Biology Year 9

• Plant and Animal Cells
• Cell membrane


  Permeable, controls movement in and out of the cell
• Cytoplasm
• Nucleus controls activity of cell (DNA)
• Chloroplast


  • Contains chlorophyll, site of photosynthesis
• Vacuole


  • Stores sap, helps with movement and keeps cell shape
• Mitochondria


  • Site of respiration, releases energy
• Ribosomes


  • Site of protein synthesis
• Cell wall


  • Supports the cell
• Root hair cells are unlikely to contain chloroplasts as they are not photosynthesising
• Sperm cells have an acrosome containing digestive enzymes to penetrate the egg
• Types of muscle cells

  • Skeletal
  • Smooth
  • Cardiac
• Muscle cells


  • Have high density of mitochondria to provide energy
  • Layers of protein filaments for contraction
• Diffusion


  Movement of particles from high to low concentration
• Cell membranes are partially permeable
• Small, uncharged particles can pass through cell membranes easily</b>
• Glucose and urea can pass through cell membranes
• Tissue


  A group of cells with similar structure and function
• Organ


  A collection of tissues performing a specific function
• Organ system


  A group of organs working together to perform a major function
• Examples of organ systems

  • Digestive
  • Circulatory
  • Respiratory
• The stomach and large intestine are part of the digestive system
• Protein


  Macromolecule made up of amino acids, used for building cells
• Carbohydrate


  Macromolecule made up of sugars, used for energy
• Lipid


  Macromolecule made up of fatty acids, used for energy storage
• Benedict's test turns blue-green for simple sugars, yellow-red for complex carbohydrates
• Biuret test turns purple in the presence of proteins
• Cell membranes increase surface area and rate of diffusion
• Xylem and phloem are plant transport tissues
• Digestion breaks down large food molecules into smaller ones that can be absorbed
• The liver produces bile to help digest fats
• The pancreas produces digestive enzymes
• The small intestine is where most food absorption occurs
• The large intestine absorbs excess water from undigested food
• Catalysts speed up chemical reactions without being consumed
• Enzymes are biological catalysts that control metabolism
• Different enzymes catalyse different metabolic reactions
• Factors affecting enzyme activity include temperature, pH, and concentration
• Carbohydrases break down carbohydrates into simple sugars
• Aerobic respiration releases energy from glucose using oxygen