Transport Across Cell Membranes Flashcards
What is the cell membrane
The cell membrane consists of phospholipids and proteins and is selectively permeable
What is passive transport
Passive transport occurs down a concentration gradient and does not require energy
What are two examples of passive transport
Diffusion & osmosis
What is Diffusion
Diffusion is the movement of molecules down a concentration gradient from a higher to lower concentration
What is osmosis
Osmosis is the movement of water molecules from a higher water concentration to a lower water concentration through a selectively permeable membrane through a selectively permeable membrane
What do animal cells or plant cells do when diffusion or osmosis occurs
Animal cells can burst or shrink and plant cells can become turgid or plasmolysed
Active transport requires ……… for membrane proteins to move molecules and ions against the concentration gradient
Fill the blank
Energy
All cells are enclosed by a _____ ________ . This structure has __ layers
- Cell membrane
2. 2
Where is the Extracellular environment?
It is the area outside of the cell
Each layer of the cell membrane has 2 components, name them both
Phospholipids and proteins
What do the phospholipids do?
The phospholipid molecules are able to move around within the layer and give the cell membrane flexibility
Where can you find protein molecules
Protein molecules are found embedded in the two layers of the phospholipids
Cell membrane is selectively permeable. What does this mean?
It lets some substances pass through rapidly and some substances pass through more slowly, but prevents other substances passing through it at all
Name some smaller molecules that can pass through the phospholipids in the cell membrane
Water, oxygen and carbon dioxide
Larger molecules such as glucose require __ ______ ___________ _______to facilitate their movements across the cell membrane
A specific transport protein
