MEMBRANE STRUCTURE AND FUNCTION

Label the structure of the cell membrane

Phospholipid

Label the cell membrane

Functions of the phospholipids and carbohydrates

Functions of membrane proteins Activity 5E

MEMBRANE TRANSPORT

Simple Diffusion Definition: What is the energy source of the diffusion? Is it an active or passive transport?

What are the factors that affect diffusion rate: 1- the concentration gradient 2- temperature 3- size of the molecule 4- charge of the molecule 5- lipid solubility of the molecule

Diffusion of solvent

Hypertonic solution: Hypotonic solution: Isotonic solutions:

Transport across membranes 2. Transport with a protein Facilitated diffusion Active transport 3. Transportation of large molecules (bulk transport) Endocytosis Exocytosis 1. Simple diffusion Diffusion of solute Diffusion of solvent

Plasmolysis: Deplasmolysis:

Osmotic pressure: the tendency of a solution to take up water Turgor pressure: the force applied to a cell wall after the swelling of the cell .

What is the water balance problem of the cells which do not have cell wall?

What is the water balance problem of the cells which have cell wall?

Facilitated Diffusion

Fig. 5.6 Solute molecule Transport protein Figure 5.6 Transport protein providing a channel for the diffusion of a specific solute across a membrane. Transport protein 23

Facilitated Diffusion 1 Definition: Does not require ATP Which molecules are transported by facilitated diffusion?

Fig. 5.8 Transport protein Protein changes shape Phosphate detaches Solute Figure 5.8 Active transport of a solute across a membrane. 1 Solute binding 2 Phosphorylation 3 Transport 4 Protein reversion

Active Transport 1 Definition:

Which one is passive transport?

Exocytosis

The cell secretes macromolecules by the fusion of vesicles with the plasma membrane This process is called exocytosis

Endocytosis

In endocytosis, the cell takes macromolecules and particulate matter by forming new vesicles from plasma membrane.

There are two types of endocytosis: 1. Phagocytosis 2. Pinocytosis

Active transport animation

In phagocytosis, a. the cell engulfs a particle by wrapping pseudopodia (false feet) around it b. And packages the particle within a membrane- enclosed sac WBC, amoeba

In pinocytosis, the cell ‘gulps’ droplets of extracellular fluid into tiny vesicles

Fig. 5.9