science year 8 biology

• Cell


  Fundamental unit of all living organisms
• Plant and animal cells


  • Have certain parts or components in common
  • Some components are found in both plant and animal cells
  • Some components are only in plant cells
• Cell components


  • Cell wall
  • Cell membrane
  • Chloroplasts
  • Cytoplasm
  • Mitochondria
  • Nucleus
  • Ribosomes
  • Permanent vacuole
• Each component of a plant or animal cell has a specific function
• Almost all cells are too small to be seen using your eyes
• Cells are microscopic and require microscopes to see them
• Microscopes allow us to see inside the cells of larger organisms
• Roots


  • Take in all the water they find
• Leaves


  • Take in Co2 (carbon dioxide)
  • With sun it makes glucose
• Chlorophyll


  Green pigment of the leaves that is stored in the chloroplasts
• Stomata


  • Pores for oxygen and Co2 which is used to diffuse gases in and out
• Photosynthesis word equation


  carbon dioxide + water --> glucose + oxygen
• Aerobic respiration


  A chemical process in which oxygen is used to make energy from carbohydrates (sugars)
• Aerobic respiration word equation

  glucose + oxygen ---> carbon dioxide + water
• Large intestine


  • Contains bacteria which lives in the fibre of our diet
• Bacteria


  Makes important vitamins like vitamin K
• Vitamins made by bacteria

  Are absorbed by the body and helps to keep you healthy
• Enzymes


  Special proteins that can break large molecules of nutrients into small molecules
• Enzymes


  Chop large molecules into small molecules
• Carbohydrase


  An enzyme that breaks down carbohydrates into sugar molecules
• Carbohydrate digestion


  1. Mouth

  2. Stomach

  3. Small intestine
• Carbohydrase present in your saliva breaks down the starch in bread into sugar
• Protease


  An enzyme that breaks down proteins into amino acids
• Protein digestion


  1. Small intestine

  2. Stomach
• Acid in the stomach helps digestion and kills harmful microorganisms in the food
• Lipid digestion


  Bile breaks down lipids into small droplets that are easier for lipase enzymes to work on
• Digestive system


  A group of organs that work together to break down food
• Digestion


  1. Large molecules are broken down into smaller molecules of nutrients

  2. Nutrients can pass them in to the blood where they can be used by the body
• Mouth


  • Food is chewed and mixed with saliva
  • Teeth help to break down food into smaller chunks
• Gullet


  • Food passes down this tube
• Stomach


  • Food is mixed with digestive juices and acids
• Small intestine


  • Digestive juices from the liver and pancreas are added and digestion is completed
  • Small molecules of nutrients pass through the intestine wall into the bloodstream
• Large intestine


  • Only food that cannot be digested can come this far
  • Water passes back into the body leaving a solid waste of undigested food called feces
• Rectum


  • Feces are stored here until it's released from the body
• Anus


  • Muscular ring where the feces pass out of the body
• Fibre isn't digested but adds bulk to the body
• Muscles push against this, forcing food along the gut
• Small intestine


  • Thin and covered with small structures called villi
  • Villi increase the surface area so more nutrients are absorbed
• Seven nutrients


  • Carbohydrates
  • Protein
  • Lipids
  • Vitamins
  • Fibre
  • Minerals
  • Water
• Carbohydrates


  Found in pasta, bread