Chapter 1 - Cell Ultrastructure & Movements Flashcards
What type of process is diffusion?
Passive
What is diffusion?
Movement of molecules from a high concentration to a low concentration until an equal concentration is achieved
Does diffusion show substances moving up or down a concentration gradient?
Down as it requires no energy
What is osmosis?
Movement of water molecules from a HWC to a LWC through a selectively permeable membrane
What type of movement is osmosis?
Passive
Is osmosis up or down a concentration gradient?
Down, as it requires no energy
What is active transport?
Movement of molecules from a HC to a LC
Does active transport require energy?
Yes it is an active process
Active transport - signifies a movement of up or down a concentration gradient?
Up, as it requires energy
How are the ions in active transport pumped across the membrane?
Protein carriers
Associate active transport with a cellular process
ALWAYS respiration
Hypotonic
More water
Hypertonic
Less water
Isotonic
Equal water
What is endocytosis?
Cell engulfs large molecules - ENTERS
Example of endocytosis
Phagocytosis
What is exocytosis?
Secretion of large molecules by membrane movements - EXITS
What is the cell membrane?
Outer boundary in animal cells - inner boundary in plant cells
What structure is the cell membrane?
Phospholipid bilayer - patchy arrangement of proteins making it have a fluid mosaic structure
The plasma membrane is …… permeable
Selectively
Give 4 examples of the uses of proteins in the cell membrane
Receptor for hormones Enzyme Protein carrier Supporting protein Channel-forming protein Anti-genic marker
What is the cell wall?
Outer boundary in plant cells
What is the cell wall made from?
Cellulose fibres and pectin
The cell wall gives the cell…
Structure, strength and slight elasticity
The cell wall prevents…
The cell from bursting
The cell wall is ….. permeable
Freely
