biology ffs

1. ⭐ What should you label on plant and animal cell diagrams

Plant cell labels: cell wall, cell membrane, cytoplasm, nucleus, mitochondria, ribosomes, chloroplasts and large permanent vacuole. Animal cell labels: cell membrane, cytoplasm, nucleus, mitochondria and ribosomes.

Label an Artery & Vein

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Label the Heart

2. What is the function of each organelle in plant and animal cells

Nucleus contains DNA; membrane controls movement; mitochondria release energy in respiration; ribosomes make proteins. Cellulose wall supports; chloroplast chlorophyll absorbs light; vacuole contains cell sap and helps keep the cell firm.

3. How is a model cell similar to and different from a real cell

A model represents selected structures, but may not show true scale, complexity, movement, interactions or every organelle. Real cells are three-dimensional and their structures interact.

4. How do prokaryotic and eukaryotic cells differ

Prokaryotic cells are smaller and have no nucleus; their circular DNA is free in the cytoplasm and they may have plasmids. Eukaryotic cells have a nucleus and membrane-bound organelles.

Label A Bacterial Cell

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Label a red blood cell.

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Label a White Blood Cell.

Label a Platelet.

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Label a Plasma Cell.

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6. How should you obtain results independently while noting major hazards

Follow the method, use apparatus correctly, identify hazards and precautions, control variables, measure carefully, record results clearly and repeat when appropriate.

7. ⭐ What parts of a light microscope should you label, and what are they for

Label the eyepiece lens, body tube, objective lenses, stage, light source, diaphragm, arm, base and coarse- and fine-focus knobs. Eyepiece/objectives magnify; the stage holds the slide; the light source illuminates; the diaphragm controls light; the focus knobs sharpen the image.

⭐ What parts of an electron microscope should you label, and what are they for

An electron microscope should be labeled with its electron gun, electromagnetic lenses (condenser, objective, projector), specimen stage, fluorescent screen, and vacuum system. These components generate a tightly focused electron beam, pass it through or across a sample in an air-free chamber, and project the magnified data onto a digital detector or viewing screen.

8. Why are stains used to view cells

Many cell structures are transparent. A stain increases contrast so structures and their boundaries are easier to see.

9. ⭐ What rules should you follow when drawing a cell, and how do you calculate magnification

Draw with clear single lines, no shading, correct proportions and straight label lines. Magnification = image size ÷ actual size. Convert both measurements to the same units first.

10. How has electron microscopy improved understanding of cells

Its much higher resolution reveals smaller sub-cellular structures and finer detail that a light microscope cannot distinguish.

11. What advantages does an electron microscope have over a light microscope

It has higher magnification and resolution, so smaller structures can be seen as separate details. Electron microscopes require a vacuum and cannot observe living specimens.

12. How do you compare microscope resolution limits in standard form

Convert both values to the same units, divide the light-microscope resolution limit by the electron-microscope limit, then express the ratio in standard form.

How do temperature and pH affect enzyme activity?

Increasing temperature increases the rate until the optimum temperature is reached. Above the optimum, the enzyme’s active site changes shape, so the substrate no longer fits properly. Extreme pH can also denature an enzyme.

13. ⭐ What are the three parts you should label on a DNA nucleotide

Label the phosphate group, deoxyribose sugar and nitrogen-containing base (A, T, C or G).

How do you test food samples for biological molecules?

Reducing sugars: add Benedict’s solution and heat in a water bath. Blue changes to green, yellow, orange or brick-red. Starch: add iodine; orange-brown turns blue-black. Protein: add Biuret reagent; blue turns lilac or purple. Lipids: add ethanol, then water; a cloudy white emulsion indicates lipids.

14. What is the role of a gene

A gene is a section of DNA with a particular base sequence that provides instructions for a protein and can influence a characteristic.

15. How do you manipulate experimental apparatus appropriately and independently

Choose suitable apparatus, assemble and use it correctly, take measurements at suitable precision, control variables, follow the method and observe safety precautions.

16. What is the structure of an enzyme

An enzyme is a protein folded into a specific three-dimensional shape. Its active site has a shape complementary to its substrate.

17. How does an enzyme work

Substrate binds to the active site → enzyme–substrate complex forms → reaction occurs → products leave; the enzyme remains unchanged and can be reused.

18. ⭐ What structures and stages should you label in a diagram of enzyme action

Know the stages: the substrate binds to the enzyme active site, an enzyme-substrate complex forms, the reaction occurs, and products leave. Label the enzyme, active site, substrate, complex and products. The enzyme remains unchanged.

19. How are carbohydrates, proteins and lipids built and broken down

Condensation joins smaller molecules and releases water; hydrolysis uses water to split molecules. Sugars build carbohydrates, amino acids build proteins, and glycerol plus fatty acids build many lipids.

20. How are metabolic rate, activity and food intake related

Activity usually raises energy demand and metabolic rate, so more energy-containing food may be required. Needs also vary with age, body size, growth and other factors.

21. How do you use scientific vocabulary and definitions accurately

Use precise biological terms, define them correctly, link each term to the process being explained, and write clear sentences with correct spelling and meaning.

22. What is the balanced chemical equation for aerobic respiration

Glucose + oxygen → carbon dioxide + water. Symbol equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O.

23. Why is aerobic respiration an exothermic reaction

It transfers energy from glucose to the cell for biological processes; some energy is released to the surroundings as heat.

24. How do you plot a suitable line graph from experimental data

Put the independent variable on the x-axis and dependent variable on the y-axis; label axes with units, choose an even sensible scale, plot points accurately and draw an appropriate line.

25. What is the word equation for anaerobic respiration in muscles

Glucose → lactic acid. It releases less energy per glucose molecule than aerobic respiration.

26. How does anaerobic respiration differ in muscles and yeast

Muscle cells produce lactic acid. Yeast produces ethanol and carbon dioxide (fermentation). Both release energy without oxygen.

27. How do you collect accurate measurements independently in an experiment

Use appropriate calibrated equipment, read scales consistently, keep control variables constant, repeat measurements, calculate a mean and identify anomalies.

28. What is the balanced equation for photosynthesis

Carbon dioxide + water → glucose + oxygen, using light energy. Symbol equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.

29. Why is photosynthesis an endothermic reaction

It absorbs light energy from the surroundings and transfers it into chemical energy stored in glucose.

30. ⭐ What should you label in a diagram of photosynthesis

Labels to know: leaf, chloroplasts/chlorophyll, light energy, carbon dioxide entering, water supplied from roots, glucose produced and oxygen released.

31. How do you use the starch test to investigate whether photosynthesis occurred

Destarch plant in darkness; expose it to the test condition; remove leaf; boil leaf in water; heat it in ethanol in a hot-water bath; rinse; add iodine. Blue-black shows starch; orange-brown shows no starch.

32. How do you carry out a photosynthesis practical safely

Follow the method and wear eye protection as directed. Take care with hot water and glassware. Heat ethanol in a water bath, away from a naked flame, because ethanol is flammable.

33. How do you draw a valid conclusion from photosynthesis observations

Describe the results, compare the relevant conditions and use evidence to decide whether starch was made, explaining what this suggests about photosynthesis.

34. How do light intensity, carbon dioxide concentration and temperature affect photosynthesis rate

Increasing light intensity or CO₂ increases rate until another factor limits it. Increasing temperature raises rate to an optimum; above it, enzymes lose function and the rate falls.

35. How do you calculate a class mean

Add all valid measurements together and divide by the number of valid measurements. Exclude a result only when there is a justified reason to treat it as anomalous.

36. How can practical difficulties affect repeatability

Changing light, temperature, timing, plant condition, leaks or inconsistent measurements can make repeated results differ. Standardise conditions and repeat trials.

37. What is a limiting factor in photosynthesis

A factor in shortest supply that restricts the rate, such as light intensity, carbon dioxide concentration or temperature.

How do you investigate the effect of solution concentration on potato mass?

Cut equal-sized potato pieces and measure their initial masses. Place them in different solution concentrations for the same time. Remove and blot them consistently, then measure their final masses. Calculate percentage change in mass: (change in mass ÷ initial mass) × 100.

38. How do you calculate relative light intensity using the inverse-square law

Relative light intensity ∝ 1 ÷ distance². If distance doubles, relative intensity becomes one quarter; if distance triples, it becomes one ninth.

39. How can light intensity, carbon dioxide and temperature be controlled in an experiment

Change one independent variable at a time. Keep the others constant, for example by fixing lamp distance, controlling CO₂ supply and using a monitored water bath.

40. What is diffusion

The net movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient.

41. Which factors affect the rate of diffusion

A steeper concentration gradient, higher temperature, larger surface area and shorter diffusion distance generally increase the rate.

42. How would you explain diffusion in a structured scientific paragraph

Define diffusion, state that particles move down a concentration gradient, then explain how the relevant temperature, gradient, surface-area or distance factor affects the rate.

43. What is osmosis

The net movement of water molecules through a partially permeable membrane from a more dilute solution (higher water concentration) to a more concentrated solution (lower water concentration).

44. Why does osmosis occur

A difference in water concentration exists across a partially permeable membrane, so water moves down its concentration gradient until the difference is reduced.

45. Which key terms must appear in an accurate explanation of osmosis

Water molecules; partially permeable membrane; net movement; from higher water concentration to lower water concentration.

46. Give examples of active transport in plants and animals.
Root hair cells absorb mineral ions from dilute soil. Cells in the small intestine can absorb nutrients against a concentration gradient.

Root hair cells absorb mineral ions from dilute soil. Cells in the small intestine can absorb nutrients against a concentration gradient.

47. How does active transport move substances

Carrier proteins move substances against a concentration gradient, from lower to higher concentration, using energy released by respiration.

48. How do you calculate percentage change in mass

Percentage change = (change in mass ÷ starting mass) × 100. Change = final mass − starting mass. A negative answer means mass decreased.

Should you ignore this?

Yes

50. What happens during mitosis

The replicated chromosomes are separated into two nuclei, each receiving the same genetic information and chromosome number as the original nucleus.

51. How can a model represent the key events of the cell cycle

The cell cycle includes growth, DNA replication, chromosome separation during mitosis and cell division. It ends with two genetically identical daughter cells.

52. Why do cells become differentiated

They become specialised, developing structures that enable them to perform particular functions within an organism.

53. How are specialised cells adapted to their functions

Sperm: tail and many mitochondria. Root hair: large surface area. Red blood cell: haemoglobin, biconcave shape and no nucleus. Palisade cell: many chloroplasts.

54. How do you summarise information about a specialised cell accurately

Name the cell, identify a structural feature and link it directly to the function it helps the cell perform.

Describe the structure of an artery and explain how it is adapted to its function.

Arteries have thick walls containing muscle and elastic fibres, and a relatively narrow lumen. The thick walls withstand high blood pressure. Elastic fibres stretch and recoil, helping maintain blood flow.

Describe the structure of a vein and explain how it is adapted to its function.

Veins have thinner walls with less muscle and elastic tissue, a wider lumen and valves. Blood travels at relatively low pressure. The wide lumen reduces resistance, and valves prevent backflow.

Draw and label cross-sections of an artery, vein and capillary.

55. What is the difference between a stem cell and a differentiated cell

A stem cell can divide and develop into different specialised cell types. A differentiated cell has a specialised structure and function.

56. What is the function of stem cells

They divide to make more cells and can differentiate into specialised cells for growth, development and tissue repair.

57. How should scientific sources support an opinion about stem cells

Use relevant, reliable scientific sources; distinguish established treatments from experimental research; compare benefits, risks and ethical concerns; support claims with evidence.

58. ⭐ What should you label on an alveolus, and what makes its exchange surface efficient

For an alveolus, label the thin wall, moist lining, large surface area and surrounding capillary. Efficient exchange surfaces have a large area, a thin barrier and good blood supply or ventilation to maintain a concentration gradient.

59. How do you calculate surface-area-to-volume ratio

Calculate surface area and volume, then divide surface area by volume. Example: SA = 24 cm² and volume = 8 cm³, so SA:V = 3:1.

60. How do you interpret observations and data from an exchange-surface experiment

Identify the pattern, quote supporting measurements, compare conditions and use biological ideas such as surface-area-to-volume ratio and diffusion distance to explain it.

61. ⭐ What should you label in a double-circulatory-system diagram

Know the structures and vessels: body, vena cava, right side of the heart, pulmonary artery, lungs, pulmonary vein, left side of the heart and aorta. Pulmonary circulation is heart to lungs and back; systemic circulation is heart to body and back.

62. What is the structure of the blood and the main blood vessels

Blood contains plasma, red blood cells, white blood cells and platelets. Arteries have thick muscular elastic walls; veins have thinner walls and valves; capillaries have walls one cell thick.

63. How would you describe the circulatory system using precise vocabulary

Use pulmonary circulation (heart to lungs and back) and systemic circulation (heart to body and back). Explain how the two circuits keep oxygenated and deoxygenated blood separate.

64. What are the functions of the main components of blood

Red blood cells carry oxygen using haemoglobin; white blood cells defend against pathogens; platelets help blood clot; plasma transports cells, nutrients, hormones, CO₂ and urea.

65. ⭐ What is the route of blood through the heart, and which parts should you label

Blood travels from the body through the vena cava to the right atrium, right ventricle and pulmonary artery, then to the lungs. It returns through the pulmonary vein to the left atrium and left ventricle, then leaves through the aorta. Valves prevent backflow; the left ventricle has a thicker wall.

66. What are the functions of the main heart structures

Atria receive blood; ventricles pump blood out; valves prevent backflow; the septum separates the two sides; coronary arteries supply the heart muscle with oxygenated blood.

67. What is the function and distribution of xylem

Xylem forms vessels distributed through roots, stems and leaves. It transports water and mineral ions mainly from roots to leaves and its lignified walls provide support.

68. What is the function and distribution of phloem

Phloem forms sieve tubes with companion cells in plant vascular tissue. It translocates dissolved sugars from sources, such as leaves, to sinks, such as roots, fruits and growing tissues.

69. ⭐ What should you label on a plant transport diagram

Label roots, stem, leaves, xylem and phloem. Xylem transports water and mineral ions mainly upwards from roots to leaves. Phloem translocates dissolved sugars from sources, such as leaves, to sinks, such as roots, fruits and growing tissues.

70. What is the transpiration stream

Water evaporates from leaf cells and diffuses out through stomata. This creates a pull that moves water up the xylem from roots to leaves.

71. ⭐ What parts should you label on a stoma

Label the two guard cells, stomatal pore and surrounding epidermal cells. Guard cells change shape to open or close the pore.

72. How do you explain observations from transpiration experiments

Relate changes in water uptake or bubble movement to transpiration rate. Explain the effects of light, temperature, humidity and air movement, while considering other possible causes.

73. How do environmental factors affect transpiration rate

More light, higher temperature and greater air movement usually increase transpiration. Higher humidity usually decreases it by reducing the water-vapour concentration gradient.

74. ⭐ What parts should you label on a potometer diagram

Label the leafy shoot, airtight seal/connector, water-filled capillary tube, air bubble, scale and water reservoir. Cut the shoot underwater, assemble the apparatus airtight and measure bubble movement over time. A potometer measures water uptake, not water loss directly.

75. What limitations of a potometer can affect results

It measures water uptake, not water loss directly. Leaks, air bubbles, changes in shoot condition and uncontrolled environmental factors affect accuracy; repeat trials and standardise conditions.

How does the skin control body temperature?

When too hot, sweating increases heat loss and skin blood vessels widen (vasodilation). When too cold, sweating decreases, skin blood vessels narrow (vasoconstriction), and muscles shiver to generate heat.

76. ⭐ What structures should you label along a nervous response pathway

Know the pathway: a stimulus is detected by a receptor; a sensory neurone carries the impulse to the central nervous system (CNS); a relay neurone passes it on; a motor neurone carries it to an effector (muscle or gland); the effector produces a response.

How do the kidneys help maintain water balance?

The kidneys adjust how much water is reabsorbed into the blood, changing urine volume and concentration. Dehydration generally produces a smaller volume of more concentrated urine.

77. ⭐ How do you identify the three neurone types and their labelled structures

Sensory neurone: carries impulses from receptor to CNS. Relay neurone: connects neurones within the CNS. Motor neurone: carries impulses from CNS to an effector. Where shown, label the cell body, nucleus, dendrites, axon, myelin sheath and nerve endings.

What is the role of ADH in controlling water balance?

ADH increases the permeability of kidney collecting ducts to water, causing more water to be reabsorbed into the blood. More ADH produces less, more concentrated urine; less ADH produces more, dilute urine.

78. Why can measured reaction times differ

Reaction time varies with attention, anticipation, fatigue, practice, distractions and individual differences. The impulse travels from receptor through neurones and CNS to an effector; measurement method also affects results.

79. ⭐ What parts should you label in a reflex arc

Know the order: stimulus, receptor, sensory neurone, relay neurone in the spinal cord/CNS, motor neurone, effector and rapid response. Label each part and the direction of the nerve impulse.

80. How does a reflex action differ from a voluntary action

A reflex is rapid, automatic and reduces harm; it is coordinated through a reflex pathway. A voluntary action is consciously chosen and involves conscious processing by the brain.

81. How could you investigate the iris reflex safely

Compare pupil size in bright and dim light, changing one condition at a time. Do not shine intense light into eyes. Use consistent distances and timing, record observations and repeat.

82. How does a hormone reach its target organ

An endocrine gland releases a hormone into the bloodstream. It travels in blood and affects target cells with receptors for that hormone.

83. What are the roles of insulin, glucagon, adrenaline and thyroxine

Insulin lowers blood glucose; glucagon raises it. Adrenaline prepares the body for fight or flight. Thyroxine helps control metabolic rate and supports growth and development.

84. How should you describe hormone action accurately

Name the gland, hormone, target organ or cells, and effect. Explain the sequence clearly and use terms such as bloodstream, receptor and target cell.