Chapter 3

Question 1

Cytoplasm

Answer 1

consists of cellular contents between the plasma membrane and the nucleus.

Consists of cytosol and organelles.

Question 2

Cytosol

Answer 2

The fluid portion of the cytoplasm.

Contains water, dissolved solutes, and suspended particles.

Also called “intracellular fluid”.

Question 3

Organelles

Answer 3

Little organs with a specific function.

eg. mitochondria.

Question 4

Nucleus

Answer 4

A large organelle which contains the DNA.

Question 5

Chromosome

Answer 5

A single molecule of DNA.

Associated with many proteins, and contains thousands of hereditary units called genes.

Question 6

Genes

Answer 6

Control most aspect of cellular structure and function.

Question 7

Lipid Bilayer

Answer 7

Two back to back layers made up of three types of lipid molecules (phospholipids, cholesterol, Glycolipids)

Question 8

Phospholipids

Answer 8

A lipid the contains phosphorus.

Is polar and hydrophilic, loves water,(the head part)

The two fatty acid “tails”are non-polar and hydrophobic,fears water(the tail).

Question 9

Cholesterol

Answer 9

Molecules are found in both layers of the plasma membrane.

Cholesterol molecules are steroids with an attached OH (hydroxyl) group, which forms hydrogen bonds with the polar heads of phospholipids and glycolipids.

Question 10

Glycolipids.

Answer 10

Attaches to carbohydrate groups that form a polar head.

The fatty acid “tails” are non polar.

Appear only in the layer of the plasma membrane that faces the extracellular fluid, which is why the two sides of the bilayer are different.

Question 11

Integral Proteins

Answer 11

Extend through the lipid bilayer, among the fatty acid tails and firmly attaches to it.

They are transmembrane proteins, which means that they span, covering the entire lipid bilayer, and cover the cytosol and extracellular fluids.

They have hydrophilic regions that can extend as far as the fatty acid tails.

Question 12

Peripheral Proteins

Answer 12

Not as firmly attached to the membrane.

They are attached to the polar heads of membrane lipids, plasma membrane, and other proteins.

Question 13

Glycoproteins

Answer 13

Proteins with carbohydrate groups attached to the ends, that produce extracellular fluid.

Question 14

Glycocalyx

Answer 14

The carbohydrate portions of glycolipids and glycoproteins, that form a sugary coat.

Acts as a molecular “signature” that allows cell to recognize each other.

Allows cells to attach to one another in some tissues.

Protects the cells from being eaten by enzymes in the extracellular fluids.

Question 15

Ion channels

Answer 15

Pores through which specific ions can flow through to get in and out of the cell.

Question 16

Carriers

Answer 16

Selectively move a polar substance or ion from one side of the membrane to the other, by CHANGING shape

Question 17

Receptors

Answer 17

Serve as a cellular recognition site.

Question 18

Ligand

Answer 18

A specific molecule that binds to a receptor.

Question 19

Enzymes

Answer 19

Speeds up a specific chemical reaction at the inside or outside of the surface of the cell.

Question 20

Linkers

Answer 20

Anchor membrane proteins of the neighboring cell to one another of protein filaments inside and outside of the cell.

Help support the plasma membrane.

Provide temporary binding sites that assist in the moving of materials and organelles within the cell.

Assist in the movement of the cell itself. And allows changes in the cell shape in dividing and contracting cells.

Question 21

Cell Identity Markers

Answer 21

Allows a cell to recognize other cells of the same kind, during tissue formation or to recognize and respond to potentially dangerous foreign cells.

EX. in a transfusion, blood types must be compatible in order for the receiver to survive.

Question 22

Selective Permeability

Answer 22

Plasma membranes allows some substances to pass more readily than others.

The lipid bilayer portion of the membrane is permeable to non-polar, uncharged molecules. Impermeable to large, uncharged polar molecules.
And slightly permeable to small uncharged polar molecules.

Question 23

Concentration Gradient

Answer 23

A difference in the concentration of a chemical from one place to the other.

Question 24

Electrical Gradient

Answer 24

When the plasma membrane creates a difference in distribution of positively and negatively charged ions between the two sides of the plasma membrane.

Typically the inner surface of the plasma membrane is more negatively charged. And the outside surface more negatively charged.

Question 25

Electrochemical Gradient

Answer 25

When a positively charged substance will tend to move to a negatively charged are, and a negatively charge substance would move to a positively charged are. Therefore reaching equilibrium.

Question 26

Passive Processes

Answer 26

When a substance moves down its concentration, to cross the membrane using its own kinetic energy. (ex. simple diffusion)

Question 27

Active Processes

Answer 27

When cellular energy is used to drive its substance “uphill” against its concentration, the energy being used is ATP (ex. active transport)

Question 28

Diffusion

Answer 28

A passive process in which the random mixing of particles in a solution occurs because of the particle’s kinetic energy.

Both the solute and the solvent undergo diffusion.

Factor that influence diffusion: 
Temperature 
Steepness Of Concentration Gradient 
Mass Of Diffusing Substance
Surface Area 
Diffusion Distance

Question 29

Simple Diffusion

Answer 29

A passive process in which substances move freely through the lipid bilayer of the plasma membrane of the cells, without the help of membrane transport proteins.

Nonpolar molecules, hydrophobic molecules, and uncharged polar molecules move through the lipid bilayer through simple diffusion.

Important in the movement of oxygen and carbon dioxide between the blood and the cells, and between the lung and the air within the lungs during breathing.

It is also the route for absorption of some nutrients and excretion of waste by cells.

Question 30

Facilitated Diffusion

Answer 30

A process in which an integral membrane protein assists a specific substance across the plasma membrane. The integral membrane protein can be either a channel or carrier.

Question 31

Channel- Mediated Facilitated Diffusion

Answer 31

When a solute moves down its concentration gradient, across the lipid bilayer, through a membrane channel.

Most membrane channels are ion channels, integral transmembrane proteins that allow passage of small ions that are to hydrophilic to penetrate the nonpolar interior of the lipid bilayer.

Question 32

Carrier-Mediated Facilitated Diffusion

Answer 32

When a carrier moves a solute down its concentration gradient across the plasma membrane.

This is a passive process, which means that no energy is needed.

The rate of this diffusion is determined by the steepness of the concentration gradient across the membrane.

Question 33

Osmosis

Answer 33

A type of diffusion in which a solvent, such as water, moves through a selectively permeable membrane.

Osmosis is a passive process.

Osmosis occurs only when a membrane is permeable to water, but is not permeable to certain solutes.

Question 34

Hydrostatic Pressure

Answer 34

Forces water molecules to move back into the left arm. Equilibrium is reached when just as many molecules move from right to left due to this pressure, and move from left to right due to Osmosis.

Question 35

Osmotic Pressure

Answer 35

Stops the water movement from the left tube to the right tube, by applying pressure.

Question 36

Isotonic Solution

Answer 36

Any solution in which a cell maintains its normal shape and volume.

The concentration of solutes that cannot cross the plasma membrane are the same in both sides of the membrane.

Question 37

Hypotonic Solution

Answer 37

A solution that has lower concentration of solutes in the cytosol and