Molecule Movement

Question 1

5 processes molecules move across membranes

Answer 1

. Diffusion (Facilitated and Simple)
. Osmosis
. Active transport
. Bulk transport

Question 2

Simple Diffusion defined

Answer 2

. Random Net movement of particles from a region of high to low concentration

Question 3

Does simple diffusion require energy?

Answer 3

No

Question 4

Does simple diffusion require a membrane?

Answer 4

. No

Question 5

Simple Diffusion goes ________ the concentration gradient

Answer 5

Down

Question 6

Summary of Simple Diffusion Process

Answer 6

. Molecules will move from an area of high to low concentration till equilibrium is reached
. Is passive (no energy)
. Will diffuse across the membrane

Question 7

Examples of substances moving by simple diffusion

Answer 7

. Small and non-polar molecules

. eg has exchange at the alveoli

Question 8

Facilitated diffusion definition

Answer 8

. Passive movement of molecules down a conc gradient across a membrane
. Involves special carrier and channel proteins in the membrane

Question 9

Does facilitated diffusion require energy?

Answer 9

No

Question 10

Does facilitated diffusion require a membrane?

Answer 10

Yes

Question 11

Facilitated diffusion goes ________ the concentration gradient

Answer 11

Down

Question 12

Brief summary of facilitated diffusion process

Answer 12

. If carried by carriers will move
. Carrier= Will change shape for specific molecules and will facilitate diffusion
. Channel= For pores/channels for molecules/ions to pass through

Question 13

Examples of substances using facilitated diffusion

Answer 13

. For large and polar molecules

. Glucose, sodium ions and potassium ions

Question 14

Definition of Osmosis

Answer 14

Movement of water molecules from an area of high to low concentration

Question 15

Does osmosis require energy?

Answer 15

No

Question 16

Does osmosis require a membrane?

Answer 16

No

Question 17

Brief summary of osmosis process?

Answer 17

. Water will move from a high to low conc
. Water molecules will pass through a partially permeable membrane
. This will continue till equilibrium is reached

Question 18

Examples of substances moving by osmosis

Answer 18

. Water molecules only

. Example would be potato chip experiment

Question 19

Definition of Active Transport

Answer 19

Movement of ions or molecules across a cell membrane into a region of low to high concentration

Question 20

Does active transport require energy?

Answer 20

Yes

Question 21

Does active transport require a membrane?

Answer 21

Yes

Question 22

Active transport goes ________ the concentration gradient

Answer 22

Against

Question 23

Summary of active transport process

Answer 23

• Molecule binds to receptor on carrier protein
• ATP binds on. It hydrolyses which releases energy (phosphate still on)
• Provides energy for protein to change shape
• Molecule then released inside the cell

Question 24

Examples of substances moving by active transport

Answer 24

. Mineral ions moving from the soil into the root hair cell

Question 25

Definition of Bulk Transport

Answer 25

Movement of macromolecules into or out of a cell

2 types exocytosis and endocytosis

Question 26

Does bulk transport require energy

Answer 26

Yes

Question 27

Does bulk transport require a membrane

Answer 27

Yes

Question 28

Bulk transport goes _________ the conc gradient

Answer 28

Against

Question 29

Summary of Bulk Transport process

Answer 29

• Specific molecules bind onto the receptor protein on the cell’s surface
• Cell membrane punches in
• Coated Vesicle forms
• Coated vesicle fuses with lysosome

Question 30

Examples of substances moved in this way

Answer 30

Proteins and Polysaccharides

Question 31

Osmosis goes _____ the concentration gradient

Answer 31

Down

Question 32

Hypotonic Solution

Answer 32

A solution with more water in it than solute, compared to another solution

Question 33

Hypertonic Solution

Answer 33

• A solution with more solute in it than water compared to another solution

Question 34

Isotonic Solution

Answer 34

Two solutions/cells that have the same water potential

Question 35

What happens if an animal cell is placed inside a Hypotonic Solution (More Dilute Solution)

Answer 35

. Outside environment of the cell has a higher Water Potential
. Water enters the cell by osmosis (high to low WP) via the partially permeable membrane
. Increases the hydrostatic pressure inside the cell
. Cell-Surface membrane cannot withstand the pressure increase
. Animal Cell bursts
. Called Cytolysis (Lysis)

Question 36

What happens if an plant cell is placed inside a Hypotonic Solution (More Dilute Solution)

Answer 36

. The outside environment of the cell has a higher WP
. Water enters the cell by osmosis (high to low WP) via the partially permeable membrane
. Inc the hydrostatic pressure inside the cell
. The cell surface membrane pushes against the cell wall but doesn’t burst
. Cell now TURGID

Question 37

What happens if an animal cell is placed inside a Hypotonic Solution (More Concentrated Solution)

Answer 37

. Inside environment of the cell has a higher WP
. Water leaves the cell by osmosis (high to low WP) via the partially permeable membrane
. Decreases the hydrostatic pressure inside the cell
. Animal cells shrivel up and shrink
. Cell is now crenated

Question 38

What happens if an plant cell is placed inside a Hypotonic Solution (More Concentrated Solution)

Answer 38

. Inside the cell has a higher WP
. Water leaves the cell by osmosis (High to Low WP) via the Partially Permeable Membrane
. Lowers the hydrostatic pressure inside the cell
. Cell surface membrane pulls/peels away from the cell wall site so the different in pressure
. Cell now PLASMOLYSED