1.2 Cell types and rules

• Cell theory

  1-all living things are made of one or more cells

  2-cells are the basic structural unit of all organisms

  3-all cells arise from pre existing cells
• prokaryotes: simple single celled organisms (bacteria)
• eukaryotes: complex multi cellular organisms (plants, animals, fungi)
• all cells have a plasma membrane, dna for genetic material and ribosomes to synthesise proteins.
• prokaryotes

  -smaller than eukaryotes

  -have an outer cell wall

  -has no nucleus

  -no membrane bond organelles

  -ribosomes present

  -divide through binary fission
• Eukaryotes

  • Usually larger than prokaryotes (~10-500 μm)

  • Have a cell nucleus

  • DNA is contained in chromosomes

  • Have membrane-bound organelles

  • Usually grouped together to make

  complex multi-cellular organisms

  • Divide through mitosis and meiosis

  • Two types of eukaryote cells
• Eukaryote animal cell

  
• Eukaryote plant cell

  
• Prokaryote cell

  
• Cells are microscopic
• bacterial, prokaryote, 0.4_5 um

  plant, eukaryote, 10-400um

  animal, eukaryote, 10-130um
• Cell shape types

  
• Star shaped - neuron cell

  spherical- egg cells

  columnar- gut cells

  flat-skin cells

  elongated-human smooth muscle cells

  disc shaped- human red blood cells

  cuboidal-human kidney cells
• Cells can also move freely and do not have fixed shapes because of their flexible plasma membrane.
• they include

  -cancer cells

  -white blood cells

  -amoebas
• flagellum

  direction of motion ->
• Cell motion

  
• M-movement: have some level of self powered movement

  r-respiration: the conversion of carbohydrates to a useable energy form

  s-sensitivity to stimuli: the response of an organism to its environment (e.g- plant responding to light)

  g-growth: a irreversible change in mass

  r-reproduction: production of offspring and passing attributes from generation to the next.

  e-excretion of wastes: produce wastes such as dead cells and urine that need to be removed

  n-nutrition: intake of food or nutrients.

  d-DNA: the molecule that codes for the production of proteins.
• An organelle is any specialised structure that performs a specific function.
• Bacterial/microbial

  prokaryote

  small and 0.4-5 micro meters
• Plant

  eukaryotic

  10-400 micro meters
• animal

  eukaryotic

  10-130 micro meters
• The size of prokaryotes is usually 1-2 micro meters.
• The size of eukaryotes ranges from 10-100 micro meters.
• Chromosomes in prokaryotes are present as a single circular DNA molecule.
• Chromosomes in eukaryotes are present as multiple linear DNA molecules.
• Ribosomes in prokaryotes are present in a small size (70S).
• Ribosomes in eukaryotes are present in a large size (80S).
• The plasma membrane (cell membrane) in prokaryotes is present.
• The plasma membrane (cell membrane) in eukaryotes is present.
• Eukaryotes have a cell wall which is present in plants and fungi but not animals and is chemically simple.
• Prokaryotes do not have a membrane bound nucleus.
• Prokaryotes have a cell wall which is chemically complex.
• Eukaryotes have a membrane bound nucleus.
• Prokaryotes do not have membrane bound cell organelles.
• Eukaryotes have membrane bound cell organelles.
• Prokaryotes do not have a cytoskeleton.
• Eukaryotes have a cytoskeleton.
• Prokaryotic organisms belong to the kingdoms Bacteria and Archaea
• eukaryotic organisms belong to the kingdoms Protista, Fungi, Plantae, and Animalia.