3.1 Plasma Membrane

Question 1

The Lipid bilayer is made up of which parts?

Answer 1

-About 75% of the membrane lipids are lipids that contain phosphorus. -A steroid with an attached OH (hydroxyl) group,
-glycolipids (about 5%), lipids with attached carbohydrate groups.

Question 2

Membraneproteins are classified as either

Answer 2

integral or peripheral

Question 3

integral Proteins are ?

Answer 3

Integral proteins extend into or through the lipid bilayer and are firmly embedded in it.

Question 4

peripheral proteins are?

Answer 4

not as firmly embedded in the membrane. They are attached to the polar heads of membrane lipids or to integral proteins at the inner or outer surface of the membrane.

Question 5

What is the glycocalyx?

Answer 5

glycoproteins form an extensive sugary coat called the glycocalyx

-the glycocalyx acts like a molecular “signature” that enables cells to recognize one another.

Question 6

When stimulating a cell, the hormone insulin first binds to a protein in the plasma membrane. This action best represents which membrane protein function?

Answer 6

Receptor integral Protein

Question 7

True Or False
In ion channels, Integral Proteins. Most ion channels are not selective

Answer 7

False
Most ion channels are selective

Question 8

What is interesting about Carriers Integral Proteins

Answer 8

are also known as transporters.

Question 9

What is a ligand?

Answer 9

specific molecule that binds to a receptor is called a ligand

Question 10

“kink” in the fatty acid tail (see Figure 2.18), which increases membrane fluidity by preventing lipid molecules from packing tightly in the membrane

Question 11

What factors contribute to an electrochemical gradient?

Answer 11

a positively charged substance will tend to move toward a negatively charged area, and a negatively charged substance will tend to move toward a positively charged area. The combined influence of the con- centration gradient and the electrical gradient on movement of a particular ion is referred to as its electrochemical gradient.

Question 12

the inner surface of the plasma membrane is more negatively charged and the outer surface is more positively charged

Question 13

What are the three sides of the Golgi Complex?

Answer 13

-entry (cis) face is a cistern that faces the rough ER.

-The concave exit (trans) face is a cistern that faces the plasma membrane.

• Sacs between the entry and exit faces are called medial cisterns. Transport vesicles (desc

Question 14

Function of the Cis face in a Golgi Complex?

Answer 14

The entry face receives and modifies proteins produced by the rough ER

Question 15

Function of the exit (trans) in a Golgi Complex?

Answer 15

The exit face modifies the molecules further and then sorts and packages them for transport to their destinations.

Question 16

Function of the medial cistern in a Golgi Complex?

Answer 16

The medial cisterns add carbohydrates to proteins to form glycoproteins and lipids to proteins to form lipoproteins.

Question 17

What are the three general destinations for proteins that leave the Golgi complex?

Answer 17

1: transport vesicles carry digestive enzymes to lysosomes;

2: Some of the processed proteins leave the exit face and are stored in secretory vesicles.

Question 18

What is the name of the process by which worn-out organelles are digested by lysosomes?

Answer 18

autophagy

Question 19

How do the mitochondrial cristae contribute to its ATP-producing function?

Answer 19

the elaborate folds of the cristae pro- vide an enormous surface area for the chemical reactions that are part of the aerobic phase of cellular respiration, the reactions that produce most of a cell’s ATP

Question 20

Mitochondria also play an important and early role in apopto- sis

Answer 20

cytochrome c and other substances initiate a cascade of activation of protein-digesting enzymes that bring about apoptosis.

Question 21

Are Mitochondria maternal or paternal?

Answer 21

mitochondrial genes are inherited only from your mother. This is due to the fact that all mitochondria in a cell are descendants of those that were present in the oocyte (egg) during the fertilization process.

Question 22

Which organelles contribute to synthesizing protein hormones and packaging them into secretory vesicles?

Answer 22

Golgi complex