Cellular processes Flashcards
Name the type of cell:…
- no membrane bound organelles
- Small
- Relatively unstructured
- Not organised internally
- A type of cell wall.
Prokaryotic (bacterial) cells.
Name the type of cell:
- Membrane bound
-Larger than prokaryotic cells (many are multi-cellular organisms)
- More complex than prokaryotes
Eukaryotic cells.
Organelles definition
Specialised structures inside the cell that carry out various functions.
- Contains phospholipid bilayer made of two layers with hydrophobic tails and hydrophilic heads.
- Proteins move freely in this fluid/flexing structure
- Certain substances are able to move in and out of cell.
Cell membrane structure (semi-permeable)
Cell membrane function. (compartments)
Membranes create compartments, control entry and exit and allow cell communication.
- No energy required
- substances move from high to low concentration
- substances move with the concentration gradient
passive transport
Diffusion
passive transport
is the net movement of particles from an area of high concentration to an area of low concentration., until concentration equilibrium is met.
Factors that affect rate of diffusion
- size of molecules ( small molecules move faster)
- temperature (warmer molecules move faster
- state of matter (gas molecules move faster than liquids
- concentration of chemicals (greater concentrations gradient the faster the rate of diffusion.)
Diffusion of cells in relation to cell size.
Diffusion is less efficient when cells are larger.
As ratio of surface area to cell volume decreases.
Facilitated diffusion
- Passive transport
- Transportation of molecules that are too big to move across cell membrane.
- Requires proteins embedded in cell membrane.
- Proteins contain channels molecules diffuse through
- Transport molecules are specific.
Osmosis.
Transportations of water molecules from high water concentration to low water concentration. Transport molecules towards highest solute concentration.
Hypertonic solution
more solute than water molecules.
Hypotonic solution:
More water molecules than solute molecules.
Isotonic solution.
equal amounts of solute and water molecules.
If you put a cell in a hypertonic solution….
water moves from high water concentration to low concentration outside the cell.
If you put a cell in a hypotonic solution….
water moves from high water concentration to low water concentration, inside the cell.
A hypotonic solution can cause the cell to….
burst/ cell rupture.
A hypertonic solution can cause the cell to….
shrink.
Active transport
substances that require energy (ATP) to enter the cell. Substances travel against the concentration gradient.
How does ATP work in relation to creating energy and moving molecules against concentration gradient.
- ATP binds to transport protein.
- Molecule/ ion binds to protein.
- Water is added to ATP, and energy (phosphate) is released and ADP is formed - molecule moves across membrane)
- molecule is released.
What is endocytosis? Active or passive transport?
infolding of membrane to form vesicles that enter cytoplasm. If it contains liquid it is Pinocytosis. And if it’s solid it is Phagocytosis.
Active transport
What is exocytosis. Is it passive or active transport?
vesicles from intracellular environment fuse with membrane and releases content outside of cell.
Active transport.
Carrier proteins: Ion pumps
Active or passive?
are transmembrane proteins that use energy to move ions.
Active transport.
- made of proteins
- speed up chemical reactions in cytoplasm.
- needed only in small amounts
- remain unchanged after reaction.
- specific for a substrate.
Properties of Enzymes.
Plasmolysis
Membrane that pulls aways from the cell wall. This happens when cell shrinks inside its cell wall while the cell wall remains intact.
Anabolic reactions
small molecules assembled into larger ones. Energy is required.
Catabolic reactions
larger molecules are broken down into smaller ones.
Energy is released.
Lock and key model.
Substrate has specific shape which fits perfectly into enzyme’s active site
Induced fit model
enzymes active site is flexible and changes to fit substrate.