Exam Review 2

Acids, Bases, & pH

Carbon

Carbohydrates

Lipids

Nucleic Acids

100

One water molecule in ~500 million naturally dissociates into a hydrogen ion and a hydroxide ion. Which of the following denotes a hydroxide ion?

a. H₂O

b. H⁺

c. OH^-

d. H₃O⁺

c. OH^-

100

True or False.

Functional groups give the molecule it's attached to unique properties.

TRUE

100

True or False.

Monosaccharides can be broken down into smaller sugars.

False.

Monosaccharides are simple carbohydrates consisting of one carbohydrate unit.

100

Which lipid makes up the cell membrane?

a. triglycerides

b. cholesterol

c. phospholipids

d. steroids

c. phospholipids

100

True or False.

DNA is double stranded. These strands are parallel and complementary.

False.

200

As the concentration of hydrogen ions increases, the pH ________. As the concentration of hydroxide ions decreases, the pH _________.

a. decreases; decreases

b. decreases; increases

c. increases; decreases

d. increases; increases

a. decreases; decreases

200

How many carbon atoms does this molecule have?

a. 5

b. 7

c. 10

d. 12

b. 7

200

What is the molecular formula of an oligosaccharide made up of five hexose sugars?

a. C₃₀H₆₀O₃₀

b. C₃₀H₅₂O₃₀

c. C₃₀H₅₂O₂₆

d. C₃₀H₆₈O₃₄

c. C₃₀H₅₂O₂₆

200

Which type of lipid consists of a glycerol molecule covalently bonded, via an ester linkage, to three fatty acid molecules?

a. triglycerides

b. cholesterol

c. phospholipids

d. steroids

a. triglycerides

200

It refers to the DNA sequence that codes for a specific protein.

a. Genome

b. Gene

c. DNA

d. RNA

b. Gene

300

True or False.

The Carbonic Acid-Bicarbonate buffer system is the most important buffer for maintaining the pH homeostasis of our blood. This buffer system works by neutralizing our pH level.

False.

A buffer system does not keep a solution neutral. It STABILIZES the solution to keep it in the desired pH range.

300

Identify the functional group present in the image above. Is it polar or nonpolar?

a. carbonyl, polar

b. carbonyl, nonpolar

c. carboxy, polar

d. carboxy, nonpolar

a. carbonyl, polar

300

Monosaccharides are the building blocks of carbohydrates. Which of the following is the covalent bond that holds monosaccharides together?

a. ester linkages

b. peptide bonds

c. phosphodiester linkages

d. glycosidic linkages

300

Which of the following is a precursor to reproductive hormones, and is responsible for maintaining the fluidity of our cell membranes?

a. triglycerides

b. cholesterol

c. phospholipids

d. steroids

b. cholesterol

300

Polynucleotides are held together via phosphodiester linkages. The hydroxyl group of the pentose at the ___ carbon of one nucleotide is covalently bonded to the phosphate group at the ___ carbon of another nucleotide.

a. 5'; 5;

b. 3'; 5'

c. 5'; 3'

d. 3' 3'

b. 3'; 5'

400

Milk has a pH of 6. Soda has a pH of 3. Which of the two is more acidic and by how much more?

a. Milk; 3x

b. Milk; 1,000x

c. Soda; 3x

d. Soda; 1,000x

400

Glucose molecules can be covalently bonded to other glucose molecules to form a polysaccharide. Glucose is considered to be the:

a. macromolecule

b. polymer

c. monomer

d. hydrocarbon

c. monomer

400

Compare the following polysaccharides according to function and kingdom use/location: glycogen, starch and cellulose.

Glycogen - energy storage in animals (particularly in the muscles and livers in humans)

Starch - energy storage in plants

Cellulose - provides structure, shape, and support in plants

400

Saturated fats tend to be _____ in room temperature. Unsaturated fats tend to be ______ in room temperature.

a. liquid, liquid

b. liquid, solid

c. solid, liquid

d. solid, solid

c. solid, liquid

400

Nucleotides are made of a phosphate group, a pentose sugar, and a nitrogenous base. Identify the pentose (ribose or deoxyribose) and nitrogenous base (purine or pyrimidine).

a. ribose, purine

b. ribose, pyrimidine

c. deoxyribose, purine

d. deoxyribose, pyrimidine

c. deoxyribose, purine

500

An aqueous solution has an [OH^-]= 10^-5. Calculate the [H⁺] and pH.

a. [H⁺]= 1x10^-9; pH=5

b. [H⁺]= 1x10^-9; pH=9

c. [H⁺]= -9; pH=5

d. [H⁺]= -9; pH=9

b. [H⁺]= 1x10^-9; pH=9

500

Which reaction is involved in the synthesis of polymers?

a. hydrolysis

b. dehydration

c. hydrogenation

d. neutralization

b. dehydration

500

Give at least three functions of carbohydrates.

*immediate energy source (glucose)

*energy storage (starch in plants, glycogen in animals)

*structural support (cellulose, chitin)

*cell communication (glycolipids, glycoproteins)

500

Which of the following is a defining characteristic among lipids?

a. lipids are polar

b. lipids are amphipathic

c. lipids are hydrophilic

d. lipids are hydrophobic

500

A DNA molecule is 26% cytosine. Following Chargaff's rule, the molecule is ___ thymine and ___ guanine.

a. 24%; 52%

b. 48%; 24%

c. 24%; 26%

d. 48%; 52%

c. 24%; 26%