Chapter 8.2

Question 1

What are fatty acids

Answer 1

-carboxylic acids that contain a hydrocarbon chain and terminal carboxyl group

Question 2

What are triacylglycerols

Answer 2

• they are the storage lipids involve in human metabolic processes
• > they contain three fatty acid chains esterified to a glycerol molecule

Question 3

What are two important essential fatty acids for humans

Answer 3

-alpha-linolenic acid and linoleic acid

Question 4

What are saturated fats

Answer 4

-they are the main components of animal fats and tend to exist as solids at room temperature

Question 5

What can phospholipids assemble into

Answer 5

-they assemble into micelles (monolayer vesicles) or liposomes(bilayered vesicles)

Question 6

What does the phosphate group of glycerophospholipids provide

Answer 6

-they provide attachments to water-soluble groups

Question 7

Are waxes rarely found in cell membranes

Answer 7

• yes
• > as they are very hydrophobic
• long chain fatty acid and a long chain alcohol which means it has high melting point
• most waxes serve as an extracellular function where they provide protection or waterproofing

Question 8

What is the difference between transmembrane proteins and embedded proteins

Answer 8

• transmembrane spans the whole membrane, while embedded is either on the cytoplasmic side or on the exterior side of the cell membrane
• > together, transmembrane and embedded proteins make up integral proteins

Question 9

What are peripheral proteins

Answer 9

• they are membrane associated proteins
• > bound through electrostatic interactions with the lipid bilayer
• > especially at lipid rafts or to other transmembrane or embedded proteins
• > like the G proteins found in G coupled receptors

-transporters, channels and receptors are generally transmembrane proteins

Question 10

What are gap junctions

Answer 10

• they allow for direct cell to cell communication and are often found in small bunches together
• gap junctions are also called connexons and are formed by the alignment and interaction of pores made up of six molecules called connexin
• note gap junctions allow for the movement of water and some solutes directly between cells
• > proteins are not transferred between gap junctions

Question 11

What are tight junctions

Answer 11

• they prevent solutes from leaking into the space between cells via a paracellular route
• tight junctions are found in epithelial cells and form as a single layer of tissue

Question 12

What are desmosomes

Answer 12

• bind adjacent cells by anchoring their cytoskeletons
• > they are formed by interactions between transmembrane proteins associated with intermediate filaments inside adjacent cells
• desmosomes are primarily found at the interface between two layers of epithelial tissues
• hemidesmosomes attach epithelial cells to underlying structures like the basement membrane