biology paper 1

• what are the typical features of a eukaryotic cell?

  cell membranes, organelles, DNA in a nucleus
• give an example of a eukaryotic cell

  plant or animal cell
• Eukaryotic cell


  Typical features: cell membranes, organelles, DNA in a nucleus
• Eukaryotic cell


  • Plant or animal cell
• Prokaryotic cell


  • Bacteria
• Prokaryotic cells vs eukaryotic cells

  • Prokaryotic cells are smaller
• Genetic material of bacteria

  Not contained in a nucleus - it is free floating in the cytoplasm
• Plasmids


  Additional loops of DNA in bacteria
• Cell parts often found in plant cells but not in animal cells


  • Cell wall
  • Vacuole
  • Chloroplasts
• Chloroplast


  Function: Photosynthesis takes place here
• Vacuole


  Contains sap
• Cell wall


  Function: Strength and support
• Cell wall


  Made of cellulose
• Cell membrane


  Function: Control what enters and leaves the cell
• Mitochondria


  Where respiration takes place
• Ribosomes


  Function: Making proteins
• Structures found in a plant cell but not in an animal cell

  • Vacuole
  • Chloroplast
  • Cell wall
• Stage


  Part of the microscope where the slide sits
• Eyepiece lens


  The lens you look down
• Using a microscope


  1. Start with lowest magnification

  2. Turn the focusing wheel to make cells less blurry

  3. Increase the magnification to see more detail
• Objective lens


  The lens near the stage
• Total magnification


  Eyepiece x objective lens
• Electron microscope vs light microscope

  • Electron microscope has much greater magnification
  • Electron microscope has much better resolution
• Resolution


  The ability to distinguish between 2 objects
• Electron microscopes have developed the understanding of cells by allowing us to see organelles like ribosomes and mitochondria and how they function
• Cell specialisation and division

  • Tasat
  • Nucleus
  • Organ
  • Cell
  • Organ system
• Differentiation


  The process by which stem cells form different types of cell as an organism develops
• Sperm cell


  • Streamlined
  • Contains many mitochondria
• Plant root cell


  • Contains many root hairs which give them increased surface area
  • Allows efficient water uptake
• Nucleus


  Contains the DNA
• Chromosomes


  Made of DNA
• Chromosomes in body cells

  Found in pairs
• Cell cycle


  1. Interphase

  2. Mitosis

  3. Cytokinesis
• Interphase


  All the DNA is copied and so are all cell organelles like mitochondria, ribosomes etc
• Mitosis


  The chromosomes move to opposite sides, the nucleus divides
• Cytokinesis


  The cytoplasm and cell membranes divide
• Mitosis


  • Important for growth and repair
  • Replaces damaged cells or repairs tissues
• Stem cell


  An unspecialized cell capable of becoming any type of cell
• Meristem


  The source of stem cells in plants
• Cells obtained from stem cells in bone marrow

  • Blood cells