topic b1- cell biology

• eukaryotic

  • plant cells
  • animal cells
• plant cells have

  • (permanent) vacuole
  • chloroplasts
  • cytoplasm
  • nucleus
  • ribosomes
  • mitochondria
  • cell membrane
  • cell wall
• animals cells have

  • cell membrane
  • mitochondria
  • ribosomes
  • nucleus
  • cytoplasm
• prokaryotic

  • bacteria cells
• bacteria cells have

  • flagellum
  • plasmids
  • single DNA loop/ large DNA strand
  • cytoplasm
  • cell wall
  • cell membrane
• nucleus

  • controls the cell
  • contains DNA
• cytoplasm

  where the chemical reactions occur
• cell membrane 


  controls what enters and leaves the cell
• mitochondria

  • site of aerobic respiration
  • creates energy
• ribosomes

  site of protein synthesis
• cell wall

  • supports the cell
  • strengthens it
• vacuole

  contains cell sap
• chloroplasts

  site of photosynthesis
• subcellular structures

  • nucleus
  • cytoplasm
  • cell membrane
  • mitochondria
  • ribosomes
  • cell wall
  • vacuole
  • chloroplasts
• eukaryotic vs prokaryotic

  • eukaryotic contains a nucleus
  • eukaryotic are bigger
  • prokaryotic don't contain mitochondria or ribosomes
  • prokaryotes are single-celled organisms
• bacteria cells are known as

  prokaryotic cells
• magnification

  image size/ actual size
• light microscope

  • cheaper
  • easier to use
• electron microscope

  • better magnification
  • better resolution
  • requires dead specimen
• stem cell

  a cell that can differentiate into different types of specialised cells
• examples of specialised cells

  • nerve
  • sperm
  • egg/ ovum
  • brain
  • muscle
  • fat
  • root hair
  • red blood
  • white blood
  • xylem
  • phloem
• cell specialisation

  the process by which cells differentiate to become specialised for certain functions
• stem cells/ what specialised cells can become

  • root hair
  • nerve
  • RBC
  • sperm
• what are stem cells

  • can differentiate and become specialised cells
  • embryonic stem cells are totipotent
  • adult stem cells are multi-potent
  • used to cure disease
• totipotent 


  can become any type of cell
• multi-potent

  have potential to become most types of cells
• nerve cells

  • axons + dendrite to connect nerve cells together
  • myelin sheath to insulate impulses
  • long + thin to make travel quicker
• red blood cell

  • biconcave shape- more surface area
  • no nucleus- more space for oxygen
• mitosis

  • DNA duplicates + grows
  • chromosomes line up at the centre
  • spindle fibres pull them apart
  • nuclei reforms
  • cell membrane splits
  • two daughter cells are formed
• mitosis is used in the

  root and shoot of plants (growth)
• diffusion

  • the net movement of particles/ spreading out of particles from an area of high concentration to an area of low concentration down a concentration gradient
  • a passive process
• osmosis

  • the net movement of water particles from an area of high concentration to an area of low concentration across a partially permeable membrane/ down a concentration gradient
  • a passive process
• active transport

  • the net movement of particles from a high concentration to a low concentration against a concentration gradient
  • using energy
  • an active process
• cell transport

  how do particles move between substances
• factors affecting cell transport

  • surface area
  • temperature
  • short diffusion pathway
  • good blood supply
  • constant concentration gradient
  • steepness of the concentration gradient