Grade 11 AP Biology Exam Review Chapter 1: Intro to Biology (20 Questions) No-Brainers: Biology is defined as the study of life An organism's structure is directly related to its function There is unity in the diversity of all life, we are more alike than we are different Descent with modification - Artificial Selection: Selecting and breeding organisms for specific traits (by humans) Natural Selection: Process in which individuals that have certain heritable traits survive and reproduce at a higher rate than other individuals because of it (natural) Themes of Living Things: 1. New properties emerge at each level in the biological hierarchy 2. Organisms interact with their environment 3. Structure and function are correlated at all levels of biological organization 4. Cells are the basic unit of structure and function 5. The continuity of life is based on the transfer of DNA 6. Feedback mechanisms regulate biological systems 7. Unity in the diversity of life Definitions: Eukaryotes: Organisms made up of cells that possess a membrane-bound nucleus that holds genetic material and membrane-bound organelles. Prokaryotes: Organisms made up of cells that lack a cell nucleus or any membrane-enclosed organelles. Negative Feedback: reduces change to return to a stable state (called homeostasis) - ie) Thermoregulation: Sweating after running, so body temp. goes back to ideal temperatures Positive Feedback: Amplifies change so more of the reaction happens. - ie) Childbirth: Oxytocin is released which intensifies and speeds up contractions Science and Experiments A hypothesis is either a suggested explanation for an observable phenomenon or a well-reasoned prediction based on facts (Falsifiable and testable) A theory is tested, well-substantiated, unifying explanation for a set of verified, proven factors. A control group is used to show the “normals” No variable has acted upon it - no change Quantitative data is presented by numbers. - ie) Graphs, other measurements Qualitative data is descriptive, and regards phenomenon which can be observed but not measured - ie) colour, smell, feeling, and behaviour Main characteristics of science: - Experiments can be replicated by other people to produce the same results - Findings are based on facts and not belief (such as in the supernatural - Explanations are never "right" they can only be proven to be wrong- in other words, you can't be 100% sure that an explanation will hold true forever Scientific Method: Observation/Question: Starts with someone asking why things happen Research: Understand the thing of interest by doing more research Hypothesis: What you think will happen if... happens; your prediction. Experiment: Come up with a way to test your hypothesis - limit extraneous variables - make sure the experiment is recorded so others can replicate it Collect data: Collect the data of your experiment Analysis: What does your data tell you? Is your hypothesis right? Should you alter your hypothesis with this information and go back to experimenting? Conclusion: Compared your hypothesis to others and so they can replicate your findings The Hierarchy of Biological Structure (From largest to smallest) ● Biosphere: All of earth's environment where life exists ● Ecosystem: All living and nonliving components in an environment ● Community: All species of organisms living in an ecosystem ● Population: All individuals of one particular species living in the same place ● Organism: Entire living thing ● Organ systems: Group of organs that perform a specific function ● Organs: Composed of two or more tissues that perform a specific function ● Tissues: Group of similar cells that perform a specific function ● Cells: Basic unit of structure and function in all living things ● Organelles: Functional parts of a cell known as "little organs" of cells ● Molecules: Two or more atoms held together by covalent bonds ● Atoms: You should know this by now Chapter 2: Chemistry (17 Questions) CHNOPS - Stands for Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus and Sulfur - Their covalent bonds compose most biological molecules on Earth Matter - Anything that takes up space and has mass Element - Substance that cannot be broken down to other substances by chemical reactions – 92 naturally occurring elements Compound - Two or more different elements combined in a fixed ratio (H20, CH4, etc) * Essential Elements (O, C, H, N, Ca, P, K, S, Na, Cl, and Mg) Trace Elements - Required only in minute quantities Atom - The smallest unit of matter that still retains the properties of an element. # Atomic Number = number of protons # Atomic Mass = protons + neutrons # Atomic Weight in Daltons = Atomic Weight in atomic mass units Isotope - Same element with different number of neutrons Valence Electrons - Involved in bonding; outermost electrons in shell Electron Orbital - Where an electron has a strong chance of being located Covalent Bond (Strong) - Involves the sharing of pairs of valence electrons (single, double, and triple bonds) Polar Covalent Bonds (Strong) - Occurs when one atom is hogging more of the electrons than the other smaller atom Nonpolar Bonds (Strongest) - Equal sharing of electrons; net zero charge Ionic Bond (Moderate) - Electrostatic attraction between a positive and negative ion Hydrogen Bond (Weak) - Relatively weak attraction between H in one molecule with an H or N in another molecule Van der Waals Forces (Very weak) - Dispersion forces, IMF’s and are very weak. Chapter 3: Water (22 Questions) Why is water so important to living organisms? Cohesive - Water molecules are attracted to one another and bond with weak hydrogen bonds. - Results in surface tension, which is the tendency of a liquid’s surface to resist rupture when placed under tension or stress. Adhesive - The attraction of molecules of one kind for molecules of a different kind, - Water is attracted to any other polar molecule, thus allowing it to stick with it - In plants, this occurs when the water molecules stick to the cell walls and move up against the force of gravity Evaporative coolant - When heat is applied to water the more energetic molecules transform into a vapor state while the ones that don't have enough energy, stay behind - Results in a cooling effect since the water that is left has less energy, and thus lower the temperature Less dense as a solid than as a liquid - This occurs because the water molecules are more ordered and there is more space between them thus lowering the density - Where there is ice, there is life Good solvent - It's a polar molecule and can dissolve any polar molecule/compound out there - Exceptions include covalent bonds, but otherwise, it's known as the universal solvent High specific heat - High specific heat is defined as the amount of heat needed to raise the temperature of one gram of a substance by one degree Celsius. - When the temperature of water decreases, the hydrogen bonds are formed and release a considerable amount of energy - When heat is absorbed, hydrogen bonds are broken and water molecules can move freely. - 4.184 Joules for Water Hydrophilic - Having an affinity for water; able to absorb, or be wetted by water - Polar substances are lovin it Hydrophobic - Lacking an affinity for water; unable to absorb, or be wetted by water - Substances include Alkanes, Oils, and Fats **H2O -- H+ + OH- (Dissociation of a water molecule - this is the basis of acids and bases)** H is short for H30 (Hydronium) and OH- is Hydroxide Acid - Increases the H+ concentration of a solution (Less OH-) Base - Reduces the H+ concentration of a solution (More OH-) Buffers - Keeps pH constant by shuffling H+ (release of these ions makes things more acidic, pick up of these ions makes the solution more basic) - H2C03 a.k.a. Carbonic Acid is vital for living things in ph regulation A pH of 7 is considered neutral, 1-7 is acidic, and 8–14 is alkaline or basic. *As (H+) gets smaller, scientific notation exponents get BIGGER, and pH goes UP. *As (H+) gets larger, scientific notation exponents get SMALLER, and pH goes DOWN. *In pure water or a neutral solution the [H + ] = 1.0 × 10 -7 M Chapter 4: Carbon (17 Questions) Organic chemistry: Carbon-based because Carbon can bond with up to 4 other atoms. - Can form single bonds, double bonds, triple bonds, straight-chain molecules, branching molecules, and rings. Hydrocarbons - Molecules that consists only of carbon and hydrogen - Major components of fossil fuels Isomers - Molecules that have the same structural formula but a different arrangement of molecules - Cis = Same side and Trans = Different/Opposing sides of one another Unsaturated Fatty Acids - Contains a double bond between carbons - Includes vegetable oils and wax - Liquid at room temperature Chapter 5: Macromolecules (30 Questions) Macromolecules: Pain in the ass to remember, but vital Dehydration / Condensation Reactions - Building process where monomers are joined together - A molecule of water is removed in the process Hydrolysis Reactions - A break-down process where polymers are broken into monomers through - A molecule of water is added in the process Polymer - Long strand of similar monomers (Poly - many + mer - piece) Monomer - Building block of a larger molecule (Mono - one + mer - piece) Carbohydrates - Sugars and polymers of sugars - Characterized by the presence of multiple hydroxyl groups and a carbonyl group. Monosaccharide: Known as a simple sugar - Generally has a formula that is a multiple of the unit CH2O - A simple sugar typically has 3 – 7 carbons in its carbon skeleton Glucose (C6H12O6) is the most common monosaccharide Disaccharide: A combination of two monosaccharides held together with a glycosidic linkage - Covalent bond between two monosaccharides formed by dehydration synthesis. Polysaccharide: Many monosaccharides bonded together - Starch: Plant energy storage - Glycogen: Animal energy storage - Cellulose – Structural carbohydrate, a major component of cell walls - Chitin: Structural carbohydrate, a major component of arthropod exoskeletons, also found in the cell walls of fungi Lipids - Have no affinity for water and are mostly hydrocarbons - An important storage molecule for cells Fats - Made up of glycerol and fatty acids - Saturated = Single bonds only, Unsaturated = Double/Triple bonds Proteins - Are made of 20 different amino acids joined by peptide bonds (also called “polypeptides”) Levels of Protein Structure: 1. Primary: A chain of amino acids (as the protein is formed on the ribosome) 2. Secondary: The result of hydrogen bonding between the components of the polypeptide backbone (Alpha helix & Beta pleated sheet) 3. Tertiary Structure: The result of interactions between the components of the “R” chain (van der Waals forces, hydrophobic interactions, etc.) 4. Quaternary Structure: The results from the aggregation of polypeptide subunits Denaturation - Proteins are denatured (broken down) by heat, acids, and high ion concentrations. Renaturation - The process of returning proteins to their original state (very hard to do, but not impossible). Chaperonins - A group of proteins that have functional similarity and assist in protein folding. Functions of Proteins Phospholipid - One of the fatty acids of a triglyceride is replaced by a phosphate group. - A major component of cell membranes. Steroid - Carbon skeleton made up of 4 fused rings. Cholesterol - A component of animal cell membrane; precursor of many other hormones. Chapter 6: The Cell (15 Questions) Endosymbiotic Theory: Prokaryotic cell was engulfed by another cell and formed a symbiotic relationship.. - Mitochondrial/chloroplast contains own DNA, double membrane, ribosomes and similar size to prokaryotic cell. Important note on cell size: - Smaller size has a greater surface area to volume ratio and diffusion will be more efficient. That’s why there are no egg-sized cells. Cytology: The branch of biology concerned with the structure and function of plant and animal cells. Plant Cells vs. Animal Cells Have plastids (chloroplasts) Do not have plastids Have a cell wall made of cellulose Do not have a cell wall Large central vacuole Small temporary vacuoles Storage is in the form of starch Storage is in the form of glycogen Have plasmodesmata Have gap junctions (rough equivalent) Do not have centrioles Have centrioles Fixed regular shape Amorphous shape (not fixed) In plant cells but not animal cells: - Chloroplasts - Central vacuole - Cell wall - Plasmodesmata Eukaryotic Cells vs. Prokaryotic Cells Fairly large in size Significantly smaller in size Nuclear region is surrounded by a membrane Nuclear region is NOT surrounded by a membrane No nucleolus Nucleolus is present Contains membrane bound organelles NO membrance bound organelles Cell division by mitosis or meiosis Cell division by fission Linear DNA and multiple chromosomes Circular DNA and only 1 chromosome Both contain cell membranes and ribosomes Organelles of the Cell: Endoplasmic Reticulum $mooth ER - Lacks ribosomes but rich in enzymes. - Synthesizes lipids, phospholipids, steroids, sex hormones. - Enzymes help detoxify poisons and drugs, liver cells, increasing rate of detoxifications. - Creates higher tolerance of drugs and alcohol Rough ER - Ribosomes are attached to the outside and the outside of the nuclear envelope. - Abundant in cells that secrete proteins. - Secretory protein are packaged in transport vesicles. (usually glycoproteins - Membrane-bound proteins and phospholipids are synthesized directly into membrane. Golgi apparatus - Centre of manufacturing, warehousing, sorting and shipping. - Molecule identification tags are added to products. - Flattened membranous sacs are called cisternae. - In the Cis face, receives material by fusing with transport vesicles from the ER and Trans side, that travel to other sites after modified. - Golgi can manufacture its own macromolecules. Lysosomes: - A membrane-bound sac of hydrolytic enzymes that an animal cell uses to digest macromolecules. - Enzymes hydrolyze proteins, fats, polysaccharides, and nucleic acids. *Work best at pH 5. - Lysosomal enzymes and membrane are synthesized by rough ER and then transferred to Golgi. - Play a role in recycling of the cell’s organelles and macromolecules. - Critical role in the programmed destruction/development of cells. Vacuoles - Storage of water, ions, nutrients or waste and water. - Large versions are membrane-bound sacs. - Selective membrane in transport of solutes into the central vacuole. - Stockpiling proteins or inorganic ions by disposing of metabolic by-products, holding pigments and stronger defensive compounds. Contractile Vacuole - Expulsion of water from the cell. Mitochondria and chloroplasts - Change energy from one form to another; both in animal and plant cells. - Mitochondria: Cellular respiration, producing ATP from the catabolism of sugars, fats, and other fuels in the presence of oxygen release chemical energy. - Chloroplasts: Sites of photosynthesis, converting solar energy to chemical energy. Are flattened sacs/stacks and produces 3-Carbon molecules. Both... - Have two membranes separating from cytosol. - Have membrane proteins that are made by free ribosomes in the cytosol and by ribosomes within the organelles. - Small quantities of DNA that direct the synthesis of polypeptides. - Mobile and move around the cell along the cytoskeleton. Vesicle - Sacs made of membrane, used in transporting materials separate from the cytosol. Peroxisomes - Transfer hydrogen and breakdown or detoxifies peroxides. - Break down fatty acids to be sent to the mitochondria for fuel Cytoskeleton: - Network of fiber that organize structures and activities. - Provides mechanical support for cell shape and allows for the anchorage for many organelles and cytosolic enzymes. - Dynamic and can be dismantled and reassembled to change shape of cell. Motor Proteins - Cillia: Clears debris. Found in lungs, respiratory, and middle ear. - Flagella: Used for movement, sensations and signal transduction. Animals have 3 types of intercellular links (ONLY IN ANIMALS): - Tight Junctions: Membrane of adjacent cells are fused, thus preventing the leakage of extracellular fluid. - Desmosomes: Anchors cells together, between cells, think of rivets. - Gap Junctions: Communicate junctions, provide cytoplasmic channels, permits free passage by letting ions flow through them. Chapter 7: Membranes and Movement (50 Questions) - Selective permeability: When the membrane only allows certain ions/proteins to pass through it. - Amphipathic Molecule: Molecule containing hydrophobic and hydrophilic region. - Fluid mosaic model: It describes the structure of the plasma membrane, Including phospholipids, cholesterol, proteins, and carbohydrates. - Freeze-Fracture Technique: Consists of physically breaking apart (fracturing) a frozen biological sample. - Extracellular matrix: extracellular matrix (ECM) is a three-dimensional network of extracellular macromolecules, such as collagen, enzymes, and glycoproteins, that provide structural and biochemical support to surrounding cells. - Glycoprotein: carbohydrate-attached protein - Glycolipid: carbohydrate-attached lipid - Integral Proteins: Penetrate the hydrophobic core. - Peripheral Proteins: Are bound to the surface of the membrane. - Transmembrane Proteins: Integral proteins that span the membrane. - Transport Proteins: Allow passage of hydrophilic substances across the membrane. - Channel proteins: Transport proteins that have a hydrophilic channel that certain molecules or ions can use as a channel. - Carrier Proteins: Bind to molecules and change shape to shuttle them across the membrane. - Aquaporins: Channel proteins that facilitate the transport of water. - Diffusion: Molecules of a substance of a substance tends to spread from a region in which they are more concentrated to regions in which they are less concentrated. - Concentration Gradient: Differences in concentration between regions of high concentration and low concentration. - Equilibrium: Particles move from areas of high to low concentration. - Passive Transport: Transport of molecules in which no cellular energy is used when materials flow in the direction of the concentration gradient. *Most of this section on the exam will come from info/procedures from labs including one water potential question AP Water Potential Sample Questions - Answer Key (2 Questions on the Exam) 1. If a plant cell’s ΨP = 2 bars and its ΨS = -3.5 bars, what is the resulting Ψ? Ψ = ΨP + ΨS = 2 bars + (-3.5 bars) = -1.5 bars 2. The plant cell from question #1 is placed in a beaker of sugar water with ΨS = -4.0 bars. In which direction will the net flow of water be? The pressure potential of a solution open to the air is 0. Therefore, the water potential of the sugar water is -4.0 bars [Ψ = 0 bars +(-4.0) bars]. Since free water always flows towards the solution with a lower water potential, the flow of water would be outside of the cell. 3. The original cell from question # 1 is placed in a beaker of sugar water with ΨS = -0.15 MPa (megapascals). We know that 1 MPa = 10 bars. In which direction will the net flow of water be? -0.15 MPa = -1.5 bars The water potential of the sugar water is -1.5 bars [Ψ = 0 bars + (-1.5 bars)]. Since the water potential of the original cell was also -1.5 bars, there would be no net flow of water. The cell and the sugar water are in equilibrium. 4. The value for Ψ in root tissue was found to be -3.3 bars. If you place the root tissue in a 0.1 M solution of sucrose at 20°C in an open beaker, what is the Ψ of the solution, and in which direction would the net flow of water be? ΨS = -iCRT ΨS = -(1)(0.1 mol/L)(0.0831 L*bars/mol*K)(293 K) = -2.43 bars Ψ = ΨP + ΨS = 0 bars + -2.43 bars = -2.43 bars The Ψ of the root tissue is -3.3 bars and the Ψ of the sucrose solution is -2.43 bars. Water will flow into the root tissue because free water always moves towards the lower overall water potential. 5. NaCl dissociates into 2 particles in water: Na+ and Cl-. If the solution in question 4 contained 0.1 M NaCl instead of 0.1 M sucrose, what is the Ψ of the solution, and in which direction would the net flow of water be? ΨS = -iCRT ΨS = -(2)(0.1 mol/L)(0.0831 L*bars/mol*K)(293 K) = -4.87 bars Ψ = ΨP + ΨS = 0 bars + -4.87 bars = -4.87 bars The Ψ of the root tissue is -3.3 bars and the Ψ of the NaCl solution is -4.87 bars. Water will flow out of the root tissue and into the salt solution because free water always moves towards the lower overall water potential. Chapter 8: Metabolism, ATP, and Energy Conversions (27 Questions) Enzymes: Speeds up metabolic reactions by lowering energy barriers, regulates metabolic pathways.. Enzyme Catalyzed Reactions: Enzymes speed up reactions by lowering the activation energy. Activation Energy: The initial investment of energy for starting a reaction- the energy required to contort the reactant molecules so the bonds can break Cofactors: Bind to the enzyme and are non-protein. Coenzymes: Always organic! - Competitive inhibitors: Resemble substrates and directly compete to bind to the active site. - Non-Competitive Inhibitors: Delay reactions by binding to another part of the molecule. Anabolic pathways = Energy is needed, endergonic Catabolic pathways = Energy is released, exergonic Allosteric: Away from the active site ● A. Inhibition: Alters shape of enzyme so reaction can't occur ● A. Activation: Takes up space on enzyme and stimulates it before another substrate can bind to the active site. Lock and Key Concept: No change needed on the surface and only certain types will fit. Induced Fit: The active site will change to help to substrate fit. Factors affecting enzyme action: - Temperature and pH - Ideally at around 35 C to 40 C, and pH depends on the type of enzyme - Substrate concentration: The increase in substrate concentration leads to an increase in the rate of an enzyme-catalyzed reaction - Enzyme concentration: Increasing the enzyme concentration will speed up the reaction (as long there are substrates to bind to) *Amount of substrates and inhibitors ATP: Adenosine Triphosphate - Broken by hydrolysis, because phosphate bonds are weak covalent bonds. - Unstable, hydrolysis yields energy because products are more stable - Energy released comes from chemical change to a state of lower free energy and not from bonds. - Hydrolysis of ATP almost always power the 3 types of work in cell. - A phosphate group is transferred from ATP to another molecule and the phosphorylated molecules is changed and performs work. - ATP is renewable, can be regenerated with the addition of a phosphate group to ADP - Catabolic pathways provide energy for exergonic regeneration of ATP *ATP - P = ADP and ADP - P = AMP Chapter 9: Cellular Respiration Cellular Respiration - Uses oxygen in the breakdown of sugars, producing energy, heat, carbon dioxide, and water Equation for Cellular Respiration: (Note that this is flipped for Photosynthesis) Anaerobic Respiration -Produces very little energy and Oxygen is not needed. Aerobic Respiration -Done in the presence of Oxygen and yields large amounts of energy. Fermentation - Occurs without oxygen and is the partial breakdown (degradation) of sugars and release of energy Alcoholic Fermentation - Pyruvate (the product of glycolysis) is converted into acetaldehyde and then ethanol. CO2 is released (the 2 ATP of glycolysis are produced) Lactic Acid Fermentation - Pyruvate is broken down to form lactic acid (ATP from glycolysis). Muscle cells make ATP by this process when energy demand is high and the oxygen supply is low. Oxidation-Reduction Reactions (Redox Reactions) ● Involves the partial or complete transfer of one or more electrons from one reactant to another *Oxidation = Loss of electrons *Reduction = Addition of electrons *Even though fermentation happens without oxygen, it isn't the same as anaerobic respiration. Instead of ending with glycolysis, as fermentation does, anaerobic respiration creates pyruvate and then continues on the same path as aerobic respiration. Chemiosmosis: The movement of ions across a semipermeable membrane, down their electrochemical gradient. - The generation of adenosine triphosphate (ATP) by the movement of hydrogen ions (H+) across a membrane during cellular respiration or photosynthesis Cellular Respiration Takes Place in 3 Stages: (Also their Cellular Locations) 1. Glycolysis - Occurs in the cytoplasm (outside the mitochondria) - Glycolysis is common to fermentation and respiration. It probably evolved in ancient prokaryotes before oxygen was present. 2. Krebs or Citric Acid Cycle - Occurs in the matrix of the mitochondria 3. Electron Transport Chain (Oxidative Phosphorylation) - Occurs in the inner membranes of the mitochondria Chapter 11: Cell Communication Pathways (22 Questions) Signal Transduction Pathway - Series of steps involved in the conversion of a cell surface signal to a cellular response - Similarities among the pathways in bacteria, yeast, plants, and animals suggest an early evolution of cell-signaling mechanisms Paracrine Signaling - In animals, a signaling cell releases messenger molecules into the extracellular matrix fluid and these local regulators influence nearby cells. Synaptic signaling - A nerve cell releases neurotransmitter molecules into the synapse separating it from its target cell. Hormones - Chemical signals that travel to more distant parts of an organism. Stages in Cell Signaling: 1. Reception – Chemical signal binds to a receptor protein on the surface of the cell or inside 2. Transduction – Chemical pathway 3. Response – Activation of cellular processes Reception: A signal molecule binds to a receptor protein, causing it to change shape ● The binding between a signal molecule (ligand) and a receptor is highly specific ● A conformational change in a receptor is often the initial transduction of the signal ● Intracellular receptors are cytoplasmic or nuclear proteins ● Signal molecules that are small or hydrophobic and can readily cross the plasma membrane use these receptors There are three main types of membrane receptors: 1. G-protein-linked receptors 2. Tyrosine kinases receptors 3. Ion channel receptors Changes in Signal Transduction pathways can alter cellular response ● Conditions where signal transduction is blocked/defective ● Examples: Diabetes, heart disease, neurological disease, autoimmune disease, cancer, cholera ● Effects of neurotoxins, poisons, and pesticides or Drugs Applications to the Human Body (10 Questions) - Covers reading guides 44, 45 and 49. (Mostly Nervous and Endocrine Systems) - Questions will give you a lengthy description of a body system and you should be able to use knowledge from other chapters (ie, signaling) to answer the question - “There will be a lot of overlap with other units and is not as hard as you might think" Tips for Interpreting Graphs Independent variable - Something that is being manipulated and sits on the x-axis Dependant variable - Outcome of the variable that is being manipulated and sits on the y-axis - Time is always on the x-axis *Don't forget your units!!! Inverse relationship - As one variable goes up, the other goes down (vice versa) Direct relationship - As one variable goes up, so does the other. (vice versa) - Moving opposite directions of one another *Remember that you have to explain the relationship in detail, not just that it's inverse or direct *Usually the dots are connected, but you should know what to look for if it isn’t *Also chances are that the experiments that we have to analyse have already shown up in our previous tests or labs.
