Biology AQA

• What is mitosis? What is it used for?

  1 mother cell splits into 2 daughter cells. Growth and repair
• What is the process of cell division?

  - DNA replicates

  - Pair of chromosomes is pulled to each side of the cell

  - Cell membrane and cytoplasm split
• What is the cell cycle?


  the life cycle of a cell

  
• What are chromosomes? Where are they found?

  Coiled up lengths of DNA molecules. Found In nucleus
• What is the total number of chromosomes that we have?

  46 - 23 from mother, 23 from father
• What is binary fission?

  A form of asexual reproduction in prokaryotic cells
• What are the steps of binary fission?

  1. DNA replication

  2. cell elongation

  3. septation

  4. cell pinches off
• When do cells typically divide?

  For growth, repair, and maintenance of cells
• Before dividing (mitosis), what must a cell do?

  Duplicate its genetic information
• What is a


  Eukaryotic cell? Remember:

  "Eu" - YouA cell that contains a nucleus
• What are plasmids?


  Small, circular DNA molecules found in bacteria
• What is a stem cell?

  An undifferentiated cell - A cell which has not yet become specialised is called unspecialised
• What is differentiation?


  The process by which cells become specialised
• What is therapeutic cloning?

  An embryo is produced to have the same genetic information as the patient, then stem cells are harvested from the embryo
• What can therapeutic cloning stop?

  Therapeutic cloning can stop the cells from being rejected by the patient as they have the same genes
• What are the issues with stem cells?

  - May not be able to be manipulated to produce all cell types

  - Ethical issues - An embryo must be sacrificed

  - Adult stem cells can cause abnormalities

  - Expensive to gather
• What is an embryo?

  It is the fertilised egg that is the early stages of the foetus
• What are the benefits of using stem cells?

  Uses unwanted embryos from fertility which otherwise would have be destroyed
• Who would benefit from using stem cells? Acronym:

  
  

  S

  T

  A

  P

  People with:

  
  

  - Spinal cord injuries

  - Type one diabetes

  - Parkinson's disease

  - Alzheimers disease
• Stem cell type, and what can be produced:

  
• How do you calculate magnification?

  magnification = image size/actual size

  
• What is a prokaryotic cells?


  Cells with no nucleus
• What characteristics do prokaryotic cells have? (4)

  - Single celled

  - No nucleus - single loop of DNA

  - Plasmids

  - Smaller than eukaryotic cells
• Animal and plant cells, similarities and differences:

  
• Similarities, and differenced between bacteria, plant, and animal cells:

  
• What is the function of a sperm cell?

  To fertilise an ovum
• What adaptations do sperm cells have?

  - A long tail to swim,

  - Lots of mitochondria to release energy from respiration
• What is the function of a red blood cell?

  Transport oxygen around the body
• What adaptations red blood cells have?

  - No nucleus, so there is more room to carry oxygen

  - Contains haemoglobin which binds to oxygen

  - Bi-concave shape to increase surface area-to-volume ratio
• What is the function of a muscle cell?

  Contract and relax to allow movement
• What adaptations do muscle cells have?

  - Contain protein fibres which can contract

  - Contains lots of mitochondria to release energy from respiration
• What is the function of a nerve cell?

  To carry electrical impulses around the body
• What adaptations do nerve cells have?

  - Branched endings make connections with other neurones

  - Myelin sheath insulates the axon to increase the transmutation speed
• What is the function of a root hair cell?

  Absorbs water and mineral ions from the soil
• What adaptations do root hair cells have?

  - Long projections to increase surface area

  - Lots of mitochondria to release energy for active transport

  - No chloroplasts
• What is the function of a palisade cell?

  Enables photosynthesis in a leaf
• What adaptations do palisade cells have?

  - Lots of chloroplasts, containing chlorophyll, to absorb light energy

  - Located at the top surface of the leaf where it can absorb the most light energy
• What Is a light microscope?


  A microscope that uses visible light and lenses
• What Is an electron microscope?

  electrons shoot through the cells to create an image
• Differences between electron, and light microscopes: