Transport Across the Cell Membrane

Question 1

What is facilitated diffusion?

Answer 1

Is a passive process

Diffuses certain substances that can’t diffuse directly through phospholipid bilayer of cell membrane.

instead diffuses through carrier proteins or channel protein and it doesn’t require energy.

Question 2

what are the large molecules that can’t diffuse directly through phospholipid bilayer in CM?

Answer 2

amino acid
glucose
changed particle e.g ions

Question 3

What is carrier protein?

Answer 3

moves large molecules in and out of cell
down the concentration gradient
different carriers protein facilitates diffusion of different carrier protein.

Question 4

How does carrier proteins work?

Answer 4

In membrane;
larger molecule attach to carrier protein
protein changes shape
this releases the molecule on other side of membrane.

Question 5

How does protein channel work?

Answer 5

In membrane channel protein;
forms pores for charged particles to diffuse through
different channel protein facilitates diffusion of different charged particles.

Question 6

What is active transport?

Answer 6

Uses energy to move molecules and ions across plasma membrane, against concentration gradient through the process of carrier proteins.

Question 7

How the process of active transport works?

Answer 7

In membrane;
larger molecule attach to carrier protein
protein changes shape
this releases the molecule on other side of membrane.

but it uses energy which come from ATP;
*ATP produced by respiration
*acts as immediate source of energy in cell
*ATP is hydrolysed which releases energy in cells to move molecules against concentration gradient.

Question 8

what is endocytosis?

Answer 8

is a term describing the process by which cells absorb external materials by engulfing it with cell membrane

Question 9

what is the process of endocytosis?

Answer 9

takes in the large molecules that cant me taken in by carrier proteins, so the cell surrounds the substance with section of cell membrane

membrane pinches off to form vesicle inside cell containing ingested substance

even larger abjects like white blood cells (phagocytes) are taken in cell by endocytosis to take in microorganisms and dead cell to destroy them.

like active transport it uses energy aswell.