Key Bio Paper 1 Notes

What is the key difference between diffusion and osmosis?

Diffusion is movement of particles; osmosis is movement of water through a partially permeable membrane.

Is energy made during respiration?

No; energy is released, not created, during respiration.

Does Benedict’s test for glucose require heating?

Yes; you must heat Benedict’s solution for a correct result.

Are chloroplasts whole cells?

No; chloroplasts are organelles found in plant cells, not entire cells.

Do enzymes die when they denature?

No; they change shape and stop working, but they do not die.

What direction does xylem and phloem transport materials?

Xylem moves water up; phloem moves food up and down.

Xylem description

Made of dead cells, hollow space, walls made of strong lignin (impermeable to water)

Respiration VS Breathing

No; respiration is cellular energy release, breathing is ventilation.

Are enzymes general or specific?

Specific; each enzyme fits only one substrate (lock and key model).

What’s the difference between arteries and veins?

Arteries: thick walls, high pressure, away from heart. Veins: thin walls, valves, to the heart.

Do red blood cells have a nucleus?

No; mature red blood cells have no nucleus to carry more haemoglobin.

What is the difference between a gene and a chromosome?

Gene: a DNA section coding for a protein. Chromosome: a long strand of DNA with many genes.

Does vaccination only involve antibodies?

No; long-term immunity also depends on memory cells.

Does anaerobic respiration in animals produce alcohol?

No; animals produce lactic acid, not alcohol (which happens in yeast).

What must be included in the definition of osmosis?

Movement of water through a partially permeable membrane.

Where does respiration happen in the cell?

In the mitochondria.

What’s the difference between genotype and phenotype?

Genotype is the genetic makeup (e.g., Bb), phenotype is the physical trait (e.g., brown eyes).

Can food chains start with animals?

No; they must start with a producer (like a plant or algae).

Is energy recycled in ecosystems?

No; energy flows through and is lost as heat. Only nutrients are recycled.

Is CO₂ a waste product in photosynthesis?

No; CO₂ is used in photosynthesis to make glucose.

What causes genetic vs environmental variation?

Genetic variation is inherited; environmental variation is due to surroundings or lifestyle.