Deck 24: Integration of Metabolism: Cellular Signaling

Question 1

The American Heart Association advocates that 30% or less of our calories should come from fats,but the typical US diet actually exceeds 40% fat.

Answer 1

True

Question 2

What happens to the nitrogen from excess protein?

A) It is stored as carbohydrate.
B) It is stored as fat.
C) It is eliminated through the urea cycle.
D) It is exhaled as N₂ gas.

Answer 2

C

Question 3

For which of the following is there no RDA (recommended daily allowance)?

A) calcium
B) fluoride
C) iodine
D) iron

Answer 3

B

Question 4

Sweets and fats are at the top of the food pyramid,because they are so important in our diet.

Question 5

Which of the following is not true concerning leptin?

A) It is a hormone related to obesity
B) It stimulates acetyl-CoA carboxylase
C) It stimulates fatty acid oxidation
D) It is produced by the ob gene
E) all of these are true

Question 6

In addition to all the other problems,why can a person get fat from overdrinking alcohol?

A) Alcohol inhibits carnitine palmitoyltransferase I
B) Ethanol is converted to acetate and then to acetyl-CoA which makes lipids
C) Ethanol converts carbohydrates into lipids
D) none of these

Question 7

Which of the following link photosynthesis and carbon dioxide fixation?

A) ATP:ADP and NADP⁺:NADPH
B) ATP:ADP and NAD⁺:NADH
C) NTP:NDP
D) none of these

Question 8

Proteins are always being degraded,so there is a constant need for quality protein in order to maintain the body's structures.

Question 9

Dietary supplements are sometimes indicated for which of the following minerals?

A) calcium
B) chloride
C) potassium
D) sodium

Question 10

Low levels of iodide in the diet can lead to an enlarged thyroid.

Question 11

Proteins eaten in excess can be stored to satisfy future protein requirements.

Question 12

Studies of metabolism usually separate the reactions into pathways,such as the Krebs' Cycle or the Pentose Phosphate Pathway.This is really an artificial designation,since these pathways are all intimately linked and overlap.

Question 13

Which of the following is a water-soluble vitamin?

A) A
B) B₆
C) D
D) E

Question 14

The following are not essential in the human diet.

A) Ethanol.
B) Nucleic acids.
C) Heme containing compounds.
D) Neither ethanol nor heme-containing compounds are required.
E) None of these is required in the human diet.

Question 15

Overdoses are possible for which of the following vitamins?

A) vitamins A, D, and E
B) vitamins A, C, and E
C) vitamins A, B₁, and C
D) vitamins A, B₁, and B₆

Question 16

What function do vitamins usually serve?

A) coenzymes or precursors of coenzymes
B) intermediates of the TCA cycle
C) precursors of amino acids
D) hormones or second messengers

Question 17

An essential nutrient is one which is either not made in the body or is not made in sufficient quantity to allow for survival.

Question 18

Which of the following compounds does not overlap between several pathways?

A) Acetyl-CoA
B) Oxaloacetate
C) Cholesterol
D) Pyruvate

Question 19

Which of the following is not a macronutrient?

A) carbohydrates
B) fats
C) proteins
D) iron

Question 20

Which pathway is central to virtually all living organisms?

A) glycolysis.
B) citric acid cycle
C) electron transport chain
D) photosynthesis
E) fatty acid metabolism

Question 21

Which of the following best describes protein kinases?

A) Protein kinases act by transferring a phosphate from a protein to ADP to make ATP.
B) Protein kinases act by transfering a phosphate from a donor molecule, like ATP, to a protein molecule, thereby changing its activity
C) Protein kinases phosphorylate enzymes and activate them
D) Protein kinases phosphorylate key tyrosine residues on receptors

Question 22

Most hormones accomplish their activity by direct inclusion in the cell,where they carry out their catalytic function.

Question 23

Intracellular second messengers include all of the following except

A) Ca²⁺
B) DAG
C) cATP
D) nitric oxide (NO)

Question 24

Which of the following produces hormone-releasing factors?

A) hypothalamus
B) anterior pituitary
C) posterior pituitary
D) adrenal cortex

Question 25

When cyclic AMP is a second messenger

A) cyclic AMP inhibits a protein kinase
B) the binding of hormone produces the desired effect in the cell by stimulating the production of cyclic AMP
C) the G protein plays no role
D) a target enzyme is phosphorylated with cyclic AMP as the source of the phosphate group

Question 26

Growth hormone imbalance does not lead to

A) acromegaly
B) dwarfism
C) giantism
D) Cushing's syndrome

Question 27

Steroid hormones affect which of the following?

A) carbohydrate metabolism.
B) inflammatory and stress reactions.
C) sexual development.
D) All of these

Question 28

Epinephrine is an example of a hormone which uses calcium ion as a key part of its intracellular effect.

Question 29

Fine tuning of the hormone process is done by such mechanisms as using other hormones to cause the release of the final active hormone.

Question 30

A second messenger is

A) a substance that brings about a desired effect in a cell as a result of a hormone binding to its receptor on the cell surface
B) a hormone that acts on a target cell, not one of the releasing factors or trophic hormones that act on specific endocrine glands
C) a hormone that affects the DNA of the target cell
D) a specialized form of mRNA

Question 31

Which of the following is not a typical structure for a hormone?

A) steroid
B) carbohydrate
C) amino Acid derivative
D) protein or polypeptide
E) All of these structures are seen as hormones.

Question 32

Many hormones come in pairs,which have opposing metabolic activity.

Question 33

Hormones are

A) transported to their site of action by the lymphatic system.
B) intercellular messengers.
C) present in large quantities in organisms.
D) not well characterized.

Question 34

Which of the following is a second messenger?

A)Cyclic AMP
B)GTP-binding proteins.
C)Proteins kinases.
D)Phospholipase C.
E)All of these can act as second messengers.

Question 35

Hormone activity frequently turns metabolic pathways on and off by adding phosphate to or removing it from lipids within the cell.

Question 36

Trophic hormones act on

A) specific endocrine glands.
B) liver cells.
C) muscles cells.
D) all of the above.

Question 37

A hormone is defined as a substance which is made in one tissue,but actually acts on a different tissue.

Question 38

Which of the following fats are linked with high cholesterol and heart disease?

A) saturated fats
B) monounsaturated fats
C) polyunsaturated fats
D) all fats, regardless of saturation

Question 39

Which of the following statements concerning iron deficiency in humans is false?

A) Iron requires a carrier molecule for absorption and transport.
B) Iron can only be absorbed in the iron (III) state.
C) Iron often forms insoluble complexes with other food substances.
D) Other ions may compete with iron for uptake into the body.

Question 40

Amino acid and protein hormones usually act by binding to a receptor on the cell surface.

Question 41

Which of the following is not a potential mechanism to activate protein kinases?

A) Cyclic AMP binding to regulatory subunits on the protein kinase.
B) Binding of a calcium complex to the protein kinase.
C) Binding of inositol phosphate to the protein kinase.
D) All three of these mechanisms activate protein kinase.

Question 42

Which of the following statements is not a characteristic of aerobic catabolism?

A) molecular oxygen is the final electron acceptor
B) the oxidation of acetyl groups in the citric acid cycle and oxidative phosphorylation pathways ultimately yields CO₂ and H₂O
C) pyruvate and acetyl-CoA are major metabolic intermediates
D) roughly equal quantities of energy are produced in each of the three stages of aerobic catabolism, namely glycolysis, the citric acid cycle, and oxidative phosphorylation

Question 43

Which of the following best describes insulin's structure?

A) nucleotide
B) peptide
C) mineral
D) carbohydrate

Question 44

The action of Ca²⁺ in a second messenger scheme

A) involves the calcium-binding protein calmodulin as the actual second messenger
B) relies entirely on intercellular reservoirs of Ca²⁺ in the endoplasmic reticulum
C) does not involve the G protein
D) produces sustained responses by controlling the flow of Ca²⁺ into the cell

Question 45

Regulatory cascades have what advantage over direct action by the signal molecule?

A) Amplification.
B) Fine tuning of regulatory effects.
C) Coordinated response among multiple systems.
D) All of these

Question 46

Which of these hormones regulates the level of glucose in human blood?

A) insulin
B) glucagon
C) glucagon and epinephrine
D) insulin and glucagon
E) insulin, glucagon and epinephrine

Question 47

Glycogen metabolism is influenced by

A) phosphorylase kinase
B) phosphoprotein phosphatase
C) epinephrine
D) all of these

Question 48

Which of the following is not a characteristic of catabolic pathways?

A) ATP is generated by catabolism
B) reducing equivalents are most often released in the form of hydrogen atoms
C) NAD⁺ is one of the major electron carriers in catabolic reactions
D) NADH produced in catabolic reactions is reoxidized to NAD⁺ in the mitochondria

Question 49

G proteins act on

A) tyrosine kinases.
B) adenylate cyclase.
C) insulin receptors.
D) steroid hormones.

Question 50

Chronic high carbohydrate diets can result in over-release of insulin,which actually causes hypoglycemia.

Question 51

Which of the following is not a characteristic of anabolic pathways?

A) macromolecules are synthesized
B) ATP is generally consumed in these pathways
C) the pathways are exergonic
D) the molecules undergo reduction

Question 52

Insulin exerts its effects through

A) cyclic AMP.
B) calcium ions.
C) tyrosine kinases.
D) direct action on DNA-binding proteins.

Question 53

The G protein

A) is a tetramer
B) is inactivated by cholera toxin
C) mediates the production of second messenger
D) is a hexameric complex in the cytosol

Question 54

Which of the following is not a strategy for the regulation of metabolic pathways?

A) competing pathways are located in the same organelle
B) allosteric enzymes
C) feedback inhibition
D) covalent modification of enzymes

Question 55

Insulin affects which of the following?

A) GLUT 4 transporter
B) Pyruvate dehydrogenase
C) Acetyl-CoA carboxylase
D) Glycogen synthase
E) Glycogen synthase and Glycogen phosphorylase
F) all of these

Question 56

Which of the following is not a characteristic of catabolic pathways?

A) macromolecules, such as carbohydrates, are hydrolyzed to monomers and then oxidized
B) ATP is a common product in such pathways
C) the pathways are exergonic
D) energy input is required for these pathways to take place

Question 57

Between meals,the blood glucose levels are regulated mostly by

A) glycogen phosphorylase
B) insulin
C) glucagon
D) epinephrine
E) insulin and glucagon
F) none of these

Question 58

The following reactions are all common parts of some hormone processes: 1.Binding of the hormone to a receptor.
2)Synthesis of cyclic AMP
3)Phosphorylation of the target enzyme.
4)Release of a G-protein from the interior cell membrane.
5)Activation of a protein kinase.
A typical path of reactions would follow this sequence:

A) 1 2 4 3 5.
B) 1 4 2 3 5.
C) 1 4 2 5 3.
D) 1 2 4 5 3.
E) 2 1 4 5 3.

Question 59

Which of these hormones causes elevation of the level of glucose in human blood?

A) Insulin
B) Glucagon.
C) Glucagon and Epinephrine.
D) Insulin and Glucagon.
E) All of these Hormones elevate the blood glucose levels.

Question 60

Which of the following is not a role for hormones?

A) maintenance of homeostasis
B) mediation of responses to external stimuli
C) growth and development
D) antioxidants