General Biology: Cell Membrane Transport Mechanism

Question 1

Function of Plasma Membrane: Channels & Pumps

Answer 1

Transport of Molecules

Question 2

Function of Plasma Membrane: Engulfing particles

Answer 2

Phagocytosis and Pinocytois

Question 3

Function of Plasma Membrane: Due to the presence of carbohydrates

Answer 3

Cell-cell communication

Question 4

Function of Plasma Membrane: Cell membrane bound receptors, enzymes, and proteins.

Answer 4

Cell signaling

Question 5

Function of Plasma Membrane: Protects the cellular _________

Answer 5

organelles

Question 6

Function of Plasma Membrane:
Segregates one part of the cell from another.

Answer 6

Compartmentalization

Question 7

Function of Plasma Membrane: Myelin sheat of neurons, microvilli in intestine.

Answer 7

Membrane modifications for specialized functions

Question 8

This refers to why small, nonpolar molecules get in ions and polar molecules don’t get in.

Answer 8

Selective Permeability

Question 9

Cell Membrane. Described as ____________. The structure of it is FLEXIBLE and fluid rather than a rigid solid barrier.

Answer 9

fluid mosaic

Question 10

Fluid Mosaic Model. Similar with a mosaic art, it is also made up of different molecules namely ——(4)——- that made up one functional structure, the cell membrane

Answer 10

phospholipids, proteins, carbohydrates and cholesterol

Question 11

Phospholipid.
Hydrophobic? Hydrophilic?
(a) Tail
(b) Head

Answer 11

(a) Hydrophobic
(b) Hydrophilic

Question 12

Membrane Proteins.

• Penetrate the hydrophobic inside of lipid bilayer.
• most are transmembrane proteins

Answer 12

Integral Proteins

Question 13

Membrane Proteins.

Appendages loosely bound to either surface

Answer 13

Peripheral Proteins

Question 14

Membrane Proteins.

A receptor that binds to chemical messengers such as hormones sent by other cells

Answer 14

Receptor Protein

Question 15

Membrane Protein.

Breaks down a chemical messenger and terminates its effect on the target cell

Answer 15

Enzyme

Question 16

Membrane Protein.

Constantly open and allows solutes to pass into and out of the cell

Answer 16

channel protein

Question 17

Membrane Protein.

Closes and Opens to allow solutes through only at certain times

Answer 17

Gated Channel Protein

Question 18

Membrane Protein.

À glycoprotein acting as a —— distinguishing the body’s own cells from foreign cells

Answer 18

Cell-identity marker

Question 19

Membrane Protein.

Binds one cell to another

Answer 19

Cell-adhesion
molecule (CAM)

Question 20

Membrane Proteins.

Provides Hydrophilic Channel

Answer 20

Transport Proteins

Question 21

Transport Protein.
(a) Uniport
(b) Symport
(c) Antiport

Answer 21

(a) Transports 1 substance and 1 direction
(b) Transports 2 substances 1 direction
(c) Transports 2 substances in 2 directions

Question 22

Cell Membrane. It is made up of different molecules namely (4) ________________ that made up one functional structure.

Answer 22

Phospholipids, Proteins, Carbohydrates, and Cholesterol

Question 23

Membrane Protein.

They are embedded in the cell membrane to help transport too large molecules
such as glucose and amino acids to go through ion channels across the membrane.

Answer 23

Transport/Carrrier Protein

Question 24

What are the 2 parts of a phospholipid?

Answer 24

Hydrophilic Head & Hydrophobic Tail

Question 25

Animal Membranes. __________ reduces membrane fluidity at moderate temps by reducing phospholipid movement.

Answer 25

Cholesterol

Question 26

Animal Membranes. At LOW TEMPS it hinders _____________ by disrupting the regular packing of phospholipids.

Answer 26

solidification

Question 27

What are the 2 types of membrane proteins?

Answer 27

Integral Proteins & Peripheral Proteins

Question 28

A glucose molecule (C6H12O6) is ___________ large, and amino acids are even bigger than that, so they need support to pass into and out of the cell.

Answer 28

24 atoms

Question 29

____________ are a very narrow tube-shaped protein that help establish a tiny pore in the cell membrane.

Answer 29

Ion Channels

Question 30

Each ion channel open and close specifically for certain ions like (4) ________________

Answer 30

Na+, K+, Cl–, Ca+2

Question 31

Glycoproteins. Glyco means carbohydrates so these are _______________.

Answer 31

proteins with carbohydrates attached to them

Question 32

____________ are always on the outside surface and are different from receptor sites. * Allows white blood cells to recognize your cells vs foreign ones.

Answer 32

Recognition Sites

Question 33

Glycoprotein. (a) Cell recognition and _________ * Impart -ve charge to cell - repels other particles. (b) Helps in inter-cellular ______________. (c) act as ___________ (d) Cell identity markers (glycoproteins & __________), antibody processing.

Answer 33

a. communication b. attachment/adhesion c. receptors d. glycolipids

Question 34

Osmosis True or False. High Concentration moves with the flow going to solvent lower concentrations

Answer 34

True

Question 35

Recognition Sites/Cell Identity Markers. Recognizes specific ________ and alters cell's function in some way.

Answer 35

ligand

Question 36

It is diffusion of substance across membrane with no energy investment.

Answer 36

Passive Transport

Question 37

Diffusion. In the absence of other forces, a substance will diffuse from ___________ to ______________.

Answer 37

from where it is more concentrated to where it is less (it will move down the concentration gradient)

Question 38

Diffusion. No work required: spontaneous because particles have _____ and are in constant motion.

Answer 38

Kinetic Energy

Question 39

Factors Affecting Diffusion Rate. The greater the difference in concentration, the faster the molecules will go down this hence more rapid diffusion. The closer the distribution of the material gets to equilibrium, the slower the molecules will move and rate of diffusion decreases.

Answer 39

Concentration Gradient

Question 40

Factors Affecting Diffusion Rate. Higher ________ increase the energy and therefore the movement of the molecules, increasing the rate of diffusion. Lower __________ decrease the energy of the molecules, thus decreasing the rate of diffusion.

Answer 40

Temperature

Question 41

Movement of solvent (water) across a semi permeable membrane from high to low solvent concentration where ONLY solvent moves

Answer 41

Osmosis

Question 42

Factors Affecting Diffusion Rate. Heavier molecules move more slowly; therefore, they diffuse more slowly. The reverse is true for lighter molecules.

Answer 42

Mass of Particles

Question 43

Factors Affecting Diffusion Rate. Diffusion is significantly influenced by viscosity and density. * The denser or viscous the medium is, the harder it is for the given particle to diffuse through it. The diffusion rate would be lower. *If the medium is less dense or less viscous, then the particles will be able to move more quickly and will diffuse faster.

Answer 43

Solvent Properties

Question 44

Channel or CARRIER PROTEINS that allow hydrophilic substances to cross membranes moving down their concentration gradients

Answer 44

Facilitated Diffusion

Question 45

ability of a surrounding solution to cause a cell to gain or lose water

Answer 45

Tonicity

Question 46

Open/close mechanism works in response to stimuli (electrical, specific ligand).

Answer 46

Gated Ion Channels

Question 47

True or False. Tonicity depends on the concentration of solutes that cannot cross membrane relative to the concentration of all solutes in cell

Answer 47

True

Question 48

Hypertonic, Hypotonic, & Isotonic. * Higher solute OUTSIDE * Higher water INSIDE * Water moves OUT * Cell SHRINKS

Answer 48

Hypertonic (Plasmolyzed)

Question 49

Hypertonic, Hypotonic, & Isotonic. * Equal solute * Equal water * No net movement * Normal

Answer 49

Isotonic (Flaccid)

Question 50

Hypertonic, Hypotonic, & Isotonic. * Higher solute INSIDE * Higher water OUTSIDE * Water moves IN * Cell SWELLS

Answer 50

Hypotonic (Turgid)

Question 51

Cell uses transport protein * Moves substances AGAINST concentration gradient (LOWER to HIGHER) * Similar to facilitated diffusion except this requires ENERGY * cell to maintain concentration gradients

Answer 51

Active Transport