Cell Membrane Phospholipid Movement

Questions and Answers

What is the main component of the cell membrane being focused on in this video?

Phospholipids (correct)

Proteins

Cholesterol

Cell wall

What is the term used to describe the movement of phospholipids from the outer leaflet to the inner leaflet?

Transmembrane diffusion

Transbilayer diffusion (correct)

Lateral diffusion

Osmosis

What is the difference between intracellular and intercellular?

Intracellular refers to the outer leaflet, while intercellular refers to the inner leaflet

Intracellular refers to the inner leaflet, while intercellular refers to the outer leaflet

Intracellular refers to inside the cell, while intercellular refers to between cells (correct)

Intracellular refers to between cells, while intercellular refers to inside the cell

What is the term used to describe the movement of phospholipids without the need for a catalyst?

Uncatalyzed diffusion Signup and view all the answers

What is the nickname for transbilayer diffusion?

Flip-flop Signup and view all the answers

What is the region of the cell membrane that borders the extracellular environment?

Outer leaflet Signup and view all the answers

What is the region of the cell membrane that borders the intracellular environment?

Inner leaflet Signup and view all the answers

Why is the cell membrane drawn in a simplified form in this video?

To focus on the phospholipids Signup and view all the answers

What is the main difference between transbilayer diffusion and lateral diffusion?

Direction of movement of phospholipids Signup and view all the answers

What is required for catalyzed movement of phospholipids?

Both ATP and protein catalyst Signup and view all the answers

What is the function of flippase?

To move phospholipids from inner to outer leaflet Signup and view all the answers

What is the primary source of energy for catalyzed movement of phospholipids?

ATP Signup and view all the answers

What is the function of floppase?

To move phospholipids from inner to outer leaflet Signup and view all the answers

Which of the following statements is TRUE about scramblase?

It does not use ATP Signup and view all the answers

What is the result of uncatalyzed movement of phospholipids?

Slow and infrequent movement Signup and view all the answers

What is the fluid mosaic model?

A type of cell membrane structure Signup and view all the answers

Study Notes

Phospholipid Movement in the Cell Membrane

Phospholipids in the cell membrane are tightly packed and move around
The cell membrane has two layers: the outer leaflet (facing the extracellular environment) and the inner leaflet (facing the intracellular environment)

Uncatalyzed Movement

Uncatalyzed movement occurs without a catalyst
Types of uncatalyzed movement:
- Transbilayer diffusion (flip-flop): phospholipids move from one leaflet to the other (e.g., from outer to inner leaflet or vice versa)
- Lateral diffusion: phospholipids move side to side within a leaflet, allowing movement in any direction around the cell membrane

Catalyzed Movement

Catalyzed movement requires a protein catalyst
Types of catalyzed movement:
- Flippase: uses ATP and helps phospholipids move from the outer leaflet to the inner leaflet
- Floppase: uses ATP and helps phospholipids move from the inner leaflet to the outer leaflet
- Scramblase: does not require ATP and helps phospholipids move in both directions between the leaflets