Cellular Transport Review

Cell Transport

An interactive active transport review

Active Transport

• movement of substances from areas of low concentration to areas of high concentration through transport proteins

• molecules move against their concentration gradient

• active transport requires energy (ATP)

Multiple Choice

Active transport _______ and is the movement of a substance from _____ to _____ concentration

• requires energy, high to low
• requires no energy, low to high
•  requires no energy, high to low
•  requires energy, low to high

Active transport uses protein pumps!

• molecule to be transported enters the pump

• energy from ATP used to change the shape of the protein

• molecule can now pass through the membrane (via the protein)

Open Ended

Caption this figure using the following terms: energy, gradient, protein, ATP, membrane

Bulk Transport

• Also a type of active transport

• How really big molecules (or a lot of them) move across the membrane at once

Endocytosis

process by which cells take in molecules (like hormone proteins) or small cells by engulfing them

Phagocytosis

• literally means "cell eating"

• large particles like cells or cellular debris are transported into the cell

A macrophage (type of white blood cell) engulfs a pathogen

An amoeba uses phagocytosis to feed!

Pinocytosis (left)

• literally "cell drinking"

• cell takes in small amounts of extracellular fluid

• vesicle produced much smaller for pinocytosis than phagocytosis

Receptor-Mediated Endocytosis (right)

• receptor proteins embedded in cell membrane used to identify and capture specific molecule

• only that specific molecule should trigger this reaction

• some pathogens use these proteins to gain entrance to the cell (sneaky jerks)

Exocytosis

• form of bulk transport

• how cells release molecules like signaling proteins and waste products to the outside environment

• membrane-bound vesicle fuses with plasma membrane and release the material

Secretion of neurotransmitter acetylcholine

at a synapse between neurons

No follow-up questions about endo and exocytosis.

• This is NOT a common topic on the final exam from IB

• What does that tell you about what you should study?