Movement in and out of cells

Question 1

Why do substances have to go in & out of cells?

Answer 1

For cells to survive, they need to be able to exchange materials between themselves and the environment.

Question 2

How do nutrients get into our cells and wastes get out?

Answer 2

They must cross the plasma membrane.

Question 3

Diffusion

Answer 3

the random movement of gas or dissolved molecules from higher to lower concentration

Question 4

SIMPLE DIFFUSION there is __ energy required

Answer 4

no energy required

Question 5

what is the plasma membrane

Answer 5

• is the boundary that separates the living cell from its nonliving surroundings
• controls the movement of substances entering and waste products to leave.
• is able to change shape easily, grow and expand.

Question 6

Plasma Membrane is called a

Answer 6

• selectively permeable
• partially permeable
• differentially permeable
• semipermeable membrane

Question 7

Plasma Membrane is made up of

Answer 7

• two layers of phospholipids

also known as a phospholipid bilayer

Question 8

why are plasma membranes known as Fluid Mosaic Models?

Answer 8

• as the membrane is like oil, and mosaic because it has proteins and carbohydrates moving around in this oily liquid.

Question 9

what does the steroid cholesterol have effects on?

Answer 9

membrane fluidity

Question 10

Hydrophilic?

Answer 10

‘water-loving’ heads that are attracted to water.

Question 11

Hydrophobic?

Answer 11

‘water-repelling’ tails will

orientate themselves away from water.

Question 12

what is a plasma membrane made of?

Answer 12

two layers of lipid molecules come together to form a BARRIER

Question 13

A range of different proteins are?

Answer 13

• embedded within the membrane.
• rest on the surface or
• penetrate throughout the whole membrane

Question 14

Transport proteins ?

Answer 14

which have openings on both sides of the membrane, forming channels, that allow some substances to move through the membrane

Question 15

Receptor proteins ?

Answer 15

these bind hormones & other substances that cause changes to the cell’s activities

Question 16

Recognition proteins ?

Answer 16

these attach to carbohydrate molecules and act as markers, called ANTIGENS which allow the immune system to distinguish between ‘self’ and foreign invaders

Question 17

Adhesion proteins ?

Answer 17

link cells together

Question 18

Osmosis?

Answer 18

diffusion that only involves the movement of water molecules

Question 19

What does osmosis occur across?

Answer 19

a semipermeable membrane which has tiny holes in it which are small enough for water molecules to pass through but larger molecules cannot pass through.

Question 20

Where do water molecules move from?

Answer 20

a region of high water concentration to a region of low water concentration across a semipermeable membrane

Question 21

What is the movement of water molecules affected by?

Answer 21

the concentration gradient of dissolved substances (SOLUTES) or the concentration of water molecules.

Question 22

what __ energy does osmosis require?

Answer 22

no energy , no atp

Question 23

Isotonic Solutions?

Answer 23

• The concentration of solution is the same outside as it is inside the cell
• There will be NO NET movement of WATER

Question 24

Hypertonic Solution?

Answer 24

• The concentration of solutes is greater outside the cell than it is inside the cell
• The cell will lose water and Shrink.

Question 25

What is Crenation ?

Answer 25

when an animal cells Shrink in a Hypertonic solution

Question 26

Plasmolysis?

Answer 26

when a plant cell loses water→ cytoplasm will pull away from cell wall → cytoplasm shrinks.

Question 27

Hypotonick Solutions

Answer 27

• The concentration of solutes outside the cell is less than it is inside the cell
• The cell will gain water

Question 28

What happens when a plant cells are in a HYPOTONIC solution?

Answer 28

the cell wall will stop the plasma membrane from bursting

Question 29

What happens when a red blood cells are in a HYPOTONIC solution?

Answer 29

it will take in water until it swells and bursts. This is known as HAEMOLYSIS

Question 30

Facilitated Diffusion?

Answer 30

it is diffusion when large molecules need to move across a plasma membrane the process of diffusion requires the assistance of other molecules such as as proteins eg. glucose

Question 31

what is the function of Channel proteins ?

Answer 31

• provide corridors that allow a specific molecule or ion to cross the membrane

Question 32

What is the function of Carrier proteins?

Answer 32

bind to molecules or ions on one side, change shape & release the particular molecule/ion on the other side.

Question 33

What is active transport?

Answer 33

It is when Sometimes substances move into cells from a low outside concentration to a high internal concentration

• Active transport needs energy to make it happen. The cell uses ATP (Adenosine Triphosphate)

Question 34

how do minerals enter the root cell?

Answer 34

• Minerals enter a root cell by active transport.

- The plant uses energy to move minerals up the concentration gradient from the soil into its root cells.

Question 35

ENDOCYTOSIS ?

Answer 35

is the movement of very large particles INTO a cell

Question 36

PHAGOCYTOSIS ?

Answer 36

is the ingestion of large solid particles INTO the cell

Question 37

PINOCYTOSIS ?

Answer 37

is the ingestion of liquid particles – known as ‘cellular drinking’

Question 38

Exocytosis

Answer 38

vesicles transport molecules OUT of the cell

Question 39

In diffusion where does it occur and what is transported and is energy required?

Answer 39

Bilayers of phospholipids , lipid soluble molecules , no energy

Question 40

In osmosis where does it occur and what is transported and is energy required?

Answer 40

Bilayers of phospholipids , water and solvent, no energy

Question 41

In facilitated diffusion where does it occur and what is transported and is energy required?

Answer 41

carrier proteins and protein channels , water and large molecules, no energy

Question 42

In active transport where does it occur and what is transported and is energy required?

Answer 42

carrier proteins , glucose and specific molecules, yes energy