Cells as the Basis of Life Flashcards
Cell theory states…
- all organisms composed of cells
- basic unit of life
- cells arise from pre-existing cells
- unicellular or multicellular
Progression…
Molecules, cells, tissues, organs, systems
Prokaryotic cells
Appear more simple unbound, circular DNA, cytosol (no true nucleus) Few membrane bound organelles smaller by comparison exist as single cells
Eukaryotic cells
Appear more complex
DNA protein bound linear chromosomes in nucleus
Many complex organelles
Larger by comparison
Plant cells
Cell wall
Chloroplast
large centralized vacuole
Animal cells
numerous small vacuoles
cell membrane structure
phospholipid bilayer
proteins eg cannel
carbohydrates - recognition
Cholesterol - stability permeability
cell membrane function
controls movement of substances.
Impermeable to water soluble molecules, ions, polar molecules.
Permeable to lipid soluble
small uncharged molecules, large water soluble substances (active)
diffusion
Movement of solute from a region of high concentration to a region of low concentration, across a semipermeable membrane until reaching equilibrium.
Osmosis
Movement of water from a region of high concentration to a region of low concentration, across a semipermeable membrane
Osmotic gradient
Hypertonic
High solute concentration.
GAINS water
Hypotonic
low solute concentration
LOSES water
Isotonic
Same solute concentration.
No net flow of water
Turgid
High water, able to hold shape normal
Flaccid
isotonic, normal
Plasmolysed
low water, cell membrane retracts from cell wall
Lysed
bursts, too much water (ANIMAL)
Exocytosis
secretes molecules OUT
vesicles fuse with cell membrane
Requires ENERGY
Endocytosis
uptake
cell membrane to vesicles
pinocytosis (water)
Phagocytosis (solid)
