cell junctions & cel membrane

Cell membrane =

Regulates movement of substances (ions/compounds/elements)

Fluid mosaic model

Is the structure and organization of the plasma/cell membrane

Phospholipid bilayer (the fluid component)

Arranged in bilayer (hydrophophilic heads, hydrophobic tails)

Membrane proteins & carbohydrates (the mosaic component)

• embedded within or associated with The lipid bilayer

• Peripheral (Surface)

• Integral (embedded)

Protein to phospholipid ratio

1 protein per 25 phospholipids

Cell surface markers

Specific proteins or glycoproteins displayed on the cell surface act as ID tags

Integral proteins

Deeply embedded tunnels that move materials

Peripheral proteins

Surface anchors that help with signals

Carbon hydrates

Surface “ID tags” (glycoproteins and glycolipids)

Peripheral membrane protein

Are at the plasma membrane’s surface either on its exterior or intention side

Anchored membrane protiensss

A lipid tail keeps the proteins tucked into the membrane

Glycolipid

Carbohydrate attached to a lipid

Glycoproteins

Carbohydrates attached to protein

Proteoglycan

Proteins with many long carbohydrate chains

Cholesterol

Attached between phopholipid and between the two phospholipid layers

Intergins

Embedded within the phospholipid layer ; may or may not penetrate through both layers

Which plasma membrane component can be either found on its surface or embedded in the membrane structure

Protein

What is the primary function of carbohydrates attached to the exterior of cell membranes

Identification of the cell

Lateral movement

Phospholipids slide side to side

Flip flop movement

Molecules shift between the inner and outer layer

Anchored

No movement

Non-anchored

Movement

Saturated (Viscous)

• all single bonds between carbons

• Lower permeability

Unsaturated (fluid)

Presence of carbon double bond

Cannot pack tightly

Higher permeability

In the fluid mosaic model, why is the membrane described as fluid

The phospholipids and proteins can move around laterally within the layer

By energy; passive

No energy needed. Molecule flow naturally

By energy; active

Needs energy to push molecules uphill

By direction; Uniport

Moves one molecule at a time

By direction ; symport

Move two different molecules in the same direction

Antiport ; by direction

Moves two different molecules in opposite directions

Transport process involves a single enzyme or transporter

Individual ; enzymatic activity

Transport process involves multiple enzymes or transporter proteins

Linked groups

Signal transduction

Cells receive and responds to signals

The receptor

A protein on the outside catches a specific signal

The relay

The protein changes shape and passes the message

The response

The call acts on the message like growin, moving, or making new stuff ?

Proteins hook onto the cytoskeleton to maintain its shape

Internal support

Proteins also grab the extracellular matrix

The cell membrane is selectively permeable. What type of molecules can diffuse directly across the lipid layer

Non polar

Cell junction

The specific door, bolt or vent connecting two buildings

Tight junction

Creates a firm seal between two adjacent animals cells

Desmonsomes

Provide intense mechanical strength

Gap junction

Direct channel between two adjacent animals cells that allowing and nutrient to pass between cells