PLASMA MEMBRANE

Question 1

What is the function of the Cell Membrane?

Answer 1

It forms the BOUNDARY of a cell.

It MAINTAINS the INTERNAL ENVIRONMENT of the cell by CONTROLLING THE MOVEMENT OF SUBSTANCES into and out of the cell.

Question 2

What is the FLUID MOSAIC MODEL composed of?

Answer 2

THE FLUID MOSAIC MODEL OF THE CELL MEMBRANE is composed of:

PHOSPHOLIPID BI-LAYER
PROTEINS
CARBOHYDRATE CHAINS

Question 3

What type of cells are surrounded by a Cell/Plasma Membrane?

Answer 3

ALL CELLS (both PROKARYOTIC and EUKARYOTIC) are surrounded by a cellular membrane.

Question 4

What is the role of the PHOSPHOLIPIDS and PROTEINS in the Cell Membrane?

Answer 4

The PHOSPHOLIPID and PROTEIN parts of the membrane allow the passage of substances into and out of the cell

Question 5

What is the role of the CARBOHYDRATE CHAINS in the Cell Membrane?

Answer 5

CARBOHYDRATE CHAINS are involved in CELL RECOGNITION

Question 6

A PROTEIN attached to a CARBOHYDRATE CHAIN is called a ___________

Answer 6

GLYCOPROTEIN

Question 7

The PHOSPHATE HEADS of the PHOSPHOLIPIDS ARE _______________ and ___________

Answer 7

HYDROPHILIC (loves water) and LIPOPHOBIC (hates fat)

Question 8

The LIPID TAILS of the PHOSPHOLIPIDS are ________ and _________

Answer 8

HYDROPHOBIC (hate water) and LIPOPHILIC (love fat)

Question 9

Whether or not a substance can PASS THROUGH THE CELL MEMBRANE depends on:

Answer 9

THE SIZE OF PARTICLES: particles that are smaller can pass through the membrane more readily, as can large charged molecules.

THE SOLUBILITY OF PARTICLES IN WATER: substances which don’t dissolve in water can’t pass through the cell membrane.

CONDITIONS INSIDE AND OUTSIDE THE CELL: if there is a greater concentration of particles inside the cell, the particles tend to leave the cell (diffusion)

Question 10

Examples of PASSIVE PROCESSES (do not require energy) include:

Answer 10

SIMPLE DIFFUSION
OSMOSIS
FACILITATED DIFFUSION

Question 11

Example of ACTIVE PROCESSES (require energy) include:

Answer 11

ACTIVE TRANSPORT

Question 12

SIMPLE DIFFUSION is….

Answer 12

“The net movement of molecules from a region of relatively high concentration to a region where they are at a lower concentration”

Question 13

The difference between the two regions is known as the:

Answer 13

CONCENTRATION GRADIENT

Question 14

When does Diffusion end?

Answer 14

Diffusion ends when all the molecules are evenly distributed (EQUILIBRIUM)

Question 15

The steeper the CONCENTRATION GRADIENT, the

Answer 15

FASTER THE RATE OF DIFFUSION

Question 16

FACILITATED DIFFUSION is when:

Answer 16

The process of diffusion REQUIRES THE HELP OF OTHER MOLECULES (such as PROTEINS)

Question 17

FACILITATED DIFFUSION is often used when ________ molecules (such as GLUCOSE) need to pass through the Cell Membrane.

Answer 17

LARGER

Question 18

What are the TWO TYPES of PROTEINS involved in FACILITATED DIFFUSION?

Answer 18

Carrier Proteins

Channel Proteins

Question 19

Explain how CHANNEL PROTEINS assist in diffusion.

Answer 19

Channel Proteins OPEN AND CLOSE to allow certain molecules to pass through the cell membrane

Question 20

Explain how CARRIER PROTEINS assist in diffusion.

Answer 20

Carrier Proteins embedded in the cell membrane BIND to molecules, CHANGE SHAPE and RELEASE the molecule on the other side of the cell membrane

Question 21

What is OSMOSIS?

Answer 21

Osmosis is the net movement of water from across a membrane from a high water concentration (low solute concentration) to a low water concentration (high solute concentration).

Question 22

In OSMOSIS, an area where there is a HIGHER SOLUTE CONCENTRATION is described as being _________

Answer 22

HYPERTONIC

Question 23

In OSMOSIS, an area where there is a LOWER SOLUTE CONCENTRATION is described as being ________

Answer 23

HYPOTONIC

Question 24

In OSMOSIS, an area where there is an EQUAL CONCENTRATION OF SOLUTE is described as

Answer 24

ISOTONIC

Question 25

ACTIVE TRANSPORT is defined as:

Answer 25

“The net movement of dissolved substances from a relatively low concentration to a higher concentration”

This requires energy and the use of carrier proteins