Download Cell Notes - Sardis Secondary

Cells
Cell Theory
1. 
All living things are composed of one or more cell
2. 
Cell is the basic unit of life
3. 
All cells come from the division of pre-existing cells
Cells are divided into 2 categories:
•  Prokaryotes (bacteria):
•  No nucleus
•  No membrane bound organelles
Prokaryotic vs. Eukaryotic
  Euakryotic cells are generally one to one hundred times
bigger than prokaryotic cells
Anatomy of a Plant Cell
Anatomy of an Animal Cell
Animal Cell vs. Plant Cell
Animal Cell
1. No chloroplasts
Plant Cell
1. Chloroplasts
2. Cell membrane only
2. Cell membrane & cell wall
3. Centrioles
3. No centrioles
4. Small vacuoles (H2O and food)
4. Large central vacuole
Cell Membrane
  Thin membrane made of lipid and protein
  The Fluid Mosaic Model
  The properties of a solid and a liquid
  Forms a “fluid sea” in which proteins,
lipids, and carbohydrates are suspended
or anchored at various points on its
surface
  The “mosaic” part refers to the
different proteins embedded in the
bilayer
  Selectively permeable (a.k.a. semipermeable)
  The membrane will let some substances
cross but not others of the same size
Phospholipid Bilayer
  Phospholipid bilayer
  The cell membrane is made up of
two layers of phospholipids
  Phospholipid molecules
  Phosphate head – HYDROPHILIC
(“water-loving”)
  Two Lipid (fat) tails are
HYDROPHOBIC (“water-fearing”)
Structure
Function
P/A/Both
Nucleus
Large centrally located organelle that controls cellular functions including
metabolism and reproduction.
B
Mitochondria
The cell’s powerhouse. Where energy is produced by converting glucose
into ATP via a reaction called cellular respiration.
B
Rough ER
A system of membranous tubular canals that are studded with ribosomes.
This is the site of protein synthesis.
B
Cell Wall
Gives the cell its shape and provides protection.
P
Cytoplasm
A gel like fluid that suspends the cell’s organelles.
B
Ribosome
Composed of rRNA and proteins. Made up of 2 non-identical subunits.
The site of protein synthesis.
B
Centriole
A barrel shaped organelle involved in cell organization and replication.
A
Nucleolus
Found in the centre of the nucleus. This organelle is involved in rRNA
synthesis.
B
Cell
Membrane
This semi-permeable double layer is composed of phospholipids, proteins,
carbohydrates, and cholesterol. Controls what enters and exits the cell.
B
Structure
Function
P/A/Both
Chloroplast
A organelle green in colour that is involved in photosynthesis. This
process involves the conversion of light energy into chemical
energy.
P
Vesicle
A small membrane-bound sac that stores and transports substances
within the cell.
B
Nuclear Envelope A double membrane composed of phospholipids that separate the
B
nucleus from the rest of the cell.
Smooth ER
A system of membranous tubular canals that lack ribosomes.
Involved in lipid synthesis, storage and the detoxification of
chemicals and drugs in the cell.
B
Lysosome
A cellular “stomach” involved in digestion of bacteria, autodigestion of damaged cell components, and cell suicide.
A
Central Vacuole
Large fluid filled organelle that stores food and wastes. Also
maintains turgor pressure against the cell wall.
P
Golgi Apparatus
An organelle involved in modification, assembly, packaging,
storage and secretion of substances.
B
Cell Transport
Passive Transport (no energy)
Active Transport (energy)
1. Simple Diffusion
4. Active Transport
2.  Osmosis
5. Endocytosis and Exocytosis
3. Facilitated Transport
1. Simple Diffusion
  Law of Diffusion:
  molecules move from [high] to [low]
  i.e. along the concentration gradient
  Requires no energy
  Diffusion is a slow process
  To increase the rate of diffusion:
  Increase the temperature
  Increase the concentration gradient
  Decrease the size of the diffusing molecules
2. Osmosis (Diffusion of Water)
  The net movement of water molecules across a
selectively permeable membrane; from an area of high
water concentration to an area of low water
concentration
  Solute: particles which are dissolved in water
  Solvent: liquid which dissolves the solute
  Solution: combination of solute and solvent
2. Osmosis (Diffusion of Water)
• 
Cells may be placed in solutions:
•  Isotonic solution (“same strength” solution):
•  The solution contains the same number of solute
molecules per volume as the cell
•  No net movement of water across the membrane
•  Hypertonic solution (“greater strength” solution)
•  The solution has a greater number of solute
molecules per volume than the cell
•  Net movement of water out of the cell
•  Crenation (animals) or plasmolysis (plants): cell
will shrivel up
•  Hypotonic solution (“lesser strength” solution)
•  The solution has a lesser number of solute
molecules per volume than the cell
•  Net movement of water into the cell
•  Lyse: cell will burst

Osmosis in a blood cell
Osmosis in a plant cell 
3. Facilitated Transport
  Uses protein carriers to transport molecules
  Protein carriers are specific to the type of molecule
  Molecules move from [high] to [low] (i.e. along the
concentration gradient)
  Requires no energy
4. Active Transport
  Uses protein carriers to transport molecules
  Protein carriers are specific to the type of molecule
  Moves molecules from an area of [low] to [high] (i.e.
against the concentration gradient)
  Requires energy in the form of ATP
5. Endocytosis
Endocytosis
  Cell membrane forms a vesicle
around the substance to be taken
in
Phagocytosis
  Endocytosis where large particles
are taken in (“eating”)
Pinocytosis
  Endocytosis where small particles
are taken in (“drinking”)
5. Exocytosis
Exocytosis
  Vesicle within cell fuses with cell membrane
and the vesicle contents are deposited on the
outside
  Secretion and excretion in cells
DNA
  Nucleus, chromosomes, DNA, gene, base pairs,
nucleotides