Zusammenfassung der Ressource
Cell structure
and processes
- Transport across cells
- Passive processes (do
not require energy)
- Diffusion
- Net movement of molecules
of a substance from a region
of high concentration to a
region of low concentration
until equilibrium is achieved
(only for liquids/gas)
- Concentration gradient -->
difference in concentration
- Moving down/along the
concentration gradient
--> high con. to low con.
- Moving against the
concentration gradient is not
in the lower sec. syllabus
- Example: A hidden durian is brought
into the classroom (the durian smell
would diffuse until the whole
classroom smells evenly of durian)
- Osmosis
- Net movement of water molecules in
a liquid body from a region of higher
water potential through a partially
permeable membrane to a region of
lower water potential until equilibrium
is achieved
- Water potential --> % of
water a substance contains
- Hypotonic to ___ --> solution has a higher water potential
- Isotonic to ___ --> solution has an equal water potential
- Hypertonic to ___ --> solution has a lower water potential
- Symbol for <water potential> --> Ψ
- Active processes
(require energy)
- Active transport
- Structure of cells
- Eukaryotic
(membrane
bound organelles)
- Animal
cell
- Plant
cell
- Prokaryotic
(non-membrane bound
organelles)
- Root
hair cell
- Red blood cell
(erythrocyte)
- Things to know
- Nucleus
- Controls activity of the cell
- Stores genetic information (for reproduction)
- Chloroplast
- Site for photosynthesis
- Mitochondria
- Site of respiration/energy (ATP) production
- Vacuoles
- Storage
- Plasma membrane
- Compartmentalise biochemical reactions
- Regulates substances travelling in & out
- Contains the cytoplasm of the cell
- Cellulose cell wall
- Provide structural support
- Fully permeable
- Note: Cytoplasm --> cytosol + organelles