Cell Membranes

Front 1

The roles of membranes within and at the surface of cells

Back 1

separating cell contents from the outside environmentseparating cell components from the cytoplasmcell recognition and signallingholding the components of some metabolic pathways in placeregulating the transport of materials in and out of cells

Front 2

The plasma membranes are ________________ barriers

Back 2

Partially permeable

Front 3

What is the structure of the fluid mosaic model of a membrane structure?

Back 3

A bilayer of phospholipid molecules forming the basic structure

various protein molecules forming the basic structure, some completely freely some bound to other components of structures within the cell

some proteins partially embedded in the bilayer on the inside or outside

Front 4

Describe the role of phospholipids

Back 4

They form the membranes that surround the cell and intracellular organelles.

separates the cells contents from the environment

Front 5

Describe the role of cholesterol

Back 5

Gives the membranes of some eukaryotic cells mechanical stability

fits between the fatty acid tails and makes the barrier more complete

so substances like water molecules and ions cannot pass easily and directly through the membrane

Front 6

Describe the role of glycolipids

Back 6

To provide energy

serve as markers for cellular recognition

Front 7

Describe the roles of glycoproteins

Back 7

Allow hormones to bind onto them

Front 8

Describe the role of channel proteins

Back 8

Allow the movement of some substances across the membrane. (larger molecules)

Front 9

Describe the role of carrier proteins

Back 9

Actively move some substances across the membrane using ATP

Front 10

What is the effect of changing temperature on the membrane

Back 10

Increasing temperature gives molecules more kinetic energy

increased movement makes the membranes leaky which allows substances that usually do not do so enter or leave the cell

Front 11

What is cell signalling?

Back 11

Cells can communicate with one another by signals.

many molecules act as signals- some signal during processes taking place inside cells; others signal from one cell to another

Front 12

What is the role of membrane-bound receptor sites where hormones and drugs can bind?

Back 12

Any cell with a receptor for the hormone molecule is called a target cell

A hormone binds to a receptor on a target cell surface membrane.

Binding of the hormone and receptor causes the target cell to respond in a certain way

Front 13

What is passive transport? (diffusion and facilitated diffusion)

Back 13

Transport that relies on molecules moving freely.

the molecules possess kinetic energy that keeps them moving

They diffuse down a concentration gradient

Front 14

What is active transport?

Back 14

The movement of molecules or ions across membranes

which uses ATP to drive protein 'pumps' within the membrane

Front 15

What is endocytosis?

Back 15

Moves large quantities of materials into the cell (ATP)

Front 16

What is exocytosis?

Back 16

Moves large quantities of materials out of the cell (ATP)

Front 17

What is meant by osmosis in terms of water potential

Back 17

It refers to the movement of water molecules via diffusion and across a partially permeable membrane

The movement of water molecules from a region of high concentration to low concentration

Front 18

The effect that solution of different water potentials have upon plants and animals

Back 18

High water potential: water will go inside the cell. the cell will swell in animal cells this will eventually cause them to burst

low water potential: Water will go outside the cell, the cell with shrink and the membrane will wrinkle up. In plant cells the membrane will pull away from the cell wall