Nutrition

• Photosynthesis


  The process by which green plants convert light energy into chemical energy in the form of glucose.
• What are organisms that use photosynthesis to produce their own food called?

  producers
• What type of reaction in photosynthesis?

  endothermic
• Where does photosynthesis take place?

  chloroplasts
• Word equation for photosynthesis

  Carbon dioxide + Water → Glucose + Oxygen
• Symbol equation for photosynthesis

  6CO2 + 6H2O → C6H12O6 + 6O2
• Limiting factor


  A factor that limits the rate of a reaction.
• What are the three main factors which limit the rate of photosynthesis?

  - Temperature

  - Light Intensity

  - Carbon dioxide concentration
• Explain the effect of temperature on photosynthesis rate

  - The rate of photosynthesis increases with temperature.

  - As temperature increases, the particles have more kinetic energy.

  - This increases the frequency of collisions and successful collisions leading to a reaction.

  - Once the optimum temperature is succeeded, the enzymes denature and the rate of reaction decreases.
• Effect of light intensity on photosynthesis rate

  - The rate of photosynthesis increases with higher light intensity

  - At a certain point, increasing light intensity stops increasing the rate and rate is constant.

  - This is because light intensity is no longer a limiting factor and instead some other liming factor, such as temperature or carbon dioxide concentration becomes in short supply.
• Effect of carbon dioxide concentration on photosynthesis rate

  - The rate of photosynthesis increases with higher carbon dioxide concentration.

  - As carbon dioxide concentration increases, the frequency of collisions and successful collisions between molecules increases.

  - The trend will continue until some other factor becomes in short supply preventing the rate from increasing further.
• Structure of leaf tissue

  Leaf tissue is thin and consists of spongy and palisade mesophyll cells, which are responsible for photosynthesis.
• Give 3 ways leaves are adapted for photosynthesis

  - They are thin which provides a short diffusion distance.

  - The spongy mesophyll layer has lots of air spaces, which provides a larger surface area for photosynthesis.

  - Palisade mesophyll cells have lots of chloroplasts for photosynthesis.
• Use of mineral ions in plants


  Mineral ions are used for growth in plants.
• Give 2 common ions in plants

  Magnesium ion (Mg2+) Nitrate ion (NO3 - )
• Use of magnesium ions in plants

  Magnesium ions are used in the production of chlorophyll, the pigment responsible for capturing light energy in photosynthesis.
• Use of nitrate ions in organisms


  Nitrate ions are used in the synthesis of amino acids, which are building blocks of proteins.
• Importance of a balanced diet

  The body needs different substances in different proportions to function properly, too much or too little of different things can be harmful
• What 7 groups are needed for a balanced diet?

  Carbohydrates, proteins, lipids (fats), vitamins, minerals, water and dietary fibre
• Function of carbohydrates in the diet

  Carbohydrates are the main source of energy in the diet, providing fuel for the body.
• Functions of proteins in the body

  Needed for growth and repair of tissue, and to provide energy in emergencies.
• Functions of lipids in the body


  Provide energy, act as an energy store and provide insulation.
• Use of vitamin A


  - Keeping your skin and hair healthy

  - Improved vision in the dark

  - Strengthening the immune system
• Use of vitamin C


  Needed to prevent scurvy.
• Use of vitamin D


  Vitamin D is used in the absorption of calcium.
• Use of calcium in the body

  Calcium strengthens bones and teeth.
• Use of iron in the body

  Iron is a component of hemoglobin, the protein in red blood cells responsible for oxygen transport.
• Use of water in the body

  - A reaction medium

  - Temperature control

  - Transport
• Use of dietary fiber


  It helps keep everything flowing through the digestive system.
• Comparison of energy requirements of more and less active people

  Active individuals have higher energy requirements compared to less active individuals due to increased physical activity.
• Describe how energy requirements change as we age

  Children and teenagers need more energy than older people as they need energy to grow and they're generally more active.
• Describe how energy requirements change with pregnancy

  Pregnant women need more
• What is the alimentary canal?


  The complete tube that food passes through as it passes through the body.
• Difference between alimentary canal and digestive system

  The alimentary canal refers to the food-passing tubes, while the digestive system includes the alimentary canal and associated glands involved in digestion.
• Describe the passage of food through the alimentary canal

  Mouth → oesophagus → stomach → small intestine → large intestine → rectum
• Function of the mouth


  - To chew and break down food

  - To secrete digestive enzymes
• What is the oesophagus?


  The tube that carries food from the mouth to the stomach.
• Role of the pancreas in digestion


  The pancreas secretes digestive enzymes into the small intestine.
• Function of the stomach

  - It pummels the food with its muscular walls

  - It produces the protease enzyme, pepsin

  - It produces hydrochloric acid to kill bacteria and to give the optimum pH for the protease enzyme to work (pH 2 - acidic)
• What are the two parts of the small intestine called?

  Duodenum and ileum