Biology Chapter 7 Flashcards Preview

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Flashcards in Biology Chapter 7 Deck (23):
1

Membranes are made of

Phospholipid and protein, arranged in a fluid mosaic

2

There are two layers of phospholipids, with large protein molecules floating in this oily layer (most proteins go all the way across the membrane)

"Fluid" means that the membrane is liquid. "Mosaic" refers to the proteins scattered around like mosaic tiles on a floor.

3

Unsaturated fatty acids make the membrane

Fluid

4

Saturated fatty acids make the membrane

Viscous (so it does not change shape easily)

5

Cholesterol

Is added to some membranes as an antifreeze; organisms living in cold climates can survive temperatures below freezing because their membranes stay fluid.

6

What are the functions of the proteins in the membrane?

Transport, enzymes, receptors for hormones, and joining cells together

7

Carbohydrates (oligosaccharides) on the outside of the membrane do what?

Let the Immune system identify the cell

8

Carbohydrates are important in organ transplants

The donor organ has to match as closely as possible the recipient

9

Passive transport

The cell uses no energy. Includes diffusion and osmosis

10

Diffusion

The movement of molecules from high concentration to low concentration (liquid or gas)
Cells get glucose and oxygen by diffusion.

11

Plasma membranes

Surround cells, (plant cells also have a cell wall). Membranes are selectively permeable (only allow certain molecules through) and are roughly 10 nm thick

12

Osmosis

The diffusion of water through a selectively permeable membrane

13

Isotonic solution

Has the same water concentration as the cell, eg blood. Cells stay the same size

14

Hypotonic solution

Has more water than inside the cell, eg freshwater. Cells swell and may burst

15

Hypertonic solution

Has less water than inside the cell, eg seawater. Cells shrink (dehydrate)

16

Active transport requires

Energy (ATP)

17

What are the three types of active transport?

Pumps, exocytosis, endocytosis

18

Pumps

Membrane proteins that transport chemicals.

Sodium is pumped out of the cell, potassium is pumped in.

19

Examples of pumps are

Sodium/potassium pump

20

Endocytosis

Large molecules are pulled into the cell.

21

Phagocytosis - to do with endocytosis

Solids brought in.
Eg white blood cells eat bacteria.

22

Pinocytosis - to do with endocytosis

Liquids brought in.
Eg cells around blood vessels

23

Exocytosis

Large molecules are pushed out of the cell.
Eg tears, milk