Matter
Cells
Cell Metabolism
Cell Structure and Function
Human Body Systems
100
Question: An atom contains 6 protons and 8 neutrons. Identify the element and calculate its mass number. Explain how the number of protons determines the atom’s identity.
Answer: What is carbon with a mass number of 14? The atom is carbon because it has 6 protons. Its mass number is 6+8=14.
100
Question: A cell is placed in a solution containing a high concentration of salt. Explain how the cell membrane helps the cell respond to this environment.
Answer: What is selective permeability? The membrane controls which substances enter and leave the cell. Water may move out of the cell through osmosis, and the membrane helps regulate this movement to maintain homeostasis.
100
Question: Explain why cellular respiration is considered a catabolic process and identify the main usable energy molecule produced.
Answer: What is the breakdown of a larger glucose molecule into smaller molecules, releasing stored chemical energy? The primary usable energy molecule produced is ATP.
100
Question: Mitochondria have highly folded inner membranes called cristae. Explain how this structure supports their function.
Question: Mitochondria have highly folded inner membranes called cristae. Explain how this structure supports their function.
100
Question: A cut breaks through the skin. Explain how the integumentary system normally protects the body and identify two defenses that may be weakened by the injury.
Answer: What is the skin forming a physical barrier and producing substances that can inhibit pathogens? A cut can allow pathogens to enter and bypass the protective barrier. It may also reduce the effectiveness of antimicrobial secretions and immune surveillance in the damaged area.
200
Question: When an ionic compound forms between a metal and a nonmetal, describe what happens to the electrons and explain why the resulting particles attract one another.
Answer: What is the transfer of electrons from the metal to the nonmetal, forming positively and negatively charged ions? The opposite charges attract, creating an ionic compound. The transfer also gives the atoms more stable outer electron arrangements.
200
Question: Compare prokaryotic and eukaryotic cells. Explain how their structural differences affect the way cellular activities are organized.
Answer: What are prokaryotic cells lacking a nucleus and membrane-bound organelles, while eukaryotic cells contain a nucleus and specialized organelles? Eukaryotic organelles separate tasks into compartments, allowing more complex cellular organization.
200
Question: A student eats a meal containing carbohydrates, proteins, lipids, and nucleic acids. Identify the four macromolecule groups and explain why carbohydrates can provide a rapid source of energy.
Answer: What are carbohydrates, proteins, lipids, and nucleic acids? Carbohydrates can be broken down relatively quickly into glucose, which enters cellular respiration and helps produce ATP.
200
Question: A cell produces a protein that must be released outside the cell. Trace the protein’s pathway from production to secretion, naming the major structures involved.
Answer: What is ribosomes on the rough endoplasmic reticulum, followed by transport vesicles, the Golgi apparatus, secretory vesicles, and the cell membrane? The protein is synthesized, folded, modified, packaged, transported, and released by exocytosis.
200
Question: Explain how the muscular and skeletal systems work together to move a person’s arm. Include the roles of bones, joints, muscles, and tendons.
Answer: What is muscles contracting and pulling on bones through tendons at joints? Bones provide support and leverage, while joints allow movement. Opposing muscle pairs coordinate by having one muscle contract while the other relaxes.
300
Question: Carbon is found in carbohydrates, lipids, proteins, and nucleic acids. Explain how carbon’s atomic structure allows it to serve as the backbone of so many different biological molecules.
Answer: What is carbon’s ability to form four covalent bonds? Carbon can bond with other carbon atoms and with elements such as hydrogen, oxygen, nitrogen, and phosphorus, forming chains, branches, rings, and complex three-dimensional molecules.
300
Question: A virus contains genetic material but cannot reproduce without entering a host cell. Use cell theory and the characteristics of life to explain why viruses are generally not classified as living organisms.
Answer: What is that viruses are not made of cells and cannot independently perform all life processes? They require a host cell to use cellular materials and machinery for reproduction.
300
Question: Interpret the following balanced equation for cellular respiration:
Identify the reactants, products, and overall energy transformation.
Answer: What are glucose and oxygen as the reactants, and carbon dioxide, water, and ATP as the products? Chemical energy stored in glucose is transformed into usable chemical energy in ATP.
300
Question: A plant cell is placed in pure water. Explain how the cell wall and cell membrane work together to help the cell avoid bursting.
Answer: What is the cell membrane controlling water movement while the cell wall resists excessive expansion? Water may enter the cell through osmosis, but the rigid cell wall provides support and prevents the membrane from rupturing.
300
Question: After touching a hot surface, a person quickly pulls away. Describe how the nervous system coordinates this response and explain how the response helps maintain homeostasis.
Answer: What is sensory receptors detecting heat, nerves sending signals through the spinal cord, and motor neurons activating muscles? The rapid response reduces tissue damage and helps maintain the body’s internal stability.
400
Question: Using the relationship between mass and energy in E=mc2, explain why nuclear reactions can release much more energy than ordinary chemical reactions. Identify one real-world example.
Answer: What is the conversion of a small amount of mass into a very large amount of energy? Because the speed of light is squared, even a small mass difference can produce enormous energy. Examples include nuclear power plants, nuclear fusion in stars, and nuclear fission.
400
Question: Mitochondria contain their own circular DNA and have a double membrane. Explain how these features support the endosymbiotic theory.
Answer: What is evidence that mitochondria may have originated as independent prokaryotic cells that were engulfed by an ancestral eukaryotic cell? Their circular DNA, double membrane, and ability to reproduce in a bacteria-like manner support this explanation.
400
Question: Compare photosynthesis and cellular respiration by identifying the inputs, outputs, and main energy transformation in each process. Explain how the two processes are connected.
Answer: What is photosynthesis using carbon dioxide, water, and light energy to produce glucose and oxygen, while cellular respiration uses glucose and oxygen to produce carbon dioxide, water, and ATP? The products of one process serve as reactants for the other.
400
Question: A cell contains many damaged organelles and cellular waste. Explain how lysosomes help restore cellular health and predict what might happen if lysosomes stop functioning.
Answer: What are lysosomes using digestive enzymes to break down waste, worn-out organelles, and foreign materials? If they stop functioning, waste may accumulate, interfering with cell processes and potentially causing cell death.
400
Question: Compare the nervous and endocrine systems as communication systems. Explain which system would be more effective for a quick response and which would be more effective for a long-lasting change.
Answer: What is the nervous system using rapid electrical and chemical signals for short-term responses such as reflexes, while the endocrine system using hormones carried in the blood for slower, longer-lasting effects such as growth and metabolism?
500
Question: Two atoms are both carbon, but one has 6 neutrons and the other has 8 neutrons. Compare these atoms and explain why one isotope might be radioactive while the other is stable.
Answer: What are isotopes of carbon with the same number of protons but different numbers of neutrons? The isotope with an unstable neutron-to-proton ratio may undergo radioactive decay, while the other isotope may have a stable nucleus.
500
Question: A cell has damaged DNA but continues through the cell cycle. Predict two possible consequences and explain how cell-cycle checkpoints normally prevent these outcomes.
Answer: What are uncontrolled cell division or cell death? Checkpoints verify that DNA is properly copied and that chromosomes are correctly attached before division continues. If checkpoints fail, damaged cells may reproduce and contribute to cancer.
500
Question: A forest ecosystem receives less sunlight for several weeks because of heavy cloud cover. Predict how this change could affect photosynthesis, cellular respiration, and energy available to organisms in the ecosystem.
Answer: What is a decrease in photosynthesis, followed by a reduction in glucose production? Cellular respiration may continue using stored food, but producers may eventually have less chemical energy available. This can reduce the energy passed to consumers through the food web.
500
Question: Compare mitosis and meiosis in terms of the number and genetic characteristics of the resulting cells. Explain why each process is important to multicellular organisms.
Answer: What is mitosis producing two genetically identical daughter cells for growth, repair, and replacement, while meiosis produces four genetically different haploid cells used in sexual reproduction? Meiosis increases variation through processes such as crossing over and independent assortment.
500
Question: A person’s leg becomes swollen after fluid accumulates in the tissues. Explain how the lymphatic and circulatory systems normally work together to prevent this condition and support immune defense.
Answer: What is the lymphatic system collecting excess tissue fluid and returning it to the bloodstream? Lymph nodes filter the fluid and contain immune cells that identify pathogens. Together, the systems maintain fluid balance and help protect the body from disease.