Biology

• A balanced diet means eating The right amount of different nutrients.
• Plants use photosynthesis to produce glucose.
• Photosynthesis needs carbon dioxide and water.
• The movement of air in breathing is called ventilation.
• Reproduction systems produce gametes.
• In Sexual Reproduction, male and female gametes fuse (fertilisation) in an oviduct, to form a zygote.
• in multicellular organisms, cells of the same type for tissues.
• different tissues can form organs
• Tar in cigarette smoke coats the aveoli, which reduces gas exchange.
• nicotine makes arteries narrower
• plants exchange gases through the stomata in their leaves
• the stomata are small holes that can be opened and closed by guard cells
• A drug is any substance that has an effect on our bodies
• Cell nuclei contain genetic information.
• human nuclei contain 46 chromosomes, made of a molecule called DNA.
• genetic information is stored in genes.
• in human reproduction, offsprings receive 23 chromosomes from each parent.
• the DNA molecule is a double helix.
• Environmental variation is caused by physical environmental factors.
• variation that can have any value within a range is called a continuous variation. (Eg. Human height)
• variation that can only have certain values (eg. shoe size) is discontinuous variation.
• Organisms survive if they are adapted to their habitats.
• genetic material is saved in gene banks.
• the study of how muscles and bones work together is called biomechanics.
• different tissues form organs which work together in organ systems.
• Carbohydrates such as sugars and starch are used for energy.
• proteins are for growth and repair.
• vitamins and minerals are for health.
• too much or too little of a nutrient can cause malnutrition
• active people and those who are growing need more energy than less active people.
• energy is measured in kilojoules (KJ)
• the digestive system is made up of lots of different organs such as those in the gut, as well as organs such as salivary glands and the liver.
• Plants use photosynthesis to produce glucose.
• photosynthesis = Carbon Dioxide + Water -> Glucose + Oxygen.
• Aerobic Respiration = Glucose + Oxygen -> Carbon Dioxide + `water.
• the energy for photosynthesis is transferred by light (usually the sun) and becomes stored as glucose.
• in plants, water is taken out of the soil from the roots.
• roots are adapted to their function by being branched out and spread out to help absorb water and minerals.
• roots have root hair cells which have a large surface area to help them absorb water quickly.
• in plants, water flows up the xylem vessel which is made up of hollow cells and goes into the leaf.