Chapter 25: Metabolism and Nutrition
What processes directly elevate blood glucose during the postabsorptive state, and where does each occur?
Processes that directly elevate blood glucose during the postabsorptive state include lipolysis (in adipocytes and hepatocytes), gluconeogenesis (in hepatocytes), and glycogenolysis (in hepatocytes).
In the case of a person who consumes a normal, balanced diet, proteins are essential to the body for which processes?
Production of enzymes, clotting factors, and antibodies, formation of functional molecules like hemoglobin and cytochrome, and production of some hormones.
Define negative nitrogen balance.
Protein breakdown exceeds protein synthesis.
True or False: The increased use of noncarbohydrate molecules for energy to conserve glucose is called glucose sparing.
True
True or False: The most abundant dietary lipids in the diets of most Americans are triglycerides.
True
True or False: Thyroid hormones promote glycolysis.
True
True or False: Vitamin E is a fat-soluble vitamin.
True
Which substance is the gateway into the Krebs cycle for molecules that are being oxidized to generate ATP?
Acetyl coenzyme A is the gateway into the Krebs cycle for molecules being oxidized to generate ATP.
When the terminal phosphate is cut off ATP what is formed?
Adenosine Diphosphate
What group is removed from an amino acid before it can enter the Krebs cycle, and what is this process called?
Before an amino acid can enter the Krebs cycle, an amino group must be removed via deamination.
Provitamins are
Building Blocks of Vitamins
When in cellular respiration is carbon dioxide given off?
Carbon dioxide is given off during the production of acetyl coenzyme A and during the Krebs cycle.
Glycogenolysis is ________ and stimulated by ___________
Catabolic, Epinephrine
Chemical reactions that break down complex organic molecules into simpler ones are called:
Catabolism
How many molecules of oxygen are used, and how many molecules of carbon dioxide are produced during the complete oxidation of one glucose molecule?
During the complete oxidation of one glucose molecule, six molecules of oxygen are used and six molecules of carbon dioxide are produced.
Thyrotropin-releasing hormone is secreted by the
Hypothalamus
True or False: Blood volume affects heat production.
False
True or False: Except for lactose and some glycogen, the carbohydrates we ingest are mainly from animals.
False
True or False: Glycogen is a major nutrient the body needs.
False
True or False: Glycogenesis is one way to make glucose.
False
True or False: Lipogenesis is a postabsorptive state reaction.
False
True or False: Processes that break down complex molecules into simpler ones are anabolic.
False
True or False: The net result of the complete oxidation of glucose includes oxygen.
False
How many ATPs can come from substrate level phosphorylation during glycolysis?
2
How many reactions take place during the Krebs cycle?
8
Liver cells convert:
Ammonia Into Urea
Chemical reactions that combine simple molecules and monomers to form complex structures are known as
Anabolism
Accumulation of a large amount of H+ between the inner and outer mitochondrial membranes, is described as
Chemiosmosis
These transport dietary lipids.
Chylomicrons
This is a mechanism of heat transfer that involves direct contact.
Conduction
Prostaglandins play a role in ________.
Control of Blood Pressure
Excess amino acids in the body are
Converted Into Glucose
What hormone stimulates gluconeogenesis?
Cortisol
Where does glycolysis take place?
Cytosol
Oxidation-reduction reactions are catalyzed by which enzymes?
Dehyrodgenases and Oxidases
What factors can increase metabolic rate and thus increase the rate of heat production?
Exercise, the sympathetic nervous system, hormones (epinephrine, norepinephrine, thyroxine, testosterone, human growth hormone), elevated body temperature, and ingestion of food increase metabolic rate, which results in an increase in body temperature.
This is a derivative of riboflavin.
FAD
True or False: All athletes require diets high in protein and calories in order to perform and to maintain their muscle mass.
False
True or False: Beta oxidation is the initial phase of fatty acid oxidation, and it occurs in the cytoplasm.
False
Neuropeptide Y stimulates
Food Intake
What are used in "metabolic crossroads"?
Glucose 6-phosphate, pyruvic acid, and acetyl coenzyme A.
Glycolysis, formation of acetyl CoA, Krebs cycle and the electron transport chain are all involved in:
Glucose Catabolism
In the absorptive state, most glucose that enters the liver is converted to
Glycogen
Which process is also called anaerobic cellular respiration?
Glycolysis is also called anaerobic cellular respiration.
In which part of the cell does glycolysis occur?
Glycolysis occurs in the cytosol.
What types of cells can carry out lipogenesis, beta oxidation, and lipolysis?
Hepatocytes and adipose cells carry out lipogenesis, beta oxidation, and lipolysis.
What cells can carry out gluconeogenesis and glycogenesis?
Hepatocytes can carry out gluconeogenesis and glycogenesis.
What type of cell can carry out ketogenesis?
Hepatocytes carry out ketogenesis.
In a pancreatic cell that produces digestive enzymes, does anabolism or catabolism predominate?
In pancreatic acinar cells, anabolism predominates because the primary activity is synthesis of complex molecules (digestive enzymes).
The most dramatic metabolic change that occurs with fasting is
Increase in Lipolysis
What hormone stimulates glycogenesis?
Insulin
What happens to carbon dioxide given off during cellular respiration?
It diffuses into the blood, is transported by the blood to the lungs, and is exhaled.
Why is the enzyme that catalyzes step three of glycolysis called a kinase?
Kinases are enzymes that phosphorylate (add phosphate to) their substrate.
This reaction oxidizes acetyl CoA to produce carbon dioxide, ATP, NADH+H+ and FADH2.
Krebs Cycle
Which type of lipoprotein delivers cholesterol to body cells.
LDLs deliver cholesterol to body cells.
Cardiac muscles can produce ATP from
Lactic Acid
This process is the synthesis of triglycerides.
Lipogenesis
The process of breaking triglycerides down into glycerol and fatty acids is known as ________.
Lipolysis
What is the outcome of ketosis?
Metabolic Acidosis
Where can pyruvate dehydrogenase be found?
Mitochondria
Where does the Krebs cycle take place?
Mitochondria
Lipogenesis occurs when
More calories are consumed than required for ATP need
The primary reason elderly people should decrease their caloric intake is that ________.
Muscle mass and metabolism decline with age
Describe complete protein.
Must meet all the body's amino acid requirements for maintenance and growth
According to the standard height-weight chart, 4'8" Maria should weigh 100 pounds. She currently weighs 125 pounds. Clinically, Maria is described as ___.
Obese
This is the key regulator of the rate of glycolysis.
Phosphofructokinase
Are the reactions that occur during the absorptive state mainly anabolic or catabolic?
Reactions of the absorptive state are mainly anabolic.
The most abundant product of the reactions of the Krebs cycle is
Reduced Coenzymes
When a person's hypothalamic thermostat is set to a higher level and the actual body temperature is below that level, the person may ________.
Shiver
Besides hepatocytes, which body cells can synthesize glycogen? Why can't they release glucose into the blood?
Skeletal muscle fibers can synthesize glycogen, but they cannot release glucose into the blood because they lack the enzyme phosphatase required to remove the phosphate group from glucose.
The heat promoting center stimulates parts of the brain that
Stimulates skeletal muscle activity
What are the forms of phosphorylation?
Substrate level phosphorylation, oxidative phosphorylation, and photophosphorylation.
Reduction is the
The Addition of Electrons
Oxidation is
The Removal of Electrons
True or False: The amount of protein needed by each person is determined by the age, size, and metabolic rate of the person.
True
Where is the concentration of hydrogen ions highest?
The concentration of hydrogen ions is highest in the space between the inner and outer mitochondrial membranes.
What is the energy source that powers the proton pumps?
The energy source that powers the proton pumps is electrons provided by NADH and hydrogen ions.
Why is the production of reduced coenzymes important in the Krebs cycle?
The production of reduced coenzymes is important in the Krebs cycle because they will subsequently yield ATP in the electron transport chain.
For each glucose molecule that undergoes glycolysis, how many ATP molecules are generated?
The reactions of glycolysis consume two molecules of ATP but generate four molecules of ATP, for a net gain of two.
What does the wider base of each band in MyPyramid mean?
The wider base of each band represents foods with little or no solid fats or added sugars.
True or False: The higher the relative humidity the lower the rate of evaporation.
True
True or False: Antioxidant vitamins can inactivate oxygen free radicals.
True
True or False: Carbohydrate and fat pools are oxidized directly to produce cellular energy, but amino acid pools must first be converted to a carbohydrate intermediate before being sent through cellular respiration pathways.
True
True or False: Ghrelin, produced by the stomach, is a powerful appetite stimulant.
True
True or False: Glucose-6-phosphate can be converted to pyruvic acid
True
True or False: Glucose-6-phosphate can be dephosphorylated to glucose
True
True or False: Glucose-6-phosphate can be used to make ribose-5-phosphate
True
True or False: Glucose-6-phosphate can be used to synthesize glycogen
True
True or False: In the absorptive state storage of energy is important.
True
True or False: Proteins will be used by most cells for ATP synthesis if insufficient carbohydrates are ingested.
True
True or False: Release of epinephrine is a normal consequence of the activation of the heat-promoting center.
True
