f4 chap 3: movement of substances across plasma membrane

Question 1

what does each phospholipid moelcule consisit of?

Answer 1

polar head (hydrophilic), nonpolar tail (hydrophobic)

Question 2

what are the 2 protein molecules?

Answer 2

channel protein, carrier protein

Question 3

whats the function of glycoprotein and glycolipid?

Answer 3

act as receptors to hormones such as insulin, stabilise the membrane by forming hydrogen bonds with water and act as antigens for cell identification.

Question 4

function of cholesterol?

Answer 4

make the phospholipid bilayer
stronger, more flexible and less permeable to water-soluble substances

Question 5

what are the characteristics of lipid soluble substances that enables it to move across plasma membrane?

Answer 5

its nonpolar molecules

Question 6

examples of lipid soluble substances?

Answer 6

fatty acid, glycerol, fat soluble vitamins, steroid compunds

Question 7

what are the characteristics of small molecules and ions that enables it to move across plasma membrane?

Answer 7

polar molecules, ions, nonpolar molecules

Question 8

example of large molecules that can go through plasma membrane?

Answer 8

glucose, amino acid

Question 9

examples of passive transport?

Answer 9

Simple diffusion, osmosis and facilitated diffusion

Question 10

whats simple diffusion?

Answer 10

Simple diffusion is the movement of molecules
or ions from an area of high concentration to an
area of low concentration.

Question 11

example of substances that diffuses through phospholipid bilayer by simple diffusion ?

Answer 11

fatty acids and glycerol, oxygen and carbon
dioxide

Question 12

whats osmosis?

Answer 12

net movement of water molecules from area of high water potential to area of low water potential randomly through a selectively permeable membrane.

Question 13

channel protein characteristics?

Answer 13

Channels have specific internal characteristics that only allow specific ions to pass
through it.

Question 14

example of lipid insoluble molecules?

Answer 14

ions, large molecules(amino acid, glucose)

Question 15

can lipid insoluble molecules pass through the phospholipid bilayer?

Answer 15

no dawg

Question 16

are amino acid, and glucose able to pass though the phospholipid bilayer?

Answer 16

no

Question 17

how do lipid insoluble molecules move past the membrane?

Answer 17

through facilitated diffusion

Question 18

does facilitated diffusion require energy?

Answer 18

no

Question 19

why doesnt facilitated diffusion require energy?

Answer 19

bc transport proteins transport molecules down a concentration gradient

Question 20

explain the process of the movement of glucose molecules across a plasma membrane through facilitated diffusion if extracellular glucose concentrations are higher than in cytoplasm.

Answer 20

i) extracellular glucose binds with the specific site of the carrier proteins.
ii) carrier proteins change shape to allow glucose molecules to pass through the carrier proteins and to enter
the cell.
iii) carrier proteins return to their original shape

Question 20

types of transport protein?

Answer 20

carrier protein, channel protein

Question 21

what does active transport result in?

Answer 21

accumulation or excretion of molecules or ions in the cell.

Question 21

characteristics of active transport?

Answer 21

i) movement of molecule or ion substances across a plasma membrane occurs against a concentration gradient.
ii) requires energy from ATP molecules generated during cellular
respiration.
iii) requires specific carrier protein with specific sites to bind with certain molecules or ions.

Question 22

explain how sodium-potassium pump transports sodium ions into extracellular and potassium ions into cell

Answer 22

i) three sodium ions bind to the carrier protein.
ii) ATP molecules decompose into ADP and P. The
phosphate group is bound to the carrier protein.
iii) phosphate bond provides energy and changes the shape of the carrier protein, then sodium ion is transported through the
carrier protein out of a cell.
iv) two potassium ions from outside the cell bind with a carrier protein. the phosphate group leaves the carrier protein.
v) loss of the phosphate group restores original shape of the carrier protein.
vi) Potassium ion is transported through the carrier protein into the cell.

Question 23

what are pumps?

Answer 23

carrier proteins involved in active transport

Question 24

what does it mean if solution A is hypotonic
to solution B?

Answer 24

Solution A has a low solutes concentration and high water
potential. Water diffuses from solution A to B by osmosis.

Question 24

whats the function of phosphate in pumps?

Answer 24

provides energy and changes the shape of the carrier protein

Question 24

where can proton pumps be found?

Answer 24

on epithelial cells lining the stomach cavity.

Question 24

Where do active transport occur in living organisms?

Answer 24

> absorption of glucose and amino acids in the
villus
reabsorption of glucose through the renal
tubule in the kidney
transport of sucrose from a leaf to a phloem
tissue
absorption of mineral ions by a plant root hair
cell

Question 25

what does it mean if solution a and solution b are isotonic towards each other?

Answer 25

Solution A and B have the same concentrations of
solutions. theres no net movement of water

Question 25

what are the differences & similarities between passive & active transport?

Answer 25

passive transport: doesnt require energy, occurs following the concentration of gradient, occurs until dynamic equilibrium is achieved

active transport: requires energy, occurs against the concentration of gradient, theres accumulation & disposal of molecules & ions

similarities: occurs through a selectively permeable membrane, moving a substance across a membrane

Question 25

function of proton pump?

Answer 25

causes the acidity of the stomach contents.

Question 25

3 types of solution?

Answer 25

isotonic, hypotonic, hypertonic

Question 26

Where do passive transport occur in living organisms?

Answer 26

> gaseous exchange between an alveolus and
a blood capillary through simple diffusion
reabsorption of water occurs by osmosis
through the renal tubule in the kidney
absorption of water by a plant root hair cell by
osmosis
absorption of fructose molecule in the villus by
facilitated diffusion

Question 27

whats the effect of hypotonic solution on animal cell?

Answer 27

when red blood cells are placed in a hypotonic solution, water will diffuse into the cells by osmosis, causing the cells to swell and finally burst.

Question 27

what does it mean if Solution A is hypertonic to B.

Answer 27

Solution A has a high solutes concentration and low water
potential. Water diffuses from solution B to A by osmosis.

Question 28

whats the effect of hypertonic solution on animal cell?

Answer 28

when red blood cells are placed in a hypertonic solution, water will move out of the cells by osmosis. this causes cells to shrink. red blood cells undergo crenation.

Question 29

why do red blood cells burst when placed in hypotonic solution?

Answer 29

plasma membrane is too thin to withstand the osmotic pressure built up in the cells.

Question 29

effect of isotonic solution on animal cell?

Answer 29

water diffuses into and out of the cell by osmosis at the same rate, no net movement of water
across the plasma membrane, the cells maintain their normal
shape.

Question 29

whats the bursting of red blood cell known as?

Answer 29

haemolysis

Question 30

effect of hypotonic solution on plant cell?

Answer 30

water will diffuse into the vacuoles by osmosis, this will cause the vacuoles to expand and push the cytoplasm and plasma membrane against the cell wall, cells are said to be turgid.

Question 30

effect of isotonic solution on plant cell?

Answer 30

when the sap of the plant cell and extracellular solution are isotonic, water potential is the same, the movement of water diffusion in and out of cells is the same, cells become flaccid.

Question 30

effect of hypertonic solution of plant cell?

Answer 30

when plant cells are placed in a hypertonic solution, water will diffuse out of the vacuoles by osmosis, vacuoles and the cytoplasm will shrink, causing the plasma membrane to be pulled away from the cell wall

Question 31

how come plant cells do not burst when placed in hypotonic solution?

Answer 31

cell wall is rigid and strong.

Question 32

why is turgor pressure important for plants cells?

Answer 32

gives support and maintains the shape of cell.

Question 33

why is cell turgidity important for plants?

Answer 33

causes guard cell to swell to allow the stomata to remain
open for photosynthesis.

Question 34

whats plasmolysis?

Answer 34

Vacuoles and the cytoplasm shrink, causing the plasma membrane to be pulled away from the cell wall.

Question 35

can plasmolysed plants regain turgidity? if so, how and whats the process called?

Answer 35

Plasmolysed plant cells can regain their turgidity if the cells are
returned to a hypotonic solution immediately. Process: deplasmolysis