Lecture 3 - Exam 1

Question 1

The glucose molecule can exist in an…?

Answer 1

Open-chain (acyclic) as well as ring (cyclic) form.

Question 2

What form is the predominate form of glucose in cells?

Answer 2

Cyclic form

Question 3

The ring-closing reaction can give _____ products, what are they?

Answer 3

Two
The two products are denoted alpha and beta depending on the configuration.

Question 4

Monosaccharides form cyclic structures when?

Answer 4

Monosaccharides contain five or more carbon atoms, they form cyclic structures.

Question 5

Monosaccharides are joined together by __________ (_____) resulting in _____.

Answer 5

Dehydration reaction (H2O is removed) ; glycosidic bonds
Note: The glycosidic linkage contains an ether linkage.

Question 6

What are oligosaccharides?

Answer 6

Polymers of a few sugars.

Question 7

What are polysaccharides?

Answer 7

Macromolecules ; polymers of hundreds or thousands of sugars.

Question 8

What is glycogen and starch?

Answer 8

Are the storage forms of carbohydrates in animals and plants, respectively.
To store glucose (AKA energy!!)

Question 9

Amylopectin (starch) : ______ bonds join two chains at a branch point.

Answer 9

alpha-1,6

Question 10

Glycogen: Most residues are joined by _________ bonds.

Answer 10

alpha-1,4

Question 11

Cellulose: Residues are joined by _______ bonds.

Answer 11

beta-1,4

Question 12

In addition of being the major source of energy, oligosaccharides and polysaccharides also play roles in…?

Answer 12

Protein folding and act as markers involved in cell recognition and interactions.

Question 13

What is a glycoprotein?

Answer 13

Protein with carbohydrate attached.

Question 14

What is a glycolipid?

Answer 14

Lipid with carbohydrate attached.

Question 15

What are the three major roles of lipids?

Answer 15

Energy storage, major component of cell membranes, and important in cell signaling as steroid hormones and messenger molecules.

Question 16

What are lipids primarily made of?
What are their characterisitics?

Answer 16

Lipids are molecules primarily made of hydrocarbons.
They are insoluble in water (create balls in the water, hiding from the forces of water) and greasy to the touch.

Question 17

What are the simplest lipids?

Answer 17

Fatty acids.

Question 18

What are fatty acids?

Answer 18

Long hydrocarbon chains (16 or 18 carbons) with a carboxyl group (COO-) at one end.

Question 19

What are unsaturated fatty acids?

Answer 19

Have one or more double bonds.

Question 20

What are saturated fatty acids?

Answer 20

No double bonds.

Question 21

The hydrocarbon chain in fatty acids are hydrophilic or hydrophobic?

Answer 21

Hydrophobic

Question 22

Which type of fatty acid is supposed to be healthier?

Answer 22

Unsaturated because they’re kinky and don’t like to stick together.

Question 23

What are fatty acids stored as?

Answer 23

Stored as fats.
More specifically, triacylglycerols (triglycerides, or fats) : three fatty acids linked to a glycerol molecule.

Question 24

Fatty acids can be broken down for use in…?

Answer 24

Energy-yielding reactions.
They yield >2X the amount of energy as carbs!!! important for animal mobility.

Question 25

Phospholipids are comprised of…?
Describe glycerol phospholipids.

Answer 25

Two fatty acids are joined to a polar head group.
Glycerol phospholipids: The fatty acids are bound to glycerol, which is bound to a phosphate group, and often another polar group.

Question 26

Phospholipids are hydrophilic or hydrophobic?

Answer 26

Actually, amphipathic, meaning part water-soluble and part water-insoluble.

Question 27

The only non-glycerol phospholipid contains what instead of a glycerol molecule?

Answer 27

Serine
The phospholipid is called Sphingomyelin

Question 28

What are some other important amphipathic membrane lipids?

Answer 28

Glycolipids: Two hydrocarbon chains and a carbohydrate polar head group (amphipathic).
Cholesterol: Four hydrophobic hydrocarbon rings and a polar hydroxyl (OH) group (amphipathic) - bad for us b/c really big and sticky.