CP Biology Midterm Review Scientific Method 1. Define the following terms: Independent variable Dependent variable Control Constant variables Quantitative Observation Qualitative Observation Variable being tested Variable that is measured What is kept under normal conditions, to be used to compare results Variables kept the same to make experiment fair Observations involving numbers Observations without numbers 2. An experiment was designed to test the effect of sugar on the heartbeat of rats. Two groups of rats were used. Every two hours rats from both groups were selected and their heartbeats were checked. The rats of group one were given one dose of sugar five minutes before the heartbeat was checked. a. Independent variable dose of sugar b. Dependent variable heartbeat of the rat c. Control Group two without the sugar 3. List the steps of the scientific method in order and explain the steps. Problem Question to investigate AFTER making observations. Research Background information Hypothesis A testable prediction Experiment Step by step procedures to test hypothesis Data Charts, graphs, pictures collected during the experiment Conclusion Accept or reject hypothesis based on data Basic Biology 1. What is the difference between an autrotroph and heterotroph? Autotrophs are producers that make their own food by photosynthesis and then make ATP through cellular respiration. Heterotrophs are consumers and can NOT make their own food. They get food from eating plants and animals and converting this food into ATP by respiration. 2. What is metabolism? Chemical processes that a body undergoes to maintain life: ingestion, digestion, respiration, excretion. 3. List the characteristics of life. Something is LIVING if it has ALL characteristics. a. Made of cells b. Energy use/metabolism c. Responds to the environment d. Grows and develops e. Reproduces 4. What is homeostasis? Process of maintaining internal stability within an organism - Ability of organism to balance or regulate itself (ex: not too hot, not too cold, just right)
Chemistry of Life 1. Define organic: organic compounds are made of carbon (hydrocarbons hydrogens bonded to carbons) 2. All living things are made up of 6 essential elements: CHONPS. Name the six elements of life. Carbon Hydrogen Oxygen Nitrogen Phosphorous Sulfur 3. Elements join together by chemical bonds to form compounds. Name 4 types of chemical bonds. Ionic, covalent, polar covalent bonds, and hydrogen bonds (also peptide bonds in proteins). 4. Carbon is in all living things. How many bonds does carbon form? 4 5. There are 4 major categories of organic molecules that are made up of the CHONPS elements. Complete the following chart on the BIG 4. LIPIDS Monomer: fatty acids and glycerol Polymer: triglycerides (3 fatty acids bonded to glycerol) and phospholipids (2 fatty acids, glycerol, and phosphate group) Function: 1. secondary energy storage, 2. insulation, 3. phospholipids in building cell membrane Examples: fats, steroids like cholesterol, cell membrane, waxes, saturated triglycerides are animal fats (saturated means no double bonds between carbons), unsaturated triglycerides are plant oils PROTEINS Monomer: amino acids Polymer: dipeptides, polypeptides, and proteins are amino acids linked together by a peptide bond Function: 1. enzymes that speed up reactions 2. structural proteins in hair muscle, skin, tendons 3. antibodies that fight infection, 4) builds strong muscles Examples: enzymes, muscles, collagen, keratin, antibodies, catalysts, hemoglobin CARBOHYDRATES Monomer: monosaccharide (simple sugars like glucose) Polymer: polysaccharides (2 sugars joined by dehydration synthesis reaction) Function: major source of energy and plant cell walls Examples: sugars, starch (plant stored energy), glycogen (animal stored energy in liver), cellulose, plant cell walls NUCLEIC ACIDS Monomer: nucleotide (3 parts 5 carbon sugar, phosphate group, and nitrogen base) Polymer: DNA and RNA Function: DNA that stores hereditary information and RNA that builds proteins Examples: DNA, RNA Reminder: DNA bases A bonds with T (apple tree) and C bonds with G
6. Define chemical reaction: the process in which chemical bonds are broken and new ones formed, producing one or more different substances 7. Write an example of a chemical reaction and label the reactants and products. NaCl Na + Cl Reactants products 8. What is the difference between hydrolysis and dehydration synthesis reactions? Dehydration synthesis removes water and joins 2 monomers to make a polymer. Hydrolysis adds water to break bonds of a polymer to form it back into its monomers. 9. Define enzyme proteins that increase the speed of a chemical reaction - each enzyme connects to a specific substrate (substance the enzyme reacts with) 10. Define activation energy energy needed to start a chemical reaction 11. How does an enzyme affect the activation energy for a chemical reaction? Enzymes are catalysts that reduce the activation energy needed for a chemical reaction to take place. 12. Any factors that affect the shape of an enzyme affect the enzyme s activity. What effect does ph and temperature have on an enzymes ability to catalyze (speed up) a reaction? Enzymes work well within very specific ranges of ph and temperature. If the ph or temperature changes to outside of the range (too high or too low), the enzyme shape changes and no longer works to speed up the reaction.
5. Identify the hydrophilic and hydrophobic portions of a phospholipid. Fatty acid tail are nonpolar and hydrophobic Heads are polar and hydrophilic 6. What is the difference between active and passive transport? Passive transport does not require energy and moves down the concentration gradient from an area of high to low concentration. Active transport requires energy and moves against the gradient from low to high concentration. 7. Explain how diffusion, osmosis, and facilitated diffusion work. Diffusion Osmosis Hypertonic Hypotonic Isotonic Facilitated Diffusion a type of passive transport across membrane that does not require energy, particles move from high to low concentration a type of passive transport across membrane that does not require energy, WATER moves form area of high to low concentration Water leaves cell because less water/more solute in the solution than inside the cell Water enters cell because more water/less solute in the solution than inside the cell Water goes in and out of cell equally A type of passive transport across membranes that does not require energy, the help of a carrier protein moves particles from high to low concentration 8. Explain the types of active transport. Protein pumps (3 Na out and 2K in) use ATP to pump ions from low to high concentration or against the concentration gradient. Endocytosis uses ATP to change cell membrane to enclose particles and make it ENter the cell. Exocytosis uses ATP to change cell membrane to let particle EXit the cell. 9. Write the chemical formula for photosynthesis, aerobic cellular respiration, and anaerobic cellular respiration. C 6 H 12 O 6 ------> lactic acid + 2ATP (lactic acid fermentation anaerobic) C 6 H 12 O 6 + O 2 -------> H 2 O + CO 2 + 38 ATP (aerobic cellular respiration) C 6 H 12 O 6 ------>ethyl alcohol + 2CO 2 + 2ATP (alcohol fermentation anaerobic) Sunlight + H 2 O + CO 2 ------> C 6 H 12 O 6 + O 2 (photosynthesis)
10. Define photosynthesis: the process that captures the sunlight s energy in the chloroplast of plant cells and converts it to glucose 11. How does photosynthesis take place? a. Light energy used to break water into H and O 2 in the thylakoid of chloroplast during the light cycle. b. O 2 leaves the chloroplast. H is attached to NADP to make NADPH. c. CO 2, ATP, NADPH enter dark cycle and H combines with the C and O to make glucose. d. ADP and NADP returned to light cycle. 12. Define cellular respiration: the process that breaks down glucose to make 38 ATP for cells to use as energy 13. Describe the steps to cellular respiration: a. Glycolysis: splits glucose into pyruvic acid and release 2 ATP (happens in cytoplasm) of ALL CELLS b. Kreb s Cycle: pyruvic acid is broken down into CO 2 in mitochondria and form 2 ATP c. Electron Transport Chain: electrons from Kreb s cycle convert ADP into 34 ATP 14. How are photosynthesis and cellular respiration related? Cellular respiration is the opposite process of photosynthesis. 15. What is ATP? Label the parts. ATP is adenosine tri-phosphate and is the energy currency of the cell 16. What happens when a phosphate group is removed from ATP? Energy is released for the cell to use and ATP becomes ADP. ANATOMY and PHYSIOLOGY 1. Describe the levels of structural organization in the human body. Cells tissue organ organ system organism 2. Complete the chart with the missing information. Function: breaks down and absorbs nutrients from food, removes waste, maintains water balance, used by cells for DIGESTIVE SYSTEM Path of Food: Mouth - teeth mechanically break down food and amylase in saliva chemically breaks starch into sugar Pharynx moves clump of food to esophagus Esophagus clump moves down tube by peristalsis (squeezing of esophagus) Stomach mixes the food and pepsin breaks down the proteins to form chyme Small intestines chyme mixes with enzymes from pancreas, liver, and villi absorb nutrients
energy/repair/growth Function: transports nutrients and oxygen and hormones to cells, removes waste gallbladder to finish digestion and villi absorb nutrients from chyme Large intestines removes water from chyme Rectum removes waste Circulatory System Path of blood Heart: pumps the blood to lungs and the rest of the body Arteries: carry oxygen rich blood from the heart to the body (large) Capillaries bring nutrients and oxygen to the tissues and absorb carbon dioxide and waste Veins carries oxygen-poor blood from body back to heart Red Blood Cells carry oxygen though the body, contain the protein hemoglobin which binds oxygen in the lungs Function of Kidneys: regulate the amount of water and salt in the blood, remove waste as urine Excretory System Function of Liver: secretes bile which helps break down fats and absorb vitamins: regulates sugar levels in blood Function: move air into and out of lungs, controls gas exchange between blood and lungs, brings in oxygen from air we breathe in and releases carbon dioxide when we breathe out Respiratory System Path of oxygen/carbon dioxide: Nose filter, moisten, and warm air Pharynx controls movement of air into larynx and food into esophagus Larynx air moves through vocal cords to produce sound Trachea traps particles in air and push particles/mucus away from lungs back to pharynx Lungs divides into smaller and smaller passageways until reach alveoli Alveoli tiny air sac that provide surface area for gases to exchange, oxygen diffuses into blood from alveoli and carbon dioxide diffuses into alveoli from blood Function: collects info about body s internal and external environment, regulates behavior, maintains homeostasis, regulates organs, controls sensory and motor functions Basic Unit How does the neuron work? Neuron is made up of dendrites that receive an electrical signal which is then carried to the cell body which is then carried through the axon and passed Nervous System Major Components: Central Nervous System brain and spinal cord Peripheral Nervous System contains sensory and motor neurons Main parts: Brain control center responsible for processing and relaying information Spinal Cord main communication link between brain and rest of the body Sensory Neurons transmits info about internal and external environments to the CNS
onto the next neurons dendrites. Motor Neurons transmits impulse from the CNS to the muscles and glands Function of Muscles: help in movement of bones, contraction of heart and other organs 3 Types of Muscle Tissue & Their Function Skeletal muscles that move bones Smooth involuntary controlled like muscles that cause the stomach to contract Cardiac involuntary controlled muscles that makes heart beat Muscular/Skeleton System Function of bones: provides shape and support to the body, produce red and white blood cells in the bone marrow 2 types of connective tissue: ligaments attach bone to bone tendon attaches muscle to bone 3. The organ systems of the human body work closely together to maintain the health of the entire body. An organism who can not maintain homeostasis within all its systems will die. Explain how the nervous system, muscular system, skeletal system, and circulatory system work together to help you keep a constant body temperature when it is cold. When it is cold out, the sensory neurons (nervous system) send a signal to the spinal cord then to the brain. The brain interprets the signal and sends a message to the motor neurons. The motor neurons trigger the muscles (muscular system) in your body to shiver and the muscles contract/relax over and over again, which also causes the bones to move (skeleton system). This increases warmth in the body. The heart (circulatory system) also beats faster sending warm blood more quickly throughout the body to increase warmth. 4. What is a feedback loop? Way to maintain homeostasis when internal or external conditions change. Example: body sweats when too hot, liver stores excess glucose after a big meal and then releases the glucose when needed