topic b1- cell biology

• animal cell

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


  where most of the chemical reactions happen
• mitochondria

  where most of the reactions for aerobic respiration take place
• cell membrane 


  controls what goes in and out
• ribosomes

  where proteins are made
• nucleus

  contains genetic material (DNA)
• plant cell

  • cell membrane
  • cell wall
  • cytoplasm
  • chloroplasts
  • permanent vacuole
  • nucleus
  • ribosomes
  • mitochondria
• cell wall

  made of cellulose= strengthens the cell
• chloroplasts

  where photosynthesis occurs
• permanent vacuole

  contains cell sap
• bacterial cell

  • cell membrane
  • cell wall
  • flagellum- movement
  • cytoplasm
  • no nucleus
  • dna loop floating in cytoplasm
  • plasmid- small ring of dna
• advantages of light microscopes

  • cheap
  • portable
  • image is in colour
  • easy to use
• advantages of electron microscope

  • magnify up to 500000
  • clearer image
  • 3d image
  • higher resolution
• disadvantages of light microscope

  • magnify up to 2000
  • 2d image
  • image is not as clear
• disadvantages of electron microscope

  • expensive
  • black and white image
  • hard to use
  • static
  • got to be dead
  • large
• magnification

  observed cell length / actual cell length
• length of cell

  field of view (FOV) / number of cells
• 1m= 100cm= 1000mm= 10000mm (micrometers)
• 1mm

  1000um
• mia

  mag= image/ actual
• specialised animal cells

  • red blood cell
  • nerve cells
  • sperm cells
  • ciliated epithelial cell
• red blood cell

  • carries blood around the body
  • they are bio concave
  • they do not have a nucleus
• nerve cells

  • carry impulses through the body
  • it has branches to connect to other nerves
  • they all connect and they are long
• sperm cells

  • are used to fertilise eggs, for reproduction
  • they have a tail to swim to the egg to fertilise it
• ciliated epithelial cell

  • is used to carry and move the egg cell to the womb
  • they have hairs, to move the egg to the womb
• muscle cells are a specialised animal cells for contraction

  • function- contract quickly
  • long- space to contract
  • mitochondria- energy for contraction
• specialised plant cells

  • leaf cells
  • root hair cell
  • xylem and phloem
• leaf cells

  • absorb sunlight from the sun and turn it into food for the plant to survive
  • it has lots of chloroplast to photosynthesise
• the root hair cell

  • absorbs water from the ground so the plant can survive
  • it has a large surface area
  • it has no chloroplasts
• the xylem and phloem

  • carry water and nutrients up the stem of the plant, to the flower
  • it is very strong, this is so it can hold up the plant without it snapping
• chromosomes

  coiled up lengths of dna molecules, which carry genes. they're found in the nucleus, normally in pairs of body cells.
• cell cycle

  • a series of stages in which cells divide to produce new cells
  • before it divides it
  • grows in size
  • increases the amount of subcellular structures
  • duplicates its dna
• mitosis

  • the stage of the cell cycle when the cell divides
  • it allows growth and repair to damaged cells
• mitosis steps

  • starts with a parent cell and chromosomes
  • the cells dna has been doubled
  • one set of chromosomes is pulled to each end of the cell
  • the cytoplasm and cell membrane divide
  • two cells are formed which are identical to each other
• stem cells

  • undifferentiated cells, which can divide to produce lots more stem cells, and can differentiate into many other types of cells
  • adult bone marrow- many kinds of cells e.g. blood cells
  • human embryo- any kind of human cell
  • plant meristem- any kind of plant cell
• stem cells

  • uses in medicine:
  • stem cells could produce nerve cells, to treat paralysis, or insulin-producing cells to treat diabetes
  • uses in plants:
  • produce clones of whole plants quickly and cheaply, e.g. to grow more plants of a rare species
  • can be grown in a lab and made to differentiate into specialised cells
• diffusion

  • the movement of particles from an area of high concentration to an area of low concentration
  • only very small molecules can diffuse through cell membranes- o2 or glucose
  • factors that increase the rate of it:
  • a high concentration gradient
  • a high temperature
  • a large surface area
• osmosis

  • the movement of water particles across a partially-permeable membrane from an area of high water concentration to an area of low water concentration
  • a type of diffusion
• active transport

  • the movement of a substance against the concentration gradient- requires energy from respiration
  • it allows
  • mineral ions to be absorbed from the soil into root hair cells
  • glucose to be absorbed into the bloodstream from the gut
• surface area to volume ratio

  • single-celled organism:
  • large surface area to volume ratio
  • enough substances can pass across the outer surface to meet needs of organism
  • multicellular organism:
  • small surface area to volume ratio
  • many cells are too far away from outer surface to get substances in and out this way