Topic Two - Diffusion and Osmosis stuff

Question 1

what is diffusion

Answer 1

net movement of particles from a region of high concentration to a region of low concentration.

Question 2

What is passive transport

Answer 2

Diffusion and Osmosis

no energy and it uses a concentration gradient

Question 3

What is active transport

Answer 3

Movement across membranes that does require energy, low to high

Question 4

Where can diffusion occur?

Answer 4

Liquid and gas, because the molecules are always moving

Question 5

Diffusions occurs until…

Answer 5

equilibrium or homeostasis is reached

Question 6

What factors affect the rate of diffusion

Answer 6

Large concentration gradient
Heat is applied
molecules are smaller
when movement occurs through a gaseous membrane

Question 7

Why is diffusion important to life

Answer 7

Oxygen, food and waste products are some of the substances that move by diffusion. The substances are transported in the bloodstream, from where they can diffuse in and out of the cells.

Question 8

Diffusion and Breathing

Answer 8

oxygen is inhales through the lungs, into the bloodstream and around the body.
Carbon dioxide waste from oxygen, exhaled via the lungs.

Question 9

facilitated diffusion

Answer 9

When molecules are to large to pass through via regular diffusion, they are assisted by proteins in the membrane

Question 10

What are the proteins that are involved in facilitated diffusion

Answer 10

Channel proteins
Carrier Proteins

Question 11

Does facilitated diffusion require energy?

Answer 11

No

Question 12

Carrier Proteins

Answer 12

Carrier proteins open and close along the membrane when open, molecules can pass through.
They bind to the molecules on one side of the membrane and release them on the other side.

Question 13

Channel Proteins

Answer 13

form narrow passageways through whcih small ions can diffuse rapidly from where they are in high concentration and then to low concentration. Only ions of a specific size and shape can pass through a particular protein channel

Question 14

Osmosis

Answer 14

The movement of water molecules across a semi-permeable membrane from a region of high-water concentrations to a low-water concentration. At the same time water is moving from a low solute concentration to a high solute concentration. Until Equilibrium or Homeostasis is reached

Question 15

Dilute vs Concentrated

Answer 15

during osmosis, water molecules diffuse from pure water or a dilute solution to more concentrated solution.

Question 16

Dilute Solutions have…

Answer 16

medium concentration of water molecules

Question 17

Concentrated Solutions have…

Answer 17

a low concentration of water molecules

Question 18

What is osmosis

Answer 18

osmosis is the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a cell’s partially permeable membrane

Question 19

Hypertonic

Answer 19

when the intracellular fluid has a higher water concentration than the extracellular fluid.

Question 20

Hypotonic

Answer 20

When the extracellular fluid has a higher water concentration than the intercellular fluid

Question 21

Isotonic

Answer 21

When the extracellular fluid and intercellular fluids are at the equal concentration

Question 22

Animal Cells

Answer 22

• don’t have a cell wall
• dilute solutions - osmosis can cause animal cells to swell and burst LYSIS
• concentrated solutions - water loss causes the cells to shrink - CRENATION
• to remain healthy, animal cells need to maintain an isotonic water balance.

Question 23

Lysis

Answer 23

When animals cells swell and burst

Question 24

Crenation

Answer 24

Water loss causes the cells to shrink

Question 25

The concentration of water + salt in blood is controlled by the ______

Answer 25

Kidneys

Question 26

The Kidneys are controlled by the_______

Answer 26

Hypothalamus

Question 27

Osmosis and plants

Answer 27

Root cells in plants absorb water through osmosis
SA increase - more water
water strengthens plant cells

Question 28

Osmosis and cells

Answer 28

water and other small molecules pass through the plasma membrane.

Question 29

Active Transport

Answer 29

Requires transport proteins (carrier proteins)

ATP/energy required

Transport against a concentration gradient

occurs through protein channels

Energy ATP binds to the protein and allows the particles to cross the membrane against the concentration gradient

Passive transport until equilibrium is reached, the movement of substances can continue through active transport.

Question 30

In active transport…

Answer 30

diffusion is slow
some substances need to be accumulated in cells against the concentration gradient
For this to occur, energy must be used to move the needed substances across the cell membrane.

Question 31

Examples of active transport

Answer 31

Cell metabolism produces wastes

Active transport enables cells to get rid of unwanted substances even when their concentration is much greater outside the cell.

Question 32

Active transport in plants

Answer 32

the concentration of minerals in lower, the plant is higher. Active transport moves minerals against the concentration gradient

Question 33

Active transport in humans

Answer 33

during digestion, the villi in the small intestine absorb the nutrient, overtime once equilibrium is reached, active transport is used to continue the concentration gradient.

Question 34

Sodium Potassium Pump

Answer 34

Animal Cells have a high concentration of potassium ions but low sodium ions

The mechanism responsible for this is the sodium–potassium pump, which moves these two ions in opposite directions across the plasma membrane.

The sodium–potassium pump has a particular significance for excitable cells, such as nerve cells, which respond to stimuli.

Question 35

Bulk Transport

Answer 35

Cells need to move large quantities of materials into or out of the cytoplasm, and the pores in the cell membrane cannot do this.

The process of bulk transport may achieve this. As with active transport, large amounts of energy are necessary for this to function.

There are two forms of bulk transport: endocytosis & exocytosis.

Question 36

Exocytosis (exiting)

Answer 36

Exocytosis is the movement of substances out of a cell

A transport vesicle containing a particular
substance, maybe a waste product or a hormone, fuses with the plasma membrane releasing the substance to the outside of the cell

Question 37

Endocytosis

Answer 37

Endocytosis is the movement of substances into the cell

Part of the plasma membrane encloses a substance

This section of the membrane then pinches off and forms a vesicle

There are two types of endocytosis, which differ according to the type of material taken in: phagocytosis & pinocytosis.

Question 38

Phagocytosis

Answer 38

The bulk transport of solid materials into a cell

It can be selective, and the cell can discriminate between different kinds of particles

It involves the cell membrane engulfing the solid material, forming a vesicle, which moves into the cytoplasm

Question 39

Pinocytosis

Answer 39

Occurs when a cell’s plasma membrane engulfs a drop of extracellular fluid, forming a vesicle, which moves into the cytoplasm

Question 40

Factors affecting the rate of osmosis

Answer 40

Water potential gradient
membrane thickness
surface area

Question 41

why do cells need buffering agents

Answer 41

to minimize the changes in pH of the internal environment