Biology

• What is the function of the nucleus in a cell?

  It contains genetic material and controls the activities of the cell.
• What is the role of cytoplasm in a cell?

  It's a gel-like substance where most of the chemical reactions happen.
• What does the cytoplasm contain that is crucial for chemical reactions?

  It contains enzymes that control these chemical reactions.
• What is the function of the cell membrane?

  It holds the cell together and controls what goes in and out.
• Where do most reactions for aerobic respiration occur?

  In the mitochondria.
• What is the purpose of respiration in cells?

  It transfers energy that the cell needs to work.
• What is the role of ribosomes in a cell?

  Protein synthesis takes place in ribosomes.
• What do cell walls do?

  They support and strengthen the cell.
• What is the function of a vacuole?

  It contains cell sap and helps maintain the shape of the cell.
• What do chloroplasts do?

  Photosynthesis occurs in chloroplasts, making food for the plant.
• What pigment do chloroplasts contain that is essential for photosynthesis?

  Chlorophyll, which absorbs light needed for photosynthesis.
• What components do bacterial cells contain?

  Cytoplasm, cell membrane, cell wall, flagella, ribosomes, mitochondria, slime capsule, plasmids, and a single circular strand of DNA.
• What do bacterial cells NOT contain?

  A nucleus.
• What is the equation for magnification?

  Image size divided by actual size.
• What is differentiation in biology?

  The process by which a cell changes to become specialised for its job.
• What are undifferentiated cells called?

  Stem cells.
• What is the specialization of sperm cells?

  They are specialized for reproduction and transport male DNA to female DNA.
• How are sperm cells specialized for their function?

  They have a flagella, a streamlined head, lots of mitochondria, and enzymes in their head.
• What is the specialization of nerve cells?

  They are specialized for rapid signaling and carry electrical signals.
• How are nerve cells specialized for their function?

  They are long to cover more distance and have branched connections.
• What is the specialization of muscle cells?

  They are specialized for contraction and need to contract quickly.
• How are muscle cells specialized for their function?

  They are long and contain lots of mitochondria for energy.
• What is the specialization of root hair cells?

  They are specialized for absorbing water and minerals.
• How are root hair cells specialized for their function?

  They have long hairs that increase surface area for absorption.
• What are chromosomes?

  Coiled up lengths of DNA molecules found in the nuclei.
• What do multicellular organisms use mitosis for?

  To grow or replace cells that have been damaged.
• What are stem cells?

  Undifferentiated cells that divide to produce more undifferentiated cells.
• Where are stem cells found?

  In early human embryos or the bone marrow of adults.
• What do embryonic stem cells do?

  They replace faulty cells in sick people, like insulin-producing cells for diabetes.
• What is diffusion?

  Diffusion is the movement of particles from an area of high concentration to an area of low concentration.
• Name substances that can diffuse through cell membranes.

  Glucose, water, oxygen, and amino acids.
• Name two substances that can't diffuse through cell membranes.

  Protein and starch.
• What is osmosis?

  Osmosis is the passive movement of water molecules through a partially permeable membrane from high to low water concentration.
• What are the two main differences between active transport and diffusion?

  Active transport uses energy and goes against the concentration gradient, while diffusion does not.
• What are the adaptations of exchange surfaces?

  • Large surface area for diffusion
  • Lots of blood vessels for quick transport
  • Thin membrane for short diffusion distance
  • Often ventilated to facilitate gas exchange
• How are villi in the small intestine adapted for absorbing digested food?

  • A single layer of surface cells
  • A very good blood supply for quick absorption
• How are leaves adapted to maximize carbon dioxide intake?

  • Covered in stomata for gas exchange
  • Flattened shape increases surface area
  • Cell walls act as an exchange surface
  • Air spaces increase the area for gas exchange
• What factors affect the rate of diffusion?

  Concentration gradient, temperature, surface area, and diffusion distance.
• Give examples of active transport in plants and animals.

  Plants: Root hairs absorb minerals and water.

  Animals: Glucose is taken in from the gut and kidney tubules.
• How are alveoli in the lungs specialized for gas exchange?

  • Enormous surface area
  • Moist lining for dissolving gases
  • Very thin walls
  • Good blood supply