GCSE Biology - Detailed Key Points PDF

\#\#\# \*\*GCSE Biology -- Detailed Key Points\*\* \-\-- \#\# \*\*1. Plant Nutrients\*\* \#\#\# \*\*Essential Nutrients & Functions:\*\* Plants require \*\*mineral ions\*\* from the soil for healthy growth. The most important ones are: \- \*\*Nitrate (NO₃⁻)\*\* \- Needed to make \*\*amino acid...

\#\#\# \*\*GCSE Biology -- Detailed Key Points\*\* \-\-- \#\# \*\*1. Plant Nutrients\*\* \#\#\# \*\*Essential Nutrients & Functions:\*\* Plants require \*\*mineral ions\*\* from the soil for healthy growth. The most important ones are: \- \*\*Nitrate (NO₃⁻)\*\* \- Needed to make \*\*amino acids\*\* → proteins \- Essential for \*\*growth\*\* and \*\*cell repair\*\* \- \*\*Deficiency\*\*: Stunted growth, yellow older leaves \- \*\*Phosphate (PO₄³⁻)\*\* \- Needed for \*\*DNA, ATP\*\*, and \*\*cell membranes\*\* \- Important for \*\*root growth\*\* \- \*\*Deficiency\*\*: Poor root development, purple leaves \- \*\*Potassium (K⁺)\*\* \- Helps \*\*enzyme activity\*\* in photosynthesis & respiration \- Maintains \*\*stomatal function\*\* \- \*\*Deficiency\*\*: Yellow leaves with brown spots, weak stems \- \*\*Magnesium (Mg²⁺)\*\* \- Needed to make \*\*chlorophyll\*\* for photosynthesis \- \*\*Deficiency\*\*: Leaves turn \*\*yellow\*\* (chlorosis) \-\-- \#\# \*\*2. Digestion in Humans -- Proteins, Lipids & Carbohydrates\*\* \#\#\# \*\*Key Digestive Enzymes & Their Functions\*\* \| \*\*Nutrient\*\* \| \*\*Enzyme\*\* \| \*\*Breakdown Product\*\* \| \*\*Where it Works\*\* \| \|\-\-\-\-\-\-\-\-\-\-\-\-\--\|\-\-\-\-\-\-\-\-\-\-\--\|\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--\|\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--\| \| \*\*Proteins\*\* \| Pepsin (stomach), Protease (small intestine) \| Amino acids \| Stomach & Small Intestine \| \| \*\*Lipids (fats)\*\* \| Lipase \| Fatty acids + Glycerol \| Small Intestine \| \| \*\*Carbohydrates\*\* \| Amylase → Maltase \| Glucose \| Mouth, Small Intestine \| \#\#\# \*\*Digestive Process by Organ:\*\* 1\. \*\*Mouth:\*\* \- \*\*Amylase\*\* (saliva) starts breaking \*\*starch\*\* → maltose \- Chewing increases surface area 2\. \*\*Stomach:\*\* \- Contains \*\*HCl (pH 2)\*\* to kill bacteria and provide optimal pH for \*\*pepsin\*\* \- Pepsin starts \*\*protein digestion\*\* 3\. \*\*Small Intestine (Duodenum & Ileum):\*\* \- \*\*Bile (from liver)\*\* neutralizes stomach acid & emulsifies fats \- \*\*Pancreatic enzymes\*\* break down proteins, carbs, and lipids \- Absorption of nutrients occurs in the \*\*ileum\*\* \-\-- \#\# \*\*3. Absorption in Humans -- Peristalsis & Small Intestine\*\* \#\#\# \*\*Peristalsis:\*\* \- \*\*Definition:\*\* Wave-like \*\*muscle contractions\*\* in the oesophagus and intestines \- Moves food \*\*from mouth to stomach\*\* and through intestines \#\#\# \*\*Small Intestine Adaptations for Absorption:\*\* \| \*\*Feature\*\* \| \*\*Function\*\* \| \|\-\-\-\-\-\-\-\-\-\-\--\|\-\-\-\-\-\-\-\-\-\-\--\| \| \*\*Villi & Microvilli\*\* \| Increase \*\*surface area\*\* for absorption \| \| \*\*Thin walls (1 cell thick)\*\* \| Short diffusion distance \| \| \*\*Rich blood supply\*\* \| Maintains concentration gradient \| \| \*\*Lacteal (in villi)\*\* \| Absorbs \*\*fatty acids & glycerol\*\* \| \-\-- \#\# \*\*4. Structure of a Leaf & Adaptations\*\* \#\#\# \*\*Structure & Functions:\*\* \| \*\*Leaf Structure\*\* \| \*\*Function\*\* \| \|\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--\|\-\-\-\-\-\-\-\-\-\-\-\--\| \| \*\*Waxy Cuticle\*\* \| Reduces water loss \| \| \*\*Upper Epidermis\*\* \| Transparent → Lets light through \| \| \*\*Palisade Mesophyll\*\* \| Packed with chloroplasts for \*\*maximum photosynthesis\*\* \| \| \*\*Spongy Mesophyll\*\* \| Has air spaces for \*\*gas exchange\*\* \| \| \*\*Stomata\*\* \| Allow \*\*CO₂ in\*\* and \*\*O₂ out\*\* \| \| \*\*Guard Cells\*\* \| Control stomatal opening \| \-\-- \#\# \*\*5. Photosynthesis\*\* \#\#\# \*\*Word & Symbol Equation:\*\* \\\[ \\text{Carbon dioxide} + \\text{Water} \\xrightarrow{\\text{Light, Chlorophyll}} \\text{Glucose} + \\text{Oxygen} \\\] \\\[ 6CO\_2 + 6H\_2O \\xrightarrow{\\text{Light, Chlorophyll}} C\_6H\_{12}O\_6 + 6O\_2 \\\] \#\#\# \*\*Factors Affecting Rate:\*\* \| \*\*Factor\*\* \| \*\*Effect\*\* \| \|\-\-\-\-\-\-\-\-\-\--\|\-\-\-\-\-\-\-\-\-\--\| \| \*\*Light Intensity\*\* \| More light = faster photosynthesis (until a max point) \| \| \*\*CO₂ Concentration\*\* \| More CO₂ = faster photosynthesis (until a max point) \| \| \*\*Temperature\*\* \| Higher temp = faster reaction (until \*\*enzymes denature\*\* at \~45°C) \| \-\-- \#\# \*\*6. Transport in Plants -- Xylem & Phloem\*\* \| \*\*Tissue\*\* \| \*\*Function\*\* \| \*\*Features\*\* \| \|\-\-\-\-\-\-\-\-\-\-\--\|\-\-\-\-\-\-\-\-\-\-\--\|\-\-\-\-\-\-\-\-\-\-\--\| \| \*\*Xylem\*\* \| Transports \*\*water & minerals\*\* from roots → leaves \| \*\*Hollow tubes\*\*, thick walls with \*\*lignin\*\* (strength) \| \| \*\*Phloem\*\* \| Transports \*\*sugars (sucrose)\*\* from leaves → rest of plant (\*\*translocation\*\*) \| \*\*Living cells\*\*, two-way movement \| \-\-- \#\# \*\*7. Animal Transport -- Blood & Circulatory System\*\* \#\#\# \*\*Heart Structure:\*\* \- \*\*Double circulation\*\* (Pulmonary & Systemic) \- \*\*Valves\*\* prevent backflow \- \*\*Major vessels:\*\* \- \*\*Aorta\*\* → carries oxygenated blood to the body \- \*\*Vena Cava\*\* → returns deoxygenated blood to heart \- \*\*Pulmonary Artery\*\* → to lungs \- \*\*Pulmonary Vein\*\* → from lungs \#\#\# \*\*Blood Vessel Features:\*\* \| \*\*Vessel\*\* \| \*\*Feature\*\* \| \|\-\-\-\-\-\-\-\-\-\--\|\-\-\-\-\-\-\-\-\-\-\--\| \| \*\*Arteries\*\* \| Thick, muscular walls, high pressure, away from heart \| \| \*\*Veins\*\* \| Thin walls, valves to prevent backflow, low pressure \| \| \*\*Capillaries\*\* \| One-cell thick for \*\*diffusion\*\* of oxygen/nutrients \| \#\#\# \*\*Blood Components:\*\* \- \*\*Red Blood Cells\*\* -- Carry \*\*oxygen\*\* (haemoglobin) \- \*\*White Blood Cells\*\* -- Fight infections \- \*\*Platelets\*\* -- Help blood \*\*clot\*\* \- \*\*Plasma\*\* -- Transports \*\*nutrients, CO₂, hormones\*\* \-\-- \#\# \*\*8. Transpiration\*\* \- \*\*Definition:\*\* Loss of water vapor from leaves via \*\*stomata\*\* \- \*\*Function:\*\* Helps \*\*pull water up\*\* through the plant (\*\*transpiration stream\*\*) \#\#\# \*\*Factors Affecting Transpiration:\*\* \| \*\*Factor\*\* \| \*\*Effect\*\* \| \|\-\-\-\-\-\-\-\-\-\--\|\-\-\-\-\-\-\-\-\-\--\| \| \*\*Light Intensity\*\* \| Stomata open → More transpiration \| \| \*\*Temperature\*\* \| Higher temp → Faster evaporation \| \| \*\*Humidity\*\* \| High humidity → Slower transpiration \| \| \*\*Wind Speed\*\* \| More wind → Faster transpiration \| \-\-- \#\# \*\*9. Practicals for GCSE Biology\*\* \#\#\# \*\*1. Starch Test (Photosynthesis)\*\* \- \*\*Iodine solution\*\* → \*\*Blue-black\*\* if starch is present \#\#\# \*\*2. Oxygen Production in Photosynthesis\*\* \- Use \*\*pondweed (Elodea)\*\* → Count \*\*oxygen bubbles\*\* \#\#\# \*\*3. Food Tests:\*\* \| \*\*Nutrient\*\* \| \*\*Test\*\* \| \*\*Positive Result\*\* \| \|\-\-\-\-\-\-\-\-\-\-\--\|\-\-\-\-\-\-\--\|\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--\| \| \*\*Starch\*\* \| Iodine \| \*\*Blue-black\*\* \| \| \*\*Glucose\*\* \| Benedict's \| \*\*Brick-red\*\* (after heating) \| \| \*\*Proteins\*\* \| Biuret \| \*\*Purple\*\* \| \| \*\*Lipids\*\* \| Sudan III/Ethanol \| \*\*Red layer/Cloudy\*\* \| \#\#\# \*\*4. Transpiration Rate (Potometer Experiment)\*\* \- Measures \*\*water uptake\*\* by plant \#\#\# \*\*5. Enzyme Activity (Amylase & pH/Temperature)\*\* \- Investigate \*\*how pH or temperature\*\* affects starch breakdown using iodine \-\-- This covers all your topics in \*\*detailed but concise\*\* points! Let me know if you need further explanations! 😊