Chapter 14: Introduction to Metabolism

Question 1

two types of metabolism

Answer 1

Catabolism
Anabolism

Question 2

in which nutrients and cell constituents are broken down to
salvage their components and/or to generate energy.

Answer 2

Catabolism

Question 3

in which biomolecules are synthesized from simpler
components.

Answer 3

Anabolism

Question 4

another name for Anabolism

Answer 4

biosynthesis

Question 5

another name for Catabolism

Answer 5

degradation

Question 6

Metabolic pathway’s reactants,
intermediates, and products are referred to as

Answer 6

metabolites

Question 7

are series of connected enzymatic reactions that produce specific product

Answer 7

Metabolic pathway

Question 8

are the major free energy sources for biosynthetic reactions.

Answer 8

ATP and NADPH

Question 9

acetyl unit linked to coenzyme A to form what

Answer 9

acetyl-coenzymeA (acetyl-CoA)

Question 10

what does the citric acid cycle produce

Answer 10

the reduced
coenzymes NADH and FADH2,

Question 10

A striking characteristic of degradative metabolism

Answer 10

The pathways for the catabolism of a large number of diverse substances converge on a few common intermediates

Question 11

what does electron transport and
oxidative phosphorylation produce

Answer 11

water

Question 12

Citric acid cycle, electron transport and oxidative phosphorylation, fatty acid oxidation, amino acid breakdown

Answer 12

mitochondrion

Question 13

Glycolysis, pentose phosphate pathway, fatty acid biosynthesis, many reactions of gluconeogenesis

Answer 13

cytosol

Question 14

Enzymatic digestion of cell components and ingested matter

Answer 14

Lysosome

Question 15

DNA replication and transcription, RNA processing

Answer 15

nucleus

Question 16

Posttranslational processing of membrane and secretory proteins; formation of plasma membrane and secretory vesicles

Answer 16

Golgi apparatus

Question 17

Synthesis of membrane-bound and secretory proteins

Answer 17

Rough endoplasmic reticulum

Question 18

Lipid and steroid biosynthesis

Answer 18

Smooth endoplasmic reticulum

Question 19

Oxidative reactions catalyzed by amino acid oxidases and catalase; glyoxylate cycle reactions in plants

Answer 19

Peroxisome (glyoxysome in plants)

Question 20

is largely responsible for the synthesis of glucose from noncarbohydrate precursors so as to maintain a relatively constant level of glucose in the circulation

Answer 20

mammalian liver

Question 21

specialized for storage of triacylglycerols.

Answer 21

adipose tissue

Question 22

rate of flow

Answer 22

flux

Question 23

Most enzymes in a metabolic pathway operate near what

Answer 23

equilibrium

Question 24

are Metabolic pathways reversible

Answer 24

no

Question 25

If a metabolite is converted to another metabolite by an exergonic process, free energy must be supplied to what

Answer 25

convert the second metabolite back to the first. This energetically“uphill” process requires a different pathway for at least one of the reaction steps

Question 26

For the pathway as a whole, flux is set by what

Answer 26

the rate-determining step of the pathway

Question 27

is the pathway's slowest step, which is often the first committed step of the pathway.

Answer 27

the rate-determining step of the pathway

Question 28

Cellular mechanisms to control flux through the rate-determining steps

Answer 28

Allosteric control Covalent modification Substrate cycles Genetic control

Question 29

example of Allosteric control

Answer 29

negative feedback regulation

Question 30

the product of a pathway inhibits an earlier step in the pathway.

Answer 30

Allosteric control

Question 31

example of Covalent modification

Answer 31

enzymatic phosphorylation and dephosphorylation of ezymes

Question 32

to control by external signals such as hormones.

Answer 32

Covalent modification

Question 33

Controlling rates of two opposing nonequilibrium reactions by different enzymes.

Answer 33

Substrate cycles

Question 34

Enzyme concentrations

Answer 34

Genetic control

Question 35

The“high-energy” intermediate

Answer 35

adenosine triphosphate (A TP)

Question 36

ATP consists of what

Answer 36

adenosine moiety (adenine + ribose)

Question 37

Why are the phosphoryl group-transfer reactions of A TP so exergonic?

Answer 37

1. The resonance stabilization of a phosphoanhydride bond is less than that of its hydrolysis products. 2. Another factor is the destabilizing effect of the electrostatic repulsions between the charged groups of a phosphoanhydride compared to those of its hydrolysis products. 3. Another destabilizing influence is the smaller solvation energy of a phosphoanhydride compared to that of its hydrolysis products. Some estimates suggest that this factor provides the dominant thermodynamic driving force for the hydrolysis of phosphoanhydrides.

Question 38

In the absence of what even a thermodynamically favored reaction (ΔG < 0) may not occur in a living system.

Answer 38

an appropriate enzyme,

Question 39

functions similarly to drive some of the reactions of signal transduction.

Answer 39

GTP hydrolysis

Question 40

help maintain a relatively constant level of cellularA TP .

Answer 40

“High-energy” compounds other than ATP

Question 41

can be regenerated by coupling its formation to a more highly exergonic metabolic process.

Answer 41

ATP

Question 42

The flow of energy from“high-energy” phosphate compounds to A TP are catalyzed by enzymes known as

Answer 42

kinases

Question 43

which transfer phosphoryl groups from ATP to other compounds or from phosphorylated compounds to AD

Answer 43

kinases

Question 44

acts as an ATP “buffer” in cells of muscle and nerve cells that contain creatine kinase.

Answer 44

Phosphocreatine

Question 45

functions as a carrier of acetyl and other acyl groups

Answer 45

CoA

Question 46

Macronutrients proteins, carbohydrates, and lipids are broken down by the digestive system to their component

Answer 46

amino acids, monosaccharides, fatty acids, and glycero

Question 46

requires the intake of O2 and water, as well as micronutrients composed of vitamins and minerals

Answer 46

The metabolic utilization of the latter substances

Question 47

is involved in nearly all reactions that involve A TP and other nucleotides, including the synthesis of DNA, RNA, and proteins.

Answer 47

Mg

Question 48

is a cofactor in a variety of enzymatic reactions including that catalyzed by carbonic anhydrase

Answer 48

Zn 2+

Question 49

is a vital participant in signal transduction processes.

Answer 49

Ca

Question 50

Metabolic reactions are catalyzed by

Answer 50

enzymes