A&P Ch 23

Energy via GTP produced during enzymatic reactions

2 ATP

For each glucose molecule converted to two pyruvates, the anaerobic reaction sequence in glycolysis provides a net gain of _______

2 ATP for the cell

Oxidation

A gain of oxygen, or loss of hydrogen or electrons from an atom or molecule

Shivering thermogenesis

A gradual increase in muscle tone increases the energy consumption of skeletal muscle tissue throughout the body

Protein deficiency diseases are

A lack of one or more essential amino acids

Leptin is a

A peptide hormone produced by adipose tissue during the synthesis of triglycerides

Identify the fates of fatty acids

A source of energy or a component of triglycerides, glycolipids, phospholipids, prostaglandins, cholesterol, and steroids

Fat-soluble vitamins

A, D, E, K

Product of hydrogen ion diffusion within mitochondria

ATP

HDLs:

Absorb unused cholesterol from body tissues, returning it to the liver, where it may be packaged into new LDLs or excreted with bile salts in bile

Evaporation

Absorbs energy and cools the surface, where water changes from a liquid to a vapor

Period following a meal

Absorptive state

Nutrient pool

Accessible reserve of organic substrates that can be used for metabolic turnover or energy production

Common substrate for mitochondrial ATP production

Acetate

Catabolizing fatty acids by beta-oxidation results in the formation of what product?

Acetyl CoA

Pyruvate molecules are used by mitochondria after conversion to:

Acetyl CoA

Which molecule is a key reactant in both ATP production from fatty acids and lipogenesis?

Acetyl-CoA

Metabolism refers to

All the anabolic and catabolic reactions in the body

Milk and eggs are complete proteins because they contain _____

All the essential amino acids in sufficient quantities

The attachment of an amine group in the synthesis of an amino acid is called ____

Amination

The formation of glutamic acid from alpha-ketoglutarate is an example of

Amination

At rest, skeletal muscles increase the number of myofibrils using

Amino acids

Which nutrient in the nutrient pool is most often used to replace structural and functional components of the cell?

Amino acids

Amination

An ammonium ion is used to form an amino group that is attached to a molecule, yielding an amino acid

Phenylketonuria(PKU):

An inherited metabolic disorder resulting from an inability to convert phenylalanine to tyrosine

Cells in our body are constantly building new molecules to replace worn-out structures. This process is what part of cellular metabolism?

Anabolism

Synthesis of new organic molecules

Anabolism

The breakdown of glucose to pyruvate is

Anaerobic

Lack or loss of appetite

Anorexia

Water-soluble vitamins

B complex and C

Resting energy expenditure

Basal metabolic rate

The minimum resting energy expenditure of an awake, alert person is the ____

Basal metabolic rate

Lipids are useful as an energy reserve primarily because the process of ________ is so efficient

Beta oxidation

The process in which fatty acids are broken down into two-carbon fragments is ____

Beta oxidation

Emulsification

Bile salts break large lipid drops into tiny droplets

During the postabsorptive state,

Blood glucose begins to decrease, triggering the release of glucagon, which stimulates the liver to release glucose into the circulation

Glycogenolysis:

Breakdown of glycogen to glucose

Salivary amylase

Breaks down complex carbohydrates into a mixture of disaccharides and trisaccharide's

Source of mitochondrial CO2 production

CAC

Unit of energy

Calorie

Salivary amylase is a salivary enzyme that breaks down complex _______

Carbs

Breakdown of organic molecules

Catabolism

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

When blood glucose concentrations are elevated, the glucose molecules are

Catabolized for energy

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

Pancreatic alpha-amylase

Cholecystokinin release triggers its secretion; breaks down complex carbohydrates

Which lipoprotein carries dietary triglycerides to the liver?

Chylomicrons

6-carbon molecule

Citric acid

The first step in the sequence of enzymatic reactions in the tricarboxylic acid cycle is the formation of ____

Citric acid

The reaction in which an acetyl group from acetyl-CoA is attached to a four-carbon molecule in the mitochondrial matrix produces a six-carbon molecule of

Citric acid

Vitamin B6 (pyridoxine)

Coenzyme in amino acid and lipid metabolism

Vitamin B9 (folic acid)

Coenzyme in amino acid and nucleic acid metabolism

Vitamin B7 (biotin)

Coenzyme in many pathways; deficiency results in fatigue, muscular pain, nausea, dermatitis

Vitamin B1 (thiamine)

Coenzyme in many pathways; excessive levels cause hypotension

Carry hydrogen atoms to the ETC

Coenzymes

Glycogen forms

Compact, insoluble granules

Lipoprotein lipase

Complex protein that breaks down the chylomicrons and releases fatty acids and monoglycerides that can diffuse into the interstitial fluid

Low-density lipoproteins

Complexes that deliver cholesterol to peripheral tissues

High-density lipoproteins

Complexes that return cholesterol to the liver, where it is extracted and packaged, or excreted with bile salts in bile

Direct transfer of heat energy through physical contact:

Conduction

Balanced diet:

Contains all the ingredients needed to maintain homeostasis and prevent malnutrition

____________ accounts for roughly 15 percent of the body's heat loss indoors

Convection

Anabolism

Converts smaller molecules into larger ones

Dipeptidases break dipeptides apart and release individual amino acids, which are absorbed by epithelial cells of the small intestine through two mechanisms, facilitated diffusion and ___________

Cotransport

Heat conservation mechanism that conducts heat from deep arteries to adjacent deep veins in the limps:

Countercurrent exchange

ETC proteins

Cytochromes

Poisons like cyanide bind to ____, thereby preventing the transfer of electrons to oxygen

Cytochromes

If the cells are catabolizing amino acids for energy, what is the first step in amino acid catabolism?

Deamination

Removal of amino group

Deamination

In amino acid metabolism, identify the processes by which the amino group is removed

Deamination or transamination

Lack of neuropeptide Y in the hypothalamus affects the control of appetite:

Decrease appetite

Conservation of body heat via the vasomotor center

Decreased blood flow to the dermis reduces losses by radiation and convection

Vitamin B3 (niacin)

Deficiency results in a condition called pellagra; part of NAD, involved in multiple pathways

Vitamin B2 (riboflavin)

Deficiency results in epithelial and mucosal deterioration; part of FAD, involved in multiple pathways

Incomplete protein:

Deficient in one or more of the essential amino acids

LDLs:

Deliver cholesterol to body tissues

Conduction

Direct transfer of energy occurs through physical contact

Buffers from the pancreas and liver moderate the pH of the arriving chyme in which region?

Duodenum

ATP produced anaerobically examples

During peak levels of physical activity, at all times in red blood cells, or when a tissue is temporarily deprived of oxygen

Identify when most of the CO2 is released during the complete catabolism of glucose

During the CAC

When do ketone bodies form?

During the postabsorptive state, when lipids and amino acids are broken down in the liver

The flow and transformation of energy

Energetics

Lingual lipase:

Enzyme that attacks triglycerides, breaking them down into monoglycerides and fatty acids

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

Vitamin K

Essential for liver synthesis of prothrombin and other clotting factors

The mechanism of heat loss that involves the skin and alveoli of the lung is ___

Evaporation

Why is hypervitaminosis involving water-soluble vitamins relatively uncommon?

Excessive amounts of these vitamins are readily excreted in the urine

The __________ soluble vitamins are absorbed primarily from the digestive tract along with specific contents of micelles

Fat

Beta oxidation

Fatty acid catabolism that produces molecules of 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 2 molecules of pyruvic acid

Glycogenesis:

Formation of glycogen from glucose

What is an important energy source during periods of starvation, when glucose supplies are limited?

Free fatty acids

Stomach hormone

Ghrelin

The hormone ______ , which is secreted by the gastric mucosa, stimulates appetite

Ghrelin

Which hormone inhibits the satiety center and stimulates appetite in the short term?

Ghrelin

Glucose synthesis from smaller carbon chains is known as

Gluconeogenesis

If absorption by the digestive tract fails to maintain normal nutrient levels, triglycerides and glycogen reserves in the liver cells are broken down and ________ is released

Glucose

Neural tissue requires a continuous supply of

Glucose

Sucrase

Glucose + fructose

Lactase

Glucose + galactose

Maltase

Glucose + glucose

Glycolysis:

Glucose is broken down into two three-carbon molecules/chains

Glycogenolysis

Glucose is released from glycogen

Gluconeogenesis

Glucose is synthesized from smaller carbon chains

Glycogenesis

Glycogen is synthesized from glucose

The breakdown of glucose into 2 3-carbon molecules is

Glycolysis

Which process in the aerobic metabolism of glucose takes place in the cytosol?

Glycolysis

Explain when glycolysis is important in cellular metabolism

Glycolysis is important when ATP must be produced anaerobically

For which basic food group is it recommended that at least half of the total amount consumed be whole (unprocessed), in order to prevent a rapid rise in blood glucose and insulin levels?

Grains

ETC by-product

H2O

Excess cholesterol leaves somatic cells and is absorbed by __________, which then transport the cholesterol back to the liver

HDLs

Glycolysis

There is a net gain of two ATP molecules for each glucose molecule.

Homeostatic control of body temperature

Thermoregulation

What happens to the ammonium ions that are removed from amino acids during deamination?

They combine with CO2 to form urea

Why is glucose the primary energy source for cells?

It can be efficiently stored as glycogen, which forms compact, insoluble granules

Complete protein

It contains all the essential amino acids

Intestinal absorption of nutrients occurs in the

Jejunum

Fat catabolism

Ketone bodies

In the post absorptive state, liver cells break down lipids and amino acids, and as levels of acetyl-CoA increase, which compounds begin to form?

Ketone bodies

When glucose supplies are limited, the breakdown of fatty acids and some amino acids in liver cells elevates acetyl-CoA levels and results in the production of small organic acids called

Ketone bodies

What lipoproteins transport cholesterol to cells of the body?

LDL

The absorptive state

Lasts 4 hours, period after a meal when nutrient absorption is underway

Adipose tissue hormone

Leptin

The hormone released by adipose tissues as they synthesize triglycerides is

Leptin

Which peptide hormone stimulates the satiety center and suppresses appetite?

Leptin

Long term of regulation of appetite:

Leptin stimulates the satiety center

Where is cholesterol in chylomicrons extracted and packaged into low-density lipoproteins (LDLs), or excreted?

Lipid

Micelle:

Lipid-bile salt complexes (containing fatty acids, glycerol, and monoglycerides) formed in the intestinal lumen

Chylomicron

Lipid-protein complex that contains insoluble lipids

Carbohydrates (such as glucose) are generally preferred for catabolism because proteins and _________ are more important as structural components of cells and tissues

Lipids

What releases the greatest amount of energy per gram during catabolism?

Lipids

Lipolysis

Lipids are broken down into pieces that can be either converted to pyruvate or channeled directly into the citric acid cycle

Lipid synthesis

Lipogenesis

The synthesis of lipids

Lipogenesis

Lipid breakdown

Lipolysis

Lipid transport

Lipoproteins

Lipids circulate through the bloodstream as

Lipoproteins and free fatty acids

Chylomicron:

Lipoproteins formed in intestinal epithelial cells and contain newly synthesized triglycerides, cholesterol, and other lipids surrounded by phospholipids and proteins

Earliest step of lipolysis

Lysosomal enzymes break down triglyceride molecules into one glycerol molecule and three fatty acids

What is the primary focus of nutritional processing in the postabsorptive state?

Maintaining blood glucose levels

Release of hormones; increased metabolism

Nonshivering thermogenesis

What is a response coordinated by the heat-gain center?

Nonshivering thermogenesis

Collection of all the cell's organic substances

Nutrient pool

Condition when cells preferentially break down carbohydrates

Nutrients abundant

Condition when cells preferentially break down lipids

Nutrients scarce

Final acceptor of electrons from the ETC

O2

A cell with excess carbohydrates, lipids, and amino acids will break down carbohydrates in order to _____

Obtain energy

The CAC:

Occurs in the matrix of mitochondria; organic molecules are broken down, carbon dioxide molecules are released, and hydrogen atoms are transferred to coenzymes that deliver them to the electron transport chain

Oxidative phosphorylation

Occurs within mitochondria in which hydrogen atoms are used to generate ATP

In terms of the movement of electrons, the gain of electrons is called reduction, whereas the loss of electrons is called _____

Oxidation

Process that produces over 90% of ATP used by body cells

Oxidative phosphorylation

The process that produces 90% of the ATP used by our cells is

Oxidative phosphorylation

When chyme arrives in the duodenum, cholecystokinin (CCK) release triggers the secretion of which enzyme?

Pancreatic alpha-amylase

Leptin

Peptide hormone released by adipose tissues as they synthesize triglycerides

Stimulation of vasomotor center

Peripheral vasoconstriction

Inhibition of vasomotor center

Peripheral vasodilation

Which nutritional/metabolic disorder results from an inability to produce specific enzymes involved in amino acid metabolism?

Phenylketonuria

The primary mechanisms for increasing heat loss from the body include

Physiological responses and behavioral modifications

Heat loss and heat gain involve the activities of many systems, which are coordinated by the thermoregulatory centers in the ____________ area of the hypothalamus

Preoptic

Vitamin E

Prevents breakdown of vitamin A and fatty acids

Although small quantities of lipids are normally stored in the liver, most of the synthesized triglycerides are exported and bound to _____

Proteins

Explain why carbohydrates are preferred over proteins and lipids as an energy source

Proteins and lipids are more important as structural components of cells and tissues

What chemical in the catabolism of glucose enters the mitochondria?

Pyruvate

More than 50% of the heat you lose indoors is attributable to

Radiation

What heat transfer process accounts for about one-half of a person's heat loss when indoors?

Radiation

Which primary mechanism of heat transfer results in the loss of more than 50 percent of the heat humans lose indoors?

Radiation

The processes involved in heat transfer between the body and the environment are

Radiation, conduction, convection, and evaporation

The reactants required and products generated by mitochondria:

Reactants required are 2-carbon substrates and O2; the mitochondrial products are CO2, H2O, and ATP

During the catabolism of glucose, some energy is captured by __________ molecules, while the rest of the energy is lost mainly as ____

Reduced; heat

What is the primary role of the citric acid cycle in the production of ATP?

Removal of electrons from substrates

CAC

Removes hydrogen atoms from organic molecules and transfers them to coenzymes

Vitamin D3

Required for normal bone growth, intestinal calcium and phosphorus absorption, and retention of these ions by the kidneys

The enzyme that breaks down complex carbohydrates into a mixture of disaccharides and trisaccharide's in the mouth is

Salivary amylase

Sweat gland activity; heat loss

Sensible perspiration

Vitamins role in nutrition:

Serve as coenzymes in metabolic pathways

Short-term mechanism of control of the hypothalamic satiety and feeding centers:

Several hormones of the digestive tract, including CCK, suppress appetite during the absorptive state

A person's BMR is influenced by

Sex, body weight, age

Result of increased skeletal muscle tone

Shivering thermogenesis

Glycogen reserves

Skeletal muscle

Where does most nutrient absorption occur?

Small intestine, mostly jejunum

Describe the role of CCK release and its effects on proteins

Stimulates the production and release of inactive pancreatic proenzymes

Balanced diets:

Supplies all ingredients to maintain homeostasis

Lipogenesis

Synthesis of lipids

Nutrition:

The absorption of nutrients from food

The period following a meal when nutrient absorption is underway is _____

The absorptive state

Deamination

The amino group is removed from an amino acid, and an ammonium ion is released

Transamination

The amino group of one amino acid is shifted to another molecule, yielding a different amino acid

Countercurrent exchange

The arrangement in which the deep veins lie alongside the deep arteries, trapping the heat close to the body core

Why are minerals, vitamins, and water classified as essential nutrients?

The body cannot synthesize these nutrients in sufficient quantities

Catabolism

The breakdown of large molecules into smaller ones

Catabolism refers to

The breakdown of organic substrates

Beta-oxidation

The catabolism of fatty acids to acetyl-CoA

Conduction:

The direct transfer of heat through physical contact

Insensible perspiration

The evaporation of water from the skin and alveolar surfaces of the lungs

Hypervitaminosis involving water-soluble vitamins is relatively uncommon because

The excess amount is readily excreted in the urine

Oxidative phosphorylation

The generation of ATP as the result of the transfer of electrons from the coenzymes NADH and FADH2 to oxygen by a sequence of electron carriers within mitochondria

Most of the absorbed nutrients enter into which blood vessel?

The hepatic portal vein and transported to the liver

Thermoregulation

The homeostatic control of body temperature

How do ketone bodies form?

The increased concentration of acetyl-CoA that results from their breakdown

What does the liver do with the chylomicrons it receives?

The liver absorbs chylomicrons, removes the triglycerides, combines the cholesterol from the chylomicron with recycled cholesterol, and alters the surface proteins

Reduction

The loss of oxygen, or gain of hydrogen or electrons to an atom or molecule

An individual's basal metabolic rate ideally represents _____

The minimum resting energy expenditure of an awake, alert person

Basal metabolic rate

The minimum resting energy expenditure of an awake, alert person

Describe the role that hydrogen ion channels play in the generation of ATP

The passageways for the diffusion of hydrogen ions from the inner membrane space of the mitochondria to the matrix; powers the production of ATP by ATP synthase

Metabolic turnover

The process in which cells continuously replace their cellular components

Leptin stimulates

The satiety center and suppresses appetite

Oxidative phosphorylation:

The stepwise passage of electrons by coenzymes embedded in the cristae of the mitochondrion releases energy

Energetics

The study of the flow of energy and its change from one form to another

ATP to initiate glycolysis

-2 ATP

The net result of one turn of the citric acid cycle is

1 ATP

Products of glycolysis:

2 molecules each of pyruvate, ATP, and NADH

What molecules forms the common substrate for the CAC?

2-carbon acetate ion, CH3COO−, which is attached to coenzyme A to form acetyl-CoA

ATP from NADH generated in the citric acid cycle

24 ATP

At which body temperature are the thermoregulatory capabilities of the body likely to be lost?

27 degrees C

ATP from FADH2 generated in the citric acid cycle

4 ATP

ATP from NADH produced in glycolysis

4 ATP

ATP produced during enzymatic reactions in the cytosol

4 ATP

The energy yield for carbohydrates is

4.18 cal/g

% of catabolic energy captured as ATP

40%

% of catabolic energy released as heat

60%

Basal metabolic rate (BMR) is

70 cal/hr or 1680 cal/day in the average individual

Convection

Heat loss to the air that overlies the surface of the body; accounts for roughly 15 percent of the body's heat loss indoors

Convection:

Heat loss to the cooler air in contact with the skin

The lipoprotein that transports cholesterol to the liver is ______

High-density lipoprotein

During open-heart surgery, what thermoregulatory changes is induced in the patient's body?

Hypothermia

The most important factor of good nutrition is obtaining nutrients _____

In sufficient quantities and qualities

Predict the effect of peripheral vasodilation on a person's body temperature

Increase blood flow to the skin and thus the amount of heat the body can lose; body temperature would decrease

Respiratory heat loss

Increased evaporative heat losses occur through the lungs

Vasodilation and shunting of blood

Inhibition of the vasomotor center occurs

General role of satiety center

Inhibits feeding center

Where in the cell does the electron transport chain occur?

Inner mitochondrial membrane

Lung and epithelial water loss

Insensible perspiration

Absorptive state hormone

Insulin

In most tissues, the transport of glucose into the cell is dependent on the presence of a carrier protein that is stimulated by

Insulin

During the absorptive state,

Insulin prevents a large surge in blood glucose after a meal by stimulating the liver to remove glucose from the circulation

Before the large vitamin B12 molecule can be absorbed, it must be bound to ___

Intrinsic factor

Role of nonshivering thermogenesis in regulating body temperature:

Involves the release of hormones that increase the metabolic activity of all tissues, resulting in an increase in body temperature

Nonshivering thermogenesis

Involves the release of hormones that increase the metabolic activity of all tissues

The source of intestinal gas:

Is generated by bacterial activities in the colon when indigestible carbohydrates stimulate bacterial gas production

Explain the role of glycogen in cellular metabolism

Is synthesized from excess glucose molecules by liver and muscle cells, and it serves as an intracellular glucose reserve

What happens to oxygen when it functions as the final electron acceptor in the electron transport system?

It becomes part of a water molecule

Vitamin A

Maintains epithelia; supports immune system; promotes growth and bone remodeling

Complete protein:

Meets the body's amino acid requirements

All the chemical reactions that occur in an organism are called ____

Metabolism

Which part of the cell is most heavily involved in energetics?

Mitochondria

Where in the cell does the CAC occur?

Mitochondrial matrix

Lingual lipase

Monoglycerides + fatty acids

What two coenzymes transfer hydrogen atoms to the electron transport chain?

NAD and FAD

What sources generates the most molecules of ATP?

NADH generated in the citric acid cycle

Appetite-regulating neurotransmitter

Neuropeptide Y

NAD, a key coenzyme used in the process of producing ATP, is produced from which water-soluble vitamin?

Niacin

Why do cells make new compounds?

To maintain and repair structures, to support growth, and to build up nutrient reserves

Why is digestion important?

To produce energy and to replenish the intracellular nutrient pool

If daily intake exceeds total energy demands, the excess energy is stored primarily as

Triglycerides in adipose tissue

All nutrients can be used by the mitochondria to provide energy. In what form are these nutrients "fed" into the mitochondria?

Two-carbon fragments

Amino acid catabolism

Urea formation

Gout

Uric acid

Most of the lipids absorbed by the digestive tract are immediately transferred to the

Venous circulation by the thoracic duct

Vitamin required for synthesis of visual pigments:

Vitamin A

A water soluble vitamin:

Vitamin C

Identify the water-soluble vitamin that functions as a coenzyme in many pathways and results in epithelial and mucosal deterioration if it occurs in deficient levels

Vitamin C (ascorbic acid)

Radiation

Warm objects lose heat energy; the heat emanating from the sun; the human body loses heat in the same manner; accounts for more than 50 percent of the body heat lost indoors

2 classes of vitamins:

Water soluable and fat soluable

Hydrogen atoms are used to generate ATP through oxidative phosphorylation, which occurs:

Within mitochondria