Chapter 25: Metabolism
In glycolysis, each molecule of glucose that is catabolized gives a net yield of how many molecules of ATP?
2
In severe dehydration or blood loss, what would be the levels of ADH and what would be the urine flow rate?
ADH - high; low urine flow rate (0.25 ml/min)
In overhydration, what would be the levels of ADH (high, normal, or low) and what would be the osmolarity of the urine?
ADH - low; 100 mOsm (urine)
Which of the following statements about ADH (antidiuretic hormone) is correct?
ADH is released by the posterior pituitary gland.
Which energy-rich molecule produced by cellular respiration directly powers cell work?
ATP
Citric acid cycle (Krebs cycle)
Acetyl-CoA enters the citric acid cycle, where it undergoes a series of reactions to generate ATP, NADH, FADH2, and carbon dioxide. This cycle occurs in the mitochondrial matrix.
The attachment of an anime group in the synthesis of an amino acid is called
Amination
When considering the chemicals in the nutrient pool, which chemical is LEAST likely to be broken down to supply energy for the cell?
Amino acids
Removal of the amino group from amino acids in the first step of their catabolism requires a coenzyme derived from vitamin
B6
Which of the following statements describe the absorptive state?
Blood glucose is high. Triglyceride levels are high in the blood stream.
What is the correct general equation for cellular respiration?
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP energy
Which lipoprotein carries dietary triglycerides to the liver?
Chylomicrons
Which of the following is a nitrogen-containing compound that is important for energy storage in muscle tissue
Creatine
What is the basis for the labeling of low-density lipoproteins (LDLs) as "bad"?
During transit, cholesterol transported by LDLs to peripheral tissues may contribute to atherosclerosis.
The vitamin that prevents breakdown of vitamin A and fatty acids is vitamin
E
What is the term for an amino acid that either cannot be synthesized or is not synthesized in adequate amounts in the body?
Essential amino acid
What is an important energy source during periods of starvation, when glucose supplied are limited?
Free fatty acids
Which process in the metabolism of glucose is NOT part of aerobic metabolism?
Glycolysis
Which of the following is NOT a mineral required by the body
Thiamine
Which statement describes the citric acid cycle?
This process produces some ATP and carbon dioxide in the mitochondrion.
Which statement describes glycolysis?
This process splits glucose in half and produces 2 ATPs for each glucose.
What lipoproteins transport cholesterol to cells of the body?
LDL
Which statement describes the electron transport chain?
This process uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration. Submit
Why is it that lipids can not provide large amounts of ATP in a short period of time?
Lipids are insoluble in water, and it is this difficult for water-soluble enzymes to reach them. Lipids reserves are difficult to metabolize. Most lipids are processed in mitochondria, and mitochondrial activity depends on the availability of oxygen.
The synthesis of lipids is called __________
Lipogenesis
Although small quantities of lipids are normally stored in the liver, most of the synthesized triglycerides are bound to __________.
Proteins
What chemical in the catabolism of glucose enters the mitochondria?
Pyruvate
What is the primary role of the citric acid cycle in the production of ATP?
Removal of electrons from substrates
Electron transport chain (ETC)
The NADH and FADH2 produced during glycolysis, pyruvate oxidation, and the citric acid cycle donate their electrons to the electron transport chain, located in the inner mitochondrial membrane. This generates a proton gradient, which drives ATP synthesis through oxidative phosphorylation.
The period following a meal when nutrient absorption is underway is ________
The absorptive state
How is ATP used in our bodies?
The energy released from ATP is converted into kinetic energy to do work
What exactly is the link between the extra glycogen associated with carbohydrate loading and enhanced performance in endurance sports?
The extra glycogen serves as a reservoir for glucose, which serves as the main fuel molecule for increased cellular respiration, resulting in more available ATP.
transamination
The process by which an amino group from one amino acid is transferred to a carbon compound to form a new amino acid.
Synthesis of fatty acids starts with __________.
acetyl-CoA
Metabolism refers to __________.
all the chemical reactions in the body
The attachment of an amine group in the synthesis of an amino acid is called __________.
amination
Which of the following people would not likely be in positive nitrogen balance
an elderly grandmother
nutrient
an ingested substance needed by the body for growth, maintenance, or repair
Growth and repair involve primarily what type of reactions?
anabolic
A balanced diet is important to provide the body with all the necessary nutrients to ensure physiological functioning. What is the name of the process where new organic molecules are synthesized?
anabolism
proteins are made by
binding amino acids together with peptide bonds
The electron transport system doesn't produce ATP directly instead it uses the hydrogen ion gradient to drive
chemiosmosis
LDLs contain _______.
cholesterol and protein
step 4 in glycolysis
cleavage into 2 molecules of glyceraldehyde 3-phosphate (G3P), also called PGAL
lipoproteins
clusters of lipids associated with proteins that serve as transport vehicles for lipids in the lymph and blood
What is the term for the direct transfer of heat energy through physical contact?
conduction
The trace element needed as a cofactor for hemoglobin synthesis is
copper
ketogenesis
creation of ketone bodies
If the cells are catabolizing amino acids for energy, what is the first step in amino acid catabolism?
deamination
The removal of the amine group from an amino acid, resulting in the formation of an ammonium ion, is __________.
deamination
Which of the following is NOT a way your body generates or conserves heat
decreased metabolic rate
Which of the following occurs when water is released (lost) during a reaction?
dehydration synthesis
Very Low-Density Lipoproteins (VLDLs)
deliver triglycerides to the adipose tissue for storage (synthesized by liver) (8% protein, 55% triglycerides, 20% cholesterol, 17% phospholipids)
Low-Density Lipoproteins (LDLs)
delivers cholesterol to the cells (bad) (20% protein, 6% triglycerides, 53% cholesterol, 21% phospholipids)
step 6 in glycolysis
dephosphorylation (phosphate is removed from one end of the molecule then the other, added to ADP to form 2 ATP molecules) (2 molecules of pyruvic acid (pyruvate) are formed)
The series of integral and peripheral proteins in the inner mitochondria that takes NADH, FADH2, and oxygen and produces ATP and water is the __________.
electron transport system
Which of the following processes represent(s) catabolism?
endocytosis intracellular transport contraction
The cholesterol determination is _______.
enzymatic and colorimetric
Linoleic acid and linolenic acid are examples of
essential fatty acids
ketosis
excess ketone bodies in the blood from starvation and diets that do not contain enough carbohydrates
ketonemia
excess ketones in blood
ketonuria
excess ketones in the urine
Why is hypervitaminosis involving water-soluble vitamins relatively uncommon
excessive amounts of these vitamins are readily excreted in the urine
What process(es) occur(s) during beta oxidation?
fatty acids are converted into molecules of acetyl-coA
what does carbohydrate catabolism involve?
glycolysis pyruvate oxidation citric acid cycle (Krebs cycle) electron transport chain (ETC) glycogenolysis
Select the correct sequence of steps as energy is extracted from glucose during cellular respiration.
glycolysis → acetyl CoA → citric acid cycle → electron transport chain
About 40 percent of the energy content of nutrients is captured as ATP. The remainder is lost as __________.
heat
What is the osmolarity of the filtrate at the end of the proximal tubule?
isotonic - 300 mOsm
During the postabsorptive state, the liver catabolizes lipids and amino acids to produce acetyl-CoA. Which of the following can build up in the blood when levels of acetyl-CoA in the liver increases?
ketone bodies
The synthesis of lipids is called __________.
lipogenesis
endocrine regulation of lipid metabolism
lipogenesis, lipolysis, ketogenesis
lipid anabolism
lipogenesis, liver cells and adipose cells synthesize lipids from glucose or amino acids, occurs when more calories are consumed than needed for ATP production
Fat-soluble vitamin overdoses primarily affect which organ?
liver
glycogen can be found in the
liver and muscle cells
Hypocholesterolemia is linked to _______.
low levels of serotonin
anabolism
metabolic reactions that consume energy and construct more complex molecules from simpler ones. these reactions are performed for growth, repair, maintenance, and production of secretions.
catabolism
metabolic reactions that produces energy and break down complex molecules into simpler ones. these reactions are performed to provide energy for body function.
All the chemical reactions that occur in an organism are called __________.
metabolism
Which of the following foods are deficient in dietary fiber
milk and meat
The citric acid cycle occurs in the
mitochondrial matrix
In what organelle would you find acetyl CoA formation, the citric acid cycle, and the electron transport chain?
mitochondrian
During starvation,
muscle proteins are used as an energy source.
All the available nutrient molecules distributed in the blood form a
nutrient pool
Which of the following choices below is NOT one of the five basic food groups?
oils
In terms of the movement of electrons, the gain of electrons is called reduction, whereas the loss of electrons is called __________.
oxidation
step 5 in glycolysis
oxidation (loss of electrons) and addition of phosphate group (2 hydrogen atoms and one proton are lost from the PGAL and picked up by NAD+ to form NADH+H+)
The vitamin that is a constituent of coenzyme A is
pantothenic acid
step 1 in glycolysis
phosphorylation of glucose (requires ATP molecule) (phosphorylated glucose cannot diffuse out of the cell) (maintains low concentration of glucose in the cell so that more glucose will diffuse into the cell)
step 3 in glycolysis
phosphorylation to form fructose 1,6-biphosphae (requires ATP molecule) (prevents 2 phosphorylated halves to diffuse out of the cell)
gluconegenesis
production of glucose from a non-carbohydrate source (when glycogen levels are low, glucose is necessary to maintain normal blood glucose levels; can be produced from amino acids or lipids)
protein uses in the body include
structural components hormones enzymes contractile proteins (myosin, actin) transport vessels antibodies plasma proteins
The period following a meal when nutrient absorption is underway is __________.
the absorptive state
Why are minerals, vitamins, and water classified as essential nutrients
the body cannot synthesize these nutrients in sufficient quantities
The carbon dioxide of respiration is formed during
the citric acid cycle.
Milk and eggs are complete proteins because they contain
the essential amino acids in sufficient antities
Which vitamin is required for the synthesis of visual pigments
vitamin A
Which vitamin is required for the synthesis of visual pigments?
vitamin A
The element that is necessary for the proper function of the enzyme carbonic anhydrase is
zinc
Which of the following enables infants to produce or conserve heat
lipolysis of brown fat
Which of the following enables infants to produce or conserve heat?
lipolysis of brown fat Remember that this involves a special form of adipose tissue.
Which of the following tissues contains NO reserves of carbohydrates, lipids, or proteins and can metabolize only glucose?
neural tissue ' Remember that this tissue is very metabolically expensive.
A cell with excess carbohydrates, lipids, and amino acids will break down carbohydrates in order to __________.
obtain energy
For each glucose molecule converted to two pyruvates, the anaerobic reaction sequence in glycolysis provides a net gain of __________.
two ATP for the cell
Phoebe grew up in Alaska's interior and played with her friends at recess in temperatures just above 20 degrees Fahrenheit. In fact, administrators would not close her school until temperatures reached 5 degrees Fahrenheit. Which of the following terms describes her adaptation to Alaska's frigid winter climate
Acclimatization
Catabolizing fatty acids by beta-oxidation results in the formation of what product?
Acetyl-CoA
In the nutrient pool, which chemical is best suited for storage of energy content?
Fatty acids
What happens to a glucose molecule as a result of the reactions of glycolysis?
Formation of two molecules of pyruvic acid
the two types of metabolism include
anabolism, catabolism
The minimum resting energy expenditure of an awake, alert person is the
basal metabolic rate
The minimum resting energy expenditure of an awake, alert person is the __________.
basal metabolic rate
The process in which fatty acids are broken down into two-carbon fragments is __________.
beta-oxidation
The first step in a sequence of enzymatic reactions in the tricarboxylic acid cycle is the formation of __________.
citric acid
disaccharides
double sugars (sucrose, lactose, maltose) (composed of two monosaccharides)
The flow and transformation of energy is called __________.
energetics
What is the term for an amino acid that either CANNOT be synthesized or is NOT synthesized in adequate amounts in the body?
essential amino acid
The mechanism of heat loss that involves the skin and alveoli of the lung is
evaporation
Which process in the aerobic metabolism of glucose takes place in the cytosol?
glycolysis
The lipoprotein that transports cholesterol to the liver is __________.
high-density lipoprotein
The trace minerals found in extremely small quantities in the body include
iron, zinc, copper, and manganese
Which of the following contains the most energy that can be used to make ATP?
1 gram of fat
four classes of lipoproteins
1. Chylomicrons 2. Very Low-Density Lipoproteins (VLDLs) 3. Low-Density Lipoproteins (LDLs) 4. High-Density Lipoproteins (HDLs)
For each glucose molecule processed during aerobic cellular respiration, the cell gains __________.
36 molecules of ATP
an average protein has
400 amino acids in its chains
The efficiency rate for the complete catabolism of glucose is about __________.
42 percent
The basal metabolic rate (BMR) is
70 cal/hr or 1680 cal/day in the average individual
What is meant by the term balanced diet
A balanced diet supplies all ingredients to maintain homeostasis
The lipoprotein that transports cholesterol to the liver is __________
High-density lipoprotein
Pyruvate oxidation
In aerobic conditions (presence of oxygen), pyruvate enters the mitochondria, where it is converted into acetyl-CoA. This reaction generates NADH and carbon dioxide as byproducts.
Glycolysis yields two molecules of pyruvate. Which of the following statements best describes what next happens to pyruvate?
In the presence of oxygen, pyruvate enters a mitochondrion.
Where in the cell does the electron transport system occur?
Inner mitochondrial membrane
Which part of the cell is most heavily involved in energetics?
Mitochondria
Where in the cell does the citric acid cycle occur?
Mitochondrial matrix
The two most important coenzymes for glycolysis and the citric acid cycle are
NAD and FAD.
The concentration of circulating thyroid hormones is an indirect method of determining BMR. Which of the following explanations best describes why?
Thyroid hormones can travel through the cell membranes and bind to receptors that activate mitochondria to produce ATP. Additionally, thyroid hormones bind to DNA receptors and activate genes associated with metabolic processes.
All nutrients can be used by the mitochondria to provide energy. In what form are these nutrients "fed" into the mitochondria?
Two-carbon fragments
diabetic ketoacidosis
a condition that may occur in diabetics with severe insulin deficiency. (metabolic acidosis develops from accumulation of ketones)
polysaccharides
a group of carbohydrates composed of more than three molecules of monosaccharides (starch, glycogen)
Which of the following individuals would lose heat the fastest in a cold room?
a newborn infant
glycogenolysis
breakdown of glycogen stored in the liver into glucose (happens between meals when blood glucose levels fall below normal values) (In addition to breaking down glucose, cells can also break down glycogen, a storage form of glucose, to provide a quick source of energy. This process involves the enzymatic cleavage of glycogen into glucose monomers, which can then enter glycolysis.)
protein catabolism
breakdown of protein to amino acids
the six types of nutrients
carbohydrates, proteins, lipids, vitamins, minerals, water
products of cellular respiration
carbon dioxide, water, and ATP
The process that breaks down organic substrates, releasing energy that can be used to synthesize ATP or other high-energy compounds, is __________.
catabolism
In resting skeletal muscles, a significant portion of their metabolic demand is met through the __________
catabolism of fatty acids
The energy stored in ATP comes from which of the following?
food molecules
Glycogenisis
formation of glycogen (animal starch)
protein anabolism
formation of peptide bonds between amino acids to produce new proteins
Levels of which endocrine hormone are high during the postabsorptive state?
glucagon
What is glycogenolysis stimulated by?
glucagon and epinephrine
ketogenesis is stimulated by
glucagon, human growth hormone, glucocorticoids, epinephrine
The process of synthesizing glucose from noncarbohydrates is called
gluconeogenesis
The synthesis of glucose from noncarbohydrates is __________.
gluconeogenesis
Which of the following is not one of the N compounds (nitrogen-containing compounds) in the body
glucose
Which of the following molecules is broken down in cellular respiration, providing fuel for the cell?
glucose
Which of the following is NOT one of the N compounds (nitrogen-containing compounds) in the body?
glucose Remember that this is a simple sugar. purines and pyrimidines are
triglycerides are composed of
glycerol and 3 fatty acids
phospholipids are composed of
glycerol, 2 fatty acids, and a phosphate group
What is a reserve form of glucose that is utilized when muscles are contracting?
glycogen
Which of these processes is NOT characteristic of the postabsorptive state?
glycogen synthesis
Which of the following processes takes place in the cytosol of a eukaryotic cell?
glycolysis
lipogenesis is inhibited by
human growth hormone and glucagon
lipolysis is stimulated by
human growth hormone, glucocorticoids, thyroxine, epinephrine (adrenalin)
During open-heart surgery, which of the following thermoregulatory changes will be induced on the patient's body?
hypothermia
The most important factor of good nutrition is obtaining nutrients
in sufficient quantities and qualities
Physicians have found improved outcomes when forcefully cooling specific organs or the whole body prior to surgery in a process called
induced hypothermia
Lucy, a 35-year-old woman, says she cannot lose the fat around her abdomen because it is brown fat. You correct her by saying that brown fat is present primarily in
infants
Which hormone drives the most pathways in the absorptive state?
insulin
ketogenesis is inhibited by
insulin
lipogenesis is stimulated by
insulin
lipolysis is inhibited by
insulin
What is glygogenisis stimulated by?
insulin (hormone)
Before the large vitamin B12 molecule can be absorbed, it must be bound to
intrinsic factor
step 2 in glycolysis
re-arrangement of glucose 6-phosphate to fructose 6-phosphate
By keeping the other two variables constant and changing only one at a time, based on the formula: LDL = cholesterol - HDL - (Triglycerides/5), which of the following would have the greatest effect in reducing LDL levels?
reducing cholesterol levels
High-Density Lipoproteins (HDLs)
scavenges up excess cholesterol from the tissues and blood stream and returns it to the liver (good) (50% protein, 5% triglycerides, 20% cholesterol, 25% phospholipids)
glycolysis
series of reactions that break down a glucose molecule (containing 6 carbon atoms) to 2 molecules of pyruvate (each containing 3 carbon atoms)
monosaccharides
simple sugars (glucose, fructose, galactose) (composed of 3-7 carbon atoms)
An individual's basal metabolic rate ideally represents
the minimum resting energy expenditure of an wake, alert person
lipid catabolism (lipolysis)
the process of splitting triglycerides into fatty acids and glycerol
basal metabolic rate
the rate of metabolism measured under standard conditions; rate at which a quiet, resting, fasting body breaks down nutrients to liberate energy
metabolism
the sum of all the chemical reactions in the body
lipids cannot be transported in the aqueous blood because
they are hydrophobic
Which of the following is NOT a mineral required by the body?
thiamine
Why is it necessary to phosphorylate a glucose molecule, creating glucose-6-phosphate?
to trap the glucose molecule within the cell
Chylomicrons
transport absorbed triglycerides from the small intestines through the lymphatic system to the bloodstream (2% protein, 90% triglycerides, 5% cholesterol, 3% phospholipids)
lipids include
triglycerides, phospholipids, sterols
there are ______different amino acids that compose most proteins
twenty (9 are essential. 11 are not)
there is a net gain of_______ATP molecules for each glucose converted to pyruvate
two
The production of ATP provides energy to support anabolism as well as other cell functions. Which of the following is NOT supported by energy from ATP?
All of the listed functions are supported by ATP.
Which nutrient in the nutrient pool is most often used to replace structural and functional components of the cell?
Amino acids
Cells in our body are constantly building new molecules to replace worn-out structures. This process is what part of cellular metabolism?
Anabolism
The process in which fatty acids are broken down into two-carbon fragments is __________
Beta-oxidation
What is the term for the direct transfer of heat energy through physical contact
Conduction
Which process in the aerobic metabolism of glucose takes place in the cytosol?
Glycolysis
Excess cholesterol leaves somatic cells and is absorbed by __________, which then transport the cholesterol back to the liver.
HDLs
What happens to oxygen when it functions as the final electron acceptor in the electron transport system?
It becomes part of a water molecule.
Lipids circulate through the bloodstream as __________
Lipoproteins and free fatty acids
What is he primary focus of nutritional processing in the postabsorptive state?
Maintaining blood glucose levels
NAD, a key coenzyme used in the process of producing ATP, is produced from which water-soluble vitamin
Niacin
When blood glucose concentrations are elevated, the glucose molecules can be ________
catabolized for energy, used to build energy reserves, and used for growth and tissue repair
