What is metabolism?
All chemical reactions in body that involve energy transformations.
What are the 2 categories of metabolism?
Catabolism & Anabolism
Rxn that breaks down large molecules to make smaller molecules & releases energy:
Catabolism
Primary source of energy for making ATP:
Catabolism
Rxn that makes larger molecules from smaller molecules & requires energy:
Anabolism
The source of body's large energy-storage compounds:
Anabolism
Where is ATP present?
Everywhere in the cell
What does ATP stand for?
Adenosine Triphosphate
What is ATP composed of?
Adenine base, Ribose sugar, & 3 phosphate radicals
What are the nutrients that may be used for the production of ATP?
Glucose (carbohydrates), Fatty acids (triglycerides), & Amino acids (proteins)
What provides the high-energy raw materials that cells need to make ATP?
food consumption
What drives the cell's activities & eventually maintains overall body homeostasis?
ATP
The complete combustion of glucose requires the presence of ________ & yields ___ ATP for each molecule of glucose.
oxygen; 32
Some energy can be obtained in the absence of oxygen by the pathway that leads to the production of ________ ________. This process results in a net gain of ___ ATP for each glucose.
lactic acid; 2
What is the metabolic pathway by which glucose is converted to 2 pyruvates?
Glycolysis
Where does glycolysis occur?
In the cytoplasm
Does glycolysis require oxygen?
No, it can occur in presence or absence of oxygen.
What's it called when oxygen is not present?
Anaerobic conditions
What's it called when oxygen is present?
Aerobic conditions
What's the overall net equation of glycolysis?
Glucose + 2NAD + 2ADP +2Pi --- 2 pyruvates + 2NADH + 2ATP
Is glycolysis endergonic or exergonic?
Exergonic
In glycolysis glucose must be activated with ______ before energy can be obtained.
2ATP's
What does glycolysis start with?
glucose
What is the first thing glucose is converted to?
Glucose 6-phosphate
What does glycolysis end with?
2 pyruvic acid, 2 NADH, & 2 ATP
The lactic acid pathway is glycolysis under ________ (anaerobic/aerobic) conditions.
Anaerobic
To avoid product accumulation, NADH's produced in glycolysis need to give _____ away.
H's
In the absence of O2, NADH gives its H's to __________ creating ________ ________. aka anaerobic respiration.
pyruvate; lactic acid
Lactic acid pathway makes muscles feel:
fatigued
What converts Pyruvic acid to lactic acid?
LDH which stands for lactate dehydrogenase
Mature RBC's don't have ___________' so it uses what pathway?
mitochondria; lactic acid pathway
Where does lactic acid pathway occur?
in skeletal & heart muscle when oxygen supply falls below critical level.
What are some examples of when lactic acid pathway occurs?
During heavy exercise or vascular blockage; also when mitochondrial function is inhibited.
For osmotic reasons cells can't store many free glucoses; instead store glucose as __________ aka ____________.
glycogen; glycogenesis.
What does glycogenesis mean?
creation of glycogen from many glucoses
What stores lots of glycogen?
skeletal muscle & liver
What clips glucose out of glycogen as glucose 6-phosphate?
glycogenolysis
What traps molecules in cells?
phosphate groups
Skeletal muscles use trapped ________________ for own energy needs.
glucose-6-phosphate
Only _______ has glucose 6 phosphatase that removes phosphage groups leaving glucose.
liver
What is the Cori cycle aka?
gluconeogenesis
During strenuous exercise some skeletal muscle lactic acid goes to ________.
liver
When skeletal muscle lactic acid reaches liver it is converted back through __________ to __________ & ___________.
pyruvate; glucose; glycogen
The conversion of non-carbohydrate molecules: lactic acid, amino acids & glycerol into glucose.
Cori cycle (gluconeogenesis)
The newly formed glucose then moves back to skeletal muscle cells by way of the _________.
blood
In the aeorbic respiration of glucose, pyruvic acid is formed 1st by _________... and then converted into ____________ coenzyme.
glycolysis; acetyl A
What does this conversion start?
Kreb's cycle
As a result of these pathways, a huge amount of reduced NAD & FAD (NADH & FADH2) is made. These reduced coenzymes yield electrons that are needed for the ________ _________ ________ to make _____.
electron transport chain; ATP
CO2 is clipped off pyruvate forming ___________.
acetyl CoA
Coenzyme A is a carrier for ________ _______.
acetic acid
Where does the clipped off CO2 go?
lungs
Which macromolecules (nutrients) are used for energy?
carbohydrates
Why is oxygen important?
with oxygen cells are capable of making more ATP
What does the Kreb's cycle begin with?
Acetyl CoA
What does acetyl CoA combine with?
oxaloacetic acid
What does acetyl CoA & oxaloacetic acid form?
citric acid
What are the products of the Kreb's cycle?
Produces 1 GTP, 3 NADH, & 1 FADH2
What carries electrons to electron transport chain?
NADH & FADH2
What does GTP stand for?
guanosine triphosphate
What does GTP do?
donates a phosphate group to ADP to make 1 ATP
The production of NADH & FADH2 is extremely important in terms of energy production b/c they will:
donate their electrons to the ETC for huge amounts of ATP
What is a linked series of proteins on the cristae of mitochondria: ATP synthase produces most of ATP.
electron transport chain
Some lactic acid can be used in cellular respiration to produce what?
carbon dioxide & water
If skeletal muscles make too much lactic acid it gets shipped to where?
liver
The liver has the enzyme lactic acid dehydrogenase (LDH) which converts what?
lactic acid to pyruvic acid & NADH
What from Kreb's carries electrons to ETC?
NADH & FADH2
As each protein in ETC accepts electrons it is _______ (reduced/oxidized).
reduced
What are the proteins in ETC?
FMN, coenzyme Q, & cytochromes
When it gives electrons to next protein it is ________ (reduced/oxidized).
oxidized
This process is __________ (exergonic/endergonic) b/c it releases energy.
exergonic
Energy is used to phosphorylate ADP to make ____.
ATP
When energy is used to phosphorylate ADP to make ATP it is aka
oxidative phosphorylation
Electrons added to beginning of ETC are passed along until reach the end. Have to be given away or would stop ETC. What accepts these electrons? and what does it combine with?
O2; 4H's
What are the 2 ways ATP can be made?
Direct (substrate-level) phosphorylation & Oxidative phosphorylation
What is direct (substrate-level) phosphorylation?
Where ATP is generated when bonds break
Both ATPs in glycolysis made this way
2 ATPs/glucose in Kreb's made this way
What is oxidative phosphorylation?
Where ATP is generated by ETC
30-32 ATPs made this way
What is the theoretical yield of ATP?
What is the actual yield of ATP?
Theoretical 36-38
Actual yield 30-32
Triglycerides (fats) can be hydrolyzed into ___ glycerol & ___ fatty acids.
1 glycerol; 3 fatty acids
The fatty acids are important b/c they can be converted into molecules of ___________ that will enter the Kreb cycle and make ATP.
acetyl CoA
What does deaminated mean?
removal of amino group
Fats can be hydrolyzed to what?
glycerol & fatty acids
The fats that are hydrolyzed to glycerol & fatty acids can be modified to run thru _______.
Kreb's
Proteins can be broken down to ________ ______.
amino acids
Proteins that are broken down to amino acids can be deaminated & run thru ______.
kreb's
When more energy is taken in that consumed, ATP synthesis is _________ & glucose is converted into _______ & _____.
inhibited; glycogen; fat
If glycogen stores are full, the liver can help out by transferring glucose to __________ for storage in fat tissue.
trigycerides
What is a common substrate (or branch point) for energy & synthetic pathways?
Acetyl CoA
What is lipolysis?
The splitting of a triglyceride into free fatty acids & glycerol.
(Lipolysis) the splitting of a triglyceride into free fatty acids & glycerol happens via _________ by _______.
hydrolysis; lipase
Where does lipolysis occur?
In the mitochondria matrix
How does glycerol enter glycolysis?
Cori cycle (gluconeogenesis)
Each fatty acid is broken down into ____ _______ chains by ______-___________.
2 carbon chains by beta-oxidation
Each 2 carbon chains is converted to ____ molecule of ____________.
1 molecule of Acetyl CoA
Acetyl CoA's from free fatty acids serve as major _______ source for many tissues.
energy
Fat synthesis/creation of lipids aka:
Lipogenesis
Excess carbohydrates may be converted to:
1. glycerol
2. acetyl CoA --- then to fatty acids
Acetyl CoA's can be linked together to form ______ _______.
fatty acids
Fatty acids + glycerol =
fat (triglycerides)
Where does Lipogenesis mainly occur?
adipose & liver tissues
If body has no use for lipids to make ATP, they are stored as ____________ in adipose & liver tissue.
triglycerides
White fat aka
triglyceride
Fat that is the major form of energy storage in the body?
Brown fat
When is brown fat more abundant in our body?
at time of birth
Brown fat is a major site for _____________ in the newborn.
thermogenesis
Brown fat produces __________ __________, causing H+ to leak out of inner mitochondrial membrane.
uncoupling protein
Less ATP produced, causes electron transport system to be _______ (more/less) active.
more
In brown fat ______ is produced instead of ATP.
heat
Normal physiological responses to carbohydrate shortages cause the liver to increase the production of _________ __________ from the acetyl-CoA generated from fatty acid oxidation.
ketone bodies
This allows the heart & skeletal muscles primarily to use ketone bodies for ________, thereby preserving the limited glucose for use by the __________.
energy; brain
When the rate of lipolysis exceeds the rate of Acetyl CoA use, the _______ will convert some of the excess Acetyl CoA to ________ __________.
liver; ketone bodies
During fasting (starvation & unwise dieting) & DM (IDDM) lots of fat is broken down which causes _______ (high/low) levels of ketone bodies. Fat ___________, gives breath an _________ smell.
high; metabolizes; acetone
What results from a reduced supply of glucose (due to a significant decline in circulating insulin) & an increase in fatty acid oxidation (due to an increase in circulating glucagon)
Diabetic ketoacidosis
What is an abnormal rise in the concentration of ketones called?
ketosis
This acidification of the blood is dangerous chiefly b/c it impairs the ability of hemoglobin to bind oxygen.
ketosis/ low blood pH
The production of ketone bodies from Acetyl CoA in the mitochondria of the liver:
ketogenesis
Ketones can be converted back to _________ & used for the making of ________.
Acetyl CoA; ATP
Excess amino acids _________ (can/cannot) be stored as excess proteins.
cannot
The degredation of amino acids occurs in 2 steps:
1. removal of amino group (oxidative deamination)
2. metabolism of carbon skeleton by way of pyruvate - acetyl CoA - intermediates of kreb's cycle
The nitrogen component of the amino group that is removed is converted to _________, then to _______ & later excreted in the urine.
ammonia; urea
In general, since proteins are not stored for future use (as with carbohydrates & triglycerides) instead they are either:
1. oxidized to make ATP
2. used to make new proteins for growth & repair of body tissue
3. excess dietary amino acids are converted into glucose (gluconeogenesis) or triglycerides
How many essential amino acids are there?
20
How many nonessential amino acids can be produced by the body?
12
How many amino acids must come from the diet?
8
Are the 8 amino acids that come from diet essential or nonessential?
essential
When there are adequate amounts of essential & nonessential amino acids in the cell, protein synthesis can occur _________.
quickly
The synthesis of glucose from precursors in the form of amino acids & glycerol. The process occurs when the glycogen stores have been used up.
glyconeogenesis
When does gluconeogenesis occur?
When amino acids are converted to keto acids, then pyruvate, then glucose
Gluconeogenesis also occurs when _________ is converted to glucose.
glycerol
What does the brain use as its major source of energy?
glucose
Muscle, liver, and fat cells routinely catabolize fatty acids from glycerides to make __________, aka ________.
ATP; lipolysis
What refers to the conversion of glucose in the cytoplasm of living cells to pyruvic acid and then to lactic acid, when there exists a temporary absence of oxygen?
Anaerobic respiration
What are the advantage of anaerobic respiration?
Glycolysis of glucose to pyruvic acid is allowed to continue, despite the fact that fewer ATP (two) are synthesized. This provides cells with a backup or emergency source of ATP. Some peripheral tissues such as skeletal muscles commonly function anaerobic
What are the disadvantages of anaerobic respiration?
The potential to make 28 more ATP from glucose is lost. The accumulation of lactic acid in tissues such as skeletal muscle leads to an overall acidosis. By altering the active sites of enzymes, acidosis can interrupt metabolism & lead to the inadequate pr
Synthesis of larger, energy storage molecules from smaller molecules, best describes:
anabolism
Which of the following molecules is not used as a primary source of energy for the cellular synthesis of ATP? a. glucose b. fatty acids c. nucleic acids d. amino acids e. all molecules are used for ATP synthesis
c. nucleic acids
Which of these is not a final product of aerobic cell respiration? a. carbon dioxide b. water c. oxygen d. energy (ATP)
c. oxygen
In the aerobic respiration of glucose to form two molecules of pyruvic acid, four atoms of _________ are removed. a. carbon b. hydrogen c. oxygen d. carbon dioxide
b. hydrogen
Which of the following statements about glycolysis is false? a. it results in the ultimate formation of two molecules of pyruvic acid b. it results in the net gain of two ATP molecules c. it can occur with or without oxygen present d. it is exergonic e. a
e. all statements true
As a result of anaerobic respiration or lactic acid fermentation, glucose is converted to:
lactic acid
The organ most responsible for extracting & converting lactic acid to pyruvic acid, & which ultimately reforms & releases free glucose into the blood stream, is the:
liver
The process in the above question, which describes the conversion of noncarbohydrate molecules into glucose, is known as:
gluconeogenesis
The Cori cycle is the process by which:
blood lactic acid is converted to glucose by the liver
T/F: Aerobic respiration & ventilation describe two different processes.
True
T/F: During aerobic respiration the oxygen we breathe in is converted into carbon dioxide we breathe out.
False. During aerobic resp the O2 we breathe in is converted into water we breathe out.
T/F: Glycolysis can take place both inside & outside the mitochondrion organelles of the cell.
False. Glycolysis takes place only in cytoplasm.
T/F: Anaerobic respiration (or lactic acid fermentation) yields a net gain of two ATP molecules.
True
T/f: Anaerobic respiration (or lactic acid fermentation) in the cell does not require the presence of oxygen in the conversion of one glucose molecule to two molecules of lactic acid.
True
T/F: It is common for certain tissues like skeletal muscle to derive energy (ATP) from anaerobic respiration without permanent injury or damage to the tissue.
True
In addition to energy (ATP), what is (are) the final product(s) of aerobic respiration?
CO2 & H2O
Following aerobic resp, approx what % of the chemical bond energy present in a glucose molecule is captured in high-energy bonds of ATP?
40%
The vitamin from the diet that is converted into coenzyme A & that combines with acetic acid in the minochondrion is:
pantothenic acid
Which of the following processes does not occur during the completion of one circuit around the Krebs cycle? a. one GTP molecule is converted to one ATP molecule b. three NAD molecules are reduced by electrons (H's) c. one molecule of oxygen is combined w
c. one molecule of oxygen is combined with hydrogen to form water
Which of the following molecules is not part of the elctron transport chain? a. cytochrome b. flavoprotein c. coenzyme Q d. coenzyme A e. all are part of ETC
d. coenzyme A
All of the following are formed as a result of the electron transport system, or chain, except: a. carbon dioxide b. oxidized NAD c. water d. ATP e oxidized FAD
a carbon dioxide
Molecules with unpaired electrons, such as an oxygen molecule with an extra, unpaired electron, may be involved in disease processes and are collectively known as: a. antioxidants b. free radicals c. coenzymes d. cytochromes
b. free radicals
Which of the following is usually not considered an antioxidant molecule? a. vitamin E (alpha-tocopherol) b. glutathione c. hydrogen peroxide d. superoxide dismutase e. vitamin C (ascorbic acid)
c. hydrogen peroxide
The chemiosmotic theory involves the participation of proton (H+) pumps that are found within the:
mitochondrial inner membrane
Cyanide is a poison that blocks the electron transfer from cytochrome a3 to oxygen, therefore directly interrupting:
oxidative phosphorylation
The actual (not theoretical) number of ATP molecules generated by the complete aerobic resp of glucose is:
30
The breakdown of stored glycogen into individual molecules of glucose 6 phosphage occurs during the process known as:
glycogenolysis
The enzyme, found only in the liver, that removes phosphage groups and, thus, can release free glucose into the blood, is:
glucose 6 phosphatase
Glucose molecules entering skeletal muscle fibers from the blood are "trapped" when quickly converted to:
glucose 6 phosphate
T/F: In aerobic resp, the catabolism of a glucose molecule froms pyruvic acid, not lactic acid.
True
T/F: The conversion of pyruvic acid to acetyl CoA occurs in the cytoplasm.
False: The conversion of pyruvic acid to acetyl CoA occuris in the mitochondrial membrane.
T/F:Glycolysis occurs in the mitochondrion.
False. Glycolysis occurs in the cytoplasm.
T/F: Iron is the crucial atom within the cytochromes of the mitochondrion that participates in the electron transport chain.
True
T/F: Electron transport molecules are fixed within the inner membrane of the mitochondrion and are not part of the matrix.
True
T/F: The transfer of energy from the electrons of hydrogen atoms to ATP is an example of an endergonic reaction.
False. The transfer of energy from the electrons of hydrogen atoms to ATP is an example of an exergonic reaction.
T/F: The formation of ATP along the electron transport chain, which requires the presence of O2, is called oxidative phosphorylation.
True
T/F: The production of free radicals and other molecules classified as reactive oxygen species by cells of the body are always implicated in disease processes.
False. some reactive O2 species are needed by WBC's to help destroy bacteria
T/F: Antioxidants are molecules that scavenge free radicals and protect the body from the damaging effects of certain reactive oxygen species.
True
T/F: The consumption of a diet high in fruits & veges would provide the body with an abundant supply of antioxidant molecules.
True
T/F: Oxygen is the final electron acceptor of the electron transport chain.
True
T/F: The O2 we breathe in is ultimately converted to carbon dioxide (CO2).
False. converted to water
T/F: In oxidative phosphorylation, each electron pair from FADH2 froms two molecules of ATP, while each electron pair from NADH forms three molecules of ATP.
True
T/F: Organic molecules with phosphate groups, such as glucose 6 phosphate, are intracellular "prisoners" and cannot "escape" the cell by crossing the cell membrane.
True
T/F: Skeletal muscle can supply the liver with energy in the form of free glucose but the opposite is not true.
False.Liver can supply the skeletal muscle with energy in the form of free glucose but the opposite is not true.
T/F: To maintain a steady supply of ATP, more glucose molecules would have to be burned in tissues that are anaerobic than if the tissues are supplied with oxygen.
True
T/F: During exercise, the liver can supply free glucose to many tissues of the body that may have depleted glycogen stores, including the exercising muscles.
True
T/F: To summarize aerobic cell resp: the combustion of one glucose molecule has a theoretical yield of about 30-32 ATP, whereas, the actual yield is 36-38 ATP per glucose molecule.
False. theoretical yield of about 36-38; actual yield 30-32
T/F: The estimates of the actual number of ATP obtained by the cell are lower than originally thought b/c the costs of transporting ATP out of the mitochondria & into the cytoplasm were not included.
True
Acetyl CoA is an important metabolic intersection that can lead to the formation of all of the following substances, except: a. Co2 via Krebs cycle b. cholesterol & steroids c. ketone bodies d. fatty acids & triglycerides e. all substances are formed from
e. all substances formed from acetyl CoA
The two intermediates of the glucose combustion pathway that directly link glucose metabolism to fat metabolism are:
phosphoglyceraldehyde & acetyl CoA
Ranking the following stored energy forms from highest to lowest number of total calories available for the energy needs of the body, the proper sequence is: 1. glycogen (skeletal muscle); 2. glycogen (liver); 3. fat
3-1-2 (fat, glycogen (skeletal muscle), glycogen (liver)
In the cytoplasm, the removal of two-carbon acetic acid molecules from the acid end of fatty acids is an important enzymatic process known as:
B-oxidation
The primary purpose for stored fuel in the form of brown fat is to:
increase the metabolism of fatty acids, thereby generating heat
In the liver, fatty acid metabolism can result in the formation of excess acetyl CoA molecules; this "overflow" pathway ultimately results in the formation of:
ketone bodies
The formation of nonessential amino acids from essential amino acids and carbohydrates is known as:
transamination
The vitamin that serves as teh required coenzye for the successful activity of transaminase enzymes is:
pyridoxine (B6)
The enzymatic removal of the amine group from one amino acid, forming ammonia (later converted to urea), and leaving behind a ketone acid, is called:
oxidative deamination
The catabolism (breakdown) of this energy source can require the liver to convert toxic ammonia molecules into urea molecules:
proteins
Which of the following is not an energy source than can be found circulating in the bloodstream? a. glycogen b. glucose c. ketone bodies d. fatty acids e. amino acids
a. glycogen
The organ with an absolute requirement for blood glucose as its primary energy source is the:
brain
The oxygen debt following strenuous exercise is due, in part, to the extra oxygen required for the metabolism of:
lactic acid
T/F: Fatty acids are formed by the condensation of many two-carbon acetyl CoA molecules, resulting in the formation of long hydrocarbon chains.
True
T/F: Protein accounts for 15%-20% of the stored calories in the body & is used extensively as an energy source.
False. Proteins are not used daily for energy
T/F: Lipase enzymes specialize in catalyzing the hydrolysis of triglycerides into glycogen & free fatty acids.
False. Lipase enzymes specialize in catalyzing the hydrolysis of triglycerides into glycerol & free fatty acids.
T/F: Like glucose metabolism, b-oxidation of fatty acids requires coenzymes NAD & FAD for the transfer of hydrogen atoms and the subsequent release of energy for ATP synthesis.
True
T/F: The rationale behind the popular low carb (high protein) diet stems from the concept that such diets lower the secretion of insulin from the pancreas that will promote the breakdown of fat with subsequent weight loss.
True
T/F: Brown fat accumulates as one ages especially in the skin & abdominal regions of the body.
False. Brown fat is most abundant at birth; produces heat.
T/F: Many peripheral tissues can use ketone bodies as an energy source.
True
T/F: Growing children excrete less nitrogen than they ingest, therefore they are in a state of negative nitrogen balance.
False. state of positive nitrogen balance.
T/F: Excess amino acids, not used for energy, can be converted to carbohydrate and/or to fat.
True
T/F: Of the twenty amino acids required to synthesize protein, about twelve are essential, which means the body must make them.
False. There are 8 essential amino acids which must be included in the adult diet; cells make non essential amino acids thru transamination.
T/F: Ketone acids can be used in the Kreb's cycle as a source of energy, or converted to fat or glucose.
True
What compartment? electron transport chain chemiosmotic "hydrogen pumps":
mitochondrion (membranes)
What compartment? protein synthesis (translation) of enzymes for metabolism:
ribosome
What compartmen? Krebs cycle:
mitochondrion (matrix)
What compartment? b-oxidation of fatty acids to acetyl CoA:
cytoplasm
What compartment? blocks transport of phosphorylated molecules:
plasma membrane
What compartment? glucose converson to pyrivic acid molecules:
cytoplasm
What compartment? formation of acetyl CoA from pyruvic acid, linking glycolysis to the Krebs cycle:
mitochondrion (membranes)
What compartment? conversion of glycerol to phosphoglyceraldehyde
cytoplasm
What compartment? conversion of O2 gas to water in the electron transport system:
mitochondrion (membranes)
What compartment? formation of CO2 gas from carboxyl groups:
mitochondrion (membranes & matrix)
What compartment? formation of lactic acid from cluse:
cytoplasm