds o Atoms bonded by sharing electrons o Electrons spend time around both atoms o Polar Molecule – Has opposite charges on opposite ends of the molecule Has poles on the molecule (like a magnet) Electrons aren’t shared equally – Negatively charged electrons spend more time around one atom (the O atom in water) Gives this end a negative charge Ionic Compounds (Salts) o Ionic Bonds – Attraction between oppositely charged ions Ions – Atoms with a positive or negative charge Have gained or lost an electron Hydrogen Bonds o Weak electrical attractions between polar molecules (electrons not moving between molecules) o Important to the properties of water Water’s Life Supporting Properties o The polarity of water molecules and the hydrogen bonding that results explain most of water’s life-supporting properties Water molecules stick together (cohesion) Water has a strong resistance to change in temperature Frozen water floats Water is a common solvent for life sustaining reactions Does “Carbon-based” mean there’s more carbon than any other element? o No – Carbon forms the “skeleton” of molecules o Carbon Skeletons Hydrocarbons (only C and H) All nonpolar (hydrophobic) CHNOPS (Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur) o Big elements o More complex organic molecules Chemical Groups = “Functional Groups” o Groups of atoms found in organic molecules o Influence the water solubility of hydrocarbons o Influence the function of the molecule Macromolecules o Very large organic molecules o Hundreds to million of atoms o Common in cells o Carbohydrates, nucleic acids, proteins, lipids Lecture 2 (9/22/16) – Polymers and Monomers Polymer – Long chain of monomers o Broken up by hydrolysis Chemical process of breaking down polymers Water added Process requires an enzyme Dehydration Synthesis o Builds polymers from monomers o Chemical process o Water removed o Enzyme required Link to dehydration synthesis chart can be found here Sugars take on ring form in water o Glucose (an aldose) o Fructose (a ketone) Glucose monomers link together with a covalent bond called a glycosidic bond to for a disaccharide o Maltose (glucose and glucose) – used to produce liquor, malted items o Sucrose (glucose and fructose) – table sugar o Lactose (glucose and galactose) – sugar found in milk o Monosaccharides and disaccharides dissolve in water easily – HYDROPHILIC Classified by location of carboxyl and number of carbons Polysaccharides o Many sugars Linked together by dehydration synthesis o Ex. o Starch – Energy storage molecule for plants Plants store surplus starch as granules with chloroplasts and other plastids o Glycogen – Energy storage molecule for animals Humans and other vertebrates store glycogen mainly in liver and muscle cells o Cellulose – Structural polymer in plants Hydrophilic – Water sticks to the surface: absorbent Different patterns of bonds in cellulose vs. starch and glycogen Humans cannot digest cellulose (Beta Linkages): lack enzyme to hydrolyze bonds Another name: “Dietary fiber” listed on nutrition labels Many herbivores have symbiotic relationship with microbes that can digest cellulose o Chitin Also a polymer of glucose monomers Makes up insect and crustacean exoskeletons Lipids o Fats and oils (triglycerides) Glycerol: “Head” region Fatty acid “tails” Triglycerides (fats vs. oils) Fat molecules contain much more energy than carb molecules Saturated and unsaturated fats Number of bonds in the hydrocarbon chain in a fatty acid Saturated Fats Generally bad for you Animal fats (Lard, butter, shortening) Pack well – Solid at room temp. (Hll single bonds) Unsaturated Fats (Fewer hydrogens) Generally good for you Plant fats and fish (olive oil, cod liver oil) high in unsaturated fats Liquid at room temperature (have one or more double bonds) Hydrogenation Adding hydrogens to unsaturated fatty acids o Makes them saturated Fatty Acids Monomer f fat/oil/phospholipid molecules Unsaturated fatty acids can be cis or trans o Phospholipids Major component of the cell membrane Membrane structure (bilayer) Separation of water-filled cells from watery environments o Steroids Cholesterol Important component of cell membranes Can attach to blood vessel walls and cause them to thicken Cell sin our liver produce almost 90% of circulating cholesterol Steroid hormones Estrogen Testosterone o Waxes Strongly hydrophobic Protection Prevent dehydration o All hydrophobic (non-polar) o Store energy Lecture 3 (9/27/16) - Proteins Many, many different proteins o Each cell contains thousands of different proteins o Different types of cells produce different proteins Polymers of amino acids o There are 20 amino acids o Main structure Amino group Carboxyl group Central carbon Hydrogen atom R-group (side chain) o Non-polar R-groups Decrease water solubility Hydrophobic o Polar R-groups Increase water solubility Hydrophilic Amino Acids – Linked together by peptide bonds o Polypeptides Polymer of polypeptides Structure (Proteins) o A functional protein consists of one or more polypeptides twisted, folded, and coiled into a unique shape o Primary Structure Unique sequence of amino acids o Secondary Structure Local patterns/structure held together by H-bonds Coils (alpha helix) and folds (beta pleated sheets) o Tertiary Structure Overall 3-D structure of the protein held together by chemical bonds between side chains (R-groups) H-bonds, ionic bonds, hydrophilic interactions Strong covalent bonds called disulfide bridges o Quaternary Structure Two of more polypeptide chains bonded together The ability of R-groups to interact with water and/or with each other influences the formation of structure o Non-polar R-groups internalize to minimize interaction with water Polar and charged R-groups position themselves On the exterior where they will interact with water OR in positions to interact with each other o Hemoglobin (alpha) (quaternary) 4HHB Protein found in red blood cells that helps transport oxygen through the body o Hexokinase (alpha) (tertiary) 1 CZA Enzyme that helps to break down glucose o Glucagon (alpha) (secondary) Raises blood sugar if level gets too low Opposite effect from insulin Pancreatic hormone o Transthyretin (beta and alpha) (quaternary) o K+ (alpha) (qyaternary) Channel (hole) in the middle o SHAPE DETERMINES FUNCTION Butterfly Donut Globular Long fiber Protein Structure o Tertiary structure determines shape and function o Binding pockets – To bind a target molecule Lactase – Protein that breaks down lactose (shape fits lactose) Lecture 4 (9/29/16) – Denaturation, Biomolecules, Cell Theory Denaturation o Loss of 3-D “native confirmation” o Caused by excessive heating or salt, pH change o Mutations can also change the shape of proteins o Prions Proteinacious infections particles o Consequences of flawed/misfolded proteins at cellular level Generally reduced function Sometimes flawed proteins are destroyed Never get to final cellular destination Never perform intended function Sometimes flawed proteins form clusters in cell Whole or after inappropriate breakdown into pieces Interfere with normal cellular function Similarities b/w four classes of biomolecules o Organic o Contains one or more chemical groups Specific number, combination and arrangement of these groups characterize each type of molecule o Fabrication of monomers (repeating subunits) Same chemical reaction (dehydration synthesis) Requires enzyme Degradation of monomers o Degradation of monomers Same chemical reaction (hydrolysis) Requires an enzyme Biomolecular Class Monomers Polymers Nucleic Acids Nucleotides Polynucleotides Proteins Amino Acids Polypeptides Carbohydrates Monosaccharides Polysaccharides Triglycerides/Phospholip Lipids Fatty Acids/Glycerol ids Differences o Interactions with water (hydrophilic/hydrophobic) o DNA has phosphates o DNA and proteins have Nitrogen, sugars and lipids don’t o Which atoms are present? Nucleic Acids: CHNOP Proteins: CHNO and a little S Carbohydrates: CHO in 1:2:1 ratio (in the monomer) Lipids: CH and a little O (in phospholipids, only some N and P) o What chemical groups are present? Nucleic Acids: PO 4 (charged), OH (polar) on backbone, various (polar) on bases Proteins: COOH (charged), N H 2 (charged), variety of R-groups ranging from polar to non-polar Carbohydrates: Lots of OH (polar) Lipids: Mostly hydrocarbon and C H (non-polar) 3 o Which are hydrophilic/hydrophobic? All but lipids are hydrophobic What makes them this way? Their chemical groups Cell Theory o What is a cell? All living things are made up of one or more cells All cells came from pre-existing cells Cells are the basic unit of structure and function in living things (basic unit of life) o Least complex to most complex: Atom, molecule, organelle, cell, tissue, organ, organ system, organism o Cells are the lowest level or biological organization that exhibit all of the characteristics of life Characteristics of Life o Organized o Contain DNA o Reproduce (like begets like) o Grow and develop (controlled by DNA) o Process energy o Respond to environment o Regulate internal conditions (homeostasis) o Adapt o Beneficial traits become more common in a population over time Structures present in all cells o Cell membrane Outer limiting boundary Separates living cell from the non-living environment o Cytoplasm Cytosol – Gel like fluid Internal structures o DNA Genetic instructions Heredity and cellular control functions o Ribosomes Role in protein synthesis o Based on their structure, we can categorize cells into two groups Prokaryotes Domain bacteria Domain archea “Pro” = before, “karyon” = kernel/nucleus Eukaryotes Lecture 5 (10/4/16) – Bacteria, Archea, Eukaryotes, Multicellular Organisms Bacteria o Hidden life o Ex. E. coli o Human Microbiome The body contains 10 times more bacteria, fungi, and other micro-organisms than human cells Archea o Can live in harsh environments Eukaryotes o “eu” = true, “karyon” = kernel/nucleus o 1 Domain, 4 kingdoms Protists Plants Fungus Animals o Epithelial cells line our cavities and cover flat surfaces o Fibroblast cells are found in connective tissue, they secrete collagen and ECM Differences between prokaryotic and eukaryotic cells Prokaryotic Eukaryotic Smaller (1-10 μm) Larger (10-100 μm) No membrane bound internal Many membrane bound internal components (organelles) compartments (organelles) Small ribosomes Large ribosomes DNA DNA o Single circular molecule o Linear molecule o Not membrane enclosed o Many (chromosomes) o “Nucleoid Region” o Look alike “pairs” o Membrane enclosed o Nucleus Why no huge cells? Surface Area vs. Volume ratio Plant vs. Animal Cells o Animal Cells No cell wall Contain lysosomes and centrosomes o Plant Cells Have cell walls Different than prokaryotic cell wall Few sperm cells have flagella Central vacuole – stores water, other chemicals Have chloroplasts Have plasmodesmata Multicellular Organisms o Animals (humans too) and plants All eukaryotic Contain many different types of specialized (differentiated) cells Animals: Muscle, RBC, Keratinocyte, fibroblast Plants: Mesophyll, guard, epidermis All originated from the same single fertilized egg (aka Zygote) Process by which these cells formed: Cellular Differentiation Cellular Differentiation o Normal process by which immature undifferentiated cells develop distinct structures and functions of specialized cells o Underlying mechanism: Differential expression of genes in the DNA Certain genes turned on (expressed) Others turned off (silenced) o Result: Change in the number and type of proteins (the proteome) in the cell Defines morphology Defines specialized function >200 different kinds of specialized cells in human body, all begin with an undifferentiated cell (stem cell) Advantages of compartmentalization in eukaryotes o Increased surface area o Increased concentration of reactants used in chemical reactions Higher concentration, higher rate o Separation of incompatible reactions/reaction environments Synthesis vs. degradation Reactions that need different environments o Separation of products based on what they are for internal or external use Internal Inside a membrane-enclosed organelle, e.g. enzyme in a lysosome Free-floating in the cytoplasm, e.g. enzyme needed for glycolysis (cytoplasm) External (export) E.g. collagen of ECM, insulin, digestive enzymes – e.g. trypsin – for use in intestines Ribosomes: Free and bound o Free: In cytoplasm Translation of proteins used in cytoplasm o Bound: Attached to RER Translation of membrane-associated proteins Proteins to be inserted into phospholipid bilayers of membranes Proteins for export from cell by exocytosis Proteins for membrane enclosed cellular organelles Lecture 6 (10/6/16) – Cell Structures Lysosomes o Round, membrane-enclosed, acid-filled vesicles that function as garbage disposals Microfilaments (Actin filaments) o Function = Cell shape; while cell movement (e.g. amoeboid movement) o Easily disassembled and reassembled o Function in cytokinesis Intermediate Filaments o Generally not disassembled and reassembled o Function = cell shape; reinforcement of cell junctions, organelle placement, especially nucleus Microtubules – Tubulin Proteins o Hollow tubes; can be disassembled and reassembled o Functions: Arrangement of organelles; cell motility (e.g. flagellum of sperm); intracellular transport (along with accessory transport, e.g. kinesin) Membrane Functions 1. Barrier Cell membranes are gatekeepers Regulate what goes in and out Limiting boundary 2. Regulates Transport Passive transport (no energy required) is the spontaneous diffusion of molecules across a membrane Osmosis o Passive diffusion of water across a membrane o One of the most important substances to cross is water o Body is 60% water o There is water in and around cells Diffusion (high to low) o Solutes – Particles being dissolved o Solvents – Substance doing the dissolving o Solution – Combination of solute and solvent o Facilitated Diffusion – Most molecules can’t get through membranes on their own; carrier molecules – transport proteins Active transport – Requires ATP Molecules flow against their concentration gradient Needs energy Protein required Usually ions or small molecules Ex. Na+/K+ pump Bulk Transport Endocytosis and exocytosis Exocytosis – Transport of cell via vesicles that fuse with plasma membrane Endocytosis – Transport into cell via vesicles o Phagocytosis – Engulfs large particles o Pinocytosis – Cells taking in dissolved particles and liquid o Receptor-Mediated – Bind to receptor proteins in the membrane 3. Communication 4. Recognition/Identification 5. Anchor Cell attachment via “junctions” Adjacent cells in many animal tissues are often directly connected by cell junctions consisting of specific proteins o Tight Junctions – Keep things in the cell from body o Anchoring Junctions – Anchors to the cell; holds together o Gap Junctions – Used to transport molecules between cells Additional Cell Boundaries o Cell wall made of cellulose Cell Membrane Structure o Every cell is bordered by a plasma membrane o Fatty acid tails hydrophobic because they are made of carbon and hydrogen o What’s there? 1. Phospholipids – Barrier that prevents the diffusion of most material in and out of the cell 2. Proteins – Maintain cell shape; receptors; enzymes; cell to cell recognition; intercellular junctions; transport 3. Carbohydrates – CHO layer on external surface of cell (hooked onto lipids – glycolipids; hooked onto proteins – glycoproteins); recognition/identification’ interaction with other ECM and other cells 4. Cholesterol – Stabilizes the membrane; keeps it flexible (not too flexible at warm temps.; not too rigid at cold temps.) Study Questions!! Organic Molecules 1. What is a molecule? What is the distinction between an organic molecule and an inorganic molecule? A molecule is a combination of atoms held together with covalent bonds; an organic molecule has carbon and hydrogen while an inorganic molecule does not. 2. What is an atom? Draw the atomic structure of carbon, indicating the number and location of each proton, neutron, and electron. An atom is the smallest unit of matter that still retains the properties of an element 3. What kinds of bonds does carbon usually form with other atoms? How many of these bonds does carbon usually form? Covalent bonds; four 4. What is a chemical (or “functional”) group? List 4-5 chemical groups and describe how these chemical groups affect the water solubility of the molecule to which they are attached. Groups of atoms found in organic molecules. a. Hydroxyl Group – Hydrophilic b. Carboxyl Group – Hydrophilic c. Carbonyl Group – Hydrophilic d. Amino Group – Hydrophilic e. Phosphate Group – Hydrophilic f. Methyl Group - Hydrophobic 5. What is the difference between a monomer (subunit) and a polymer (macromolecule)? Provide examples on page 48 of your text (question #2) to complete your review of this subject. A monomer is a molecule that can be bonded to other identical molecules to form a polymer; a polymer is a long chain of monomers. 6. How do your cells obtain monomers needed to make different types of polymers that are essential to normal cell structure and function? They can break down other polymers using hydrolysis to get the individual monomers 7. What is the chemical reaction that produces a polymer form monomers? What does the name of the reaction tell you about what is happening in the reaction? Diagram this reaction for any one of the four classes of macromolecules. Dehydration synthesis; a water molecule is being removed 8. What is the chemical reaction that produces monomers from polymers? What des the name of this reaction tell you about what is happening in the reaction? Diagram this reaction for any one of the four classes of macromolecules. Hydrolysis; a water molecule is being added 9. What is the significance of macromolecules to the human body? They are used in common body functions and are part of the essential building blocks for cell function Proteins 1. What functions do proteins perform in your body? Give at least four examples. Catalyzing chemical reactions, protections, storage, transport, responding to stimuli, support, and movement. 2. What is the basic structure of the repeating subunit (monomer) for proteins? How many different types of this repeating subunit exist, and what makes them different? Amino group, carboxyl group, central carbon, hydrogen atom, R- group (side chain); there are 64 different kinds, and they are different because of their coding sequences 3. What is the overall structure of most functional proteins, that is, their “native conformation” (functional shape)? One or more polypeptides, twisted, folded, and coiled into a unique shape; they are either shaped in alpha helixes or beta pleated sheets. 4. What is the importance of this structure to the functioning of the protein and, hence, the cell? Shape determines function when it comes to proteins, so if the protein is not shaped correctly, it will not function correctly, and if it doesn’t function correctly, this will ultimately be detrimental to the cell. 5. What ultimately determines the primary structure of all proteins? The sequence of amino acids 6. For the first three levels of protein structure, answer the following questions: a. What does this level of structure look like? The primary structure is just the unique sequence of amino acids. The secondary structure the local pattern or structure held together by H-bonds. These look like either alpha helixes or beta pleated sheets. The tertiary structure illustrates the interactions between R-groups. b. What is the immediate determinant of this level of structure (how did it get that way)? In primary structure, it is the coding sequence. In secondary structure is the way the hydrogen bonds shape it. In tertiary structure, it is the interactions between R- groups. c. What types of bonds stabilize (hold together) this level of structure? Primary – Peptide Secondary – Hydrogen Tertiary – Covalent bonds called disulfide bridges d. What conditions can disrupt this level of structure? Primary – Mutations or wrong coding sequences Secondary/Tertiary – Denaturation (excessive heating or salt) 7. What does the fourth level of protein structure look like? What types of bonds stabilize this level of structure, and what conditions can disrupt it? The Quaternary structure is two or more polypeptide chains bonded together. The bonds can be van der Waals bonds, hydrogen bonds, ionic bonds, or covalent bonds. Excessive heat of salt can denature this structure. 8. Distinguish between globular and fibrous proteins. Globular proteins are spherical (or rounded) and soluble in water while fibrous proteins are not. 9. What is protein denaturation? Is the process reversible r irreversible? If it can be either, under what conditions is it reversible? Irreversible? Denaturation is when a protein loses its 3-D native confirmation. This process is reversible in very few cases in which the denaturing agent is removed and protein goes back to its original shape. 10. Contrast protein denaturation with protein hydrolysis, in terms of level of structure affected and reversibility. Denaturation breaks down the quaternary structures whereas hydrolysis breaks down the individual polymers in a protein. Denaturation is very rarely something that is intentionally done, therefore making it much more difficult to reverse, whereas hydrolysis is organized and has a specific function and is reversible more easily. Carbohydrates and Lipids 1. Why is CHO a good abbreviation for carbohydrates? Because all carbohydrates have these items 2. What are the monomer subunits for the carbohydrates? Monosaccharides 3. What is the structural difference between a monosaccharide, a disaccharide, and a polysaccharide? How do they differ in function? A monosaccharide is one monomer, a disaccharide is two monosaccharide monomers, and a polysaccharide is polymers of hundreds to thousands of monosaccharides linked by dehydration reactions. Monosaccharides and disaccharides are linked together in glycosidic bonds and a hydrophilic. Polysaccharides are joined through dehydration synthesis and are not all hydrophilic (only some are). There are used mostly as energy storage. 4. What four different types of lipids exist? Where would you expect to find each one in the human body? Fats and oils, phospholipids, steroids, and waxes. Fats (also known as triglycerides) are in many places (mainly adipose tissue) in the body and are mainly used for energy. Phospholipids are found mostly in cell membranes in the body. Steroids are also found partly in the cell membrane (cholesterol) but they can also be found where the hormones are located. Waxes are used for protection and prevent dehydration. One of the main places they can be found are the ears. 5. Identify the monomer subunit for triglycerides and phospholipids. Fatty acids/glycerol 6. Draw and label one phospholipid, in addition to labeling the component parts – appropriately include the terms hydrophilic and hydrophobic in your labels 7. Describe the unique structure of a steroid. A steroid has four rings of carbon atoms with an attached hydrocarbon tail and a hydroxyl group. 8. Distinguish the four different types of lipids based on their function. Fats and oils are used for energy. Phospholipids are used for cell protection and regulation. Steroid are also used in membranes as signaling molecules. Waxes are used for protection and prevent dehydration. Cell Types and Basic Cell Structure 1. What is a cell? What is the cell theory? A cell is the basic unit of structure and function in living things (basic unit of life). The cell theory says that all living things are made up of one or more cells and that all cells come from pre- existing cells. 2. What are the levels of biological organization? Atom, molecule, organelle, cell, tissue, organ, organ system, organism 3. What is the smallest/least complex level of biological organization that exhibits all of the characteristics of life? Cells 4. What are the characteristics of life? a. Organized b. Contain DNA c. Reproduce (like begets like) d. Grow an develop (controlled by DNA) e. Process energy f. Respond to the environment g. Regulate internal conditions (homeostasis) h. Adapt 5. What four structures are present in all cells? Cell membrane, cytoplasm, DNA, and ribosomes 6. What two major types of cells exist, and how do they differ? Give some specific examples. The two cells are prokaryotes and eukaryotes. Prokaryotes are smaller than eukaryotic cells. They are 1-10 micrometers while eukaryotic cells are 10-100 micrometers. There are no membrane bound organelles in prokaryotes like there are in eukaryotes. Prokaryotes have small ribosomes while eukaryotes have large one. Lastly, their DNA characteristics differ in many ways. 7. Which major cell type includes the cells in your body? Give some examples of different cell types in your body. What distinguishes these cells from one another? We are made up of eukaryotic cells. A few different cells types are epithelial cells and fibroblastic cells. These cells differ in where they are found and the function they serve in the body. 8. Plants and animals (including humans) are multicellular organisms. What characteristics do they share? If all of the cells in a multicellular organism come from the same fertilized egg, how do different types of cells form? The characteristics that these cells share are that they are all eukaryotic and contain many different types of specialized cells. Even though these cells originated in the same place, they are different because of a process call cellular differentiation. Internal Cell Structure – Eukaryotic Organelle Structure and Function 1. Why does the inside of eukaryotic cells need to be subdivided into compartments (organelles)? What separates these compartments from one another? Identify 2-3 advantages of this compartmentalization. They are compartmentalized for organization purposes. These compartments are separated by the cytoplasm as well as the membranes that are around them. One of the advantages is that there is an increased surface area. Another is the there is an increased concentration of reactants used in chemical reactions. Lastly, there is separation of incompatible reactions/reaction environments so the cell can function properly. 2. What are the major intracellular structures of a eukaryotic cell and how are they arranged? a. Nucleus (and nucleolus) – Contains the DNA and synthesizes RNA; spherically shaped with an envelope around it and pores in it allowing for transport in and out b. Ribosomes – Made of a large subunit and a small subunit; broken down into two categories: free and bound; make proteins and catalyze reactions c. RER – Complex of folded material outside of nucleus studded with ribosomes (hence, “rough”); produce protein to be inserted into the membrane d. SER – Similar to the RER, but with no ribosomes; used in liver cells; synthesizes lipids; processes drugs, alcohol, etc.; stores calcium ions e. Golgi – Stacks sacks (membraneous); molecular “warehouse” f. Lysosome – Membraneous sac of digestive enzymes; digestive organelle g. Mitochondrion – Organelle composed of two membranes and two internal compartments; used in cellular respiration and to produce energy (ATP) h. Cytoskeleton – Made up of microfilaments (easily disassembled and reassembled), intermediate filaments (not disassembled and reassembled), microtubules (can be disassembled and reassembled) 3. What do the individual structures do for the cell (their function)? Use the “cell structure self-quiz” on Blackboard. See #2 4. Do these structural parts of the cell work separately or together or both? If together, describe at least one example, listing the structure and function of the cytoskeleton. Distinguish between microfilaments, intermediate filaments, and microtubules. They work together. They all work to support and shape the cell. Microfilaments contribute to the cell’s shape and movement. Intermediate filaments contribute to cell shape and reinforce cell junctions and organelle placement. Microtubules arrange the organelles and work in the motility of the cell. They also work with intracellular transport. 5. Identify and distinguish between three types of cell junctions that allow adjacent cells to interact. Tight junctions keep things in the cell from the body. Anchoring junctions anchor to the cell and hold it together. Gap junctions are used to transport molecules between cells. 6. What is the difference between a plasma membrane and a cell wall? A cell wall is made of cellulose and is much more rigid than a plasma membrane. Cell Membrane Structure and Function 1. What is the structure of the plasma membrane of the cell? What molecules are present in this membrane? Draw a diagram of a segment of the membrane, and label each type of molecule. Membrane made of phospholipids with polar heads and non-polar tails. 2. How can a signaling molecule from one cell alter gene expression in a target cell without even entering the target cell? There are intercellular communications. 3. What are the major functions of this outer membrane? Barrier, regulating transport, communication, recognition/identification, anchor 4. What are the major types or membrane transport, i.e. ways by which material gets into and out of cells? How are they similar? How do they differ? Provide an example of a material that might be transported by each type of membrane transport. Passive transport, active transport, and bulk transport. Passive transport uses no energy while active and bulk both do. Passive transport doesn’t always require a protein (though sometimes it does) while active and bulk always require one. One of the most common examples of passive is osmosis, the diffusion of water across the membrane. A good example of active transport would be the sodium potassium pump. And bulk transport would be large molecules that can’t even go through the active transport proteins. 5. What is osmosis? What is the relationship between osmosis and diffusion? Osmosis is the diffusion of water across the membrane. So osmosis is a kind of diffusion (diffusion is just the passive transport of molecules either by protein channels ore just through the membrane itself. 6. How does a cell move material in bulk (large quantities) across the plasma membrane? The cells use two different kinds of transport: exocytosis (out of the cell) and endocytosis (into the cell). Also in endocytosis are subcategories: phagocytosis (engulfing large particles), pinocytosis (taking in liquid/dissolved particles), and receptor- mediated (binding to receptors proteins on the membrane.
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