Section 3.3

Question 1

Phospholipids

Answer 1

Have tails, make up cell membrane, contains 2 fatty acid chains, heads are hydrophilic, tails hydrophobic, also makes membrane “selective”

Question 2

Fluid

Answer 2

Because individual phospholipids and proteins can move side-to-side within the phospholipid Bilayer like a liquid

Question 3

Mosaic

Answer 3

Because of the pattern produced different molecules

Question 4

Semipermeable Membrane

Answer 4

Ions, hydrophobic molecules larger than water, and large molecules such as proteins do not move through membrane on their own

Question 5

Types of transportation across cell membranes

Answer 5

Simple diffusion, osmosis

Question 6

Simple diffusion

Answer 6

Requires NO energy; molecules move from HIGH to LOW concentration.

Question 7

Simple diffusion through cell membrane

Answer 7

Solute moves DOWN concentration gradient (high to low). Only allows a few Solutes through

Question 8

Osmosis

Answer 8

Diffusion of water across a membrane; water move from HIGH concentration to LOW concentration

Question 9

Diffusion of H2O across membrane

Answer 9

High H2O concentration –> low solute concentration

Low H2O concentration –> high solute concentration

Question 10

Aquaporins

Answer 10

Water channels; protein pores used during osmosis

Question 11

Direction of Osmosis

Answer 11

Depends on concentration of Solutes on each side of membrane

Question 12

3 solutions of osmosis that cause water to move

Answer 12

Hypotonic, hypertonic, isotonic

Question 13

Hypotonic

Answer 13

Less solute, more water (cytolysis)

Question 14

Hypertonic

Answer 14

Lots of solute, little water (plasmolysis) (explode)

Question 15

Isotonic

Answer 15

Solute levels equal inside and out (no net movement)

Question 16

Plasma Membrane

Answer 16

Considered “fluid mosaic model”; “gateway” of the cell. Consists of the Phospholipid Bilayer

Question 17

Plasmolysis

Answer 17

Contraction of the protoplast of a plant cell as a result of loss of water from the cell

Question 18

Cytolysis

Answer 18

The dissolution or disruption of cells, especially by an external agent

Question 19

Turgor pressure

Answer 19

The pressure of water pushing the plasma membrane against the cell wall of a plant cell

Question 20

Tonicity

Answer 20

A measure of the effective osmotic pressure gradient (as defined by the water potential of 2 solutions) of 2 solutions separated by a semipermeable membrane. In other words; the relative concentration of solutions that determine the direction & extent of diffusion

Question 21

Active transport

Answer 21

Energy is needed (because substance is moving from low to high concentration), it is like moving uphill, CAN NOT be done without energy. The energy comes from ATP,like passive transport active transport can involve transport proteins

Question 22

Sodium Potassium pump

Answer 22

Ex: of active transport
When in operation sodium ions are pumped out of the cell and potassium in. Both move from low to high concentration. The ATP provides “uphill” energy

Question 23

Vesicle transport

Answer 23

When molecules (like proteins) are too large the pass through regardless of concentration they use Vesicle transport to help them across the membrane, requires energy, for of active transport

Question 24

2 types of Vesicle Transport

Answer 24

Endocytosis & Exocytosis

Question 25

Endocytosis

Answer 25

Plasma membrane completely engulfs substance, a Vesicle pinches off from membrane, then Vesicle carries substance into cell.

Question 26

Phagocytosis

Answer 26

When an entire cell is engulfed in endocytosis. (Immune system)

Question 27

Pinocytosis

Answer 27

when fluid is engulfed in endocytosis

Question 28

Exocytosis

Answer 28

A vesicle containing the substance moves through the cytoplasm to the cell membrane then the vesicle membrane fuses with the cell membrane & the substance is released outside of the cell.

Question 29

Cell function

Answer 29

For cell to run properly things like salts & nutrients must be in certain range, things must be maintained inside the cell. This process is Homeostasis.

Question 30

Homeostasis

Answer 30

Requires constant adjustments because conditions inside and outside of the cell change constantly. By moving things into and out of a cell helps maintain cell.