Ch.7: Membranes

Question 1

The plasma membrane is composed of

Answer 1

phospholipid and proteins

Question 2

contain hydrophobic and hydrophilic regions that maintain a bilayer

Answer 2

phospholipid

Question 3

states that a membrane is a fluid structure with a “mosaic” of various proteins embedded in it
An ocean of phospholipids with islands of protein

Answer 3

fluid mosaic model

Question 4

What maintain the membrane structure.?

Answer 4

The properties of the phospholipids

Question 5

determine most of the membrane’s specific functions

Answer 5

membrane-protein

Question 6

are bound to the surface of the membrane

Answer 6

peripheral protein

Question 7

penetrate the hydrophobic core

XXXXXx that span the membrane are called trans-membrane proteins

Answer 7

Integral proteins

Question 8

Six major functions of membrane proteins

Answer 8

Transport
Enzymatic activity
Signal transduction
Cell-cell recognition
Intercellular joining
Attachment to cytoskeleton

Question 9

is the tendency for molecules to spread out evenly into the available space
Molecules naturally try to XXXX in and out of cells
Cells are constantly fighting XXXX to maintain internal homeostasis

Answer 9

diffusion

Question 10

From high concentration to low concentration

Answer 10

concentration gradient

Question 11

The diffusion of a substance across a biological membrane is ______ ______
It requires no energy to make it happen
Water is always diffusing into and out of cells

Answer 11

passive transport

Question 12

is the diffusion of water across a selectively permeable membrane
Water diffuses across a membrane from the region of lower solute concentration to the region of higher solute concentration

Answer 12

osmosis

Question 13

Solute concentration is the same; no net water movement

Answer 13

isotonic

Question 14

Solute concentration is greater; cell loses water

Answer 14

hypertonic

Question 15

Solute concentration is less; cell gains water

Answer 15

hypotonic

Question 16

transport proteins speed the passive movement of molecules across the plasma membrane
Transport proteins are often needed to move large molecules across a membrane
Remember, these proteins serve to maintain selective permeability of the membrane

Answer 16

facilitated diffusion

Question 17

moves substances against their concentration gradient
XXXXX requires energy, usually in the form of ATP
________ ______is performed by specific proteins embedded in the membranes
Na / K pump

Answer 17

active transport

Question 18

However, large polysaccharides and proteins, cross the membrane differently
by?

Answer 18

bulk transport

Question 19

the cell takes in macromolecules by forming vesicles from the plasma membrane

Answer 19

endocytosis

Question 20

There are three types of endocytosis

Answer 20

Phagocytosis (“cellular eating”)
Pinocytosis (“cellular drinking”)
Receptor-mediated endocytosis

Question 21

transport vesicles migrate to the membrane, fuse with it, and release their contents

Answer 21

exocytosis

Question 22

Many secretory cells use exocytosis to export their products

Examples include:

Answer 22

protein hormones