Cell Membrane 1

Question 1

Biological rhythms and changes in set point

Answer 1

Variables are regulated within a normal range around a set point, but set points vary

Question 2

Variables that change predictably and create repeating patterns or cycles of changes:

Answer 2

Biorhythms

Question 3

What separates one compartment of a cell from another

Answer 3

Membranes: bilateral of phospholipids with protein molecules inside (lipid bilayer)

Question 4

Functions of a cell membrane: Physical Isolation

Answer 4

-physical barrier seperating intracellular fluid and extra cellular fluid
-separates cell from environment

Question 5

Functions of a cell membrane: Regulation of exchange with environment:

Answer 5

-controls entry, elimination, and release
(Selectively permeable)

Question 6

Functions of a cell membrane: Communication

Answer 6

-between cell and its environment
-contains proteins that allow for responding or interacting with external environment

Question 7

Functions of a cell membrane: Structural Support

Answer 7

-proteins in membrane are used to make cell-to-cell connections (tissue) and anchor to cytoskeleton

Question 8

Average Composition of a cell membrane:

Answer 8

55% proteins
45% lipids
Small amount of carbohydrates
-not all cell membranes are created equally

Question 9

Three Types of lipids found in the cell membrane:

Answer 9

Phospholipid: major lipid: main: 50-60%
Sphingolipids: lipid rafts: 30%
Cholesterol: increases viscosity and decreases permeability: 10-20%

Question 10

T or F: All homeostatic set points for variables in the body remain constant

Answer 10

False

Question 11

What is the Fluid Mosaic Model?

Answer 11

Current cell membrane model
-proteins dispersed throughout
-extracellular surface contains glycoproteins and glycolipids

Question 12

What can be loosely or tightly bound to membranes?

Answer 12

Cell Membrane Proteins

Question 13

Types of integral proteins

Answer 13

: Transmembrane and Lipid Anchored proteins

Question 14

Roles of Integral Proteins

Answer 14

Membrane receptors
Cell adhesion molecules
Transmembrane movement (channels, carriers, pores, pumps)
Enzymes
Mediators of intracellular signalling

Question 15

What do Peripheral Proteins do

Answer 15

Attach to integral proteins and are loosely attached to phospholipid head
Participate in intracellular signalling
Form submembraneous cytoskeleton

Question 16

What type of proteins associate with sphingolipids instead of phospholipids?

Answer 16

Lipid Anchored Proteins