Cell Membrane and Cellular Transport

Question 1

What is meant by a cell being an ‘open system’?

Answer 1

The cell allows for the exchange of matter and energy between itself and its surrounding.

Question 2

What decides what is allow to move in and out of the cell?

Answer 2

The cell membrane through selective permeability.

Question 3

What is the function of selective permeability?

Answer 3

To maintain equilibrium, homeostasis or balance inside the cell.

Question 4

What is the cell membrane also referred to and what does it consist of?

Answer 4

The cell membrane is know as the plasma membrane. It consists of a phospholipid bilayer.

Question 5

What is the phospholipid bilayer?

Answer 5

It is a double layer of lipids (fats), each having a phosphate group attached on either surface of the membrane.

Question 6

What is interspersed in the phospholipid membrane?

Answer 6

Proteins. Some hav sugar molecules (carbohydrates) attached to them.

Question 7

Passive transport

Answer 7

exchange of material occurs using only the kinetic energy of molecules involved.

Question 8

What is active transport?

Answer 8

Transport of cell material that requires the input of additional energy, provide by a molecule called ATP, produce through cellular respiration.

Question 9

The difference in energy requirements has to do with the _________ of molecules _______ as compared to _______, the cell.

Answer 9

concentration, inside, outside

Question 10

A difference in concentration of molecules is called a

Answer 10

concentration gradient

Question 11

When is extra energy (ATP) required to move molecules?

Answer 11

When you move molecules up (against) a gradient; from an area of low to high concentration.

Question 12

Is extra energy (ATP) required to move molecules down (with) a gradient: from and are of hight to low concentration?

Answer 12

no

Question 13

What is diffusion?

Answer 13

The spontaneous movement of particles from an area of higher concentration to an area of lower concentration.

Question 14

Diffusion continues until all particles are evenly spread out. The molecules are in ________.

Answer 14

Equilibrium

Question 15

Rate of diffusion can be increased by…

Answer 15

adding energy and increasing molecular movement (heating or stirring)

Question 16

Diffusion is explained using the particle model of matter that states that:
S - large ________ exist between the particles of matter.
A - __________ forces are found between particles. These forces are most significant for _______ and least for _______.
M- particles ar ein contant _______. With motion being the most significant for ______ and the least for _______/

Answer 16

S- spaces
A - attractive, most significant for solids and the least for gases.
M- motion. With motion being the most significant for gases and the least for solids.

Question 17

What is osmosis?

Answer 17

The diffusion of water across a membrane that is permeable to water, but not the solute (semi-permeable). ex: starch and iodine diffusion across a semipermeable membrane.

Question 18

Tonicity refers to

Answer 18

the concentration of a solution in comparison to that of another.

Question 19

What does knowing the tonicity of a solution in comparison to that of a cell allow you to predict?

Answer 19

The direction of water movement.

Question 20

Isotonic (normal) =

Answer 20

same as cell (normal red blood cell)

Question 21

Hypotonic solution (dilute) =

Answer 21

less solute than cell (swollen red blood cell)

Question 22

Hypertonic solution (concentrated) =

Answer 22

more solute than cell (shrunken (crenated) red blood cell )

Question 23

Which soluble substance moves freely across membranes and why?

Answer 23

Only fat soluble substance can move freely because the cell membrane is made of lipids (fat).

Question 24

Water soluble substance needs assistance to move accross the cell membrane in the form of a ….

Answer 24

protein channel or carrier protein

Question 25

Facilitated diffusion is still the movement from ______ to _______ concentration but with _______ facilitating the movement.

Answer 25

higher to lower concentration, proteins facilitate the movement.

Question 26

What are the 2 types of active transport?

Answer 26

Active transport with carrier proteins and endocytosis/exocytosis.

Question 27

Active transport with carrier proteins is _________ to facilitated diffusion, but required energy to move molecules from a _____ to a _____ concentration.

Answer 27

similar. move molecules from a low to high concentration. May bring needed entities into the cell or expel materials from the cell.

Question 28

What type of molecules are involved in transport across the cell membrane by carrier proteins in endocytosis and exocytosis?

Answer 28

It involves molecules that are too large to be transported by carrier proteins.

Question 29

Both endocytosis and exocytosis require energy from ATP for what?

Answer 29

For vesicle formation and the rearrangement of the cell membrane.

Question 30

What are the 2 typed of Endocytosis:

Answer 30

phagocytosis and pinocytosis

Question 31

What does phagocytosis involve:

Answer 31

The intake of larger molecules.

Question 32

What does pinocytosis do?

Answer 32

It engulfed liquid and dissolve molecules.