Cell Membrane Structure Reviewer Papers [CRNM] BIO101-Q2 PDF

Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. Are amphipathic molecules Cell Membrane Structure ○ Containing hydrophobic OUTLINE (“water-fearing”) and hydrophilic (“water-loving”) regions I. Cell Membrane A. Phospholipids II. Fluid Mosaic Model III. Fluidity of Membranes A. Factors Affecting the Fluidity of Membranes: 1. Temperature 2. Type of Lipid 3. Cholesterol IV. Membrane Proteins A. Integral Membrane Proteins B. Peripheral Membrane Proteins C. Functions of Membrane Proteins Hydrophobic Hydrophilic V. Cell-Surface Proteins & HIV Tails Heads VI. Practice Assessments LOCATION Sheltered INSIDE Exposed to water the membrane on either side Cell Membrane (OUTER) of the Also known as the Plasma Membrane membrane. A thin, semi-permeable barrier that surrounds CHARACTERISTICS “Water-repelling” “Water-loving” the outer edge of a cell, separating the interior parts of the parts of the molecule molecule of the cell from its external environment. - do NOT mix well - attracted to ○ Exhibits selective permeability: allowing with water water molecules some substances to cross it more COMPOSITION Composed of Contains a easily than others long hydrocarbon phosphate chains, usually group, which is The boundary that separates the living cell from consisting of fatty charged and its surroundings. acids polar, along with glycerol Consists largely of specialized lipids called phospholipids. Phospholipids A class of lipids (fats) that are essential structural components of biological cell membranes. Are the most abundant lipids in the plasma membrane. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. Fluid Mosaic Model ○ Most lipids & some proteins can move Describes the structure of the biological cell sideways (lateral) within the membrane. membrane Provides a dynamic and flexible representation ○ Rarely, a lipid may flip-flop of the cell membrane. (transverse) across the membrane, The membrane is a mosaic of protein from one phospholipid to another. molecules bobbing in a fluid bilayer of phospholipids. Proteins are not randomly distributed in the membrane. Shows that lipids are constantly moving (fluid). Shows that the cell membrane is composed of different molecules: lipids, proteins, and cholesterol. ★ Fluid = liquid in nature ; can move freely. ★ Mosaic = composed of different The quick mixing of the fluorescent labels molecules/materials put together. means that the proteins that are on the surface of the cell are not fixed in place – they can and do diffuse rapidly around the exterior of the cell, while still being embedded in the plasma membrane. Fluidity of Membranes Plays a role in the structure and function of biological cell membranes Refers to the dynamic and flexible nature of the Factors Affecting the Fluidity of Membranes: lipid bilayer, which allows movement for the movement of its constituent molecules. 1. Temperature Membranes are held together by weak Will affect how phospholipids move and how hydrophobic interactions close together they are. ○ Can be destroyed through chemicals ○ As temperature increases, so does the Movements: rotational, lateral, transverse phospholipid bilayer fluidity ○ LOWER temperature: not as much kinetic energy and they cluster Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. together more closely; increasing intermolecular interactions and decreasing membrane fluidity. ○ HIGHER temperature: enough kinetic energy to overcome intermolecular forces holding the membrane together; increasing membrane fluidity. Additional Keywords Cold / lower temp. ★ Close together rigid ★ ★ not as fluid 3. Cholesterol ★ may break (not Are randomly distributed across the flexible) ★ minimal movement phospholipid bilayer, helping the bilayer stay Hot / higher temp. fluid in different environment conditions. ❖ Far away from each other Holds the phospholipids together so that they ❖ too fluid/flexible don’t separate too far, letting unwanted ❖ won’t hold shape ❖ would eventually substances in, or compact too tightly, disintegrate if too hot restricting movement across the membrane. Regulates or opposes the movements of phospholipids. 2. Type of Lipid ○ Without cholesterol: phospholipids in Saturated - have no double bonds, resulting in your cells will start to get closer straight, unkinked tails. together when exposed to cold, making Unsaturated - have double bonds, resulting in it more difficult for small molecules, like crooked, kinked tails. gases, to squeeze in between the phospholipids like they normally do. The Saturated Fatty Acids Unsaturated Fatty Acids phospholipids start to separate from each other, leaving large gaps. - chains of carbon - chains of carbon atoms that have only atoms that have double ○ High temperature with Many single bonds between bonds between some of Cholesterol: more rigid & less fluid or them the carbons permeable; decreases fluidity. - chains are straight and - double bonds create ○ Low temperature with Many easy to pack tightly kinks in the chains, making it harder for the Cholesterol: less rigid and more chains to pack tightly permeable; increases fluidity. Membrane Proteins a diverse group of proteins that are embedded within or associated with cell membranes. are integral to the structure, communication, and transport processes of cells. Determines most of the membrane’s specific functions. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. Integral Membrane Proteins ○ There are active and passive transport membranes firmly embedded within the lipid bilayer of the membrane. have regions that are hydrophobic, allowing them to interact with the hydrophobic fatty acid tails of the phospholipids. Some integral proteins span the entire membrane (transmembrane proteins), with portions exposed on both sides of the 2. Enzymatic Activity - A protein built into a membrane. membrane (integral membrane protein) may ○ transmembrane proteins - spans or be an enzyme with its active site exposed to the reaches the 2 layers of the substances in the adjacent solution. phospholipid (or the entire lipid). ○ Enzymes build or break down molecules Peripheral Membrane Proteins not embedded within the membrane attached to the membrane's surface, often interacting with the polar head groups of phospholipids. Some of these proteins are enzymes 3. Signal Transduction - A membrane protein (receptor) may have a binding site with a specific shape that fits the shape of a chemical messenger, such as a hormone. 4. Cell-Cell Recognition - Some glycoproteins serve as identification tags that are specifically recognized by membrane proteins of other cells. Functions of Membrane Proteins ○ To identify the cell 1. Transport - protein that spans the membrane (transmembrane protein) may provide a hydrophilic channel across the membrane that is selective for a particular solute. ○ Other transport proteins require energy (ATP) to transport. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. 5. Intercellular Joining - Membrane proteins of adjacent cells may hook together in various CCR5 (Chemokine Receptor 5) kinds of junctions ○ protein that is found on the surface of certain immune cells, including T cells and macrophages. ○ serves as a co-receptor, along with CD4 (the primary receptor), for HIV to enter and infect these cells. Cell-surface proteins are important in the medical field. 6. Attachment to the Cytoskeleton and ○ HIV must bind to the immune Extracellular Matrix (Anchorage) - Attachment cell-surface protein CD4 and a points for cytoskeleton and extracellular matrix “co-receptor” CCR5 in order to infect a ○ Helps maintain cell shape and cell. stabilizes the location of certain ○ HIV cannot enter the cells of resistant membrane proteins. individuals who lack CCR5. ○ Proteins that can bind to ECM molecules can coordinate extracellular NO CCR5 = NO INFECTION (or LIMITS and intracellular changes. infection) ★ Needs to be attached to TWO receptors in order to “hack” the fluidity or function of the cell. Practice Assessment 1. These are randomly distributed across the Cell-Surface Proteins & HIV phospholipid bilayer, helping the bilayer stay HIV (Human Immunodeficiency Virus) fluid in different environment conditions. ○ a virus that attacks the immune a. Enzymes system b. Phospholipids ○ specifically targets CD4+ T cells (a type c. Cholesterol of white blood cell) that are crucial for d. Proteins the body's defense against infections. ○ If left untreated, HIV can lead to the 2. Identify what type of Membrane-Protein disease known as AIDS (Acquired Function: Some glycoproteins serve as Immunodeficiency Syndrome), which identification tags that are specifically makes individuals highly susceptible to recognized by membrane proteins of other opportunistic infections and certain cells. cancers. a. Cell-Cell Recognition ○ infects cells by involving its interaction b. Intercellular Joining with cellular receptors, particularly the c. Transport CCR5 co-receptor. d. Signal Transduction Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. a. Phospholipids 3. The following are characteristics or effects of b. Cholesterol having high temperature and many cholesterol, c. Fats EXCEPT. d. Steroids a. More rigid b. Decrease in fluidity 9. The following are types of movements of the c. More permeable components of the cell membrane, EXCEPT. d. None of the above a. Lateral b. Rotational 4. The boundary that separates the living cell from c. Transverse its surroundings. d. Diagonal a. Mitochondria b. Ribosome 10. It is a virus that attacks the immune system. c. Golgi Apparatus a. Rheumatic Heart Disease d. Cell Membrane b. Acquired Immunodeficiency Syndrome c. Human Immunodeficiency Virus 5. Type of protein that spans the entire d. Alzheimers membrane, with portions exposed on both sides of the membrane. ANSWER CHOICES: a. Integral Membrane Protein a. If statement A is correct and statement B is b. Transmembrane Protein false c. Peripheral Membrane Protein b. If statement B is correct and statement A is d. Glycoproteins false c. If both statements are correct 6. Identify what type of Membrane-Protein d. If both statements are false Function: Membrane proteins of adjacent cells may hook together in various kinds of junctions. 11. Statement A: HIV is still able to enter the cells a. Enzymatic Activity of resistant individuals who lack CCR5. b. Attachment to the Cytoskeleton and Statement B: CCR5 serves as a co-receptor, Extracellular Matrix along with CD4 (the primary receptor). c. Intercellular Joining d. Signal Transduction 12. Statement A: Saturated Fats have no double bonds. 7. It plays a role in the structure and function of Statement B: This results in having crooked, biological cell membranes. kinked tails. a. Fluidity of Cholesterol b. Fluidity of the Membrane 13. Statement A: Hydrophobic Tails are the c. Fluid Mosaic Model “water-repelling” parts of the membrane. d. Fluidity of Enzymes Statement B: Hydrophobic Heads are the “water-repelling” parts of the membrane. 8. A class of lipids (fats) that are essential structural components of biological cell membranes. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. 14. Statement A: The factors that affect the fluidity of the membrane are temperature, pH level, and type of lipid. Statement B: As temperature increases, so does the phospholipid bilayer fluidity. 15. Statement A: The cell membrane consists largely of specialized lipids called fats. Statement B: The cell membrane exhibits selective permeability: allowing all substances to cross it more easily. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. ANSWER KEYS 1. C. 2. A. 3. D. 4. D. 5. B. 6. C. 7. B. 8. A. 9. D. 10. C. 11. B. 12. A. 13. A. 14. C. 15. D. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. Cell Transport Mechanisms relies on the natural movement of molecules or ions along their concentration gradient, from an OUTLINE area of higher concentration to an area of lower concentration. I. Cell Transport Mechanisms II. Passive Transport A. Definition B. Simple Diffusion C. Facilitated Diffusion D. Osmosis 1. Tonicity 2. Osmoregulation III. Active Transport A. Definition B. Sodium-Potassium Pump C. Bulk Transport IV. Familial Hypercholesterolemia V. Practice Assessments Simple Diffusion Cell Transport Mechanisms Small, non-polar molecules (like oxygen and processes by which substances move in and carbon dioxide) move directly through the out of cells. phospholipid bilayer from an area of higher are essential for maintaining cellular concentration to an area of lower homeostasis and allowing cells to interact with concentration until equilibrium is reached. their environment. tendency for molecules to spread out evenly into the available space. Passive Transport driven by the random kinetic motion of does not require energy input from the cell. molecules. relies on the natural kinetic energy of molecules to move across the cell membrane. ○ Cells will exert less effort/energy (ATP) or no energy at all, letting molecules fall or transport without spending energy. does not require the cell to expend energy. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. - Form pores or channels - Bind to specific in the membrane, molecules and change allowing specific ions or shape to transport them molecules to pass across the membrane. through. - undergo - Examples include ion conformational changes channels and aquaporins. to facilitate the movement of the molecule. Facilitated Diffusion involves the use of specialized proteins Osmosis embedded in the cell membrane to assist the Diffusion (or movement) of water across a movement of specific molecules that cannot selectively permeable membrane. freely pass through the lipid bilayer. occurs when a solute cannot pass through the ○ Larger or charged molecules that membrane, but water can. cannot pass through the lipid bilayer The movement of water is driven by the use specialized proteins (transport concentration of solute particles. proteins) to move across the ○ Water moves from areas of lower membrane. solute concentration (higher water This process still moves molecules from areas concentration) to areas of higher of higher concentration to lower solute concentration (lower water concentration. concentration) until the solute Speed up the passive movement concentration is equal on both sides. There is a “helper” (transport protein) “Kung nasaan ang mas maraming solute (being dissolved), doon pupunta o mas attracted ang solvent (used to dissolve).” Tonicity The ability of a surrounding solution to cause a cell to gain or lose water. The tonicity of a solution depends on its Transport Proteins concentration of solutes that cannot cross the membrane relative to that inside the cell. Channel Proteins Carrier Proteins Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. 1. Hypertonic the cell to try to equalize the ○ has a higher concentration of solutes concentration of solutes. compared to another solution. causing the cell to SWELL, ○ There are more dissolved particles in undergoing lysis (bursting) in the hypertonic solution. animal cells or turgid in plant ○ When a cell is placed in a hypertonic cells (which is the normal state solution, water will tend to move out of of plant cells). the cell to try to equalize the concentration of solutes Causes the cell to SHRINK, undergoing crenation (in animal cells) or plasmolysis (in plant cells) ★ For plant cells undergoing plasmolysis, the cell itself will not shrink or shrivel because of its rigid cell wall, but instead its cytoplasmic region will become Osmoregulation smaller. the control of solute concentrations and water 2. Isotonic balance. ○ has the same concentration of solutes a necessary adaptation against osmotic as another solution. problems created by hypertonic or hypotonic ○ both solutions have an equal number environments. of dissolved particles. Example: a contractile vacuole acting as a ○ When a cell is placed in an isotonic pump for Paramecium (a unicellular solution, there is no net movement of eukaryote), which is hypertonic to its pond water, so the cell maintains its original water environment. shape and size. ○ Equal solute concentration in and out of the cell ○ The normal state of animal cells 3. Hypotonic ○ has a lower concentration of solutes compared to another solution. ○ there are fewer dissolved particles in Active Transport the hypotonic solution. requires the expenditure of energy (ATP) to ○ When a cell is placed in a hypotonic move molecules or ions against their solution, water will tend to move into concentration gradient, from an area of lower Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. concentration to an area of higher 5. Loss of the phosphate group restores the concentration. protein’s original shape, which has a lower facilitated by specialized proteins called affinity for K+. “pumps.” 6. K+ is released; affinity for Na+ is high again, ○ Actively transports specific molecules and the cycle repeats. or ions across the cell membrane. All proteins involved in active transport are carrier proteins. Sodium-Potassium Pump A transmembrane protein composed of multiple subunits. A transport protein energized by transfer of a phosphate group from the hydrolysis of ATP spans the cell membrane and has binding sites for sodium and potassium ions. plays a crucial role in maintaining the electrochemical gradients of sodium (Na⁺) and potassium (K⁺) ions across the cell membrane. Delivers sodium and potassium. ★ 3 sodium ions are transported OUT of the cell ★ 2 potassium ions are transported INTO the cell. Cycle 1. Cytoplasmic Na+ binds to the REMEMBER: from LOW to HIGH sodium-potassium pump. concentration: ○ The affinity for Na+ is high when the ★ OUTSIDE the cell: Sodium is High; protein has this shape. Potassium is Low ★ INSIDE the cell: Sodium is Low, 2. Na+ binding stimulates phosphorylation by Potassium is High ATP. 3. Phosphorylation leads to a change in protein shape, reducing its affinity for Na+, which is Bulk Transport released outside. a cellular process that involves the movement ○ Reduce in affinity = changes of large molecules or a large quantity of conformation = releasing Na+ / substances into or out of a cell using expelling sodium outside specialized vesicles or membrane-bound 4. The new shape has a high affinity for K+, which compartments. binds on the extracellular side and triggers the allows the cell to transport materials that are release of the phosphate group. too large to pass through the cell membrane by ○ 2 extracellular K+ bind to the pump simple diffusion or active transport. requires energy. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. 2. Pinocytosis Exocytosis ○ "cellular drinking" ○ involves the non-selective uptake of ○ substances are released or secreted small droplets of extracellular fluid from the cell. containing dissolved substances. ○ involves the fusion of vesicles with the ○ It is a continuous process in many cells. cell membrane, thereby expelling the ○ For in-taking fluids or smaller vesicle's contents into the extracellular molecules. environment. ○ Used to release molecules (hormones, 3. Receptor-Mediated Endocytosis neurotransmitters, enzymes, and other ○ specific process where specific cellular products) into the surrounding molecules are recognized and bound to tissues or into the extracellular space. receptors on the cell surface. ○ Used by secretory cells. ○ Very specific to certain molecules ○ The membrane then invaginates to form a vesicle containing the bound molecules. ○ Used to take in cholesterol Endocytosis ○ The cell engulfs substances from its Familial Hypercholesterolemia external environment by forming genetic disorder that causes elevated levels of vesicles derived from the cell low-density lipoprotein (LDL) cholesterol membrane. ○ often referred to as "bad cholesterol" ○ Takes in macromolecules. leads to an increased risk of early cardiovascular disease, especially coronary 1. Phagocytosis artery disease. ○ "cellular eating" Can clog or block the flow in blood vessels ○ the cell engulfs large particles such as food, bacteria, or debris. ○ Specialized cells, like white blood cells (phagocytes), are particularly adept at phagocytosis. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. Human cells use receptor-mediated endocytosis to take in cholesterol, which is carried in particles called low-density lipoproteins (LDLs). Individuals with the disease familial hypercholesterolemia have missing or defective LDL receptor proteins. ★ Mild disease = less receptors = less LDL to absorb ★ Severe disease = no receptors = no LDL to absorb (leading to blockage) Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. a. Peripheral Protein Practice Assessment b. Carrier Protein 1. A type of bulk transport where substances are c. Sodium-Potassium Pump released or secreted from the cell. d. Channel Protein a. Endocytosis b. Pinocytosis 7. Active Transport requires the expenditure of c. Exocytosis _____ to move molecules or ions against their d. Phagocytosis concentration gradient. a. ATP (energy) 2. A genetic disorder that causes elevated levels b. water of low-density lipoprotein (LDL) cholesterol. c. substances a. Familial Hypercholesterolemia d. fuel b. Familial Hypocholesterolemia c. Sickle Cell Anemia 8. How many sodium ions are transported out of d. Human Immunodeficiency Virus the cell? a. 3 3. The following are types of membrane transport b. 5 that move their molecules or ions from an area c. 2 of lower concentration to an area of higher d. 6 concentration, EXCEPT. a. Active Transport 9. What is the normal state of plant cells? b. Bulk Transport a. Plasmolysed c. Osmosis b. Turgid d. Facilitated Diffusion c. Isotonic d. Crenated 4. It is the control of solute concentrations and water balance. 10. What happens when a cell is placed in a a. Osmosis hypotonic solution? b. Osmoregulation a. There is no net movement of water. c. Tonicity b. Water will tend to move out of the cell to try d. Hydrolysis to equalize the concentration of solutes. c. Water will tend to move into the cell to try to 5. It is essential for maintaining cellular equalize the concentration of solutes. homeostasis and allowing cells to interact with d. The water will change color. their environment. a. Fluidity of Cell Membrane ANSWER CHOICES: b. Cell Transport Mechanism a. If statement A is correct and statement B is c. Biological Molecules false d. Enzyme b. If statement B is correct and statement A is false 6. It is a type of transport protein that forms pores c. If both statements are correct or channels in the membrane, allowing specific d. If both statements are false ions or molecules to pass through. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. 11. Statement A: Human cells use phagocytosis to take in cholesterol, which is carried in particles called low-density lipoproteins (LDLs). Statement B: Having the severe case of familial hypercholesterolemia means there are less receptors to absorb LDL. 12. Statement A: Phagocytosis is also known as “cellular eating.” Statement B: Phagocytosis is for in-taking fluids or smaller molecules. 13. Statement A: Tonicity refers to the ability of a surrounding solution to cause a cell to gain or lose water. Statement B: The tonicity of a solution depends on its concentration of solutes that cannot cross the membrane relative to that inside the cell. 14. Statement A: Simple diffusion moves small, non-polar molecules directly through the phospholipid bilayer from an area of lower concentration to an area of higher concentration until equilibrium is reached. Statement B: Facilitated diffusion, on the other hand, moves molecules from areas of higher concentration to lower concentration. 15. Statement A: When the Na+ ions bind to the sodium-potassium pump, the protein’s affinity for Na+ is low. Statement B: Phosphorylation leads to a change in protein shape, releasing Na+ outside. The new shape then has a high affinity for K+. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. ANSWER KEYS 1. C. 2. A. 3. D. 4. B. 5. C. 6. D. 7. A. 8. A. 9. B. 10. C. 11. D. 12. A. 13. C. 14. B. 15. B. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. Structures and Functions of Biological Molecules OUTLINE I. Food Pyramid II. Biological Molecules III. Monomer VS Polymer A. Definitions B. Synthesis and Breakdown of Polymers Tier with the bigger area = should be consumed 1. Dehydration Synthesis more. 2. Hydrolysis of Polymers IV. Four Major Classes of Biomolecules Biomolecule A. Carbohydrates Found in every level of the food pyramid. B. Lipids C. Proteins Aka macromolecules. 1. Four Levels of Protein ○ Large molecules and complex. Structure The essential compounds that make up the 2. Hemoglobin and Sickle Cell structure and function of all living organisms. Anemia Would be broken down into smaller molecules D. Nucleic Acid to be absorbed or consumed. V. Practice Assessments Involved in every biological process, from energy storage to genetic inheritance. Made up of polymers. Food Pyramid a visual representation of how different foods Monomers VS Polymers and drinks contribute towards a healthy balanced diet. Monomer allows individuals the flexibility to choose foods small, basic molecular unit that can join and drinks from each shelf depending on their together with other monomers to form larger food preferences. molecules. Comparable to beads in a necklace. ○ Just like how beads can be strung together to make a necklace, monomers can bond to each other to form bigger structures. Also referred to as the “building blocks of molecules.” Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. polymers are broken down into their individual monomers by the addition of water. crucial for digestion and the breakdown of large molecules for energy or to be used in different cellular processes. “Hydro” = water ; “lysis” = breakdown Four Major Classes of Biomolecules Molecules can have more than one type of monomer. Carbohydrates Are organic compounds composed of Carbon, Polymer Hydrogen, and Oxygen in a ratio of 1:2:1. A large molecule made up of repeating units of includes sugars and polymers of sugar. monomers. Monomers: monosaccharides. Similar to a long necklace made by connecting many beads (monomers). Monosaccharide play various important roles in the structure and function of cells. have molecular formulas that are usually True Polymers - consist of many identical or multiples of CH2O. similar monomers linked by covalent bonds. Glucose (C6H12O6) is the most common ○ Have the same type of monomers. monosaccharide. ○ Example: All monomers are made up of Are used for major “fuel.” lego, therefore there are no other ○ Glucose - used to generate ATP. monomers but just lego. Classification of monosaccharides: ○ The number of carbons in the carbon skeleton. Ends in suffix “-ose.” Synthesis and Breakdown of Polymers Dehydration Synthesis Aka “Condensation Reaction.” the process by which monomers are joined together to form polymers. “Dehydration” - a water molecule is removed as two monomers bond to each other. An enzyme removes water to build or connect 3 carbon = prefix “tri” = “triose” monomers and form polymers. 5 carbon = prefix “penta” = “pentose” Hydrolysis 6 carbon = prefix “hex” = “hexose” The reverse of dehydration synthesis. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. ○ The location of the carbonyl group (as Plants store surplus starch as aldose or ketose). granules within chloroplasts Aldose = located on the and other plastids terminal end of the carbon The simplest form of starch is skeleton. amylose. Ketose = located in the middle Glycogen = storage / within the carbon skeleton. polysaccharide in animals. stored mainly in liver and muscle cells Hydrolysis of glycogen in these cells releases glucose when the demand for sugar increases. ○ Structural Polysaccharides Provides support or structural purposes. ➔ (on the left) Aldose-Triose ; (on the right) Chitin is found in the Ketose-Pentose exoskeleton of arthropods. ◆ Can alternate the name (ex: also provides structural Pentose-Ketose) support for the cell walls of many fungi (ex: Disaccharide mushrooms). formed when a dehydration reaction joins two ○ Cell wall is monosaccharides. made of chitin. The covalent bond is called a glycosidic Humans do NOT have linkage. chitin. cellulose is a major component of the tough wall of plant cells Also a polymer of glucose, but the glycosidic linkage is different from starch. Can’t be digested by Polysaccharide humans. Starch and Long chains of monosaccharides (e.g., starch, cellulose differ based glycogen, cellulose). on two ring forms for have storage and structural roles: glucose: alpha (α) and ○ Storage Polysaccharides beta (β). Stores energy Starch is easier to Starch = storage digest than cellulose polysaccharide of plants; due to differences in consists of glucose monomers. their molecular Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. structure and how the polysaccharide of plants. digest cellulose. body processes these carbohydrates. Starch Cellulose ★ Easy-to-Confuse Terms #2 Glucose units are Glucose units are linked by connected by alpha (α) beta (β) glycosidic bonds. AmylOse AmylAse glycosidic bonds. Simplest form of starch. A digestive enzyme; Alpha bonds form a Beta bonds create a strict, breaks down spiral or branched rigid structure. carbohydrates (starch) structure. into glucose. Easily broken down by Form long chains that are digestive enzymes (such packed tightly together, as amylase), converting giving cellulose its Lipids starch into glucose for structural strength, energy. resulting in human organic compounds composed of Carbon, digestive enzymes being Hydrogen, and Oxygen with no definite ratio or unable to break down beta bonds. proportion. This leads to cellulose passing Not considered as true polymers due to being through the composed of 2 different monomers: glycerol human digestive system largely and fatty acids. undigested. function in the storage of energy and components of the cell membrane. All monomers are in the Every glucose monomer is same orientation. upside down (alternating) to its neighbors. Fats constructed from two types of smaller molecules: glycerol and fatty acids. Glycerol is a three-carbon alcohol with a hydroxyl group attached to each carbon. ★ Enzyme needed to digest cellulose: cellulase Fatty acid consists of a carboxyl group ○ Humans lack cellulase. attached to a long carbon skeleton. ○ Cellulose passes through the digestive system as fiber, aiding in digestion by promoting bowel movements but not providing any usable energy. ○ It would be easier to break down if the monomers (glucose) are on the same side or have the same orientation. For long term energy storage. ○ Whenever the liver and muscle cells ★ Easy-to-Confuse Terms #1 cannot store any more excess sugar, CellulOse CellulAse said sugar goes to (or are absorbed by) fats. The structural The enzyme needed to Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. ○ Long-term food reserves (or energy) Phospholipids are stored in adipose cells/tissues. Two fatty acids and a phosphate group are Serves as a “cushion” to protect attached to glycerol. internal/abdominal/vital organs. Amphipathic in nature (has 2 regions: ○ Which is why the abdomen “fattens.” hydrophilic and hydrophobic). ○ Two fatty acid tails are hydrophobic. For insulation. ○ The phosphate group and its ○ Serves as thermoregulator. attachments form a hydrophilic head. Ester linkage - covalent bond between glycerol and fatty acids. Types of Fatty Acids: Steroids ○ Saturated Fats: made from saturated lipids characterized by a carbon skeleton fatty acids; are solid at room consisting of four fused rings (structure). temperature; can maintain solid Cholesterol structure at room temp due to its ○ type of steroid compact structure; single bond Most ○ a component in animal cell animal fats are saturated. membranes and a precursor from ○ Unsaturated Fats: made from which other steroids are synthesized. unsaturated fatty acids; are liquid (oil) at room temperature; liquid at room temp because of more spaces in between caused by its crooked/kinked shape; double bond. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. Proteins (Defensive) A biologically functional molecule that consists Storage To store proteins/amino acids. of one or more polypeptides. Transport Transport of substances; Used for enzymatic activity. embedded in the Plasma Some enzymes speed up chemical reactions. Membrane that is used to facilitate transport. Account for more than 50% of the dry mass of most cells. Hormonal Coordination of organism’s Other functions: defense, storage, transport, activities. cellular communication, movement, and Receptor Response of cell to chemical structural support. stimuli; to receive signals from other cells. Monomers: Amino acids Contractile and For movement; fibers in muscles contract due to motor Motor proteins. Structural Strengthens foundation of cells (ex: collagen); for support. Amino Acids Building blocks (monomers) of proteins. organic molecules with amino and carboxyl groups. linked by covalent bonds called peptide bonds. Proteins are all constructed from the same set of 20 amino acids. ○ They only differ in their properties due to differing side chains, called R groups. Functions Enzymatic Activity To build or break down molecules; selective acceleration of chemical reactions; have suffix “-ase.” Defense Protection against disease. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. DO NOT MEMORIZE! The 20 amino acids of proteins: 1. Primary Structure - unique sequence of amino acids; has a linear structure. 2. Secondary Structure - found in most proteins; consists of helix and sheets in the polypeptide chain; can be helical or folded in shape; 3-dimensional. 3. Tertiary Structure - determined by interactions among various side chains (R groups); combines the structures from secondary level (helical and folded structures). 4. Quaternary Structure - protein consists of multiple polypeptide chains (tertiary structures) combined. Polypeptides unbranched polymers built from the 20 sets of amino acids. range in length from a few to more than 1,000 monomers. “Poly” = many ; “peptide” = amino acids Hemoglobin and Sickle Cell Anemia Four Levels of Protein Structure Hemoglobin - complex protein found in red Proteins perform their specific functions blood cells because of their unique three-dimensional ○ responsible for transporting oxygen shapes. from the lungs to tissues throughout ○ These shapes result from the way the the body and returning carbon dioxide chain of amino acids folds. from the tissues back to the lungs for ○ creates active sites or regions that exhalation. allow it to interact with other molecules, ○ composed of four subunits such as substrates in enzymes, with (polypeptides), each containing a great precision. heme group that can bind to oxygen. The structure of hemoglobin If a protein loses its shape (due to heat, pH changes, etc.), it also loses its allows it to pick up oxygen function. efficiently and release it where The protein's shape is directly needed. linked to what it does. Specific shape is CRUCIAL for the right interaction to occur. Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. Sickle Cell Anemia - genetic blood disorder caused by a mutation in the gene that encodes the beta chain of hemoglobin. ○ Instead of producing normal hemoglobin (HbA), individuals with this condition produce an abnormal form known as hemoglobin S (HbS). ○ Individuals with this disease are at risk for various complications, including stroke, acute chest syndrome, and organ failure. ○ mutation involves a single nucleotide ★ The shape is not flexible = can cause blockage change in the DNA sequence that in the blood vessels. results in the substitution from ○ “Nagdikit-dikit ang hemoglobin glutamic acid to valine in the beta molecules, resulting in a crescent or chain of hemoglobin. sickle shape.” a slight change in primary structure can affect a protein’s Denaturation structure and ability to function. Loss of a protein’s native structure. Alterations in pH, salt concentration, temperature, or other environmental factors can cause a protein to unravel. A denatured protein is biologically inactive. Some are reversible through renaturation, but the majority are irreversible. ★ The proteins are NOT supposed to associate with each other or stick to one another. Sickle-Cell Anemia results in aggregating the Nucleic Acid proteins into a fiber. Stores, transmits, and helps express hereditary information. Needed to pass genetic information from one generation to another. two types of nucleic acids: Disclaimer: The reviewer papers of the Cranium Committee are intended solely for personal academic assistance and educational purposes. Unless stated otherwise, the reviewers have not been approved by any faculty member. All necessary information can be seen in your respective textbooks and modules. Deoxyribonucleic acid (DNA) ○ a nucleic acid made of Sugars: monomers called nucleotides. ○ DNA - deoxyribose (w/o oxygen) ○ Does NOT contain oxygen. ○ RNA - ribose (w/ oxygen) Ribonucleic acid (RNA) ○ Contains oxygen. The amino acid sequence of a polypeptide is programmed by a unit of inheritance called a gene. ○ Genes consist of DNA. Nucleotides Monomers of Nucleic Acids. Each nucleotide consists of a nitrogenous base, a pentose sugar, and one or more phosphate groups. Nucleoside: portion of a nucleotide without the phosphate group. ★ Easy-to-Confuse Terms #3 NucleoTides NucleoSides Monomers of Nucleic Nucleotides but WITHOUT Acids. (or does not have) the phosphate group. MAIN DIFFERENCE BETWEEN DNA & RNA Nitrogenous Bases DNA RNA ○ two families of nitrogenous base: Pyrimidines - cytosine, double-strand single-strand thymine, and uracil; have a Has THYMINE and not Has URACIL instead of single six-membered ring. uracil. thymine. Purines - adenine and guanine; have a Base Pairs: Base Pairs: six-membered ring fused to a Cytosine-Guanine Cytosine-Guanine

Cell Membrane Structure Reviewer Papers [CRNM] BIO101-Q2 PDF

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