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• In both animal and plant cells:

  nucleus

  cell membrane cytoplast

  mitochondria

  ribosomes
• just in plant cells:

  chloroplast

  cell wall

  permeant vacuole
• Nucleus- contains genetic material and controls the activities of the cell.

  cell membrane-controls substances coming in and out of cell.

  cytoplast-chemical reactions take place

  mitochondria-provides cell with energy to function
• Ribosomes -site of protein-synthesis
• Bacterial cells do not have :

  nucleus

  chloroplast

  mitochondria
• Bacterial cells have:

  plasmids- small rigs of dna

  flagella-tail like protein-strand

  slime capsule-stops cell from dying out
• Magnification:

  process of enlarging appearance not the physical size
• magnification-

  image size ~ object size
• Electron microscope-

  invented in 1930’s

  uses electrons , not light

  mag of x2000000
• Factors affecting diffusion-

  temperature -increases rate of diffusion

  surface area-has fold’s in in it has larger surface area increases rate
• Osmosis-

  movement of across a preamble membrane from a less concentrated area to higher solution
• Active transport -

  Active transport allows substances to travel from an area of low concentrationto high concentration, against the concentration gradient.

  It
• active transport-

  needs energy from respiration to work
• diffusion- larger concentration difference means faster rate of diffusion
• active transport allows:

  • minerals to be absorbed into plant root hair from dilute solution in soil
  • glucose molecules to be absorbed from the lower concentrations
• Specialised cells + differentaton

  • Differentiation is the process by which different types of cells develop their specific set of cell structures and become specialised
• specialised cells +differentation

  • as Cells change they develop different subcellor structure , allowing them to carry out different functions
• Plant cells

  • differentiate all throughout their life
• Sperm cell adaptations :

  • tail -allows them to swim to egg cell
  • mitochondria- release energy from reparation to operate tail
  • Acrosome- contains enzymes that allows it to penetrate egg cell
  • Naloud nucleus - half dna needed to make embryo
• Nerve cell-

  • long axon- extends cell, so it connect to diffrent part of body
  • dendries and nerve endings -
  • makes connections allowing communication with other cells
• Phloem cells-

  • sieve plants- allows dissolved sugars move about plant
  • companion cells - keeps cell alive
• what is a stem cell ?

  • a undifferentiated call that can divide to give rise to many more cells of same type
• Stem cells :

  • used in medicine / research
  • embryonic cells used to replace cells
  • mused to make cells for a paralysis patient
• plant Stem cells :

  Meristem tissue in plants can differentiate into any type of plant cell
• Meristem cells can be used for :


  Produce clones for plants quickly and economically
• Meristem can also be used for :

  Clone rare species of plant with special features like resistance to certain diseases
• Exchanging substances if you’re big :

  Large multi cellar organisms can’t get the nutrients needed from diffusion because of small surface to volume ratios .
• have adaptions for exchanging substances :

  large surface area

  thing membrane

  well ventilated

  Efficent blood supply
• Exchanging substances , small intestine is lined with ?

  Lined with finger like villi , increases surface are of walls
• Small intenstine have -

  a single layer surface cell and a network of capillaries

  molecules have a short diffusion difference into blood
• Lungs are responsible for :

  Taking oxygen out of the air and to the cells that need it for anaerobic respiration.
• Longs have :


  Air sacks called alveoli which allow efficient gas exchange
• The alveoli in the lungs provide :

  Massive surface air

  moist lining for dissolving gases

  thin walls for a short diffusion distance

  good blood supply