Chapter 3

Question 1

About how many cells are there in the human body?

Answer 1

75 trillion

Question 2

What is differentiation?

Answer 2

When cells specialize.

*As a result of differentiation, cells vary in size and shape due to their unique function.

Question 3

What is a composite cell, and what are its major parts?

Answer 3

Also called a "typical cell". 
Major parts include:
• Nucleus
• Cytoplasm
• Cell membrane

Question 4

What is a cell membrane (plasma membrane) and what is its function?

Answer 4

• Outer limit of the cell (phospholipid bilayer)

* Controls what moves in and out of the cell which is also known as selective permeabilitly

Question 5

What are the characteristics of a phospholipid bilayer?

Answer 5

• Water-soluble “heads” form surfaces (hydrophilic)
• Water-insoluble “tails” form interior (hydrophobic)
• Permeable to lipid-soluble substances

Question 6

What does cholesterol do to the membrane?

Answer 6

stabilizes it

Question 7

What proteins are found in the membrane?

Answer 7

• Receptors
• Pores, channels and carriers
• Enzymes
• CAMS
• Self-markers