Cell Structure, Metabolism & Transport

Cell Structure
1. Cell Membrane
  1. surrounds cell and fills outer boundary
  2. made up of a double layer of lipid molecules and proteins
2. Cytoplasm
  1. thick fluid, fills inside of cell
3. Organelles
  1. Golgi Body
    1. stack of flattened channels; packages proteins for secretion from the cell
  2. Mitochondria
    1. 'powerhouses' of the cell
    2. working organelles that keep the cell full of energy
  3. Nucleus
    1. large organelle, contains DNA
  4. Lysosomes
    1. break down materials that are taken into cell, break down worn-out organelles
  5. Centrioles
    1. located near nucleus, involved in cell division
  6. Endoplasmic reticulum
    1. forms channels through cytoplasm, used for storage, support, synthesis and transport within the cell
    2. rough ER contains ribosomes attached to outside of membrane
  7. Ribosomes
    1. amino acids joined together at ribosomes to make proteins
4. Cytoskeleton
  1. assists in cell movement, protein fibres
Structure of Cell Membrane
1. fluid mosaic model
2. phospholipid bilayer; main structure
  1. contains hydrophilic and hydrophobic heads and tails
3. cholestrol and protein molecules embedded in phopholipid bilayer
4. channel proteins, pore that allows ions, water and small molecules to pass through
Types of Transport
1. Diffusion
  1. passive, high conc -> low conc
  2. substances: alcohol, steriods, fat-soluble substances, O2, CO2
  3. results in random movement of particles
2. Osmosis
  1. passive, diffusion of water, high conc -> low conc
  2. important for living cells, results in osmotic pressure
3. Carrier- Mediated
  1. carrier proteins bind to molecules for transport, proteins are specific
  2. can become saturated -> max rate of transport
  3. carrier proteins can be regulated by hormones
4. Facilitated-Diffusion
  1. passive; still diffusion, high -> low conc
  2. substances: glucose, amino acids
5. Active Transport
  1. needs energy, happens against conc. gradient, low -> high conc
  2. substances: glucose, certain ions, amino acids
6. Vesicular Transport
  1. always active, needs energy as vesicles (memranous bags) need to be built
    1. Endocytosis (into cell) -> cholestrol, iron ions
    2. Pinocytosis (liquids) Phagocytosis (solids - cell debris, microrganisms)
    3. Exocytosis (out of cell), contents of vesicles are pushed out through cell membrane
      1. mucus, enzymes, breastmilk
Tissues
1. Epithilium
  1. covers and lines organs/hollow organs, ducts
  2. location: outer layer of skin, lining of stomach, covering of heart
2. Connective
  1. provides support and helps hold all body parts together
  2. location: bone, ligaments & tendons, fat storage, tissue, cartilage
  3. non-cellular material - matrix, cells not close together
3. Muscular
  1. responds to a stimulus by contracting, becoming shorter
  2. skeletal (voluntary, striated), attaches to bones
    1. involuntary (smooth, non-striated), iris, uterus, stomach, intestines, walls of blood vessels
4. Nervous
  1. when part of a neuron is stimulated messages are carried along these projections
  2. location: brain, spinal cord & nerves
Cell Metabolism
1. Anabolism - needs energy, e.g Protein synthesis
  1. Catabolism - releases energy, e.g Cellular respiration
  2. also known as Synthesis
2. Organic Compounds
  1. Carbohydrates
    1. main source of energy, contains C, H, O2
    2. simple unit: Monosaccharides (glucose), Disachharides (lactose)
      1. complex unit: Polysaccharides (starch, glycogen)
  2. Proteins
    1. enzymes and structural materials, brokendown for energy, contains C, H, O2, N - often P, S
    2. simple unit: Amino acids (glycine, alanine), Peptides (dipeptide)
      1. complex unit: all Enzymes, Proteins contain 100+ Amino acids
  3. Lipids
    1. store energy, phopholipid bilayer, steriods, contains C, H, O2
    2. simple unit: Glycerol, Fatty acids
      1. complex unit: Triglyceride
  4. Nucleic Acids
    1. RNA, DNA, large molecules, contains C,H, O2, N ,P, made of nucleotides
    2. simple unit: RNA
      1. complex unit: DNA
3. Cellular Respiration
  1. glucose + oxygen -> carbon dioxide + water + energy
4. ATP/ADP
  1. tranporter of energy, Adenosine Triphosphate, continually recycled
  2. formed when energy releases, Adenosine Diphophate can be reused to store energy from Cellular Respiration
5. Anaerobic Respiration
  1. respiration that does not require energy, allows cells to produce energy when no oxygen
  2. glucose -> lactic acid + energy
6. Aerobic Respiration
  1. glucose + oxygen -> carbon dioxide + water + energy
  2. requires oxygen

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	Criado por Courtney Kennedy mais de 9 anos atrás