Chapter 2: Molecules of Cells

Question 1

What do carbohydrates include?

Answer 1

Simple sugars and polysaccharides

Question 2

What are some functions of polysaccharides?

Answer 2

Storage forms of sugars
Form structural components of the cell 
Cell recognition 
Transport proteins intracellularly 
Protein folding

Question 3

What are monosaccharides?

Answer 3

Simple sugars that are the major nutrients of the cell with the formula (CH2O)n

Question 4

What is glucose?

Answer 4

Simple 6-carbon sugar that provides principle source of cellular energy with the formula C6H2O6.

Question 5

Ions and polar molecules are ____ in water

Answer 5

Hydrophillic

Question 6

Nonpolar molecules are ______ in water

Answer 6

Hydrophobic

Question 7

What are the four classes of organic molecules?

Answer 7

Carbohydrates
Nucleic Acids
Proteins
Lipids

Question 8

What are oligosaccharides?

Answer 8

Polymers with few sugars

Question 9

What are polysaccharides?

Answer 9

Macromolecules that have polymers of hundreds or thousands of sugars

Question 10

What is the result of monosaccharides being joined together by dehydration reactions?

Answer 10

Glycosidic bonds

Question 11

What are the two common polysaccharides? Which type of eukaryotic cells are they located in?

Answer 11

Glycogen: stores glucose in animal cells
Starch: stores glucose in plant cells

Question 12

What is cellulose?

Answer 12

The main structural component of plant cell walls. Composed entirely of glucose molecules in the beta configuration

Question 13

What is the advantage of beta(1-4) configuration?

Answer 13

Linkages cause cellulose to form long extended chains that pack side by side to form fibers of great mechanical strength

Question 14

What is chitin?

Answer 14

The animal version of cellulose. It forms the exoskeletons of crabs and insects.

Question 15

What are the main roles of lipids?

Answer 15

Energy storage
Major component of cell membranes
Important in cell signaling as steroid hormones and messenger molecules

Question 16

What are fatty acids?

Answer 16

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

Question 17

What are unsaturated fatty acids?

Answer 17

Have one or more double bonds

Question 18

What are saturated fatty acids?

Answer 18

Have no double bonds.

Question 19

How are fatty acids stored?

Answer 19

Stored as triacylglycerols (triglycerides/fats)

Question 20

What are triacylglycerols (triglycerides/fats)

Answer 20

Three fatty acids linked to a glycerol molecules. Insoluble in water and accumulate as fat droplets in cytoplasm. Can be broken down for energy.

Question 21

Why are fats important?

Answer 21

Yield more energy than carbs which allows energy to be stored in less than half the body weight which is important for the mobility of animals.

Question 22

What are phospholipids?

Answer 22

The principle components of cell membranes in which two fatty acids are joined to a polar head group.

Question 23

What is the only nonglycerol phospholipid in cell membranes?

Answer 23

Sphingomyelin (polar head formed from serine)

Question 24

What are glycolipids composed of?

Answer 24

Two hydrocarbon chains and a carbohydrate polar head group (present in the cell membrane)

Question 25

What is cholesterol composed of?

Answer 25

Four hydrophobic hydrocarbon rings and a polar hydroxyl (present in the cell membrane)

Question 26

What are steroid hormones?

Answer 26

Derivatives of cholesterol and they act as chemical messengers

Question 27

What are nucleic acids? What do they include?

Answer 27

Principle informational molecules of the cell which include DNA and RNA

Question 28

What is messenger RNA? (mRNA)

Answer 28

Carries information from DNA to the ribosomes

Question 29

What are ribosomal RNA and transfer RNA involved in?

Answer 29

Protein synthesis

Question 30

DNA and RNA are polymers of nucleotides, what do those nucleotides consist of?

Answer 30

Purine and pyrimidine bases linked to phosphorylated sugars