COMBINED BIOLOGY PAPER 1 ASSORTED QUESTIONS

What is the role of hemoglobin in oxygen transport?

Hemoglobin binds to oxygen in red blood cells and transports it to body cells.

What is the pathway of blood through the heart in double circulatory system?

Deoxygenated blood enters right atrium, goes to right ventricle, lungs, oxygenated blood returns to left atrium, then left ventricle, and out to the body.

List the factors that affect the rate of photosynthesis.

Light intensity, temperature, and carbon dioxide concentration.

What additional organelles do plant cells contain that animal cells do not?

Chloroplasts and a permanent vacuole.

What is the inverse square law relating to light intensity?

Light intensity decreases proportionally to the square of the distance from the light source.

How is the actual size of a cell calculated using a microscope?

Actual size = Image size divided by magnification.

What are the main functions of the digestive enzymes amylase, protease, and lipase?

Amylase breaks down starch into sugars; protease breaks down proteins into amino acids; lipase breaks down fats into glycerol and fatty acids.

Describe the process of bacterial reproduction via binary fission.

Bacteria replicate by duplicating genetic material, dividing, and splitting into two identical cells.

What are the components of blood and their functions?

Plasma transports substances; red blood cells carry oxygen; white blood cells fight infection; platelets help blood clot.

What are the products of anaerobic respiration in muscles?

Lactic acid and a small amount of energy.

What are the components of blood and their functions?

Blood contains plasma, red blood cells (oxygen transport), white blood cells (immune response), and platelets (clotting).

What is mitosis and what are its key stages?

Mitosis is cell division where genetic material duplicates, chromosomes separate, and two identical nuclei form.

How does vaccination provide immunity?

Vaccination exposes the immune system to a dead or inert pathogen, prompting it to produce specific antibodies and memory cells for future protection.

What factors limit the rate of photosynthesis?

Temperature (enzymes denature), light intensity, and CO₂ concentration; any of these can be limiting factors.

What is the difference between a benign and malignant tumor?

Benign tumors do not spread; malignant tumors invade other tissues and spread.

What factors increase the rate of transpiration in plants?

Higher temperature, increased air movement, and decreased humidity increase transpiration by accelerating water evaporation from leaves.

Describe the structure and function of alveoli in the respiratory system.

Alveoli are air sacs with large surface area where oxygen diffuses into blood.

How is the rate of photosynthesis practically measured?

By measuring the volume of oxygen produced by pondweed under different light conditions.

What is the function of white blood cells in fighting infections?

White blood cells produce antibodies and antitoxins, and engulf pathogens to eliminate them.

How do pathogens such as viruses, bacteria, and fungi infect humans?

Viruses enter and replicate inside cells; bacteria produce toxins and invade tissues; fungi infect skin or tissues.

What is the purpose of enzymes in biological reactions?

Enzymes act as catalysts, speeding up chemical reactions without being consumed.

How does temperature affect enzyme activity?

Enzyme activity increases with temperature until enzymes denature at high temperatures, reducing activity.

How do tissues, organs, and organ systems relate?

Tissues are groups of similar cells, organs are made of tissues, and organ systems are groups of organs working together.

How does vaccination confer immunity?

By introducing a dead or inert pathogen to stimulate the immune system to produce antibodies and memory cells.

How do pathogens such as viruses and bacteria cause illness?

Viruses reproduce inside host cells causing damage; bacteria release toxins and damage cells; fungi can infect tissues; protists can burrow into cells and produce toxins.

What is active transport and when does it occur?

Active transport uses energy to move substances against a concentration gradient, like mineral ions into root hair cells.

What is the significance of the thicker walls of the left ventricle?

Thicker walls enable the left ventricle to pump blood with enough force to reach the entire body.

What is the inverse square law in relation to light intensity?

Light intensity decreases proportionally to the square of the distance from the light source.

What are the main factors that increase the rate of diffusion and osmosis?

Higher concentration gradient, increased temperature, and larger surface area.

What is the lock and key principle in enzyme function?

Substrates must have a specific shape to fit into the enzyme's active site for the reaction to occur.

What is the role of bile in digestion?

Bile neutralizes stomach acid and emulsifies fats, increasing their surface area for enzyme action.

What are the differences between benign and malignant tumors?

Benign tumors don't spread and are easier to treat; malignant tumors invade surrounding tissue and spread through the body.

Define metabolism in biological systems.

The sum of all chemical reactions occurring in a cell or organism.

What is the relationship between light intensity and distance from a light source?

Light intensity follows an inverse square law: doubling the distance quarters the light intensity.

What is the primary function of mitochondria in cells?

Site of respiration, providing energy for cellular processes.

What is photosynthesis and its balanced chemical equation?

Photosynthesis is the process where plants convert light energy into chemical energy: 6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂.

What is monoclonal antibody therapy used for?

Monoclonal antibodies are used to treat diseases, diagnose conditions, and detect molecules in tissues.

What is the purpose of stem cells in plants and animals?

Stem cells are undifferentiated cells capable of becoming specialized to produce new cells for growth, repair, or specific functions.

What is the function of the xylem and phloem in plants?

Xylem transports water upwards; phloem transports sugars and food throughout the plant.

What is the purpose of vaccines?

Vaccines stimulate the immune system to produce memory cells against specific pathogens, providing immunity.

What is the primary difference between eukaryotic and prokaryotic cells?

Eukaryotic cells have a nucleus where DNA is stored, while prokaryotic cells do not have a nucleus.

What is the role of guard cells in regulating gas exchange?

Guard cells control the size of the stomata, opening them to allow gas exchange and closing them to reduce water loss.

What is the lock and key principle in enzyme function?

Substrates fit into the active site of enzymes like a key fitting a lock, enabling specific reactions.

Write the balanced chemical equation for photosynthesis.

6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂.

What are monoclonal antibodies and their uses?

Monoclonal antibodies are clones of cells that produce specific antibodies, used for treating diseases, diagnosis, pathogen detection, and tissue marking.

What role do white blood cells play in immune response?

White blood cells produce antibodies and antitoxins, and destroy pathogens through phagocytosis.

What is the function of bile in digestion?

Bile neutralizes stomach acid and emulsifies fats to increase enzyme efficiency.

What are the main organelles found in both animal and plant cells?

Cell membrane, cytoplasm, mitochondria, and ribosomes.

How do white blood cells produce antibodies?

They produce specific antibodies that bind to antigens on pathogens, neutralizing them and marking them for destruction.

What are the main functions of xylem and phloem in plants?

Xylem transports water upwards; phloem transports sugars and nutrients throughout the plant.

What is the purpose of bile in digestion?

Bile neutralizes stomach acid and emulsifies fats to increase surface area for enzyme action.

What is the main function of phloem in plants?

Phloem transports sugars, food, and sap in both directions throughout the plant (translocation).

How can the rate of photosynthesis be practically measured?

By submerging pondweed in an inverted measuring cylinder and measuring the volume of oxygen produced over time.

How do arteries differ structurally from veins?

Arteries have thicker walls and a thinner lumen to withstand higher pressure, whereas veins have thinner walls, a wider lumen, and contain valves to prevent backflow.

What is the main function of xylem in plants?

Xylem transports water and mineral ions from the roots to the leaves in one direction.

How does temperature affect enzyme activity?

Enzyme activity increases with temperature until the enzyme denatures at an optimum temperature.

How does vaccination provide immunity?

Vaccination introduces dead or inactive pathogens to stimulate antibody production and memory cell formation.

What are the products of photosynthesis used for in the plant?

Glucose is used for respiration, stored as starch or fat, or used to make cellulose and amino acids.

What is the function of guard cells in leaves?

They control the size of stomata to regulate gas exchange and water loss.

What are the products of anaerobic respiration in muscles?

Lactic acid, which can cause muscle fatigue and soreness.

What is the role of guard cells in leaf gas exchange?

Guard cells control the opening and closing of stomata to regulate gas exchange and water loss.

What is the balanced chemical equation for photosynthesis?

6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂.

What is the role of the xylem and phloem in plant transport?

Xylem transports water and minerals upward; phloem transports sugars and nutrients bidirectionally.

What is the purpose of enzymes in biological reactions?

Enzymes act as biological catalysts, speeding up reactions by lowering activation energy.

What is the role of the valves between the atria and ventricles?

Valves prevent backflow of blood from the ventricles into the atria during heart contraction.

How is the rate of photosynthesis measured practically?

By measuring the volume of oxygen produced by pondweed under different light conditions over time.

How do pathogens like bacteria and fungi cause disease?

They produce toxins, damage tissues, or reproduce within the host, leading to illness.

What is the pathway of blood through the heart in a double circulatory system?

Deoxygenated blood enters the right atrium via the vena cava, passes to the right ventricle, is pumped to the lungs via the pulmonary artery for oxygenation, returns through the pulmonary vein to the left atrium, moves into the left ventricle, and is then pumped out to the body through the aorta.

What is the function of the coronary artery?

The coronary artery supplies oxygen-rich blood to the heart muscle itself.

What is aerobic respiration and its chemical equation?

Respiration with oxygen, represented by: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy.

What are the main products of anaerobic respiration in muscles?

Lactic acid, which causes muscle fatigue and soreness.

What is the function of white blood cells in immune response?

White blood cells produce antibodies and antitoxins, and phagocytes ingest and destroy pathogens.

What are the main digestive enzymes and their functions?

Amylase breaks down starch into glucose; proteases break down proteins into amino acids; lipases break down fats into glycerol and fatty acids.

What is the process of mitosis?

Mitosis involves duplication of genetic material, breakdown of the nucleus, separation of chromosome pairs, and formation of two identical nuclei, resulting in two identical daughter cells.

What are fermentation products in yeast and plant cells?

Ethanol and carbon dioxide, used in baking and alcohol production.

What factors increase the rate of transpiration in plants?

Higher temperature, lower humidity, increased air movement, and increased wind speed.

What is the inverse square law as it relates to light intensity?

Light intensity is inversely proportional to the square of the distance from the light source.

How is the rate of photosynthesis measured in practical experiments?

By measuring the volume of oxygen produced or the rate of bubble formation from pondweed.

How does vaccination provide immunity against diseases?

Vaccines stimulate the immune system to produce memory cells, enabling quick response to future infections.

What is the function of stomata and guard cells in leaves?

Stomata allow gas exchange; guard cells regulate stomatal opening and closing to control water loss.

What does it mean for a variable to be limiting in a graph of reaction rate?

A variable is limiting when increasing other variables does not increase the reaction rate because the limiting variable constrains it.

How do bacterial cells reproduce?

By binary fission, dividing into two identical cells.

What are the limiting factors of photosynthesis?

Light intensity, carbon dioxide concentration, and temperature.

What is the main function of the phloem in plants?

Transport sugars and food produced by photosynthesis throughout the plant.

What is the purpose of monoclonal antibodies?

They are used in disease treatment, diagnosis, and targeting specific molecules in tissues.

What is the function of white blood cells in fighting infections?

White blood cells produce antibodies, phagocytose pathogens, and produce antitoxins.

How do viruses infect humans?

Viruses reproduce inside host cells by injecting genetic material, causing cell damage and disease.

What is the lock and key principle in enzyme activity?

Enzymes have specific active sites that only fit particular substrates, enabling specific reactions.

What happens during anaerobic respiration in muscles?

Glucose is converted into lactic acid, releasing less energy and causing muscle ache during intense exercise.

What is the role of stomata and guard cells in leaf gas exchange?

Stomata allow gases to enter and exit; guard cells regulate their opening and closing.

What is the main function of the xylem in plants?

Transport water and mineral ions from roots to leaves.

What is mitosis and its main stages?

Cell division where genetic material duplicates, and chromosomes are separated to form two identical nuclei.