B1 biology

• Active transport

  The movement of substances from a dilute solution to a more concentrated solution against a concentration gradient, requiring energy from respiration
• Algae


  Simple aquatic organisms (protista) that make their own food by photosynthesis
• Alveoli


  Tiny air sacs in the lungs that increase the surface area for gaseous exchange
• Bacteria


  Single-celled prokaryotic organisms
• Cell membrane


  The membrane around the contents of a cell that controls what moves in and out of the cell
• Cell wall


  The rigid structure around plant and algal cells. It is made of cellulose and strengthens the cell
• Cellulose


  The complex carbohydrate that makes up plant and algal cell walls and gives them strength
• Chlorophyll


  The green pigment contained in the chloroplasts
• Chloroplasts


  The organelles in which photosynthesis takes place
• Cytoplasm


  The water-based gel in which the organelles of all living cells are suspended and most of the chemical reactions of life take place
• Diffusion


  The spreading out of the particles of any substance in a solution, or particles in a gas, resulting in a net movement of particles from an area of higher concentration to an area of lower concentration down a concentration gradient
• Eukaryotic cells


  Cells from eukaryotes that have a cell membrane, cytoplasm, and genetic material enclosed in a nucleus
• Hypertonic (osmosis)


  A solution that is more concentrated than the cell contents
• Hypotonic (osmosis)


  A solution that is less concentrated than the cell contents
• Isotonic (osmosis)


  A solution that is the same concentration as the cell contents
• Mitochondria


  The site of aerobic cellular respiration in a cell
• Eukaryotic cells


  Animal and plant cells have genetic material (DNA) that forms chromosomes and is contained in a nucleus
• Cell membrane


  • Controls the movement of substances in and out of a cell
• Nucleus


  Organelle found in many living cells containing the genetic information surrounded by the nuclear membrane
• Animal cell


  • Nucleus contains DNA
  • Mitochondria where energy is released through respiration
• Osmosis


  The diffusion of water through a partially permeable membrane from a dilute solution (which has a high concentration of water) to a concentrated solution (with a low concentration of water) down a concentration gradient
• Partially permeable membrane


  A membrane that allows only certain substances to pass through
• Plant cell


  • Cell wall made of cellulose, which strengthens the cell
  • Permanent vacuole contains cell sap
  • Chloroplasts contain chlorophyll to absorb light energy for photosynthesis
  • Ribosomes are the site of protein synthesis
• Bacteria


  • Single-celled
  • No nucleus, have a single loop of DNA
  • Have small rings of DNA called plasmids
  • Smaller than eukaryotic cells
• Permanent vacuole


  Space in the cytoplasm filled with cell sap
• Specialised cells


  • Sperm cell
  • Red blood cell
  • Muscle cell
  • Nerve cell
  • Root hair cell
  • Palisade cell
• Sperm cell


  Fertilise an ovum (egg)
• Phloem


  The living transport tissue in plants that carries dissolved food (sugars) around the plant
• Sperm cell


  • Tail to swim to the ovum and fertilise it
  • Lots of mitochondria to release energy from respiration, enabling the sperm to swim to the ovum
• Red blood cell


  Transport oxygen around the body
• Plasmolysis


  The state of plant cells when so much water is lost from the cell by osmosis that the vacuole and cytoplasm shrink and the cell membrane pulls away from the cell wall
• Red blood cell


  • No nucleus so more room to carry oxygen
  • Contains a red pigment called haemoglobin that binds to oxygen molecules
  • Flat bi-concave disc shape to increase surface area-to-volume ratio
• Prokaryotic cells


  From prokaryotic organisms have a cytoplasm surrounded by a cell membrane, and a cell wall that does not contain cellulose. The genetic material is a DNA loop that is free in the cytoplasm and not enclosed by a nucleus. Sometimes there are one or more small rings of DNA called plasmids
• Muscle cell


  Contract and relax to allow movement
• Resolving power


  A measure of the ability to distinguish between two separate points that are very close together
• Muscle cell


  • Contains protein fibres, which can contract to make the cells shorter
  • Contains lots of mitochondria to release energy from respiration, allowing the muscles to contract
• Ribosomes


  The site of protein synthesis in a cell
• Nerve cell


  Carry electrical impulses around the body
• Nerve cell


  • Branched endings, called dendrites, to make connections with other neurones or effectors
  • Myelin sheath insulates the axon to increase the transmission speed of the electrical impulses
• Sperm


  The male sex cells or gametes that carry the genetic material from the male parent