Nutrition CH 8

Insulin

Anabolic; Increases glycolysis and glycogenesis in liver

T/F: Body size, being male or female, and prior drinking history affect an individual's rate of alcohol metabolism.

True

T/F: Lactate is a molecule that accumulates in tissues when oxygen is not available.

True

After a carbohydrate containing meal, beta cells detect a rise in blood glucose levels (_________________ state) and secretes insulin

absorptive

The body's metabolic state can be categorized as either ______________ (when the digestive tract is absorbing nutrients) or ____________________ (when the digestive tract is not active)

absorptive ; post absorptive

to access and use the energy stored in the "biological fuels" such as glucose, cells utilize specific chemical reactions that occur in sequences called...

chemical pathways

When cells need energy, acetyl CoA enters the ___________ ________ cycle (TCA or Krebs cycle)

citric acid

Enzymes generally will not catalyze reactions without the help of ______________________

coenzymes

the capacity to perform work

energy

Most naturally occurring fatty acids have an _________ number of carbon atoms

even

When adequate oxygen is present in a cell, mitochondria can make lots of ATP

aerobic metabolism

Fatty acids bind to _____________, a protein that is water soluble and serves as a carrier molecule

albumin

metabolic reactions are either ______________ or _________________

catabolic or anabolic

In a series of repeating sequential reactions, two-carbon acetyl CoA units are bound together to form the _________________ chain of the fatty acid.

hydrocarbon

Insulin directs liver and muscle cells to slow down their glycogenolysis rates and _____________ their rates of glycogenesis; such actions shift glucose molecules into storage as ________________

increase; glycogen

When cells, especially muscle cells, need to catabolize fatty acids for energy, HSL facilitates ____________ by removing the three fatty acids from the glycerol backbone of a triglyceride

lipolysis

The _________ is the main target organ for glucagon's action.

liver

The ____________ and _____________ tissue are the primary sites for glycogen storage and degradation.

liver and muscle tissue

approximate kcal stored in carbohydrates (energy stores in body)

liver glycogen: 300-400 muscle glycogen: 1200-1600

coenzymes that contain b vitamins, such as thiamin and riboflavin, participate in several of the reactions that release energy from ________________________

macronutrients

Insulin attaches to special receptors the cell _______________ of adipocytes and muscle cells.

membranes

the sum of all chemical reactions that occur in living cells

metabolism

If glucose is unavailable, most cells are resourceful in that they can ______________ more than one fuel for energy.

metabolize

The electron transport chain consists of enzymes within ___________________

mitochondria

organelles that synthesize most of the ATP that cells need to function; "powerhouses" inside cells that catabolize macronutrients and transfer energy released from these molecules to ATP

mitochondria

Fatty acids undergo catabolism in the _________________. they are prepared for catabolicm by binding to coenzyme ____

mitochondria; coenzyme A

The fatty acids that are typically in foods contain _______ carbon atoms than the six-carbon glucose molecule, so the fatty acids have the potential to form more acetyl CoA, NADH, and FADH2 molecules during their catabolism than glucose; (explains why an ounce of pure fat provides more energy than an ounce of pure carbohydrate)

more

Cells may use excess dietary glucose molecules to form triglycerides, but the conversion requires more ________ and _____________

more steps and energy

When the diet provides an excess of amino acids, they will be stripped of their _____________ group and be used to either make glucose or fat.

nitrogen

The formation of acetyl CoA is the point of ______ _________________ for glucose catabolism

no return

ATP is a _________ energy phosphate compound.

high

During certain catabolic processes macronutrients release hydrogen ions (H+) that contain ______-____________ electrons

high-energy

Because glycolysis, resulted in the formation of two pyruvate molecules, _______ molecules of acetyl CoA can be formed from one molecule of glucose

two

When NAD+ picks up ____ hydrogen ions and ____ electrons, the coenzyme becomes NADH.

two hydrogen; two electrons

During beta-oxidation, fatty acid molecules are separated into ______ carbon segments that are converted to ____________________

two; acetyl CoA

Glycolysis uses ______ ATP to get started, but the process forms _______ ATP.

two; four

ATP yields for each NADH and each FADH2 that enter the electron transport chain are not precisely known. The estimated values are _____ ATP for NADH and _____ for FADH2

2.5; 1.5

The cell gains ______ ATP from the process of glycolysis

2; does not provide much energy

The complete catabolism of one glucose molecule yields approximately ____ to ____ molecules of ATP.

30 to 32

glucose yields _____-______ ATP

30-32

Limiting carbohydrate intake to less than ______g per day rapidly depletes glycogen stores and results in ketosis.

50g

Cells may catabolize remaining amino acids for ________ production, or convert them into other molecules, particularly glucose and fatty acids

ATP

Glucagon is made by the __________ calls of the pancreas.

Alpha

___________ cells remove lactate from the bloodstream and recycle it into glucose, using a pathway called the __________ cycle

Liver; Cori

The coenzymes, _________, coenzyme A, and thiamin pyrophosphate are needed to form acetyl CoA from pyruvate

NAD+

_________ is a component of the coenzyme nicotinamide adenine dinucleotide (NAD+)

Niacin

palmitic acid yields ______ ATP

106

Vitamin B-6 is a component of _______

PLP

Action's of metabolic hormones depend on the body's...

metabolic state

Side effects of a ketogenic diet may include.....

-constipation -hypoglycemia -hunger -vomiting -lack of energy -elevated blood lipids -kidney stones

Signs and symptoms of ketoacidosis

-excessive thirst -frequent urination -blood glucose level more than 250mg/dL -fruity odor to breath

Signs and symptoms of glycogen storage disease (GSD) are...

-hypoglycemia -fatigue -irritability -liver and kidney enlargement

What are the three major events that occur in the complete breakdown of glucose, resulting in the production of CO2, H20, and ATP?

1) Glycolysis -Pyruvate's aerobic conversion to acetyl CoA 2) Citric Acid Cycle 3) Electron Transport Chain

Stages of Glucose Breakdown

1) glycolysis 2) pyruvate-> acetyl CoA 3) citric acid cycle 4) electron transport chain

alanine yields _____ ATP

14

__________ cells in the pancreas synthesize insulin

Beta

During the formation of acetyl CoA, pyruvate releases a molecule of ________ and two hydrogen ions that are picked up by NAD+; this reaction is _________________

CO2 ; reversible

Cortisol

Catabolic; Increases glycogenolysis and gluconeogenesis in liver

Epinephrine

Catabolic; Increases glycogenolysis and gluconeogenesis in liver

Glucagon

Catabolic; Increases glycogenolysis and gluconeogenesis in liver

Complex series of chemical reactions that converts two-carbon acetyl CoA molecules into CO2 and H20 molecules. Much of released energy is ultimately captured in ATP.

Citric Acid Cycle

T/F: Fats are metabolized by a process called glycolysis.

False

T/F: Ketosis is characterized by an abnormally elevated blood pH level.

False

T/F: Excess protein intake will build muscle.

False; It will produce excess fat.

Thyroid hormone

Regulates metabolic rate; Can be catabolic OR anabolic

_______________ is a component of the coenzyme flavin adenine dinucleotide (FAD)

Riboflavin

T/F: Acetyl CoA cannot be used to re-form pyruvate.

True

T/F: Many B vitamins are components of coenzymes that work with enzymes in energy metabolism.

True

T/F: Several steps in the glycolytic pathway can flow in either direction.

True

T/F: Some amino acids are both glucogenic and ketogenic.

True

T/F: The benefits of energy drinks do not live up to the marketing hype used to promote the products.

True

During beta-oxidation, fatty acid molecules are cleaved into two-carbon segments that are converted into ____________ _______

acetyl CoA

When the body has access to plenty of oxygen, the pyruvate molecules enter mitochondria and undergo a conversion into a two-carbon compound resulting in

acetyl coenzyme A or acetyl CoA

In response to the signal, the glucose transport molecules pass the monosaccharide __________ the cell membrane and into the cytoplasm.

across

When ATP loses its terminal phosphate group, it becomes...

adenosine diphosphate (ADP)

Most of the energy released by the breakdown of macronutrients is captured in chemical form as ______________ _________________

adenosine triphosphate (ATP)

When a person consumes a surplus of glucose, their cells catabolize the monosaccharide molecules for ATP production instead of breaking down fatty acids. The end result of this metabolic shift is the synthesis and storage of triglycerides in ________________

adipocytes

approximate kcal stored in fats (energy stores in body)

adipose cell triglycerides: 80,000-100,000

Abnormal glucose metabolism occurs in _______ cases of GSD.

all

Cells can use the energy lost during ATP cleaving reaction for _______________ activities.

anabolic

refers to metabolic pathways that build larger molecules from smaller ones; require the input of more energy than is released by the reactions

anabolism

When the cell's oxygen supply is inadequate to support the functioning of mitochondria, the cell can obtain ATP from a pathway that does not require oxygen

anaerobic metabolism

Glycolysis is an _____________ pathway that occurs in the _____________ of cells

anaerobic; cytoplasm

Alcohol dehydrogenase pathway a) is primarily for heavy drinking b) occurs in the liver c) is a catabolic pathway

b, c

In mitochondria, the catabolism of an activated fatty acid begins with a chemical pathway called...

beta-oxidation

Muscle cells lack the enzymes necessary to make glucose from lactate, so it is released into the __________________

bloodstream

When certain cells, such as muscle cells, need ATP, they can take up fatty acids from the....

bloodstream

Approximate energy values for glycogen and fat stores in the average healthy adult may vary significantly based on things such as....

body size, composition, level of physical fitness, and diet.

Cells ____________ release energy from vitamins, minerals, or water.

cannot

Glucagon, cortisol, and epinephrine are hormones that instruct cells to use _______________ pathways

catabolic

If the diet does not supply enough water-soluble B vitamins such as thiamin, which are components of coenzymes such as TPP, then the cells will be unable to synthesize the coenzymes necessary for __________________

catabolism

The ___________________ of macronutrients and alcohol supplies energy to produce ATP

catabolism

refers to metabolic pathways that break down larger molecules into smaller ones ; result in release of more energy than that which is used to initiate reaction

catabolism

human cells obtain energy by releasing ______________ energy from macronutrients

chemical

When an enzyme ___________ the bond between the last two phosphate groups of ATP, the high-energy molecule _________ some of its power

cleaves; loses

The most important products produced during the citric acid cycle are ________________

coenzymes

particular group of organic compounds that often have B vitamins in their chemical structures

coenzymes

the most important products of the chemical transformations that occur during the citric acid cycle are the ____________ that are produced

coenzymes

ketoacidosis is potentially life-threatening and requires immediate medical attention. If untreated, it can lead to....

coma and death

In many instances, oxygen participates in oxidative reactions by chemically _________________ with a substance

combining

the total amount of energy in a system is ____________ ; can neither be created nor destroyed but can undergo ________________________

constant ; transformations

The chemical pathway that initiates the breakdown of glucose and produces some ATP occurs in the..

cytoplasm

When the diet does not supply enough vitamin B, cells cannot convert enough pyruvate into acetyl CoA to meet their needs. Lack of acetyl CoA leads to _______________ ATP formation and signs/symptoms of vitamin B deficiency disorders.

decreases

The liver ___________ its supply of glycogen and releases glucose into the bloodstream for the eventual uptake by the cells

degrades

the coenzymes NADH and FADH2 (produced by citric acid cycle) carry hydrogen ions and their high-energy electrons from the citric acid cycle to a linked series of enzymes called the....

electron transport chain

Under normal conditions the body does not _____________ excess glucose by excreting the monosaccharide in urine.

eliminate

With each addition of an acetyl CoA molecule, the fatty acid _____________ and stores energy.

elongates

Although caffeine increases alertness, the compound does not provide any _____________ (calories)

energy

In the liver, glycogenolysis occurs when any tissue of the body needs ______________

energy

involves chemical pathways that enable human body to obtain and use energy from macronutrients and alcohol

energy metabolism

In most cells, pyruvate cannot be used to re-form glucose because the cells lack the unique set of ______________ that are required for reversing the glycolytic pathway.

enzymes

Most chemical reactions that occur in living cells require specific _______________ that catalyze the reactions, but remain unchanged as a result of the process

enzymes

Healthcare providers may use low-calorie, ketogenic diets to treat children and adults with _______________, particularly in cases that do not respond well to medicine

epilepsy

If cells do not have enough glucose to "burn" for energy, beta-oxidation of fatty acids increases, which produces ________________ amounts of acetyl CoA.

excessive

Glycerol and fatty acids molecules ________ adipocytes and ___________ the bloodstream

exit; enter

NAD+ and FAD shuttle hydrogen ions and electrons to a place within cells where their energy can be _________________

extracted

Most of the energy in a triglyceride is stored in its _________ ___________

fatty acids

The NADH and FADH2 that result from beta-oxidation yield about ________ ATP

four

Cells can also use ___________ and ________________ to synthesize ATP, particularly in the liver.

fructose and galactose

If excessive amounts of acetone are exhaled, the breath will have an unusual _____________ odor.

fruity

After the liver releases newly made glucose (from lactic acid) into circulation, it is available again as ________ for cells

fuel

Amino acids that are those that are broken down into either pyruvate or intermediates of the citric acid cycle

glucogenic

When the body is in need of glucose it can synthesize glucose from noncarbohydrate precursors in a process known as a....

gluconeogenesis

the synthesis of glucose from noncarbohydrate precursors that include glycerol, lactate, pyruvate, and most amino acids

gluconeogenesis

Cells in the CNS are highly dependent on _______________, rather than fatty acids or amino acids, to meet their energy needs.

glucose

Under normal conditions, human cells rely heavily on ____________ to function properly.

glucose

Instead of excreting excess glucose in urine, liver and muscle cells can store glucose as glycogen through a pathway called __________________

glycogenesis

When the body needs energy but its cells do not have a direct source of glucose readily available, cells can obtain the monosaccharide by ________________

glycogenolysis

the breakdown of glycogen into glucose molecules

glycogenolysis

Gluconeogenesis is not the reverse of _____________ because some steps in the glycolytic pathway flow in only one direction (towards citric acid cycle)

glycolysis

The first phase of glucose catabolism occurs in a series of chemical reactions called...

glycolysis

Fat cells (adipocytes) contain the enzyme _______________ sensitive lipase (HSL)

hormone

Glucagon signals liver cells to ____________ glycogenolysis and gluconeogenesis from glucogenic amino acids. This action enables the liver to produce ________ glucose for release into the bloodstream.

increase; more

Insulin _____________ the fatty acid uptake and triglyceride synthesis of adipocytes

increases

After a fatty meal, the absorption of triglycerides results in an ________ of triglycerides into the liver

influx

inborn error of metabolism

inherited metabolic defect

Phosphorylation reactions require the ____________ of some energy

input

what protein serves as the primary anabolic hormone?

insulin

Key hormones that direct or regulate metabolic activities are...

insulin, glucagon, cortisol, epinephrine, and thyroid hormone

The cells that synthesize these catabolic hormones release higher amounts of them in response to...

intense exercise, extreme stress, or starvation.

In muscle tissue, glycogenolysis releases glucose molecules, but the glucose is in an ___________________ form that cannot leave muscle cells.

intermediate

ketone body formation

ketogenesis

amino acids that enter the catabolic energy pathways as acetyl CoA

ketogenic

diet that supplies most of its energy from fat

ketogenic diet

acetoacetate, beta-hydroxybutyrate, and acetone are collectively referred to as _____________ _______________; they are released into the bloodstream

ketone bodies

Common signs and symptoms of vitamin B deficiencies include...

lack of energy (fatigue) and weakness ; this is because cells are unable to metabolize macronutrients for energy

Muscle cells ___________ the enzyme that is required for the final step of glycogenolysis, which prepares an intermediate form of glucose for release into the bloodstream

lacks

Lactic acid releases two H+, forming ___________ as a result

lactate

Under anaerobic conditions, each molecule of pyruvate converts to _________ acid, another three carbon molecule

lactic

The energy made under low oxygen conditions in anaerobic metabolism is much __________ than the amount of energy made by aerobic metabolism

less

Except for the final cleavage reaction, ______ NADH and ______ FADH2 are also produced when a two-carbon segment is removed from the fatty acid.

one; one

When excessive amounts of acetyl CoA is produced, the citric acid cycle cannot use the fatty acid molecules efficiently because the acetyl CoA molecules outnumber the _________________ molecules that are available.

oxaloacetate

Glycolysis ultimately leads to ATP production from the _________________ of glucose.

oxidation

involves the loss of electrons during chemical reactions

oxidation

Human cells use pyruvate in two major ways, depending on availability of __________________

oxygen

ATP can be re-formed by ____________________, an anabolic reaction that results in the attachment of a Pi group to ADP.

phosphorylation

Alpha cells secrete glucagon in response to blood glucose levels that drop below normal levels (______________ state)

postabsorptive state

The coenzyme _____________ phosphate (PLP) is needed for the conversion of glycogen to glucose molecules

pyridoxal

Both deamination and transamination require the coenzyme ______________ _________________

pyridoxal phosphate (PLP)

Glycerol is chemically similar to _____________ in that it contains three carbons

pyruvate

In a series of chemical reactions, the six-carbon glucose molecule is converted into two, three-carbon molecules of ________________; during this process ______ NADH and ________ ATP molecules form

pyruvate ; two NADH and four ATP

The liver can remove glycerol from the blood and convert it to _____________ or _____________

pyruvate or glucose (gluconeogenesis)

The _______________ of ATP from ADP and Pi is essential for meeting the energy demands of cells

recycling

Consuming an energy drink that contains caffeine and other naturally occurring stimulants may __________ feelings of fatigue, but will not lead to having ________ energy

reduce; more

After a fatty meal, some fat ____________ in the liver, but a considerable amount of the lipid is incorporated into very-low-density lipoproteins

remains

Ketogenic amino acids cannot be used to make glucose because the steps that convert pyruvate to acetyl CoA are not...

reversible

The process of glycogenesis involves the help of specific enzymes that bind _____________ glucose molecules together into long branched chains of glycogen

single

The cori cycle pathway requires the energy of ______ ATP to make glucose from lactate.

six

Under normal conditions, liver cells convert __________ amounts of acetyl CoA to acetoacetate, beta-hydroxybutyrate, and acetone.

small

Under normal conditions, cells use amino acids derived from proteins to synthesize essential proteins, such as enzymes, __________________ molecules, and certain hormones.

structural

Inherited metabolic defects usually result from the inability to _______________ an enzyme needed for a chemical pathway to proceed

synthesize

ATP is comprised of adenosine bound to __________ inorganic phosphate groups (Pi)

three

Once fatty acids are bound to albumin, the fatty acid circulates to ___________, where it can be picked up and used for energy.

tissues

acetone is ___________ to cells, but the lungs remove the compound through exhalation.

toxic

The attachment of insulin to special receptors results in a signal to glucose ________________ proteins

transport

__________________ are the most energy dense macronutrient group, and the human body stores more energy in _______ cells than in its glycogen stores

triglycerides; fat

The activation process (for catabolism of fatty acids) requires energy from ______ ATP. After activation, FAs must pass through outer and inner mitochondrial membranes with the help of a molecule called _____________

two; carnitine

FAD can pick up ____ hydrogen ions along with ____ electrons ; when this occurs, FAD becomes ___________

two; two ; FADH2

The amount of ATP formed by the catabolism of a carbon skeleton depends on ____________ it entered into the catabolism pathways

where

Since muscle cells lack the coenzyme required for the final step of glycogenolysis, the glucose must be catabolized for energy _____________ the muscle cell where the glycogen had been stored. This adaptation enables muscles to have stockpiles of glucose in case of a __________ or ______________ response

within; fight-or-flight