| Feature | Xylem | Phloem |
|---------|-------|--------|
| Transport | water & minerals | sucrose & amino acids |
| Direction | upward only | up & down (translocation) |
| Living cells? | no (dead tubes) | yes (sieve tubes + companion cells) |
| Wall type | lignified (strong) | cellulose |
Transpiration – loss of water vapour from leaves
| Feature | Animal Cell | Plant Cell | Function | | :--- | :--- | :--- | :--- | | Cell Wall | Absent | Present (Cellulose) | Provides structural support and rigidity. | | Chloroplasts | Absent | Present | Site of photosynthesis (contains chlorophyll). | | Vacuole | Small or absent | Large, central | Stores cell sap; maintains turgor pressure. | | Shape | Irregular | Fixed, regular shape | N/A | biology o level 5090 notes better
| Enzyme | Produced In | Site of Action | Substrate | Product | | :--- | :--- | :--- | :--- | :--- | | Amylase | Salivary glands, Pancreas | Mouth, Small Intestine | Starch | Maltose (then Glucose) | | Protease (Pepsin/Trypsin) | Stomach, Pancreas | Stomach, Small Intestine | Proteins | Amino Acids | | Lipase | Pancreas | Small Intestine | Fats (Lipids) | Fatty Acids & Glycerol |
O Level Biology 5090 has a practical paper (Paper 5) or Alternative to Practical (Paper 6). Most theory notes ignore this. Better notes dedicate a separate section. | Feature | Xylem | Phloem | |---------|-------|--------|
| Organ | Waste removed | |-------|----------------| | Lungs | CO₂ (from respiration) | | Kidneys | Urea (from protein breakdown), excess water, salts → urine | | Skin (sweat) | Water, salts, small urea |
Most students confuse aerobic and anaerobic. Your better notes should include: | Feature | Animal Cell | Plant Cell
Then add two exam-only notes (rare in textbooks):
Why this is better: You now understand the why, not just the what. Paper 2 and 3 (Alternative to Practical) love asking for explanations, not just equations.
| Organ | Function | |-------|----------| | Mouth | Teeth (mechanical), amylase (starch → maltose) | | Oesophagus | Peristalsis (wave-like muscle contraction) | | Stomach | Pepsin (protein → peptides), HCl (kills bacteria, denatures protein, activates pepsin) | | Small intestine (duodenum) | Pancreatic amylase, trypsin, lipase; bile (emulsifies fat) | | Small intestine (ileum) | Villi & microvilli → absorption of glucose, amino acids, fatty acids | | Large intestine | Water absorption → faeces formation |