Cell Biology

• What’s a prokaryotic cell?


  A single celled organism, with no nucleus
• What’s a eukaryotic cell?


  A multicellular organism, contains a nucleus
• What are the sub-cellular structures in a bacterial cell?

  Cell membrane, cell wall, cytoplasm, a single strand of DNA and plasmids
• What are the sub-cellular structures in plant and animal cells?

  Nucleus, cytoplasm, cell membrane, mitochondria and ribosomes
• What does a plant cell contain which an animal cell doesn’t?

  Cell wall, permanent vacuole and chloroplast
• What’s the function of the nucleus?

  Contains genetic material, and controls cell activity
• What’s the function of the cytoplasm?

  Where most of the chemical reactions take place, it also contains enzymes to control these reactions
• What’s the function of the cell membrane?

  Controls what goes in and out of the cell
• What’s the function of the mitochondria?

  Where aerobic respiration place, which transfers energy for the cell
• What’s the function of the ribosomes?

  Protein synthesis
• What’s the function of the cell wall?

  Supports the cell and strengthen it, is made of cellulose
• What’s the function of the permanent vacuole?

  Contains cell sap
• What’s the function of the chloroplasts?

  Where photosynthesis occurs contains chlorophyll which absorbs light for photosynthesis
• What are specialised cells?

  Cells which are specialised to carry out specific functions
• How do specialised cells become specialised?

  Through differentiation - the process the cell changes to become specialised for its job
• What are undifferentiated cells?

  STEM cells
• How are sperm cells specialised?


  Specialised for reproduction. Adaptions -has a long tail and streamlined head to help it swim towards the egg, there’s lots of mitochondria in the cell to provide energy. It carries enzymes in its head to digest through the eggs cell membrane.
• How are nerve cells specialised?

  Specialised for rapid signalling. Adaptions - cells are long for larger distance and branched connections to connect to other nerve cells to form a network.
• How are muscle cells specialised?

  Specialised for contraction.

  Adaptions - long (space to contract), contain lots of mitochondria to generate energy for the contraction.
• How are root hair cells specialised?

  Specialised for absorbing water and minerals. Adaptions - long “hairs“ that stick into the soil, provide large surface area for absorbing water and minerals.
• How are phloem and xylem cells specialised?

  Specialised for transporting substances.

  Adaptions - Xylem, hollow in the centre (so water can flow through it). Phloem, very few sub-cellular structures (so minerals can flow through them).
• When do the majority of animal cells differentiate?

  At an early stage, as the organism develops
• What’s the main use of cells that differentiate in mature animals?

  repairing and replacing blood cells,

  e.g. skin or blood cells
• What microscope has the highest magnification?

  Electron microscope
• What microscope has the highest resolution?

  Electron microscope
• What’s resolution?

  The ability to distinguish between two points
• What’s the magnification equation?

  Magnification = size of image/ size of real object
• What are chromosomes?

  Chromosomes are coiled up lengths of DNA molecules, found in the nucleus. Chromosomes are normally found in pairs.
• What’s the cell cycle process?

  1-before the cell divides it increases the number of sub-cellular structures, such as mitochondria and ribosomes, to help the cell grow

  2-the cell then duplicates its DNA to form two copies of each chromosomes
• What’s the process of mitosis?

  The cell cycle repeats then;

  1-one set of chromosomes is pulled to each end of the cell, then the nucleus divides

  2-finally the cytoplasm and cell membrane divide to form two identical daughter cells
• Why is mitosis important in cells?

  For growth and development of the cells, and to replace damaged cells
• What’s a stem cell?

  An undifferentiated cell, which can divide to produce lots more undifferentiated cells. They can differentiate into different types of cell depending on the instructions they’ve been given.
• Where can stem cells be found?

  In human embryos - can turn into any type of cell.

  In bone marrow - can only turn into certain cells, e.g. blood cells

  Both can be grown in a lab to produce clones and made to differentiate into specialised cells to use in medicine or research.
• How can stem cells treat disease?

  Embryonic cells can be used to replace faulty cells - can make insulin producing cells (for diabetes) or nerve cells (for paralysis).

  Bone marrow of a healthy person can replace faulty blood cells.
• What’s therapeutic cloning?

  Creating embryonic cells with the same genetic information as the patient, contains same genes as patient, no rejection from patients body
• What are the risks of stem cells in medicine?

  Stem cells grown in a lab may become contaminated with a virus - which could be passed on to the patient (which would make the patient sicker).
• What are the reasons against stem cell research?

  Embryos shouldn’t be used for experiments (one could be a potential human life), it’s banned in certain countries, religious objections, unethical.
• How can meristems be used?

  To produce clones of the plant quickly and cheaply, used to grow plants of rare species, used to grow crops of identical plants that have desirable features (e.g. disease resistance).
• Can meristems differentiate into any type of plant?

  Yes, they can differentiate into any type of plant cell.
• What’s diffusion?

  The spreading out of particles from an area of higher concentration to an area of low concentration.