Diffusion

Question 1

Passive transport

Answer 1

it is the movement of molecules across a membrane that does not require the input of energy. Move from high to low conc. gradient

Question 2

diffusion

Answer 2

Diffusion is the net movement of particles from a region of high conc to low. The difference in particle conc between the two regions is the gradient. Occurs because of the random kinetic movement of particles, exists when conc gradient exists until particles evenly distributed (equilibrium) Will continue to move randomly

Question 3

Equalbrium

Answer 3

2 Solutions have the same conc of solutes and net movement of 0 across the membrane

Question 4

Speed up diffusion

Answer 4

Increase temp or conc gradient

Question 5

particle theory

Answer 5

Particles make up matter in constant motion, an increase in temp will increase the speed of particles

Question 6

Diffusion across membrane

Answer 6

small uncharged molecules (o2, h20, co2) move easily through the membrane by simple diffusion. Alcohols such as ethanol can easily pass as they are non-polar and soluble in lipids. H20 can pass but not as easily because it is polar

Question 7

What can pass via simple diffusion?

Answer 7

gasses (co2 and h20), small molecule (h20 and ethanol), some hydrophobic (benezene)

Question 8

Facilitated diffusion

Answer 8

Charged particles (na and cl) and large (glucose) do not readily pass through the bilayer and need the assistance of proteins in the membrane. Passive and move with gradient

Question 9

Carrier proteins

Answer 9

Bind to specific molecules on one side of membrane, change shape, and release on the other side (glucose transporter protein)

Question 10

Channel proteins

Answer 10

Include aquaporins, for facilitated diffusion of water and ion channels that open and close in response to stimulus. Form a narrow passageway through which small ions diffuse rapidly through gradient, only ions of a specific size and shape can pass through a particular channel

Question 11

Osmosis

Answer 11

The diffusion of water across a semi-permeable membrane down its gradient in order to balance out the concentration of another substance. water is very important as its medium in which biochemical processes take place and keeps the shape of the cell

Question 12

conc and dilution

Answer 12

The water will move from an area where a solute is low in conc to an area in which it is high in conc, as it does this the solute becomes more dilute, lowering conc

Question 13

osmotic pressure

Answer 13

Water will move down its concentration gradient from a region of low osmotic pressure to a region of high osmotic pressure until concentrations become equal.
The higher the concentration of solute the higher the osmotic pressure.

Question 14

Isotonic

Answer 14

When two solutions have the same concentration. There will be no net change in the amount of water in either solution. If a cell is placed in a solution isotonic to the cell, the water molecules will jostle on both sides moving in both directions equally. even at equilibrium, they wont stop moving

Question 15

Hypotonic

Answer 15

When a cell is surrounded by a solution with lower solute concentration than the cytoplasm, the external solution will be hypotonic to that of cell and water will diffuse in.

Question 16

Hypertonic

Answer 16

when surrounded by a solution of high solute concentration, water will diffuse out

Question 17

Osmosis in animals

Answer 17

Water moving in can cause bursts, uni cell organisms like an amoeba that lives in freshwater have important regulatory mechanisms to combat living n hypotonic solutions and can move excess water by forming little pools of water in organs called contractile vacuoles. When stretched to a certain point will contract and expel water. In multi-cell, surrounded by isotonic em until by plasma which is controlled by kidney

Question 18

Osmosis in plants

Answer 18

Have fluid-filled vacuole and firm but permeable cell wall. Vcule contains a cell sap rich in solutes, a solution of high conc. When hypotonic, water is in the cytosol and into the vacuole. Vacule swells pushing cytoplasm and membrane against the wall, when stretches as much as possible no more enters, and is called turgid. Tugor is important as it supports them, When hot will wilt as water evaporates and the external conc becomes less which vacuoles cell and will become flaccid. If enough water is lost, the membrane pull away from the cell wall called plasmolysis

Question 19

Active transport

Answer 19

Energy is required to transport from low to high, performed by specific proteins n membranes. Enables cell to maintain reverse conc gradient of substance that cell requires.

Question 20

Example of active

Answer 20

after a meal, nutrients like glucose absorb into the cell lining of the small intestine, if diffusion alone was involved, once conc of glucose in and out of cells became equal, there would be no net movement, and would be excreted

Question 21

proteins in active

Answer 21

Transport proteins are used atp to move molecules and ions up the gradient. As carrier proteins work in only one direction, they act as one-way valves. Without active transport, kidneys can’t reabsorb useful stuff, no muscle contractions, impulses across nerves can happen

Question 22

endocytosis

Answer 22

Large molecules such as polysaccharides and proteins in bulk can be transported via endo and exocytosis. Active needs the energy to move cases around and change the shape of the cell. Tow types phago and pinocytosis. Macrophages use recognition prin in the membrane of cell the encounter to discriminate between dn engulf bacteria. Fats enter via pinocytosis

Question 23

exocytosis

Answer 23

Cell produces hormones, mucus, and proteins that are needed elsewhere. Large molecules help in vesicles in cells transported to the extracellular environment