O-Chem exam 4

Classify each of the following chemical processes as anabolic or catabolic

a. Anabolic, b. Anabolic , c. Catabolic, d. Anabolic

What are the two types of metabolic reactions?

Anabolism and catabolism

What cellular organelle is responsible for the generation of most of the energy for the cell?

Mitochondrion

What intermediate molecule in metabolic reactions is responsible for producing energy in the human body?

ATP

Why is ATP the best energy source for human beings?

It has an intermediate value in free energy, and it undergoes slow hydrolysis in an aqueous environment

Which of the following structural descriptions for metabolic carboxylate ions that are derivatives of succinic acid is incorrect?

Fumarate contains a carbon–carbon double bond in a cis configuration

How many “strained” bonds are present in an ATP molecule?

Two

What are the stages of energy production in the order of occurrence?

Digestion, acetyl group formation, the citric acid cycle, and electron transport and oxidative phosphorylation

When one acetyl CoA is processed through the citric acid cycle, how many times does each of the following events occur?

A. One B. Two C. Four D. One

How many high-energy molecules are formed in one turn of the citric acid cycle?

3 NADH, 1 FADH2, and 1 GTP

Athletes have the ability to perform at high levels of activity because of their systems’ ability to produce large amounts of energy. How is this possible?

They have an increased number of mitochondria which are able to produce large quantities of ATP

Identify the functions of carbohydrates in the human body.

All the Above

Carbohydrates are classified as:

monosaccharides, disaccharides, oligosaccharides, and polysaccharides

What is the primary function of DNA?

Storage and transfer of genetic information

DNA and RNA are two types of nucleic acids found in

the cells of organisms. What is a nucleic acid?

An unbranched polymer containing monomer units called nucleotides

What is a nucleotide?

A three-subunit molecule containing a pentose sugar bonded to a nitrogen-containing

heterocyclic base and a phosphate group

The nucleotide AMP is found in

RNA molecules, but not DNA

What are the structural differences between RNA and DNA?

RNA contains the sugar ribose and heterocyclic bases adenine, cytosine, guanine, or uracil. DNA contains deoxyribose and the heterocyclic bases adenine, cytosine, guanine, or thymine

Predict the sequence of bases in the DNA strand

complementary to the single DNA strand shown below:

5′ A–A–T–G–C–A–G–C–T 3′

3′ T–T–A–C–G–T–C–G–A 5’

What is the complementary base in DNA?

Adenine–thymine

DNA contains the genetic information in a cell, so what does DNA replication refer to?

The process of producing exact replicates of DNA molecules

Where does the digestion of carbohydrates begin

mouth

Indicate at what step in the glycolysis pathway each of the following events occur:

a. Step 10 b. Step 9 c. Step 3 d. Step 9

What statement best describes glycolysis?

A series of metabolic reactions to breakdown glucose into two pyruvate molecules, energy in the form of ATP, and NADH

Any given nucleotide in a nucleic acid contains

one sugar, one base, and one phosphate

The number of structural subunits present in a nucleoside and a nucleotide are, respectively

two and three

The number of different kinds of nucleotides present in any RNA molecule is

4

Which of the following are the three “single ring” bases that occur in nucleic acids?

cytosine, thymine, and uracil

The “backbone” of a nucleic acid molecule consists of an alternating sequence of

sugar and phosphate groups

35 percent of the bases in a certain DNA molecule are found to be A. What percent of the bases in this same molecule are G?

15%

Which of the following statements concerning the double helix structure present in DNA molecules is correct?

Base pairing between strands always involves one pyrimidine base and one purine base.

Replication of DNA produces two daughter DNA molecules in which

Each daughter molecule contains one parent strand and one newly synthesized strand.

In DNA replication the unwinding of the double helix

occurs at a single point along the length of the double helix

RNA molecules differ from DNA molecules in that they

are single stranded rather than double stranded

In a dinucleotide the phosphate linkage between nucleotide units involves

more than one correct response

In which of the following sets of nucleic acid “building blocks” are all members of the set possible components of a DNA molecule?

no correct response

Which of the following statements concerning genes and chromosomes is correct?

A gene is a segment of a DNA molecule that contains instructions for the synthesis of one or more proteins.

In a dinucleotide the phosphate linkage between nucleotide units involves

more than one correct response

Which of the following is a correct structural characteristic of a nucleotide?

More than one correct response

In DNA replication the two strands of the double helix separate, and each strand

serves as a template for the construction of its own complement

Which of the following sets of base composition data is consistent with the double helix nature of DNA molecules?

15% C and 15% G

The variable portion of a nucleic acid molecule is the sequence of bases attached to the nucleic acid “backbone

true

DNA nucleotides contain three subunits, and RNA nucleotides contain four subunits

False

Complementary base pairing in DNA involves the base combinations (A and T) and (G and C).

true

Nucleotides are related to nucleic acids in the same way that amino acids are related to proteins.

true

Which of the following statements about metabolism is correct?

Metabolism is the sum total of all the biochemical reactions that take place in a living organism.

Which of the following statements about mitochondria is correct?

Mitochondria are located within the cellular cytosol.

The missing structural subunit in the following diagram for flavin adenine dinucleotide is

ribose

The “fuel” for the citric acid cycle is

acetyl CoA

Which of the following is a correct general description of the reaction that occurs in the first step of the citric acid cycle?

C2 + C4 → C6

In which two steps of the citric acid cycle are molecules of carbon dioxide produced?

step 3 and 4

How many NADH and FADH₂ molecules are produced, respectively, during one turn of the citric acid cycle?

one, three

Which of the following substances contains three or more high energy phosphate bonds?

ATP

Which of the following is a correct letter designation for the reduced form of a coenzyme?

FADH2

Which of the following are products of the citric acid cycle?

CO2 and NADH

In which of the following citric acid cycle reactions does the coenzyme FAD participate?

succinate → fumarate

Which of the following statements concerning citric acid cycle reactions is correct?

more than one correct response

FADH₂ is the oxidized form of the coenzyme flavin adenine dinucleotide

false

Both ribosomes and mitochondria are examples of organelles

false

ATP, ADP, and AMP differ from each other in the number of adenine subunits present

False

Anabolic reactions usually require energy input in order to proceed

true

The primary site within the human body where carbohydrate digestion occurs is the

small intestine

Which of the following conversions is accomplished by the process of glycolysis?

glucose to pyruvate

The first two intermediates in the process of glycolysis are, respectively

glucose 6-phosphate and fructose 6-phosphate

How many total steps are there in the process of glycolysis?

ten

Accumulation of which of the following substances is the cause of stiff and sore muscles after vigorous exercise?

lactate

In which of the following pairs of nucleic acid bases are both members of the pair “single ring” bases?

T and U

In DNA replication the two strands of the double helix separate, and each strand

serves as a template for the construction of its own complement

The number of structural subunits present in a nucleoside and a nucleotide are, respectively

two and three

The “backbone” of a nucleic acid molecule consists of an alternating sequence of

sugar and phosphate groups

Replication of DNA produces two daughter DNA molecules in which

Each daughter molecule contains one parent strand and one newly synthesized strand

In which of the following sets of nucleic acid “building blocks” are all members of the set possible components of a DNA molecule?

no correct response

Nucleotides are related to nucleic acids in the same way that amino acids are related to proteins

true

The number of different kinds of nucleotides present in any RNA molecule is

four

In DNA replication the unwinding of the double helix

occurs at a single point along the length of the double helix

RNA molecules differ from DNA molecules in that they

are single stranded rather than double stranded

Which of the following diagrams gives the correct identities and arrangement of the structural subunits in coenzyme A?

c

The missing structural subunit in the following diagram for flavin adenine dinucleotide is

ribitol

The correct notation for the reduced form of nicotinamide adenine dinucleotide is

NADH

In which of the following pairs of metabolic carboxylate ions are both members of the pair derivatives of succinic acid?

malate, fumarate

The “fuel” for the citric acid cycle is

acetyl CoA

Which of the following is a correct general description of the reaction that occurs in the first step of the citric acid cycle?

C2 + C4 → C6

Which of the following substances has two unsubstituted ribose molecules as structural subunits?

 

NAD+

Which of the following are products of the citric acid cycle?

CO2 and NADH

Which of the following statements about metabolism is correct?

Metabolism is the sum total of all the biochemical reactions that take place in a living organism.

How many NADH and FADH₂ molecules are produced, respectively, during one turn of the citric acid cycle?

three, one

During digestion, triacylglycerols are converted by

lipases to _____ and _____.

monoacylglycerols; free fatty acids

Hydrolysis of triacylglycerols in adipose tissue is triggered by hormones that stimulate _____ production within adipose cells that stimulate lipases in these cells.

cyclic AMP (cAMP)

What is the fate of the glycerol that is produced during mobilization of triacylglycerols in adipose cells?

It is converted by a two-step process to dihydroxyacetone phosphate, which is an

intermediate in glycolysis and gluconeogenesis

What is the first step in the oxidation of a fatty acid?

It is activated by bonding to coenzyme A.

What is the net ATP production for a 16-carbon fatty acid?

106

When the lipid-carbohydrate metabolism is upset by certain body conditions, more acetyl CoA is produced that can be used in the citric acid cycle. This results in the production of _____ by a process known as _____

ketone bodies; ketogenesis

Lipogenesis occurs in the cell _____, where all intermediates are bound to _____, resulting in a fatty acid biosynthetic pathway where the fatty acid chain increases in length by _____ carbons per pathway cycle.

cytosol; ACP–SH; 2

dentify the statement that states the relationship between lipogenesis and citric acid intermediates?

The lipogenesis intermediates are four carbon monoacids, and the citric acid intermediates are four carbon diacids

Biosynthesis of cholesterol occurs in the _____.

liver

What is the product of lipid and carbohydrate metabolism that enters the citric acid cycle?

Acetyl CoA

Which of the following B-vitamin-containing coenzymes is needed in the reactions associated with the conversion of fatty acids to acetyl CoA?

FAD

Besides cholesterol being an important cell membrane component, what other function does cholesterol serve?

It is a precursor for various classes of steroid hormones.

A lipid is an organic compound found in living organisms that is:

insoluble in water and soluble in nonpolar organic solvents

A fatty acid is a naturally occurring _____ acid that nearly always contains an _____ number of carbon atoms with a carbon chain that is _____.

monocarboxylic; even; unbranched