Cell Membrane Plasma Membrane TEAM BIO Cell Membrane

Cell Membrane (Plasma Membrane) TEAM BIO

Cell Membrane: • Controls/Regulates what enters and leaves cell Cell Membrane can bend and move back and forth – IT’S FLUID

Questions: • How does the Cell Membrane maintain HOMEOSTASIS?

Identify the structure that allows molecules to enter/leave the cell:

Cell (plasma) membrane • Molecules come in…. • Molecules go out…. IN food - sugar - protein - fat - salt - O 2 - H 2 O OUT waste - salt - CO 2 - H 2 O cell brings materials in & products or waste out

Cell Membrane made up of: Lipid (fat) Bi-Layer: “ 2” layers of lipids (fats) With: Receptor Proteins: in between the lipids ØTransport molecules in/out of cell

Bi-Lipid Layer inside cell outside cell

Watch it wiggle…See it jiggle… Receptor Protein

PROTEIN/RECEPTOR MOLECULE “Hello – May I help you? Oh you’d like to enter? Sure, Come on in!” inside cell waste H 2 O salt aa sugar outside cell

Question: • What is the cell membrane made up of? • Which of these parts helps molecules enter the cell?

***Selective Permeability*** (Semipermeable) Plasma Membrane (chooses) ►Selects what can enter/what cannot enter ►Molecules are “selected” based on: ________& _______ of the molecule

How do molecules ENTER? ► 1 st : Receptor Protein recognizes molecule that wants to enter ► 2 nd : Receptor protein: changes shape to match shape of molecule ► 3 rd: Receptor pulls molecule in and molecule moves to correct organelle

Similar to a LOCK and a KEY LOCK Entering Molecule Receptor Protein

Shape of Receptors • What shape will Receptors have to become if the molecule is shaped like a

The shapes fit together

Will the orange molecule get in? Why/Why Not? • ____________________

Will the RED MOLECULE enter?

The diagram below represents a portion of a cell membrane. Which structure may function in the recognition of chemical signals? (1) A (3) C (2) B (4) D The diagram below represents two molecules that can interact with each other In order for entry into the cell. Molecules A and B most likely represent (1) a protein and a chromosome (2) a receptor protein and a hormone molecule (3) a carbohydrate and an amino acid (4) an antibody and a hormone