ks3 biology

• What are cells considered in living organisms?

  Building blocks of life
• What are the smallest units found in an organism?

  Cells
• What three components do both plant and animal cells contain?

  Membrane, cytoplasm, and nucleus
• Which additional components do plant cells have that animal cells do not?

  Cell wall, vacuole, and chloroplasts
• What is the function of specialised cells?

  They have adaptations for specific jobs
• What are the features and functions of red blood cells?

  • Function: Transport oxygen around the body
  • Features:
  • Contains haemoglobin
  • No nucleus
  • Disc-shaped to increase surface area
• What are the features and functions of nerve cells?

  • Function: Carry electrical impulses
  • Features:
  • Long and thin
  • Connections at each end
• What are the features and functions of sperm cells?

  • Function: Carry male genetic material
  • Features:
  • Long tail
  • Lots of mitochondria
  • Streamlined head
• What are the features and functions of root hair cells?

  • Function: Absorb water and nutrients
  • Features:
  • Root hair increases surface area
  • No chloroplasts (underground)
• What are the features and functions of leaf cells?

  • Function: Carry out photosynthesis
  • Features:
  • Located at the top surface of leaves
  • Packed with chloroplasts
  • Thin with a large surface area
• How do particles move into and out of cells?

  By diffusion
• What happens during diffusion?

  Particles spread from high to low concentration
• What do glucose and oxygen do in animal cells?

  Diffuse from blood into cells for respiration
• What diffuses out of cells into the blood?

  Carbon dioxide
• What is the purpose of microscopes?

  • Observe very small objects
  • Magnify images
• What must samples be when observed under a microscope?

  Very thin
• How do carbon dioxide and oxygen move in plant cells?

  Through stomata on the leaf
• How does water move in plant cells?

  Diffuses into root hair cells from soil
• What happens to water inside plant cells?

  Fills the vacuole, making the cell rigid
• What can be added to samples to enhance visibility under a microscope?

  Coloured dyes like iodine
• What is the function of the coarse and fine focus knobs on a microscope?

  To focus the image
• What is the total magnification if the eyepiece lens is ×10 and the objective lens is ×50?

  $500$
• How do you calculate total magnification in a microscope?

  Eyepiece magnification × objective magnification
• What is a unicellular organism?

  • Made up of only one cell
  • Examples: amoeba, euglena
• How do unicellular organisms reproduce?

  By splitting themselves in two
• What are the five levels of organization in multicellular organisms?

  Cells, tissues, organs, organ systems, organisms
• What is the primary function of the gas exchange system?

  To take in oxygen and give out carbon dioxide
• What structures in the lungs facilitate gas exchange?


  Alveoli
• What are the features of alveoli that aid gas exchange?

  • Large surface area
  • Thin walls (one cell thick)
  • Good blood supply
• What factors can increase lung volume?

  Exercise
• What factors can decrease lung volume?

  Asthma, old age, and smoking
• What changes occur during inhalation?

  1. Muscles between ribs contract
  2. Ribs are pulled up and out
  3. Diaphragm contracts and flattens
  4. Volume of chest increases
  5. Pressure inside chest decreases
  6. Air is drawn into lungs
• What changes occur during exhalation?

  1. Muscles between ribs relax
  2. Ribs are pulled in and down
  3. Diaphragm relaxes and moves up
  4. Volume in chest decreases
  5. Pressure inside chest increases
  6. Air is forced out of lungs
• How does exhaled air differ from inhaled air?

  Exhaled air is warmer and contains more water vapour
• What is the main function of the skeleton?

  Support, protection, production, movement
• What are the four main functions of the skeleton?

  • Support: Framework for muscles and organs
  • Protection: Shields vital organs
  • Production: Produces red and white blood cells
  • Movement: Muscles pull on bones
• What are joints and their purpose?

  Joints allow bones to bend and move
• What are the types of joints and their movements?

  • Ball and socket: shoulder, hip - forwards and backwards
  • Hinge: knee, elbow - forwards and backwards
  • Pivot: neck - around a joint
  • Gliding: skull - none
• What protects the ends of bones in joints?

  Cartilage
• What holds two bones together at a joint?

  Ligaments