Metabolism and Nutrition
Your middle-aged aunt says that she always feels more "tipsy" than her same-size husband, even though their alcohol intake is the same. You respond by saying to your aunt:
"Women have less stomach alcohol dehydrogenase enzyme and consequently absorb more of the alcohol into the bloodstream."
Definition of "heat stroke"
"heat stroke" is not defined by a set temperature; rather it is defined as "hot" and having an altered mental status (AMS).
What is glucagon's message?
"save nutrients for the brain, however, we are not in emergency mode"
facultative anaerobes
( Yeast and many bacteria) can survive using either fermentation or respiration. At a cellular level, human muscle cells can behave as facultative anaerobes.For facultative anaerobes, pyruvate is a fork in the metabolic road that leads to two alternative routes. Under aerobic conditions, pyruvate is converted to acetyl CoA and oxidation continues in the citric acid cycle. Under anaerobic conditions, pyruvate serves as an electron acceptor to recycle NAD+. Have to consume sugar faster if using ferm
FIVE BASIC FOOD GROUPS
(1) the grains group; (2) the vegetables group; (3) the fruits group; (4) the milk group; (5) the meat and beans group.
ATP
(adenosine triphosphate) main energy source that cells use for most of their work
Where is the electron transfer chain in:
-A plant cell: in the membrane of chloroplast -Gram+ cell: in the plasma membrane -Sachramoyces cerviecise(yeast): membrane of mitochondria -Dog cell: inner membrane of mitochondria
substrate-level phosphorylation
-ATP is usually generated when a high energy phosphate group is directly transferred from a phosphorylated compound (a substrate) to ADP -usually the phosphate group has acquired energy during an earlier reaction in which the substrate itself was oxidized
electron transport chain
-NADH and FADH2 are oxidized, contributing the electrons they have carried from the substrates to a cascade of oxidation reduction reactions involving a series of additional electron carriers -consists of a sequence of carrier molecules that are capable of oxidation and reduction -as electrons are passed through the chain there occurs a stepwise release of energy which is used to drive the chemiosmotic generation of ATP -the final oxidation is irreversible -like in oxidative phosphorylation, the electron transport chain is located in the plasma membrane of prokaryotes and in the inner membrane of mitochondria in eukaryotes. -there are 3 classes of carrier molecules +flavoproteins +cytochromes +ubiquinones (coenzyme Q) -main goal is to release energy as electrons are transferred from higher energy compounds to lower energy compounds. -The first step involves the transfer of high-energy electrons from NADH to FMN(the first carrier in the chain). This transfer actually involves the passage of a hydrogen atom with 2 electrons to FMN, which this picks up an additional hydrogen from the surrounding aqueous medium. From the energy of the first transfer NADH is oxidized to NAD+ and FMN is reduced to FMNH2. -In the second step FMNH2 passes 2 hydrogen to the other side of the mitochondria and passes 2 electrons to coenzyme Q (nonprotein carrier) -coenzyme Q picks up 2 extra hydrogens from the surrounding aqueous medium and releases it on the other side of the mitochondria membrane. -Next, electrons are passed to the cytochromes starting at cyt b, to cyt c1, to cyt c, to cyt a, and then to cyt a3. Each cytochrome is reduced as it pucks up the electrons and is oxidized as it gives up its electrons to the next one in the step. -The last cytochrome, cyt a3,passes it electrons to molecular oxygen (O2) which becomes negatively charged and then picks up protons from the surrounding medium to form H2O.
feedback/end product inhibition
-a control mechanism that stops the cell from akin more of a substance than it needs and stops it from wasting chemical resources -the last step in the synthesis of a chemical compound (called the end product) can allosterically inhibit one of the enzymes in the earlier steps and then it stops the rest of the steps from happening with it stopping more synthesis from occurring
substrate
-a specific substance that an enzyme will interact with
Krebs cycle
-a.k.a. citric acid cycle / tricarboxylic acid cycle -the oxidation of acetyl CoA (a derivative of pyruvic acid) to carbon dioxide, with the production of some ATP, energy-containing NADH, and another reduced electrons carrier FADH2 -pyruvic acid can't enter the Krebs cycle directly so in the preparatory step it must lose one molecule of CO2 and become a two carbon compound (this step is called decarboxylation.) the two carbon compound which is called an acetyl group attached to coenzyme acetyl CoA. During this reaction pyruvic acid is also oxidized and NAD+ is reduced to NADH. -the oxidation of one glucose molecule(in glycolysis) is reduced to two pyruvic acid molecules so for each molecule of glucose two molecules of CO2 are real eased in the step and two molecules of NADH are produced and two molecules of acetyl CoA are formed. -When acetyl CoA enter the Krebs cycle coenzyme A detaches from the acetyl group and the two carbon acetyl group combines with a four carbon compound called oxaloacetic acid to form the six carbon citric acid. (the synthesis requires energy and gets it from the splitting of high energy bond between the acetyl group and CoA.) the creation of citric acid is the first step in this cycle. -One of the categories of chemical reactions in the cycle is decarboxylation. There is decarboxylation is the preparatory step, step 3, and step 4. Since this happens all three carbon atoms in the pyruvic acid are eventually released as CO2 (this represents the conversion to CO2 of all six carbon atoms contain the the original glucose molecule before glycolysis. -Another category of chemical reactions is oxidation-reaction. When hydrogen atoms are released it means that it is being oxidized. This happens in steps 3, 4, 6, and 8. Their hydrogen atoms that are released are picked up by the coenzymes NAD+ and FAD. But since NAD+ picks up two electrons but only one additional proton, its reduced form is represented as NADH. FAD picks up two complete hydrogen atoms and reduced to FADH2. -Looking at the Krebs cycle as whole shows us that for every 2 molecules of acetyl CoA that enter the cycle, 4 molecules of CO2 are set free by decarboxylation, 6 molecules of NADH and 2 molecules of FADH2 are produced by oxidation-reduction reactions, and two molecules of ATP are generated by substrate-level phosphorylation. -the most important products of this cycle are the coenzymes NADH and FADH2 because they contain most of the energy originally stored in glucose.
glycolysis
-also called the Embden-Meryerhof pathway -the oxidation of glucose to pyruvic acid with the production of some ATP and energy-containing NADH -doesn't require oxygen 1)The preparatory stage (steps 1-4) two molecules of ATP are used as a six carbon glucose molecule is phsphorylated, restructured, and split into two three-carbon compounds(glyceraldehyde 3-phosphate(GP) and dihyroxyacetone phosphate(DHAP.)) DHAP is concerted to GP which means that from this point on in glycolysis, two molecules of GP are fed into the remaining chemical reactions. 2)The energy conserving stage (steps 6-10) the two three-carbon molecules are oxidized in several steps to two molecules of pyruvic acid. In these reactions, two molecules of NAD+ are reduced to NADH, and four molecules of ATP are formed by substrate-level phosphorylation. -since two molecules of ATP were needed to get glycolysis started and four molecules of ATP are generated by the process, there is a net gain of two molecules of ATP for each molecules of glucose that is oxidized.
NADPH
-anabolic reaction -reduced electron carrier
NADH
-catabolic reaction -reduced electron carrier but is oxidized once it passes on its electrons to NAD+ and FMN
coenzyme A (CoA)
-contains a derivative of pantothenic acid (a B vitamin0 -plays an important role in the synthesis and breakdown of fats and in a series of oxidizing reactions called the Krebs cycle
noncompetitive inhibitors
-do not compete with the substrate for the enzyme's active site -they interact with a different part of the enzyme -the process is called allosteric inhibition -the inhibitor binds to a site on the enzyme other than the active site called the allosteric site -this binding causes the active site to change its shape, making it non functional and reducing the enzyme's activity
anaerobic respiration
-doesn't use oxygen and may be killed by it -the final electron acceptor is an inorganic molecule other than oxygen (like nitrate, sulfate, carbon) -only part of the Krebs cycle and electron transport chain participate in anaerobic respiration so their energy yield is always lower than that of aerobic respiration -the amount of ATP molecules produced varies with the organism and pathway it takes
oxidative phosphorylation
-electrons are transferred from organic compounds to one group of electron carriers -the electrons are passed through a series of different electron carriers to molecules or oxygen or other oxidized inorganic and organic molecules -this process happens in the plasma membrane of prokaryotic cells and in the inner mitochondrial membrane of eukaryotic cells
catabolism
-enzyme regulated chemical reactions that release energy -the breakdown of complex organic compounds into simpler ones -exergonic reactions -(ex) when cells break down sugars into carbon dioxide and water -when complex molecules are split apart some of the energy is transferred to and stored in ATP and some is given off as heat
anabolism
-enzyme regulated chemical reactions that require energy -the building of complex organic molecules from simpler ones -endergonic reactions -(ex) the formation of proteins from amino acids, nucleic acids from nucleotides, polysaccharides from simple sugars. -ATP provides the energy for synthesis and some energy is given off as heat
holoenzyme
-enzymes consist of a protein portion (apoenzyme) and a nonprotein component (cofactor) -apoenzymes are inactive by themselves and must be activated by cofactors -when the two are together they form a holoenzyme (a whole and active enzyme)
photosynthesis
-example of photophosphorylation
collision theory
-explains how chemical reactions occur and how certain factors effect the rates of those reactions -all atoms, ions, and molecules are continuously moving and are thus continuously colliding with each other -the energy transferred by the particles in the collision can disrupt their electron structures enough to break chemical bonds or form new bonds -factors like the velocities of the colliding particles, their energy, and their specific chemical configuration determine whether a collision will cause a chemical reaction
competitive inhibitors
-fill the active site of an enzyme and compete with the normal substrate for the active site -it is able to do this because its shape and chemical structure is similar to the normal substrate -it does not undergo any reaction to form products
flavin coenzymes
-flavin mononucleotide (FMN) -flavin adenine dinucleotide (FAD) -contain derivatives of the B vitamin riboflavin and are also electron carriers
enzyme substrate complex
-formed by the temporary binding of enzyme and reactant -enables the collision to be more effective and lowers the activation energy of the reactant
Entner Doudoroff pathway
-from each molecules of glucose there are two molecules of NADPH produced and one molecule of ATP for use in cellular biosynthetic reactions -found in some gram negative bacteria
coenzyme
-if the cofactor is an organic molecule it's called a coenzyme -may assist the enzyme by accepting atoms removed from the substrate or by donating atoms required by the substrate, by being electron carriers which remove electrons from the substrate and donate them to other molecules in subsequent reactions -two important coenzymes in metabolic reactions are NAD+ (catabolic reactions) and NADP+ (anabolic reactions) -many coenzymes are derived from vitamins
cofactor
-ions of iron, zinc, magnesium, calcium, cobalt, or copper
lipids catabolism
-lipid is broken down my lipase (enzyme) into glycerol and fatty acids -glycerol can be converted into dihydroxyacetone phosphate which is then turned into glyceraldehyde 3 phosphate. -then then goes through glycolysis with the end result of pyruvic acid. -fatty acids is converted to acetyl CoA by the beta oxidation process -acetyl CoA and pyruvic acid come together to start the Krebs cycle
alternatives to glycolysis
-many bacteria have another pathway in addition to glycolysis for the oxidation of glucose -pentose phosphate pathway (or hexose monophosphate shunt) -Entner Doudoroff pathway
photophosphorylation
-occurs only in photosynthetic cells (contain light trapping pigments like chlorophylls) -in photosynthesis, organic molecules (especially sugars) are synthesized with the energy of light from the energy poor building blocks carbon dioxide and water -photophosphorylation starts this process by converting light energy to the chemical energy to ATP and NADPH which are used to synthesize organic molecules -electron transport chain is used in this process
pentose phosphate pathway
-operates simultaneously with glycolysis and provides a means for the breakdown of 5 carbon sugars as well as glucose -(ex) e.coli, bacillus subtilis
oxygenic
-photosynthesis in the presence of oxygen
cellular respiration
-process used to produce ATP energy from glucose and the final electron acceptor is almost always an inorganic molecule -the reparation of glucose typically occurs in three principal stages +glycolysis +Krebs cycle +electron transport system -the entire process can thought of as involving a flow of electrons from the energy rich glucose molecule to the relatively energy poor CO2 and H2O molecules -two types of respiration +aerobic +anaerobic
protein catabolism
-protein to extracellular proteases to amino acids *****look on powerpoint*****
flavoproteins
-proteins that contain flavin (a coenzyme derived from riboflavin, B2 vitamin) -capable of performing alternating oxidations and reductions -an important flavoprotein is flavin mononucleotide (FMN)
cytochromes
-proteins with an iron containing group (heme) -capable of existing alternately as a reduced form (Fe^2+) and as an oxidized form (Fe^3+) -the cytochromes involved with the electron transport chain are +cytochrome b (cyt b) +cytochrome c1 (cyt c1) +cytochrome c (cyt c) +cytochrome a (cyt a) +cytochrome a3 (cyt a3)
metabolic pathway
-sequences of chemical reaction -its pathway is determined by enzymes, which are determined by the cell's genetic makeup
enzymes
-serve as biological catalysts -enzymes are encoded by genes -enzymes lower activation energy -very specific as catalysts -crucial function is to speed up biochemical reactions at a temperature that is compatible with the normal functioning of the cell -when Chung says "enzyme" he really means "holoenzyme" -it is a tertiary structure
ubiquinones/coenzyme Q
-small non protein carrier
fermentation
-subset of anaerobic respiration (doesn't require oxygen) -any process that produces alcoholic beverages or acidic dairy products -does not use Krebs cycle or an electron transport chain. -produces only a small amount of ATP -uses an organic molecule as the final electron acceptor -any spoilage of food by microorganisms -begins with pyruvic acid (normally from glycolysis)
catalysts
-substances that can speed up a chemical reactions without being permanently altering themselves
factors that influence enzymatic activity
-temperature + 22-27 degrees is average for most enzymes -pH level + 6-7.5 is average for most enzymes -substrate concentration -presence or absence of inhibitors
phosphorylation
-the addition of a phosphate group to a chemical compound -3 types +substrate level phosphorylation +oxidative phosphorylation +photophosphorylation
activation energy
-the amount of collision energy required for a chemical reaction to take place and disrupt the stable electronic configuration of any specific molecule so the electrons can be rearranged
carbohydrate catabolism
-the breakdown of carbohydrates molecules to produce energy -most microorganisms oxidize carbohydrates as their primary source of cellular energy (most common is glucose) -great importance to cell metabolism
saturation
-the enzyme's active site is always occupied by substrate or product molecules -in normal conditions enzymes are not saturated with substrates
reaction rate
-the frequency of collisions containing sufficient energy to bring about a reaction -depends on the number of reactant molecules at or above the activation energy level -heat can increase the reaction rate of a substance -in living cells enzymes increase the reaction rate without raising the temperature
reduction
-the gaining one or more electrons -once a molecule is oxidized it gives its energy to another molecule which then is considered a reduction molecule because it received an electron
denaturation
-the loss of its characteristic three dimensional structure (tertiary configuration) -causes enzyme to lose its catalytic ability
oxidation-reduction/redox reaction
-the pairing of oxidation reactions and reduction reactions -much of the energy released during this is trapped with the cell by the formation of ATP
active site
-the place on an enzyme molecule where it interacts with a specific chemical substance
oxidation
-the removal of electrons from an atom or molecule -when you oxide it you release energy
metabolism
-the sum of all chemical reactions within a living organism -acts as an energy balancing act since chemical reactions either release or require energy
chemiosmosis
-the transfer of electrons from one electron carrier to the next in the electron transport chain releases energy, some of which is used to generate ATP from ADP. -in the electron transport chain in the second step where FMNH2 passes 2 hydrogens to the other side of the mitochondria membrane and in when coenzyme Q passes 2 hydrogens over also it creates a buildup of protons on one side of the membrane by proton pumps (using active transport.) -when this happens it is like how when water is stored behind a dam it has potential energy. -there is a concentration gradient and an electrical charge gradient (because of all the positively charged hydrogens) and is called the proton motive force. -the protons of the side of the mitochondria membrane with the higher proton concentration can only diffuse across to the other side through protein specific channels that contain the enzyme ATP synthesis. -when the protons move through the protein specific channels energy is released and is used by the enzyme to synthesis ATP from ADP and an inorganic phosphate group. -oxidative phosphorylation
ribozyme
-unique kind of RNA that works only on a RNA strand -function as catalysts -have active sites that bind to substrates -not used up in chemical reactions
aerobic respiration
-uses oxygen -the final electron acceptor is oxygen -the reparation of glucose typically occurs in three principal stages +glycolysis +Krebs cycle +electron transport system -the entire process can thought of as involving a flow of electrons from the energy rich glucose molecule to the relatively energy poor CO2 and H2O molecules -aerobic respiration is prokaryotes yields 38 molecules of ATP -aerobic respiration in eukaryotes yields 36 molecules of ATP. -the reason that less ATP is produced in eukaryotes is that some energy is lost when electrons are moved across the mitochondrial membranes that separate glycolysis from the electron transport chain (no separation exists in prokaryotes.)
generation of ATP
-when an inorganic phosphate group is added to ADP with the input of energy to form ATP -Adenosine and 3 phosphate groups that are high energy and daily unstable to each other
dehydrogenation
-when hydrogen atoms are removed from a molecule -also called biological oxidation
What minimum concentration of blood alcohol leads to impaired judgment and increased heart rate?
0.05
What is the minimum blood alcohol percentage that defines legal drunkenness in most states?
0.10
The amount of ethanol in a typical "drink" is
0.5 ounce
What minimum concentration of alcohol in the blood is usually fatal?
0.5%
Electron transport can only occur if what is present
02
Energy Yield of C-C cleavage
1 cleavage point (2 C) yields 1 FADH2+1 NADH= 5 ATP 7 cleavage points x 5 ATP = 35 ATP
Reactant(s) in Glycolysis
1 glucose molecule + 2 ATP
Know this:
1 glucose molecule + 6 oxygen molecules 6 carbon dioxide molecules + 6 water molecules C6H12O6 + 6O2 6CO2 + 6H2O an accurate representation of the reaction as conducted aerobically in cells is: 1 glucose + 6 oxygen 6 carbon dioxide + 6 water + potential chemical energy Or, as unorthodox chemical notation, C6H12O6 + 6O2 6CO2 + 6H2O + 36 ATP + heat
In the average healthy person, about how much time is required by the liver to process the alcohol in a typical drink?
1 hour
Describe the mechanism of enzymatic action
1) Substrate contacts region on the enzymes surface called the active site 2) a temporary intermediate compound forms, called an enzyme-substrate complex 3) substrate molecule is tranformed 4) the transformed substrate molecule is released because it no longer fits in active site - this is the product of the reaction 5) unchanged enzyme now free to react again
sequence of events in enzyme action
1) the surface of the the substrate contacts a specific region of the surface of the enzyme molecule (active site) 2) a temporary intermediate compound forms (enzyme substrate complex) 3) the substrate molecule is transformed by the rearrangement of existing atoms, the breakdown of the substrate molecule, or in combination with another substrate molecule 4) the transformed substrate molecules (products of the reaction) are released from the enzyme molecule because they no longer fit in the active site. 5) the unchanged enzyme is now free to react with other substrate molecules (it is reusable)
7 Steps to lipid absorption: 1. ______ _____ emulsify fat droplets into smaller ones. 2. ______ ______ digests triglycerides into two fatty acids and monoglycerides. 3. Monoglycerides, fatty acids and cholesterol gather into micelles, surrounded by bile salts. 4. Cholesterol uses a _______ ______ to cross the membrane. Monoglycerides and fatty acids use simple diffusion. 5. _________ reform in the cell. 6. Cholesterol, triglycerides, and protein form __________. 7. __________ released to enter the lacteal in middle of villi.
1. Bile salts 2. Pancreatic lipase 3. Monoglycerides, fatty acids and cholesterol gather into micelles, surrounded by bile salts. 4. carrier protein 5. Triglycerides 6. chylomicrons. 7. Chylomicrons
The 3 stages of metabolism (processing of nutrients):
1. Digestion, absorption, and transport to tissues 2. Cellular processing (in cytoplasm): synthesis of lipids, proteins, and glycogen, or catabolism (glycolysis) into intermediates. 3. Oxidative breakdown of intermediates into CO2 and water
KEY POINT: For each glucose molecule processed, a typical cell gains 36 molecules of ATP. All but two of them are produced within mitochondria.
1. During glycolysis in the cytoplasm, the cell gains two molecules of ATP for each glucose molecule broken down to pyruvic acid. 2. Inside the mitochondria, the two pyruvic acid molecules derived from each glucose molecule are fully broken down in the TCA cycle. Two revolutions of the TCA cycle, each yielding a molecule of ATP, provide a net gain of two additional molecules of ATP. 3. For each molecule of glucose broken down, activity at the electron transport chain in the inner mitochondrial membrane provides 32 molecules of ATP.
3 Effects of insulin:
1. Lowers blood glucose levels 2. Transports of glucose into fat and muscle cells. 3. Inhibits glycogenolysis and gluconeogenesis.
4 ways food is regulated:
1. Neural signals from the digestive tract (stretch) 2. Bloodborne signals related to body energy stores 3. Hormones 4. to a lesser extent, body temp and psychological factors (stress eating)
When the temperature at the heat-loss center exceeds its set point, three responses occur: 1. Dilation of skin blood vessels; 2. Increas of sweat gland secretion; 3. Acceleration of ventilation.
1. Peripheral blood vessels dilate, sending warm blood flowing to the surface of the body. White skin takes on a reddish color and all skin rises in temperature; heat loss through radiation and convection increases. 2. Sweat glands are stimulated, and as perspiration flows across the skin, heat loss through evaporation accelerates. 3. The respiratory centers are stimulated, and the depth of respiration increases. The individual often begins respiring through the mouth, enhancing heat loss through increased evaporation from the lungs.
Heat exchange with the environment involves 4 basic processes— radiation, conduction, convection, evaporation.
1. Radiation. Warm objects lose heat energy as infrared radiation. When we feel the sun's heat, we are experiencing radiant heat. Your body loses heat the same way. More than half of the heat you lose occurs by radiation, (primarily infrared). 2. Conduction. Conduction is the direct transfer of energy through physical contact. When you sit on a cold plastic chair in an air-conditioned room, you are immediately aware of this process. Conduction is generally not an effective mechanism of gaining or losing heat, except in a manner opposite of that desired, (i.e., trauma victims lying a ground cooler than 98F (37C) rapidly cool, partly through conduction.) 3. Convection. Convection is the result of conductive heat loss to the air that overlies the surface of an object. Warm air rises because it is lighter than cool air. As your body conducts heat to the air next to your skin, that air warms and rises, moving away from your skin surface. Cooler air replaces it, and as this air in turn warms, the pattern repeats. 4. Evaporation. When water evaporates, it changes from a liquid to a vapor. This process absorbs energy—roughly 580 calories (0.58 Cal) per gram of water evaporated— and, thus, cools any surface on which it occurs. The rate of evaporation and heat loss occurring at your skin is highly variable. Each hour, 20-25 ml of water crosses epithelia and evaporates from the alveolar surfaces of the lungs and the surface of the skin. This insensible perspiration remains relatively constant; it accounts for roughly one-fifth of the average heat loss from a body at rest. The sweat glands responsible for sensible perspiration have a tremendous scope of activity, ranging from virtual inactivity to secretory rates of 2-4 liters (or 2-4 kg) per hour. This is equivalent to an entire day's resting water loss in under an hour.
The Amino Acid pool: Three things it is a source for:
1. Resynthesizing body proteins 2. Forming amino acid derivatives 3. Glucogenesis (the creation of new glucose)
Insulin promotes nutrient use and storage in 4 ways:
1. Stimulates glucose uptake by fat cells and muscles cells by 20-fold 2. stimulates glucose utilization 3. stimulates fat synthesis and inhibits fat breakdown 4. stimulates protein synthesis
4 basic reasons cells synthesize new organic components:
1. To perform structural maintenance & repairs (all cells must expend energy for ongoing maintenance & repairs because most structures in the cell are temporary, not permanent. The continuous removal & replacement of these structures are part of the process of metabolic turnover); 2. To support growth (cells preparing to divide enlarge & synthesize extra proteins & organelles); 3. To produce secretions (secretory cells must synthesize their products & deliver them to the interstitial fluid); 4. To build nutrient reserves (most cells "prepare for a rainy day" - some emergency, an interval of extreme activity, or a time when the nutrient supply in the bloodstream is inadequate - by storing nutrients in a form that can be mobilized as needed. For example, muscle cells store glucose in the form of glycogen, adipocytes store triglycerides, & liver cells store both).
Serum Lipoproteins are categorized in 4 groups: (more protein=higher density)
1. chylomicrons 2. very low-density (VLDLs) 3. low-density (LDLs) 4. high-density (HDLs)
FFAs can have 5 fates from the liver metabolizing it:
1. converted to ATP for hepatocytes 2. stored as triglycerids, within liver, adipose, or other tissues. 3. Synthesized into cholesterol 4. Converted into ketone bodies 5. Exported to other tissues as fatty acids bound to albumin
Glucagon works in the liver to: 1. Breakdown glycogen to glucose (______) 2. Create glucose from amino acids (____) 3. Production of ketone bodies for energy from faty acids (_____)
1. glycogenolysis 2. gluconeogenesis 3. ketogenesis
3 primary roles of the liver: 1. Processes _______ and delivers appropriate amounts to other tissues via bloodstream. 2. ______ important substances and transports them via bloodstream. 3. ________ ____ that gathers waste and disposes of it.
1. nutrients 2. synthesizes 3. recycling center
Approximately what percentage of alcohol in the body is eliminated via the urine and breath?
10
Approximately what percentage of the body's energy expenditure is furnished by amino acids?
10 to 15
Approximately how many kcalories from ethanol are contained in one standard drink of vodka or rum?
100
Energy yield of Acetyl CoA oxidation
12 ATP per TCA cycle b/c 3 NADH, 1 FADH2, 1 GTP
Proteins: account for __-__% of body mass. (mostly in _______ muscle)
12-15%; skeletal
Approximately how many ATP molecules are synthesized from the complete oxidation of a molecule of palmitic acid
129
Adult male: __% body fat; Female: __%
15%; 25%
What is the median weekly number of alcoholic drinks consumed by college students?
1½
One average-sized can of beer contains about the same amount of alcohol as
1½ ounces of vodka
How many ATPs can come from substrate level phosphorylation during glycolysis?
2
Reactant(s) of The Kreb's Cycle
2 Acetyl CoA ---> 2 oxaloacete
Product(s) of Transition
2 carbon dioxide 2 NADH 2 Acetyl CoA 2 ATP
The chemical structure of ethanol consists of
2 carbons and 1 hydroxyl group
What happens during the energy conserving stage of Glycolysis?
2 molecules of GP are oxidized in several steps to form 2 molecules of Pyruvic Acid. During these steps, 2 molecules of NAD+ are reduced to 2 molecules of NADH & 4 molecules of ATP are formed thru substrate-level phosphorylation. Since 2 ATP were used in the preparatory stage, the net result is 2 ATP
Reactant(s) in Transition
2 pyruvate
Product(s) of Glycolysis
2 pyruvate 2 NET ATP 2 NADH
What fraction of all domestic violence incidents involve alcohol use?
2/3
Approximately how many kcal are contained in 3 ounces of 80-proof rum?
200
Proteins are digested into __ different ____ _____, which are used to produce cellular proteins.
20; amino acids
With alcohol beverages, the ratio of proof to alcohol percentage is
2:1
In a triglyceride that contains 54 carbon atoms, how many can become part of glucose?
3
ATP yield of NADH, FADH2, GTP
3, 2, 1, respectively
If a normal person expends 1200 kcalories while at rest, approximately how many are used by the brain?
300
Approximately how many molecules of ATP are generated from the complete oxidation of one molecule of glucose?
32
Product(s) of the ETC
32-34 ATP
How much ATP is made in Electron transport chain
34 ATP per glucose
The health benefits of moderate alcohol intake occur in people with a starting age (years) of
35.
Product(s) of The Kreb's Cycle
4 carbon dioxide, 6 NADH, 2 FADH
Binge drinking is defined as the successive consumption of
4-5 drinks
Approximately what percentage of all traffic fatalities involves alcohol?
40
What percentage (by weight) of a triglyceride molecule can be converted to glucose?
5
Of the total amount of carbohydrate energy consumed by the body, approximately what percentage is used by the brain and nerve cells?
50
What is the approximate percent efficiency of conversion of food energy to ATP energy in the body?
50
Recommended percentage of carbohydrate consumption in diet?
55 - 60%
How many molecules of O2 are used and how many molecules of CO2 are produced during the complete oxidation of one glucose molecule?
6 molecules of O2 are used and 6 molecules of CO2 produced.
What is the percentage of ethanol in 120-proof scotch whiskey?
60
If a person consumes 100 kcalories in excess of energy needs from table sugar, approximately how many of the kcalories are stored in the body?
75
How many reactions take place during the Krebs cycle?
8
Reactant(s) of the ETC
8-10 NADH 2- 4 FADH
How many acetyl CoA molecules may be obtained from oxidation of an 18-carbon fatty acid?
9
Approximately what percentage of the weight of triglycerides cannot be converted to glucose?
95
If a person consumes 100 kcalories in excess of energy needs from olive oil, approximately what percentage of the kcalories are stored in the body?
95
pyruvate
A 3-carbon compound that plays a key role in energy metabolism
Fat soluble vitamsins
A D E K (absorbed from the digestive tract)
carbohydrate
A carbohydrate is an organic molecule that contains carbon, hydrogen, & oxygen in a ratio near 1:2:1. Familiar carbohydrates include the sugars & starches that make up roughly half of the typical U.S. diet.
fermentation
A catabolic process that releases energy from glucose without using the Kreb Cycle or the Electron Transport Chain; does not require oxygen; uses an organic molecule as the final electron acceptor and that produces end products such as ethanol or lactic acid. ATP is only generated during Glycolysis. Most important function is to regenerate NAD+ so that Glycolysis can continue.
Lipid Metabolism
A cell generates 144 ATP molecules from the breakdown of one 18-carbon fatty acid molecule—almost 1.5 times the energy obtained from the breakdown of three six-carbon glucose molecules. Because they are insoluble in water, lipids are stored in compact droplets in the cytosol. However, if the droplets are large, it is difficult for water-soluble enzymes to get at them. This makes lipid reserves more difficult to access than carbohydrate reserves.
Why does a cell go through fermentation?
A cell goes through fermentation when there is insufficient oxygen to run aerobic respiration
The Krebs Cycle serves as what?
A central metabolic pathway for generating building blocks for the cell.
redox reaction
A chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction.
reaction rate
A measure of how rapidly a reaction takes place
Electron Transport Chain
A sequence of electron carrier molecules that release energy used to make ATP. NADH & FADH2 are oxidized contributing their electrons to a cascade of oxidation - reduction reactions. Considerable amount of ATP are generated (most is generated during this step of cellular respiration)
monosaccharides
A simple sugar, or monosaccharide is a carbohydrate containing from three to seven carbon atoms. Included within this group is glucose, the most important metabolic "fuel" in the body. Glucose & other monosaccharides dissolve readily in water.
Nutrient
A substance in food that promotes normal growth, maintenance, and repair
enzyme
A substance produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction
What is MEOS?
A system of enzymes that oxidizes alcohol and drugs
Ribozyme
A type of RNA that acts as a catalyst
TYPICAL MIXED DIET IN THE U.S.
A typical mixed diet in the United States contains 46% carbohydrates, 40% lipids, and 14% protein.
Fat-soluble vitamins: (_,_,_,&_). What do they do?
A,D,E,&K; absorbed with dietary lipids, stored
Fat soluble vitamins include...these vitamins are absorbed with _____ ___.
A,D,E,K; dietary fat.
Most common form of energy
ATP
What is the major energy carrier molecule in most cells?
ATP
Which of the following metabolic reactions occurs when a cell uses energy? a. ATP gains a phosphate group and becomes ADP b. ADP gains a phosphate group and becomes ATP c. ATP releases a phosphate group and becomes ADP d. ADP releases a phosphate group and becomes ATP
ATP releases a phosphate group and becomes ADP
Identify the role of ATP as an intermediate between catabolism & anabolism
ATP stores energy from catabolic reactions & releases it later to drive anabolic reactions
How are micronutrients handled?
Absorbed as is into bloodstream
In this cycle, in consumes what?
Acetate (in the form of Acetyl- CoA) and water
Which of the following is classified as a ketone body? a. Sorbitol b. Pyruvate c. Acetyl CoA Acetoacetate
Acetoacetate
Even numbered chain saturated FA produce
Acetyl CoA
What is the first product of fatty acid catabolism?
Acetyl CoA
Which of the following can be synthesized from all three energy-yielding nutrients? a. Lactate b. Glycogen c. Acetyl CoA d.Oxaloacetate
Acetyl CoA
Odd numbered chain Saturated FA produce
Acetyl CoA, Propionyl CoA and then Succinyl CoA
Even or odd numbered unsaturated FA produce
Acetyl CoA/ Succinyl CoA
Which substance is the gateway into the Krebs cycle for molecules that are being oxidized to generate ATP?
Acetyl coenzyme A is the gateway into the Krebs cycle for molecules being oxidized to generate ATP.
Outline principle events and outcomes of the Krebs cycle.
Acetyl-CoA enters the TCA cycle- occurs in mitochondria -Converts carbons of the acetyl group to CO2 while producing ATP -takes 2 turns of the cycle to produce one molecule of glucose -1 complete cycle produces: 2 CO2 1 ATP (GTP) 3 NADH + H+ 1 FADH2 A-ketoglutimate - transanimated -----> glutamate - used to make purine nucleotides, e.g Arg, Pro Succinyl-CoA used to make porphrins, e.g haemoglobin The electrons from glucose oxidation feed into ETC driving synthesis of ATP Fumerate and oxaloacetate - used to make several amino acids
Which substance is the gateway into Krebs cycle for molecules that are being oxidised to generate ATP?
Acetyl-CoA is the gateway into the Krebs cycle for molecules being oxidised to generate ATP
How is acetyl-coA formed?
Acetyl-coA is formed from pyruvate Pyruvate ------> Acetyl-coA NAD+---------> NADH, H+ CoA ----------> CO2 Requires Vitamins B1, B2, B3, B5 -Enzyme is pyruvate dehydrogenase complex
When the terminal phosphate is cut off ATP what is formed?
Adenosine Diphosphate
____ tissue insulates and protects organs.
Adipose
Where are triglycerides stored in the body?
Adipose tissue
The Krebs cycle is a key component of the metabolic pathway by which all _______ organisms generate energy.q
Aerobic
Which of the following statements is not characteristic of alcohol metabolism? a. There are gender differences in the rate of breakdown b. The average person needs about two hours to metabolize two drinks c. Alcohol is metabolized by muscle and brain cells as well as by the liver d. The amount of alcohol in the breath is proportional to the amount in the blood
Alcohol is metabolized by muscle and brain cells as well as by the liver
the carbohydrate content of the diet is insufficient to meet the body's needs for glucose, which of the following can be converted to glucose?
Amino acids
What are the three interconvertible nutrient pools?
Amino acids, carbohydrates, and fats
Which of the following products is not generated via the TCA cycle or electron transport chain? a. Water b. Energy c. Ammonia d. Carbon dioxide
Ammonia
Liver cells convert:
Ammonia Into Urea
NADH
An energy-carrying coenzyme produced by glycolysis and the Krebs cycle. NADH carries energy to the electron transport chain, where it is stored in ATP.
Hormone sensitive lipase
An enzyme which hydrolizes TG to glycerol and fatty acids in adipose cells; inhibited by insulin; and stimulated by glucagon and epinephrine (change in ratio of hormones)
What is acetaldehyde?
An intermediate in alcohol metabolism
Which of the following defines a coenzyme?
An organic molecule required for the functioning of an enzyme
What term is specific to reactions in which simple compounds are combined into more complex molecules?
Anabolic
Chemical reactions that combine simple molecules and monomers to form complex structures are known as
Anabolism
Which of the following dietary components cannot be used to synthesize and store glycogen?
Animal fats
Where can you get saturated fats from:
Animal fats, butter, lard, hydrogenated oils (solid fats)
Which of the following is a consequence of alcohol intake? a.The MEOS is suppressed b.Homocysteine production is reduced c.Water content of the blood in increased d.Antidiuretic hormone production is suppressed
Antidiuretic hormone production is suppressed
Percenage of energy captured vs released as heat: 40% captured as ATP 60% released as heat
As mitochondrial enzymes break the covalent bonds that hold these molecules together, they capture roughly 40% of the energy released. The captured energy is used to convert ADP to ATP, & the rest escapes as heat that warms the interior of the cell & the surrounding tissues.
At what point is oxygen used in the electron transport chain?
At the end
Water-soluble fiber:
Attract water and form gel-like substance. Delays emptying of stomach and gives feeling of fullness. May effect blood glucose levels.
Average individuals BMR?
Average individual has a BMR of 70 Cal per hour, or about 1,680 Cal per day.
Compare the energy yield (ATP) of aerobic & anaerobic respiration. Explain why aerobic conditions generate more ATP on average than anaerobic conditions.
Average yield of ATP in aerobic respiration in prokaryotes is 38. The amount of ATP in anerobic respiration is considerably less and varies with the organism & pathway. A large amount of ATP is generated in the ETC which requires oxygen. In anaerobic pathways the ETC is not used which is why not as much ATP is generated.
What are animal proteins considered?
B Complete proteins
BMR
Basal Metabolic Rate: The resting metabolic rate of a fasting subject under normal homeostatic conditions. The result can be measured in terms of calories per hour, per day, or per unit of body weight per day.
What are complex carbohydrates found in?
Beans, whole grain, nuts, fruits
Why is the Krebs Cycle also known as the citric acid cycle?
Because citric acid is the very first product generated by this sequence of chemical conversions, and it is also regenerated at the end of the cycle.
Why are enzymes necessary for metabolism to occur?
Because enzymes catalyse reactions, meaning they speed up the rate of reaction at a temperature that is compatible with the normal functioning cell
Aerobic vs Anaerobic
Because the steps in the cytosol do not require oxygen, they are said to be anaerobic. The subsequent reactions, which occur within mitochondria, consume oxygen & are thus aerobic. The mitochondrial activity responsible for ATP production is called aerobic metabolism, or cellular respiration.
Why is enzyme specificity important?
Because the unique arrangement of each enzyme allows it to find the correct substrate from all the diverse molecules in a cell
What group is removed from an amino acid before it can enter the Krebs cycle, and what is this process called?
Before an amino acid can enter the Krebs cycle, an amino group must be removed via deamination.
Compare & contrast aerobic and anaerobic respiration
Both aerobic and anaerobic respiration go through the metabolic pathway of glycolysis. In aerobic respiration the products of glycolysis enter into the Kreb cycle and from there electron carriers carry the remaining electrons to the ETC to further oxidize to remove energy. Oxygen is required for the ETC. When oxygen is present in the cells, the products of Glycolysis proceed through the Kreb Cycle & then on to the Electron Transport Chain. In these pathways, ATP is produced through oxidative breakdown of glucose (sugar), with carbon dioxide and water created as by-products of the process. In anaerobic respiration, after glycolysis, the pyruvate molecules go through the process of fermentation which does not yield any energy but recycles NAD+ to enter back into glycolysis.
Similarities btwn cellular resp and ferm
Both use glycolysis to oxidize sugars to pyruvate with a net production of 2 ATP by substrate-level phosphorylation. Both use NAD+ as an oxidizing agent to accept electrons from food during glycolysis.
Provitamins are
Building Blocks of Vitamins
Water-soluble vitamins: (_&_). What do they do?
C&B; absorbed with water in small intestine, not stored
Overall equation of cellular respiration
C6H12O6 + 6O2 -------------------> 6CO2 + 6H2O + ~38 ATP
What is the term that refers to all chemical reactions in the body?
CELLULAR METABOLISM
Age-related changes & nutritional requirements:
Caloric needs drop 10% per decade after age 50; Decreased formation of calcitriol from Vitamin D3 due to lack of sun exposure; may require calcium supplementation; Changes in sense of taste & smell blunt appetite; Digestive system becomes less efficient at nutrient absorption.
Which of the following dietary nutrients would most rapidly reverse a state of ketosis in a starving person? a. Fat b. Protein c. Amino acids d.Carbohydrate
Carbohydrate
What 2 pools are easily interconverted?
Carbohydrate and Fat pools
Which of the following is (are) best suited for slowing alcohol absorption? a. Not eating b. Protein snacks c. Caffeine drinks d. Carbohydrate snacks
Carbohydrate snacks
3 sources of organic molecular energy & what they are broken down into:
Carbohydrates are broken down into short carbon chains; Triglycerides are split into fatty acids & glycerol; Proteins are broken down to individual amino acids.
The metabolic pathway of the citric acid cycle chemically converts what to what?
Carbohydrates, fats, and proteins into carbon dioxide, and converts water into serviceable energy.
Macronutrients
Carbohydrates, lipids, proteins, and nucleic acids
Carbs & Cellular Metabolism
Carbohydrates, most familiar to us as sugars and starches, are important sources of energy. Most cells generate ATP and other high-energy compounds by breaking down carbohydrates, especially glucose. The complete reaction sequence can be summarized as: C6H12O6 + 6 O2 6 CO2 + 6 H2O glucose oxygen carbon dioxide water
In this cycle, it produces what?
Carbon Dioxide
When in cellular respiration is carbon dioxide given off?
Carbon dioxide is given off during the production of acetyl coenzyme A and during the Krebs cycle.
Normally carbs are replaced with fat which is unhealthy for the ___________ ______.
Cardiovascular System
Glycogenolysis is ________ and stimulated by ___________
Catabolic, Epinephrine
Chemical reactions that break down complex organic molecules into simpler ones are called:
Catabolism
breakdown of more complex substances into simpler ones with release of energy
Catabolism
Distinguish between catabolism & anabolism
Catabolism is enzyme regulated reactions that release energy (breakdown of compounds). Anabolism are enzyme regulated, energy requiring reactions that build complex molecules from simpler ones. Catabolic reactions provide the building blocks for anabolic reactions and provide the energy to drive those reactions.
What happens to the carbon atoms in glucose catabolized by E. coli?
Cell fission occurs and the carbon atoms create ribonucleic acid and protein around it like a protective shell. In some cases it crystallizes
Obtaining nutrients from diet
Cells break down organic molecules to obtain energy, usually in the form of ATP. Chemical reactions within mitochondria provide most of the energy needed by a typical cell for its varied activities. To carry out their energy-generating processes, cells in the human body must also obtain oxygen & nutrients. Whereas oxygen is absorbed at the lungs, nutrients - essential substances such as water, vitamins, ions, carbohydrates, lipids, & proteins - are obtained from the diet by absorption at the digestive tract.
Cellular Metabolism
Cells obtain organic molecules from the extracellular fluid & break them down to obtain ATP. Only about 40% of the energy released through catabolism is captured in ATP; the rest is radiated as heat. The ATP generated by catabolism provides energy for all vital cellular activities, including anabolism.
How does the electron transport chain pump protons?
Certain members of the electron transport chain accept and release H+ along with electrons. At certain steps along the chain, electron transfers cause H+ to be taken up and released into the surrounding solution.
cellular respiration
Chemical process where mitochondria break down food molecules to produce ATP, the three stages are glycolysis, the kreb cycle, and the electron transport chain.
TCA cycle & Electron Transport System
Chemical reactions within the mitochondria then break down the fragments further, generating carbon dioxide, water, & ATP. This mitochondrial activity involves two pathways: the TCA cycle & the electron transport system.
Accumulation of a large amount of H+ between the inner and outer mitochondrial membranes, is described as
Chemiosmosis
Which of the following reactions is an example of an anabolic reaction? a. Pyruvate synthesis from glucose b. Acetyl CoA synthesis from cholesterol c. Carbon dioxide synthesis from citric acid d. Cholesterol synthesis from acetyl CoA molecules
Cholesterol synthesis from acetyl CoA molecules
These transport dietary lipids.
Chylomicrons
When in cellular respiration is CO2 given off, what happens to this gas?
Co2 is given off during the production of acetyl-coA and during the Krebs cycle.
What are cofactors & what role do they play in enzymatic reactions?
Cofactors are nonprotein chemical components that help facilitate enzymatic reactions; Coenzymes are cofactors with organic molecules
Distinguish competitive & non-competitive inhibition
Competitive inhibitors fill the active site of an enzyme (compete with substrate for active site). Can be reversible or irreversible. Reversible can be overcome by increasing the concentration of the substrate. Non-competitive inhibitors interact with another part of the enzyme (allosteric site) in a process called allosteric inhibition. This causes the active site to change it's shape making it non-functional. It's reversible if the active site can return to its original shape.
How efficient is respiration in generating ATP?
Complete oxidation of glucose releases 686 kcal/mol. Phosphorylation of ADP to form ATP requires at least 7.3 kcal/mol. Efficiency of respiration is 7.3 kcal/mol times 38 ATP/glucose divided by 686 kcal/mol glucose, which equals 0.4 or 40%. Approximately 60% of the energy from glucose is lost as heat. Some of that heat is used to maintain our high body temperature (37°C). Cellular respiration is remarkably efficient in energy conversion.
How are ketones formed?
Condensation of acetyl CoA molecules
This is a mechanism of heat transfer that involves direct contact.
Conduction
Minerals
Contribute osmotic pressure Play a role in action potentials, synpatic transmission, muscle contraction, bone growth & turnover, gas transport, buffers, fluid absorption, & waste removal; Act as cofactors to enzymes.
Prostaglandins play a role in ________.
Control of Blood Pressure
Excess amino acids in the body are
Converted Into Glucose
What hormone stimulates gluconeogenesis?
Cortisol
G3P
Created in Glycolysis when original glucose molecule is split in two by an enzyme; Glyceraldehyde 3-phosphate
How does the inner mitochondrial membrane generate and maintain the H+ gradient that drives ATP synthesis in the ATP synthase protein complex?
Creating the H+ gradient is the function of the electron transport chain. The ETC is an energy converter that uses the exergonic flow of electrons to pump H+ across the membrane from the mitochondrial matrix to the intermembrane space. The H+ has a tendency to diffuse down its gradient.The ATP synthase molecules are the only place that H+ can diffuse back to the matrix. The exergonic flow of H+ is used by the enzyme to generate ATP.
Location of Transition
Crosses 1st membrane of the mitochondria, passes through the inter membrane spaces past the second membrane and into the mitochondrial matrix.
Where does glycolysis take place?
Cytosol
Most nucleotides are recycled into new nucleic acids, but they can also be broken donw into what? A Simple sugars B Adenosine Triphosphate C Nitrogen bases D Both A and C
D Both A and C
Micronutrient deficiencies lead to __ _____.
DNA damage
What is the immediate fate of excess dietary protein in the body?
Deaminated
What general class of reactions form polymers? Do those reactions occur during anabolim or catabolism
Dehydration reactions form most polymers. These are considered anabolic reactions.
hydrolysis of disaccharides & some polysaccharides
Dehydration synthesis, or condensation, links molecules together by the removal of a water molecule. The breakdown of sucrose into simple sugars is an example of hydrolysis, the functional opposite of dehydration synthesis
Oxidation-reduction reactions are catalyzed by which enzymes?
Dehyrodgenases and Oxidases
How are macronutrients handled?
Digestive enzymes break down for absorption
Ketosis, Clinical signs
Dullness, nervousness, loss of condition, cowy milk flavor
Energy flow of cellular respiration
During cellular respiration, most energy flows from glucose → NADH → electron transport chain → proton-motive force → ATP.
Reduction/oxidation along the chain
During electron transport along the chain, electron carriers alternate between reduced and oxidized states as they accept and donate electrons. Each component of the chain becomes reduced when it accepts electrons from its "uphill" neighbor, which is less electronegative. It then returns to its oxidized form as it passes electrons to its more electronegative "downhill" neighbor.
ATP cell gain during catabolism:
During the complete catabolism of a glucose molecule, a typical cell gains 36 ATP molecules.
How many molecules of oxygen are used, and how many molecules of carbon dioxide are produced during the complete oxidation of one glucose molecule?
During the complete oxidation of one glucose molecule, six molecules of oxygen are used and six molecules of carbon dioxide are produced.
What happens in the electron transport chain and why is this process called chemiosmosis?
Electrons are carried by reduced coenzymes NADH and FADH2, are passed through a chain of proteins and coenzymes to drive the generation of a proton gradient across the inner mitochondrial membrane. Chemiosmosis is the pushing of electrons with the pumping of hydrogen ions Energy from NADH + H+ passes along ETC, used to pump H+ from the matrix into the space between the inner and outer mitochondrial membrane A high concentration of H+ accumulates between the inner and outer membrane ATP synthesis then occurs as H+ flow back into mitochondrial matrix through H+ channel in the inner membrane
Pancreas:
Endocrine organ that controls blood glucose levels.
Products of the citric acid cycle are used to produce what?
Energy for the cell
Which of the following is a feature of aerobic metabolism? a. Little or no oxygen is consumed b. Lactic acid is a major byproduct c. Energy is produced more slowly than in anaerobic metabolism d. Pyruvate is converted to glucose by reverse glycolysis to yield a net of 2 ATPs
Energy is produced more slowly than in anaerobic metabolism
Identify the components of an enzyme
Enzymes consist of an apoenzyme (a protein), a non-protein, inorganic component called a cofactor (typically metal ions like iron or zinc). Coenzymes are cofactors that are organic molecules. The cofactor activates the enzyme. The apoenzyme + cofactor = holoenzyme
How are essential and non essential amino acids different?
Essential amino acids must be present in diet because they cannot be synthesised in the body Non-essential amino acids can be synthesised by body cells
______ ____ _____ are ones that must be ingested. These include _____ ____.
Essential fatty acids; linolenic acids
How can yeast cells make alcohol and cause bread to rise?
Ethanol & CO2 are waste products of yeast. Ethanol from yeasts is used in alcohol and CO2 made by yeasts causes bread dough to rise
Pyruvic Acid
Even though glycolysis yields an immediate net gain of two ATP molecules for the cell, a great deal of additional energy is still stored in the chemical bonds of pyruvic acid. The cell's ability to capture that energy depends on the availability of oxygen. If oxygen supplies are adequate, mitochondria will absorb the pyruvic acid molecules & break them down completely. The hydrogen atoms of pyruvic acid are removed by coenzymes & are ultimately the source of most of the cell's energy gain. The carbon & oxygen atoms are removed & released as carbon dioxide.
Which of the following is a feature of the metabolism of surplus dietary fat? a. Excess fat is almost all stored b. Excess fat promotes increased fat oxidation c. Excess fat spares breakdown of body proteins d. Conversion of excess fat to storage fat is inefficient
Excess fat is almost all stored
Ketosis/ Acetonemia
Excess of ketones
What factors can increase metabolic rate and thus increase the rate of heat production?
Exercise, the sympathetic nervous system, hormones (epinephrine, norepinephrine, thyroxine, testosterone, human growth hormone), elevated body temperature, and ingestion of food increase metabolic rate, which results in an increase in body temperature.
This is a derivative of riboflavin.
FAD
Give an example of a carrier molecule & explain its function in the ETC
FADH2 & NADH are carrier molecules; function is to transport electrons through the electron transport chain; undergo oxidation/reduction easily, allowing electrons to flow through the system.
True or False: All athletes require diets high in protein and calories in order to perform and to maintain their muscle mass.
False
True or False: Beta oxidation is the initial phase of fatty acid oxidation, and it occurs in the cytoplasm.
False
True or False: Blood volume affects heat production.
False
True or False: Except for lactose and some glycogen, the carbohydrates we ingest are mainly from animals.
False
True or False: Glycogen is a major nutrient the body needs.
False
True or False: Glycogenesis is one way to make glucose.
False
True or False: Lipogenesis is a postabsorptive state reaction.
False
True or False: Processes that break down complex molecules into simpler ones are anabolic.
False
True or False: The net result of the complete oxidation of glucose includes oxygen.
False
Lipids
Familiar lipids include fats, oils, & waxes. Important energy reserves. Major types are: -Fatty Acids; -Fats; -Steroids; -Phospholipids.
Is glucose consumption in an anaerobic environment faster or slower the glucose consumption under aerobic conditions?
Faster
Excess carbs are stored as ___ in the body.
Fat
What is the sequence of stages that brings about advanced liver disease caused by chronic alcohol toxicity?
Fat accumulation, fibrosis, cirrhosisFat accumulation, fibrosis, cirrhosis
When energy-yielding nutrients are consumed in excess, which one(s) can lead to storage of fat?
Fat, carbohydrate, and protein
How does the Carb/Fat pool differ from the amino acid pool?
Fats & carbs are oxidized directly to produce energy. Excess carbs/fats can be stored. Increased storage=weight gain. decreased=weight loss
Which of the following cannot be used to make body proteins?
Fatty acids
Which of the following nutrients can be made from compounds composed of 2-carbon skeletons? a. Glucose b. Fructose c. Glycogen d. Fatty acids
Fatty acids
Which of the following accounts for the higher energy density of a fatty acid compared with the other energy-yielding nutrients? a. Fatty acids have a lower percentage of hydrogen-carbon bonds b. Fatty acids have a greater percentage of hydrogen-carbon bonds c. Other energy-yielding nutrients have a lower percentage of oxygen-carbon bonds d. Other energy-yielding nutrients undergo fewer metabolic reactions, thereby lowering the energy yield
Fatty acids have a greater percentage of hydrogen-carbon bonds
Lipids: Chemical precursors: precursors of prostaglandins and other eicosanoids.
Fatty acids.
Why is feedback inhibition noncompetitive inhibition?
Feedback inhibition stops a cell from making more of a substrate than it needs. Frequently a substrate moves thru an assembly line of enzyme to get to the end product. When it has enough, the end product can act as a allosteric inhibitor on the first enzyme in the assembly line - shutting it down.
What does fermentation need?
Fermentation can generate ATP from glucose by substrate-level phosphorylation as long as there is a supply of NAD+ to accept electrons. If the NAD+ pool is exhausted, glycolysis shuts down.
Fiber
Fibrous materials from plant sources that do not get digested.
Neuropeptide Y stimulates
Food Intake
collision theory
For a reaction to occur, the particles must collide, they must collide with the appropriate orientation, and they must collide with sufficient energy.
the products generated when cellular respiration oxidizes a molecule of glucose to six CO2 molecules
Four ATP molecules are produced by substrate-level phosphorylation during glycolysis and the citric acid cycle. Many more ATP molecules are generated by oxidative phosphorylation. Each NADH from the citric acid cycle and the conversion of pyruvate contributes enough energy to the proton-motive force to generate a maximum of 3 ATP. The NADH from glycolysis may also yield 3 ATP. Each FADH2 from the citric acid cycle can be used to generate about 2 ATP.
Lillie has been losing weight by following a very-low-carbohydrate diet for 2 months. Her primary care physician just diagnosed ketosis through a urine sample. Which of the following symptoms would be another way the physician might have suspected ketosis in Lillie?
Fruity odor on breath
What do most carbohydrates serve as?
Fuel
2 ATP is always...?
GLYCOLYSIS
reduction
Gain of electrons
What is gluconeogenesis and why is it important?
Gluconeogenesis is the synthesis of new glycogen Pyruvate ----> glucose Retains 7 steps of glycolysis Step 1a GNG: pyruvate ----> oxaloacetate Requires ATP + biotin (CO2 carrier) By pyruvate carboxylase Malate shuttle: oxaloacetate cannot cross mitochondrial membrane - must reduce to malate ---> transported into cytosol -----> oxidised back to oxaloacetate Step 1b: Oxaloacetate ----> PEP by PEP carboxylase Phosphorylation of GTP ------> GDP Step 7: Fructose-1,6-biphosphate ----> Fructose-6-phosphate Step 10: Glucose-6-phosphate ------> glucose Gluconeogenesis is crucial because tissues that only use glucose (brain, RBC, kidney) require continuous supply of energy from glucose Can remove metabolic products such as lactate from the blood
Which of the following cannot be formed from acetyl CoA molecules
Glucose
Which of the following compounds cannot be formed from fatty acids? a. Ketones b. Glucose c. Acetyl CoA d. Carbon dioxide
Glucose
Within the Krebs cycle, energy in the form of ATP is usually derived from the breakdown of what sugar?
Glucose
What are used in "metabolic crossroads"?
Glucose 6-phosphate, pyruvic acid, and acetyl coenzyme A.
Glycolysis, formation of acetyl CoA, Krebs cycle and the electron transport chain are all involved in:
Glucose Catabolism
How does glucose move into and out of body cells?
Glucose enters body cells via GLUTS: glucose transporters In insulin sensitive tissues (liver, muscles, fat cells) - insulin helps GLUT4 insertion into plasma membrane to transport glucose into cell - facilitated diffusion GLUT 2: glucose entry always on (neurons/liver) - don't need insulin GLUT 5: fructose transporters; don't need insulin
Why is glucose such an important molecule for organisms?
Glucose is a highly reduced compound containing a large amount of potential energy because it has so many hydrogen atoms C6H12O6)
What are the possible fates of glucose-6-phosphate, pyruvic acid and acetyl-CoA in a cell?
Glucose-6-phosphate has 4 possible fates: Release of glucose into the bloodstream - G6P can be dephosphorylated to glucose Synthesis of nucleic acids - G6P is the precursor used by cells around the body to synthesis RNA and DNA. The same sequence of reactions also produces NADPH - used for synthesis of FA and steroid hormones Glycolysis - some ATP produced anaerobically via glycolysis; G6P---> pyruvic acid Synthesis of glycogen - occurs mainly in hepatocytes and skeletal muscle fibres Pyruvic acid: Production of lactic acid: pyruvate ----> lactic acid LA diffuses into bloodstream and taken up by hepatocytes Eventually converted back to pyruvic acid 2. Production of alanine: CHO and protein metabolism are linked by pyruvic acid. Through transanimation, an amino group can either be added or removed from alanine to generate pyruvic acid Gluconeogenesis: pyruvic acid + certain amino acids can also be converted to oxaloacetic acid - used to form G6P Acetyl-CoA Breakdown of liver glycogen - can supply about 4 hours of glucose Lipolysis: TAG ---> glycerol -----> glucose Gluconeogenesis using lactic acid: during exercise skeletal muscle tissues breakdown stored glycogen ----> glucose
After the first day or so of fasting, which of the following is most depleted in the body?
Glycogen
In the absorptive state, most glucose that enters the liver is converted to
Glycogen
glycogen
Glycogen, or animal starch, is a polysaccharide composed of interconnected glucose molecules. Like most other large polysaccharides, glycogen will not dissolve in water or other body fluids. Liver & muscle tissues make & store glycogen. When these tissues have a high demand for energy, glycogen molecules are broken down into glucose; when demands are low, the tissues absorb glucose from the bloodstream & rebuild glycogen reserves.
Under what circumstances do glycogenesis and glycogenolysis occur?
Glycogenesis is the process of glucose storage. If glucose is not needed immediately, stored as glycogen in the muscle (~75%) and liver (~25%) Insulin from beta cells in pancreas stimulate liver and skeletal muscle cells to carry out glycogenesis Step 1: glucose -----> glucose-6-phosphate by glucokinase (liver) or hexokinase (muscle) Step 2: glucose-6-phosphate -------> glucose-1-phosphate by phosphoglucomutase Step 3: Glucose-1-phosphate combined with uridine triphosphate ----> uridine diphosphate-glucose by UDP pyrophosphorylase Step 4: UDP-glucose synthesise glycogen + other sugars by glycogen synthase Glycogenolysis is glucose release. Breaks down glycogen into glucose subunits When body needs ATP, liver glycogen ----> glucose Glycogen ----> glucose requires 2 enzymes Glycogen phosphorylase: breaks down long chains of glucose molecules Debranching enzyme: trims off glycogen branches Step 1: Removal of the end glucose residue of a1---> 4 linked chains by glycogen phosphorylase, releasing glucose-1-phosphate Step 2: Glucose-1-phosphate ----> glucose-6-phosphate by phosphoglucomutase Step 3: glucose-6-phosphate ----> glucose by glucose-6-phosphotase Step 4: glucose transported out of the cells by GLUT 2 In muscles: Step 3: G6P enters glycolysis to produce ATP for muscle contraction
Alternative Catabolic Pathways:
Glycogenolysis Gluconeogenesis Triglyceride (fat) catabolism Amino acid catabolism
GLYCOLYSIS:
Glycolysis (glykus, sweet + lysis, breakdown) is the breakdown of glucose to pyruvic acid. In this process, a series of enzymatic steps breaks the six-carbon glucose molecule (C6H12O6) into two three-carbon molecules of pyruvic acid (CH3 - CO - COOH). Glycolysis requires: glucose molecules, appropriate cytoplasmic enzymes, ATP & ADP, & NAD (nicotinamide adenine dinucleotide), a coenzyme that removes hydrogen atoms. Coenzymes are organic molecules, usually derived from vitamins, that must be present for an enzymatic reaction to occur. If the cell lacks any of these four participants, glycolysis cannot occur.
Which process is also called anaerobic cellular respiration?
Glycolysis is also called anaerobic cellular respiration.
In which part of the cell does glycolysis occur?
Glycolysis occurs in the cytosol.
Where does glycolysis take place in a yeast cell, gram- cell, fungal cell, & human cell?
Glycolysis takes place in the cytoplasm or all living organisms
Which of the following outlines the overall sequence of events in the complete oxidation of glucose?
Glycolysis, TCA cycle, electron transport chain
Functions of anabolism
Growth (making new organic matter); Maintenance & Repair; Secretion; & Reserves.
Trans double bond
H are on opposite sides of the double bound carbon
Cis double bond
H are on the same side as double bound carbon
___: Also transports cholesterol; good cholesterol- delivers excess _______ to liver for elimination in bile.
HDL; cholesterol
Functions of 'heat-gain center'
Heat is conserved by decreasing blood flow to the skin, thereby reducing losses by radiation, convection, and conduction. The skin cools, & with blood flow restricted, it may take on a bluish or pale coloration. In addition, blood returning from the limbs is shunted into a network of deep veins that lies beneath an insulating layer of subcutaneous fat. (Under warm conditions, blood flows through a more superficial venous network, through which heat can be lost.) In addition to conserving heat, the heat-gain center stimulates two mechanisms that generate heat: In shivering thermogenesis, muscle tone is gradually increased until stretch receptors stimulate brief, oscillatory contractions of antagonistic skeletal muscles. The resulting shivering stimulates energy consumption by skeletal muscles, & the generated heat warms the deep vessels to which the blood has been diverted. Shivering can increase the rate of heat generation by as much as 400%. In non-shivering thermogenesis, hormones are released that increase the metabolic activity of cells in all tissues. Epinephrine from the adrenal gland immediately increases the breakdown of glycogen & glycolysis in the liver and in skeletal muscles and increases the metabolic rate in most tissues. The heat-gain center also stimulates the release of thyroxine by the thyroid gland, accelerating carbohydrate use & the breakdown of all other nutrients. These effects develop gradually over a period of days to weeks.
Which part of the brain is the "body's thermostat"? HYPOTHALAMUS When body is too hot, 'heat-loss center' is activated (parasympathetic); When body is too cold, 'heat-gain center' is activated (sympathetic).
Heat loss & heat gain requires the coordinated activity of many different systems. That activity is coordinated by the heat-loss center and heat-gain center of the hypothalamus. The HEAT-LOSS center adjusts activity through the PARASYMPATHETIC division of the autonomic nervous system, whereas the HEAT-GAIN center directs its responses through the SYMPATHETIC division.
What cells carry out gluconeogenesis and glycogenesis?
Hepatocyte cells
What types of cells can carry out lipogenesis, beta oxidation, and lipolysis?
Hepatocytes and adipose cells carry out lipogenesis, beta oxidation, and lipolysis.
What cells can carry out gluconeogenesis and glycogenesis?
Hepatocytes can carry out gluconeogenesis and glycogenesis.
What type of cell can carry out ketogenesis?
Hepatocytes carry out ketogenesis.
____ _______ _____(___) have less cholesterol and more protein. (package is empty and it can pick up the extra cholesterol)
High density lipoproein (HDL)
Which lipoprotein particles are 'good' and 'bad' cholesterol, why are these terms used?
High density lipoproteins known as good cholesterol prevent cholesterol accumulating in the blood by removing excess cholesterol and transporting to the liver for elimination Low density lipoproteins known as 'bad' cholesterol. When there is an accumulation of LDL in the blood, LDL deposits in and around the smooth muscle resulting in a build up of fatty plaques.
Diet's effect on Lipogenesis
High fat diet decreases FA synthesis High starch/ glucose diets increase FA synthesis
HYPOTHERMIA = below 97 degrees F (36 C) HYPERTHERMIA = above 104 degrees F (40 C)
Homeostatic mechanisms to regulate heat are called: THERMOREGULATION
Leptin:
Hormone secreted by fat cells in response to increased body fat mass (long term regulator of food intake.) stimulates the expresion of appetite supressants.
What general class of reactions break polymers into monomers? Catabolism or Anabolism?
Hydrolysis reactions break polymers into monomers. These are catabolic reactions.
Thyrotropin-releasing hormone is secreted by the
Hypothalamus
Compare & contrast the "lock and key" and the "induced fit" models of enzyme reaction
In a lock & key reaction the substrate fits into the active site of an enzyme (fixed shape) like a key fits into a lock. In the induced fit model the enzyme will twist & contort to fit around the substrate until it is catalized and then its released
Glycolysis ATP production and oxygen
In glycolysis, glucose is oxidized to two pyruvate molecules with NAD+ as the oxidizing agent. Glycolysis is exergonic and produces 2 ATP (net).If oxygen is present, additional ATP can be generated when NADH delivers its electrons to the electron transport chain. Glycolysis generates 2 ATP whether oxygen is present (aerobic) or not (anaerobic).
In a pancreatic cell that produces digestive enzymes, does anabolism or catabolism predominate?
In pancreatic acinar cells, anabolism predominates because the primary activity is synthesis of complex molecules (digestive enzymes).
In what part of the cell does glycolysis occur?
In the cytoplasm
____ ______ are ones that lack at least one essential amino acid (eg. legumes, nuts, grains) and need to be combined with another to allow all amino acids to be used in the body.
Incomplete proteins
The most dramatic metabolic change that occurs with fasting is
Increase in Lipolysis
Which of the following is a characteristic of alcohol use?
Ingestion of alcohol cools the body
GLYCOLYSIS OCCURS WHERE?
Initially in the cytosol, then the mitochondria... Although most ATP production occurs inside mitochondria, the first steps take place in the cytosol as a sequence of reactions called glycolysis.
Calorie vs calorie (NOTE LOWER CASE vs UPPER CASE "C")
Inside cells, some of energy may be captured as ATP, but much of it is lost to the environment as heat. The unit of energy measurement is the calorie (cal),the amount of energy required to raise the temperature of 1 g of water 1° celsius. One gram of water is not a very practical measure when you are interested in the metabolic operations that keep a 70-kg human alive, however, so the kilocalorie (kcal), or Calorie (Cal), is used instead. One Calorie is the amount of energy needed to raise the temperature of 1 kilogram of water 1° centigrade.
What hormone stimulates glycogenesis?
Insulin
What happens to carbon dioxide given off during cellular respiration?
It diffuses into the blood, is transported by the blood to the lungs, and is exhaled.
Which of the following is a feature of ethanol metabolism? a.It increases gastric acid output b.It decreases activity of the MEOS c.It decreases secretion of gastric histamine d.It increases secretion of antidiuretic hormone
It increases gastric acid output
What is the Citric Acid Cycle?
It is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidization of acetate derived from carbohydrates, fats and proteins into carbon dioxide.
Which of the following is not an aspect of glycolysis?
It is irreversible
Which of the following is characteristic of alcohol absorption? a. It is slowed when the stomach is full of food b. It is increased when high-fat snacks are eaten c. It is increased when carbohydrate snacks are eaten d. It is lower in women than in men of the same body weight
It is slowed when the stomach is full of food
Which of the following is a characteristic of ketosis? a. It may lead to a lowering of blood pH b. It leads to increased appetite in most individuals c. It may be alleviated quickly by ingestion of some dietary fat d. It is a necessary physiological adjustment for maximum weight loss
It may lead to a lowering of blood pH
Which of the following functions is (are) first to be affected when a person begins to drink alcohol? a. Speech and vision b. Judgment and reasoning c. Voluntary muscle control d. Respiration and heart function
Judgment and reasoning
What are ketone bodies? What is ketosis?
Ketone bodies = products of incomplete FA oxidation Ketosis is when blood becomes acidic
Which of the following is used to supply some of the fuel needed by the brain only after the body has been fasting for a while? a. Ketones b. Glycerol c. Fatty acids d. Amino acids
Ketones
What could protein in urine signal? Good or bad?
Kidney disease; BAD!
Why is the enzyme that catalyzes step three of glycolysis called a kinase?
Kinases are enzymes that phosphorylate (add phosphate to) their substrate.
Why is the enzyme in step 3 called a kinase?
Kinases are used when one phosphate group needs to be transferred to another. In this instance, Fructose-6-phosphate --------> fructose-1.6-biphosphate, therefore gaining a phosphate group
This reaction oxidizes acetyl CoA to produce carbon dioxide, ATP, NADH+H+ and FADH2.
Krebs Cycle
___: Major transport for cholesterol to body's cells, absorbed by cells in need of cholesterol for membrane repairs or steroid synthesis.
LDLs
Which type of lipoprotein delivers cholesterol to body cells?
LDLs carry ~75% of total cholesterol in blood and deliver it to cells throughout the body for use in repair of cell membranes and synthesis of steroid hormones and bile salts
Which type of lipoprotein delivers cholesterol to body cells.
LDLs deliver cholesterol to body cells.
Cardiac muscles can produce ATP from
Lactic Acid
polysaccharide
Larger carbohydrate molecules are called polysaccharides. They result when repeated dehydration synthesis reactions add additional monosaccharides or disaccharides. Starches are glucose-based polysaccharides important in our diets. Most starches are manufactured by plants. Your digestive tract can break these molecules into simple sugars. Starches found in potatoes & grains are important energy sources. In contrast, cellulose, a component of the cell walls of plants, is a polysaccharide that our bodies cannot digest. The cellulose of foods such as celery contributes to the bulk of digestive wastes but is useless as an energy source.
When is the absorptive statE?
Lasts about 4 hours during and after each meal.
Which of the following cannot be formed from pyruvate in human beings? a. Glucose b. Fructose c. Lactic acid d. Linoleic acid
Linoleic acid
Define lipogenesis and explain it's importance.
Lipid anabolism Liver and adipose cells can synthesis lipids from glucose and amino acids Stimulated by insulin, when excess energy Glucose ----> Gly3P ------> glycerol Glucose -----> Gly3P ---------> acetyl-coA -----> FA Lipogenesis occurs when individuals consume more calories than they need to satisfy ATP needs.
This process is the synthesis of triglycerides.
Lipogenesis
What type of cells can carry out lipogenesis, beta-oxidation and lipolysis? What type can carry out ketogenesis?
Lipogenesis: liver cells and adipose cells can synthesise lipids from glucose or amino acids through lipogenesis - stimulated by insulin Occurs when individuals consume more calories than they need Excess dietary CHO, protein and fats have the same fate, converted to TAGs Beta-oxidation: occurs in matrix of mitochondria FA oxidation Enzymes remove 2C atoms at a time and attach to 2C fragment to coenzyme A, forming acetyl-CoA Acetyl-CoA then enters Krebs cycle Lipolysis: oxidation of FA derived from TAGs to produce ATP Split into glycerol and 3 fatty acids Catalyzed by lipases Insulin inhibits lipolysis Glycerol ----> glyceraldehyde-3-phosphate -------> glucose or pyruvic acid Ketogenesis: ketone bodies - products of incomplete FA oxidation Inadequate insulin production to balance glucagon action Ketone bodies = acetoacetic acid, beta-hyroxybutic acid and acetone Formation of ketone bodies occurs when production of acetyl-coA > oxaloacetate Intake high in lipids, low in CHO
The process of breaking triglycerides down into glycerol and fatty acids is known as ________.
Lipolysis
Fasted state
Lipolytic activity increases -insulin levels decrease; epinephrine increases --Hormone sensitive lipase is activated
chylomicrons
Lipoproteins are classified by size and by their relative proportions of lipid and protein. One group, the chylomicrons, forms in the intestinal tract. Chylomicrons are the largest lipoproteins, and some 95% of their weight consists of triglycerides. Chylomicrons transport triglycerides absorbed from the intestinal tract to the bloodstream, from which they are absorbed by skeletal muscle, cardiac muscle, adipose tissue, and the liver. Two other major groups of lipoproteins are the low-density lipoproteins (LDLs) and high-density lipoproteins (HDLs). These lipoproteins are formed in the liver and contain few triglycerides. Their main roles are to shuttle cholesterol between the liver and other tissues. LDLs deliver cholesterol to peripheral tissues. Because LDL cholesterol may end up in arterial plaques, it is often called "bad cholesterol." HDL cholesterol transports excess cholesterol from peripheral tissues to the liver for storage or excretion in the bile. Because HDL cholesterol does not cause circulatory problems, it is called "good cholesterol."
Where can you get unsaturated fats from?
Liquid fats: vegetable oil, fish oil, nuts and seeds
What is the primary organ that oxidizes alcohol?
Liver
Which of the following plays a major role in regulating the elimination of alcohol from the body? a. Lung respiratory rate b. Kidney antidiuretic hormone c. Liver alcohol dehydrogenase d. Brain acetaldehyde dehydrogenase
Liver alcohol dehydrogenase
Lipogenesis: Major producers of fatty acids
Liver, Adipose tissue, Mammary glands
oxidation
Loss of electrons
What type of diet is associated with the development of ketosis
Low carbohydrate
_____ ____ _____ (___) have more cholesterol than protein (package is full).
Low density lipoprotein (LDL)
Where is Vitamin B12 obtained?
MEAT (or cereals or tofu)
Know Metabolism's Functions:
Maintenance & Repairs Growth Secretion Stored Reserves
What is the outcome of ketosis?
Metabolic Acidosis
Which of the following describes the sum of all chemical reactions that go on in living cells?
Metabolism
set of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes
Metabolism
Minerals: Organic or Inorganic?
Minerals are inorganic substances found in the earth, like salt, zinc, & iron. Because they are elements, they must be obtained from the diet.
Where can pyruvate dehydrogenase be found?
Mitochondria
Where does the Krebs cycle take place?
Mitochondria
TCA Cycle & Electron Transport System
Mitochondria absorb small carbon chains produced by the breakdown of fatty acids, glucose, & amino acids from the nutrient pool. The small carbon chains are broken down further by means of the tricarboxylic acid (TCA) cycle & the electron transport system.
How is atp from pyruvate maximized?
More ATP is generated from the oxidation of pyruvate in the citric acid cycle.Without oxygen, the energy still stored in pyruvate is unavailable to the cell. Under aerobic respiration, a molecule of glucose yields 38 ATP, but the same molecule of glucose yields only 2 ATP under anaerobic respiration.
Lipogenesis occurs when
More calories are consumed than required for ATP need
Carbohydrate Metabolism
Most cells generate ATP & other high-energy compounds by breaking down carbohydrates, especially glucose. The complete reaction sequence can be summarized as: C6H12O6 + 6O2 > 6CO2 + 6H2O (glucose + oxygen) > carbon dioxide + water The ratio of carbon, hydrogen, & glucose within a carbohydrate is 1:2:1.
ETS and ATP yield
Most cells generate the ATP they need from glucose catabolism. Of the 36 ATPs that each glucose yields, all but 2 are produced in mitochondria, 32 by the electron transport system.
Why are vitamins essential metabolic factors for metabolism?
Most vitamins function as coenzymes in important metabolic reactions and are therefore essential factors
Know the 'to build up reserves of nutrients' basic function of anabolism...
Muscle cells store glucose in the form of glycogen; Adipocytes store triglycerides; Liver cells store both.
The primary reason elderly people should decrease their caloric intake is that ________.
Muscle mass and metabolism decline with age
Describe complete protein.
Must meet all the body's amino acid requirements for maintenance and growth
Which reactions produce ATP during the complete oxidation of a molecule of glucose?
NAD+ --------> NADH, H+ FAD+ --------> FADH2 GTP----------> ATP
In this cycle, it reduces what?
NAD+ and NADH
What are two sources of electrons that can enter the electron transport chain?
NADH and FADH2
Majority of energy extracted from food
NADH and FADH2 account for the vast majority of the energy extracted from the food.These reduced coenzymes link glycolysis and the citric acid cycle to oxidative phosphorylation, which uses energy released by the electron transport chain to power ATP synthesis.
What are the principal products of the Kreb cycle?
NADH and FADH2 because they carry most of the energy originally stored in glucose
Is NADH a coenzyme or cofactor? What role does it play in metabolism?
NADH is a coenzyme. It acts as an electron carrier.
Where can you get water-soluble fiber?
Oats, lentils, apples, pears, cucumbers, celery, nuts, and strawberries.
According to the standard height-weight chart, 4'8" Maria should weigh 100 pounds. She currently weighs 125 pounds. Clinically, Maria is described as ___.
Obese
Monogastric FA biosynthesis
Occurs when: energy needs are met, Glycogen stores are full excess nutrients present
Sources of Amino Acids
Of the 20 amino acids needed to create proteins, 10 must be obtained from the diet because human metabolism can't supply them. They are termed the essential amino acids because even if only one is lacking, protein synthesis ceases. Dietary shortages of amino acids cause grave illness and death. Each year, more than 5 million children under the age of 5 die worldwide from protein-energy malnourishment.
_____-_ ____ _____ are thought to ward off heart disease. These are found in some cold-water fish (salmon, sardines) and plants (flaxseed, chia, seeds, algae)
Omega-3 fatty acids
TCA Cycle
Once inside the mitochondrion, each pyruvic acid molecule participates in a reaction leading to a sequence of enzymatic reactions called the tricarboxylic acid (TCA) cycle The function of the TCA cycle is to remove hydrogen atoms from organic molecules & transfer them to coenzymes in the electron transport system.
IMPORTANT POINT TO EMPHASIZE: (don't confuse 'c' calorie, with "C" Calorie)
One Calorie is the amount of energy needed to raise the temperature of 1 kilogram of water 1° centigrade. (1000 calories = 1 Calorie)
How much is substrate level phosphorylation used in respiration?
Only 4 of 38 ATP ultimately produced by respiration of glucose are produced by substrate-level phosphorylation.Two are produced during glycolysis, and 2 are produced during the citric acid cycle.
What happens to an enzyme below its optimal temperature? Above its optimal temperature?
Optimal temp for enzyme reactions is 35C - 40C. Below this temp molecules move slowly & don't have enough energy to cause chemical reactions. Above this temp the protein is denatured and the reaction rate falls
chemotrophs
Organisms that get energy from chemicals taken from the environment
What is the final product at the end of the Krebs Cycle?
Oxaloacetic acid
Explain how oxidation of a substrate can proceed without oxygen.
Oxidation does not mean reacting with oxygen. Oxidation means that a substance loses at least one electron in the process of the reaction. This also means that at least one substance gains at least one electron and is reduced.
Which of the following leads to the production of urea? a. Oxidation of glucose b. Oxidation of amino acids c. Incomplete oxidation of fatty acids d. Synthesis of protein from amino acids
Oxidation of amino acids
summarize how oxidation enables organisms to get energy from glucose.
Oxidation removes electrons from atoms or molecules & gives them to coenzymes, thereby reducing them.The coenzymes now contain energy that can be generated in later reactions.
2 sources required by cells to make energy:
Oxygen & Nutrients
Why do humans breathe in O2 and exhale carbon dioxide?
Oxygen is used by the body for cellular respiration and other uses, and carbon dioxide is a product of these processes.
________ ______ (islets of Langerhans) contain endocrine cells.
Pancreatic islets.
Small intestine: _______ _____ digests fats into glycerol and fatty acids.
Pancreatic lipase
Protein Metabolism
Peptide bonds are broken, and the free amino acids are used to manufacture new proteins. If other energy sources are inadequate, mitochondria can break down amino acids in the TCA cycle to generate ATP.
This is the key regulator of the rate of glycolysis.
Phosphofructokinase
What processes directly elevate blood glucose during the postabsorptive state, and where does each occur?
Processes that directly elevate blood glucose during the postabsorptive state include lipolysis (in adipocytes and hepatocytes), gluconeogenesis (in hepatocytes), and glycogenolysis (in hepatocytes).
Ketone Bodies
Produced in Liver and used for energy by some tissues: Acetone Oxaloacetate Beta-hydroxybutyrate
In the case of a person who consumes a normal, balanced diet, proteins are essential to the body for which processes?
Production of enzymes, clotting factors, and antibodies, formation of functional molecules like hemoglobin and cytochrome, and production of some hormones.
How do prokaryotes use the H+ gradient
Prokaryotes generate H+ gradients across their plasma membrane.They can use this proton-motive force not only to generate ATP, but also to pump nutrients and waste products across the membrane and to rotate their flagella.
Odd chain FA lipolysis
Propionyl CoA is converted to Succinyl CoA, a TCA cycle intermediate.
During the first few days of a fast, what energy source provides about 90% of the glucose needed to fuel the body?
Protein
Define negative nitrogen balance.
Protein breakdown exceeds protein synthesis.
Proteins
Proteins are the most abundant organic components of the human body. All proteins contain carbon, hydrogen, oxygen, & nitrogen; smaller quantities of sulfur may also be present. Proteins are long chains of organic molecules called amino acids. The human body contains significant quantities of the 20 different amino acids that are the building blocks of proteins. A typical protein contains 1000 amino acids, but the largest protein complexes may have 100,000 or more. The individual amino acids are strung together like beads on a string, with the carboxylic acid group of one amino acid attached to the amino group of another. This connection is called a peptide bond. Peptides are molecules made up of amino acids held together by peptide bonds. If a molecule consists of two amino acids, it is called a dipeptide. Polypeptides are long chains of amino acids. Polypeptides containing more than 100 amino acids are usually called proteins.
What are the functions of apoproteins in lipoproteins?
Proteins that bind lipids to form lipoproteins and transport lipids through lymphatic and circulatory systems
How does the flow of H+ through ATP synthase power ATP generation?
Protons flow down a narrow space between the stator and rotor, causing the rotor and its attached rod to rotate. The spinning rod causes conformational changes in the stationary knob, activating three catalytic sites in the knob where ADP and inorganic phosphate combine to make ATP.
Krebs Cycle starts with what, which was what Cellular Respiration ended with?
Pyruvate
The ending product from glycolysis can be directed to the Krebs cycle. What does the cell gain?
Pyruvic acid from Glycolysis contain lots of potential energy. Once converted to acetyl CoA energy can be extracted through further oxidation/reduction. The most ATP is generated in ETC when the reduced coenzymes enter. ATP is generated thru several oxidation/reduction reactions.
Basal metabolic rate:
Rate of energy consumption at rest
Are the reactions that occur during the absorptive state mainly anabolic or catabolic?
Reactions of the absorptive state are mainly anabolic.
Complex carbohydrates
Recommended as good source of vitamins and minerals
The most abundant product of the reactions of the Krebs cycle is
Reduced Coenzymes
What are simple sugars found in?
Refined grains, white bread, cake, and cookies
Saturated FA Triglyceride catabolism
Repeated removal of 2 C atoms from the C chain; each 2C group is converted to acetyl CoA which enters TCA cycle
Water-insoluble fiber:
Repels water in intestine so it softens stools.
Unsaturated FA lipolysis
Same process as saturated, but the FA is hydrogenated first.
Is the Krebs Cycle the first, second, or third cycle of AEROBIC respiration?
Second
Which stage of cellular respiration is the Krebs Cycle?
Second
When a person's hypothalamic thermostat is set to a higher level and the actual body temperature is below that level, the person may ________.
Shiver
Simple sugars
Should be minimized in diet because fiber and vitamins are removed
Besides hepatocytes, which body cells can synthesize glycogen? Why can't they release glucose into the blood?
Skeletal muscle fibers can synthesize glycogen, but they cannot release glucose into the blood because they lack the enzyme phosphatase required to remove the phosphate group from glucose.
Besides hepatocytes, which body cells synthesise glycogen?
Skeletal muscle fibres can synthesise glycogen, but cannot release glucose into the blood because they lack the enzyme phosphatase required to remove the phosphate group from glucose.
What are the possible fates of amino acid from protein metabolism?
Some Amino acids are converted into other amino acids, peptide bonds are formed, and new proteins synthesised. Hepatocytes convert some amino acids to fatty acids, ketone bodies or glucose The breakdown of carbon skeletons follows 2 pathways: Glucogenic amino acids: C skeleton degraded to pyruvate or oxaloacetate - both of which can be converted to glucose Ketogenic amino acids: C skeleton degraded to acetyl-CoA or acetocetyl-CoA - both may be converted to ketone bodies.
Cholesterol lowering drugs:
Statins: block the first enzyme in a pathway that produces cholesterol in the liver.
Describe the chemical reactions of Glycolyis
Step 1: Glucose enter cell & is phosphorylated which requires a molecule of ATP creating G6P. Step 2: G6P is rearranged to form Fructose 6P Step 3: Another ATP molecule is used to form Fructose 1, 6-diphosphate Step 4: An enzyme splits the sugar into two 3 Carbon molecules (DHAP & GP) Step 5: DHAP readily converted to GP (reverse can occur too) Step 6: The next enzyme oxidizes each GP (2 molecules since DHAP can be converted to GP) by the transfer of 2 hydrogen atoms to NAD+ to form NADH (so 2 NAD+ and 2 NADH) it also converts each GP to two 3-carbon compounds. These two actions together create a high energy bond between the sugar and a phosphate of each new compound (P=CCC-P) Step 7: The high energy P on each is moved to 2 ADP (1 each) forming 2 ATP Step 8: An enzyme relocates the remaining P in each molecule Step 9: A water molecule is removed from each (2 H20) forming 2 PEP molecules each containing another high energy P bond Step 10: The high energy P on each is moved to 2 ADP (1 each) forming 2 ATP
The heat promoting center stimulates parts of the brain that
Stimulates skeletal muscle activity
What organ is first to absorb alcohol after a person takes a drink?
Stomach
Sugars do serve as _____________.
Structural Components
List & provide 3 examples of phosphorylation reactions that generate ATP
Substrate -level phosphorylation: ATP is generated when a high energy P is transferrred from a phosphorylated compound to ADP (Ex: PEP to Pyruvic Acid) Oxidative phosphorylation: Electrons are passed from organic compounds to electron carriers (NAD+) and brought to ETC to generate ATP Photophosphorylation: the phosphorylation of ADP to form ATP using the energy of sunlight
What are the forms of phosphorylation?
Substrate level phosphorylation, oxidative phosphorylation, and photophosphorylation.
Carbohydrates
Sugars & Starches that make up approximately half of the U.S. diet. Monosaccharides, disaccharides, & polysaccharides.
How does excess carbohydrate intake contribute to obesity?
Synthesis and storage of glycogen
Which of the following is a possible fate of acetyl CoA? a. Degradation to urea b. Synthesis to glycerol c. Synthesis to fatty acids d. Degradation to ammonia
Synthesis to fatty acids
Explain the principle events of the catabolism of glycerol and fatty acids.
TAG split into glycerol + 3 fatty acids Glycerol -------> glyceraldehyde-3-phosphate If ATP supply in cells is high, glyceraldehyde-3-phosphate ----> glucose If ATP supply is low, Gly3P enters catabolic pathway to pyruvic acid First stage of FA catabolism = beta-oxidation 2C atoms are cleaved 2 at a time - attach to coenzyme A to make acetyl-CoA Acetyl-CoA enters the Krebs cycle
Reduction is the
The Addition of Electrons
Oxidation is
The Removal of Electrons
activation energy
The amount of energy needed for a reaction to occur.
How does the mitochondrion couple electron transport and energy release to ATP synthesis?
The answer is a mechanism called chemiosmosis.
In a gram negative cell,how is the H+ concentration built up the fuels the ATP synthase? A. what if it is a gram positive cell? B. what if it is a human cell?
The build up of H+ ions on the outside of the ETC creates a higher concentration. Ions move from hi concentration gradient to lo through an enzyme known as the ATP synthase which produces ATP. In gram+ ETC located in cytoplasm. In human it's located in the mitochondria.
What is the energy source that powers the proton pump?
The concentration gradient between the inner and outer mitochondrial membrane. Electrons are provided by NADH + H+
Where is the concentration of hydrogen ions highest?
The concentration of hydrogen ions is highest in the space between the inner and outer mitochondrial membranes.
Proton motive force
The electron carriers are spatially arranged in the membrane in such a way that protons are accepted from the mitochondrial matrix and deposited in the intermembrane space. The H+ gradient that results is the proton-motive force.The gradient has the capacity to do work.
Importance of the ETS
The electron transport system is the most important mechanism for the generation of ATP; in fact, it provides roughly 95% of the ATP needed to keep our cells alive. Halting or significantly slowing the rate of mitochondrial activity will usually kill a cell. If many cells are affected, the individual may die. If, for example, the cell's supply of oxygen is cut off, mitochondrial ATP production will cease because the ETS will be unable to pass along its electrons.
The Electron Transport System & ATP Formation
The electrons of hydrogen atoms from the TCA cycle are transferred by coenzyme Q to the ETS (a series of cytochrome molecules), & the hydrogen ions (H+) remain in the matrix. The energy carrying electrons are passed from one cytochrome to another. Energy released by the passed electrons is used to pump H+ from the matrix into the intermembrane space. This creates a difference in the concentration of H+ across the inner membrane. The hydrogen ions then diffuse through ATP synthase in the inner membrane, & their kinetic energy is used to generate ATP. The electron transport system (ETS) is embedded in the inner mitochondrial membrane. The ETS consists of an electron transport chain made up of a series of protein-pigment complexes called cytochromes. The ETS does not produce ATP directly. Instead, it creates the conditions necessary for ATP production. The hydrogen atoms from the TCA cycle do not enter the ETS intact. Only the electrons (which carry the energy) enter the ETS; the protons that accompany them are released into the mitochondrial matrix. The electrons from both paths are passed from coenzyme Q to the first cytochrome & then from cytochrome to cytochrome, losing energy in a series of small steps. At several steps along the way, this energy is used to drive hydrogen ion pumps that move hydrogen ions from the mitochondrial matrix into the intermembrane space between the two mitochondrial membranes. This creates a large concentration gradient of hydrogen ions across the inner membrane, so the hydrogen ions then diffuse back into the matrix through a membrane enzyme called ATP synthase. The kinetic energy of the passing hydrogen ions is used to attach a phosphate group to ADP, forming ATP. This process is called chemiosmosis, a term that links the chemical formation of ATP with transport across a membrane. At the end of the electron transport system, an oxygen atom accepts the electrons & combines with two hydrogen ions to form a molecule of water.
What is the energy source that powers the proton pumps?
The energy source that powers the proton pumps is electrons provided by NADH and hydrogen ions.
what proves glycolysis has been going on for a while?
The fact that glycolysis is a ubiquitous metabolic pathway and occurs in the cytosol without membrane-enclosed organelles suggests that glycolysis evolved early in the history of life.
What is the final elecron acceptors in aerobic, anaerobic, & fermentative metabolism?
The final electron acceptor in aerobic metabolism is oxygen. In anerobic it is an inorganic molecule other than oxygen. In fermentative metabolism it is an organic molecule.
Describe the roles played in ATP and NAD+ and NADP+ in metabolism
The function of ATP is to transport chemical energy within cells. The function of NAD+:an oxidizing agent; reduced to NADH which is an electron carrier NADP+ is also an oxidizing agent; reduced to NADPH
In eukaryotic cells, the citric acid cycle occurs where?
The matrix of the mitochondrion
What is meant by the concept of the "final electron acceptor?
The molecule that accepts an electron at the final stage of cellular respiration
active site
The part of an enzyme or antibody where the chemical reaction occurs.
Why is the production of reduced coenzymes important in the Krebs cycle?
The production of reduced coenzymes is important in the Krebs cycle because they will subsequently yield ATP in the electron transport chain.
How does the proton gradient play a part in ATP synthesis
The proton gradient develops between the intermembrane space and the matrix. It is produced by the movement of electrons along the ETC. The chain uses the exergonic flow of electrons to pump H+ from matrix to innermembrane space. Protons pass back to matrix through The protons pass back to the matrix through a channel in ATP synthase, using the exergonic flow of H+ to drive the phosphorylation of ADP. Thus, the energy stored in a H+ gradient across a membrane couples the redox reactions of the electron transport chain to ATP synthesis.
Which of the following is a characteristic of the metabolism of specific macronutrients? a. The rate of fat oxidation does not change when fat is eaten in excess b. The rate of protein oxidation does not change when protein is eaten in excess c. The rate of glucose oxidation does not change when carbohydrate is eaten in excess d. The conversion of dietary glucose to fat represents the major pathway of carbohydrate utilization
The rate of fat oxidation does not change when fat is eaten in excess
Net gain of ATP during Glycolysis:
The reaction sequence of glycolysis yields a net gain of two ATP molecules for each glucose molecule converted to two pyruvic acid molecules. A few highly specialized cells, such as red blood cells, lack mitochondria & derive all of their ATP by glycolysis. Skeletal muscle fibers rely on glycolysis for energy production during periods of active contraction, and most cells can survive brief periods of hypoxia (low oxygen levels) by using the ATP provided by glycolysis alone. When oxygen is readily available, however, mitochondrial activity provides most of the ATP required by body cells.
For each glucose molecule that undergoes glycolysis, how many ATP molecules are generated?
The reactions of glycolysis consume two molecules of ATP but generate four molecules of ATP, for a net gain of two.
RECOMMENDED DAILY INTAKE OF CALORIES proteins should provide 11-12% of daily caloric intake; carbohydrates 55-60% and fats; less than 30%.
The recommended PROPORTIONS of calories provided by different foods do not change with advancing age; current guidelines indicate that for individuals of all ages, proteins should provide 11-12% of daily caloric intake; carbohydrates 55-60% and fats; less than 30%. Total caloric REQUIREMENTS, however, do change with aging. For each decade after age 50, caloric requirements decrease by 10%.
Where is the concentration of H+ the largest?
The space between the inner and outer mitochondrial matrix
What is the starting reactant & the ending product in glycolysis? What is the net gain of ATP? Why does a cell go thru glycolysis?
The starting reactant is a 6 Carbon Glucose. The ending product is 2 pyruvate molecules. The net gain of ATP is 2. Cells go through Glycolysis to derive energy from the glucose that the cell can use
Vitamin D
The term vitamin D refers to a group of steroid-like molecules, including vitamin D3, or cholecalciferol. Unlike the other fat-soluble vitamins, which must be obtained by absorption across the digestive tract, vitamin D3 can usually be synthesized in adequate amounts by skin exposed to sunlight.
Carbohydrates are most important as sources of energy. Name the 3 major types of carbohydrates:
The three major types of carbohydrates are: monosaccharides, disaccharides, & polysaccharides.
What does the wider base of each band in MyPyramid mean?
The wider base of each band represents foods with little or no solid fats or added sugars.
Relative Humidity
Thee efficiency of heat loss by evaporation varies with environmental conditions, especially the "relative humidity" of the air. At 100% humidity, the air is saturated; it is holding as much water vapor as it can at that temperature. Under these conditions, evaporation is ineffective as a cooling mechanism. This is why humid, tropical conditions can be so uncomfortable—people perspire continuously but remain warm and wet, with little or no cooling evaporation taking place.
Which of the following is the most likely explanation for the body's higher metabolic efficiency of converting a molecule of corn oil into stored fat compared with a molecule of sucrose? a. The enzymes specific for metabolizing absorbed fat have been found to have higher activities than those metabolizing sucrose b. The absorbed corn oil is transported to fat cells at a faster rate than the absorbed sucrose, thereby favoring the uptake of corn oil fat c. There are fewer metabolic reactions for disassembling the corn oil and re-assembling the parts into a triglyceride for uptake by the fat cells d. Because the energy content of corn oil is higher than sucrose, conversion of these nutrients into stored fat requires a smaller percentage of the energy from the corn oil
There are fewer metabolic reactions for disassembling the corn oil and re-assembling the parts into a triglyceride for uptake by the fat cells
Why is count of atp production inexact?
There are three reasons that we cannot state an exact number of ATP molecules generated by one molecule of glucose. 1. Phosphorylation and the redox reactions are not directly coupled to each other, so the ratio of number of NADH to number of ATP is not a whole number. One NADH results in 10 H+ being transported across the inner mitochondrial membrane. Between 3 and 4 H+ must reenter the mitochondrial matrix via ATP synthase to generate 1 ATP.Therefore, 1 NADH generates enough proton-motive force for synthesis of 2.5 to 3.3 ATP. We round off and say that 1 NADH generates 3 ATP. 2. The ATP yield varies slightly depending on the type of shuttle used to transport electrons from the cytosol into the mitochondrion. The mitochondrial inner membrane is impermeable to NADH, so the two electrons of the NADH produced in glycolysis must be conveyed into the mitochondrion by one of several electron shuttle systems. In some shuttle systems, the electrons are passed to NAD+, which generates 3 ATP. In others, the electrons are passed to FAD, which generates only 2 ATP. 3. The proton-motive force generated by the redox reactions of respiration may drive other kinds of work, such as mitochondrial uptake of pyruvate from the cytosol. If all the proton-motive force generated by the electron transport chain were used to drive ATP synthesis, one glucose molecule could generate a maximum of 34 ATP by oxidative phosphorylation plus 4 ATP (net) from substrate-level phosphorylation to give a total yield of 36-38 ATP (depending on the efficiency of the shuttle).
What do all three (aerobic, anaerobic and fermentative metabolism) have in common?
They all release energy from glucose and other food molecules, making them similar in their processes.
Metabolic Rate
Total energy of all catabolic & anabolic processesin the body per unit time
Protein Metabolism
Transamination attaches the amino group of an amino acid to another carbon chain, creating a "new" amino acid. Transaminations enable a cell to synthesize many of the amino acids needed for protein synthesis. deamination is the removal of an amino group in a reaction that generates an ammonia molecule (NH3).
TCA stands for what?
Tricarboxylic Acid Cycle
True or False: Antioxidant vitamins can inactivate oxygen free radicals.
True
True or False: Carbohydrate and fat pools are oxidized directly to produce cellular energy, but amino acid pools must first be converted to a carbohydrate intermediate before being sent through cellular respiration pathways.
True
True or False: Ghrelin, produced by the stomach, is a powerful appetite stimulant.
True
True or False: Glucose-6-phosphate can be converted to pyruvic acid
True
True or False: Glucose-6-phosphate can be dephosphorylated to glucose
True
True or False: Glucose-6-phosphate can be used to make ribose-5-phosphate
True
True or False: Glucose-6-phosphate can be used to synthesize glycogen
True
True or False: In the absorptive state storage of energy is important.
True
True or False: Proteins will be used by most cells for ATP synthesis if insufficient carbohydrates are ingested.
True
True or False: Release of epinephrine is a normal consequence of the activation of the heat-promoting center.
True
True or False: The amount of protein needed by each person is determined by the age, size, and metabolic rate of the person.
True
True or False: The higher the relative humidity the lower the rate of evaporation.
True
True or False: The increased use of noncarbohydrate molecules for energy to conserve glucose is called glucose sparing.
True
True or False: The most abundant dietary lipids in the diets of most Americans are triglycerides.
True
True or False: Thyroid hormones promote glycolysis.
True
True or False: Vitamin E is a fat-soluble vitamin.
True
disaccharide
Two monosaccharides joined together form a disaccharide. Disaccharides such as sucrose (table sugar) have a sweet taste &, like monosaccharides, are soluble in water. Many foods contain disaccharides, but all carbohydrates except monosaccharides must be disassembled through hydrolysis before they can provide useful energy. Most sweet junk foods, such as candy & soft drinks, abound in simple sugars (commonly fructose) & disaccharides (generally sucrose).
What happens after glycolysis without oxygen?
Under aerobic conditions, NADH transfers its electrons to the electron transfer chain, recycling NAD+. Under anaerobic conditions, various fermentation pathways generate ATP by glycolysis and recycle NAD+ by transferring electrons from NADH to pyruvate or derivatives of pyruvate.
Which of the following defines a moderate level of alcohol intake per day for the average-sized woman? a.Up to 1 drink b.Up to 2 drinks c.Up to 3 drinks d.Up to 5 drinks
Up to 1 drink
Which of the following is not a possible fate of metabolized glucose? a. Urea b. Acetyl CoA c. Amino acids d. Muscle glycogen
Urea
Which of the following is an example of a catabolic reaction? a. Glucose formation from glycerol b. Urea formation from an amino acid c. Albumin formation from amino acids d. Palmitic acid formation from acetate
Urea formation from an amino acid
____: main transport form for triglycerides from the liver to rest of body
VLDLs
Micronutrients
Vitamins, minerals, and phytochemicals
In addition to energy, what are the principal end products of cellular oxidation of carbohydrates?
Water and carbon dioxide
What are the products from the complete oxidation of fatty acids?
Water, carbon dioxide, and energy
Where does citric acid come from?
When Acetyl-CoA enters the Krebs cycle it combines with a four-carbon acid called oxaloacetic acid. The combination forms the six-carbon acid called citric acid.
Where can you get water-insoluble fiber?
Whole grains, nuts, many vegetables
How soon would death occur from starvation if the body was unable to shift to a state of ketosis?
Within 3 weeks
KNOW THE AEROBIC VS ANAEROBIC YIELD OF ATP:
Within a cell's cytoplasm, glycolysis breaks down a six-carbon glucose molecule into two three-carbon pyruvic acid molecules. This process involves a series of enzymatic steps. A net gain of two ATPs results for each glucose molecule converted to pyruvic acid. Points to Emphasize: Glycolysis yields a mere two ATP molecules/glucose molecule, all that can be gained without oxygen. Aerobic metabolism liberates 17 times more ATP than anaerobic! These chemical facts dramatize the crucial importance of oxygen to human life.
Why is oxygen necessary for the ETC?
Without electronegative oxygen to pull electrons down the transport chain, oxidative phosphorylation ceases.
Which of the following is one explanation for the generally lower tolerance for alcohol in women in comparison to men? a. Women fast more often b. Women do not eat as much food with the alcohol c. Women consume more of their alcohol in sweetened drinks d. Women have lower amounts of stomach alcohol dehydrogenase
Women have lower amounts of stomach alcohol dehydrogenase
Are amino acids in urine normal?
Yes
Describe the chemical reactions of fermentation & list 3 possible products
a 6 Carbon Glucose is phosphorylated, restructured and then split (requiring the use of 2 ATP) into two 3 Carbon compounds, DHAP and GP. 2 molecules of GP enter into the remaining chemical reactions. 2 molecules of GP are oxidized in several steps to form 2 molecules of Pyruvic Acid. Net result is 2 ATP, 2 NADH and 2 Pyruvic acid. In fermentation pyruvic acid is oxidized again ito form different end products. EX: alcohol, gas, & acid
What happens during the preparatory stages of glycolysis?
a 6 Carbon Glucose is phosphorylated, restructured and then split (requiring the use of 2 ATP) into two 3 Carbon compounds, DHAP and GP. DHAP is readily converted to GP (or the reverse), therefore 2 molecules of GP enter into the remaining chemical reactions.
What is the matrix
a central fluid-filled space
All of the following are general features of starvation in people except a. a decrease in metabolic rate. b. a decrease in mental alertness. c. a decrease in immune function. d. a decrease in body temperature.
a decrease in mental alertness
What is ATP synthase?
a protein complex in the cristae actually makes ATP from ADP and inorganic phosphate
What is electron transport chain
a series of molecules built into the inner mitochondrial membrane
2 states of metabolism:
absorptive (fed state) and postabsorptive (fasting state)
Fatty acid oxidation results in the direct production of
acetyl CoA.
What is the role of acetyl-CoA in carbohydrate catabolism?
acetyl-CoA stores a large amount of petential energy which is released step by step in the Kreb cycle. Pyruvic acid cannot not enter the Kreb cycle directly so it's coverted to acetyl-CoA thru decarboxylation
Last step
after cyt a3 passes electrons, Each oxygen atom also picks up a pair of hydrogen ions from the aqueous solution to form water. For every two electron carriers (four electrons), one O2 molecule is reduced to two molecules of water.
Name 4 things enzymes have in common
all are proteins; all act as catalysts; they all have an active site; they all lower the activation energy
There are 8 ____ _____ ____ that must be attained through diet.
amino acids
What is a ketone body? (functinoally)
an alternative energy source
What is stripped from the H atoms
an electron
Chemiosmosis definition and how it is used in plants and animals
an energy-coupling mechanism that uses energy stored in the form of an H+ gradient across a membrane to drive cellular work. In mitochondria, the energy for proton gradient formation comes from exergonic redox reactions, and ATP synthesis is the work performed. Chemiosmosis in chloroplasts also generates ATP, but light drives the electron flow down an electron transport chain and H+ gradient formation.
The formation of glycogen by the liver cell is an example of
anabolism
Most enzymes end with
ase or ??
Lipolytic FFA
beta oxidation in mitochondria (ATP production using O as TEA); FAs are not gluconeogenic
Meabolism: _______ reactions inside cells involving nutrients
biochemical
Water-soluble fiber can reduce ____ ________ levels and ___ levels.
blood cholesterol and LDL
Low Glycemic Index foods do not spike _____ _______ _____.
blood glucose levels
Long term effects of low-carb diets:
body uses other molecules for energy (ketones) and can have detrimental health effects.
Glycogenolysis:
breakdown of glycogen into glucose
Catabolism:
breaking down large molecules into small ones that can be absorbed
Lipoprotein lipase
breaks down TGs in circulatory blood
What is chemiosmosis
build up of H+ gradient so H+ can flow through ATP synthase to make ATP
Anabolism:
building small molecules into larger macromolecules
anabole
building up (anabolic steroids build you up....)
Mineral functions: Calcium
builds bones and teeth, muscle contraction, neuron function, secretion from cells
How does electron transport chain work
by transporting electrons down ETC linked to ATP synthesis
Name 4 cofactors for enzymes:
calcium, iron, magnesium, and manganese
______ are the energy potential of our food
calories
Amino acids ________ be stored in the body, thus must be consumed in small amounts on a daily basis.
cannot
In photosynthesis, the plant uses energy from the sun, plus water and carbon dioxide, to synthesize
carbohydrates only
Bad cholesterol contributes to:
cardiovascular disease
How are nutrients & oxygen delivered to cells throughout the body?
cardiovascular system
Two types of metabolic reactions:
catabolism and anabolism
relationship between catabolism & metabolism in nutrition
catabolism frees the energy that cells need for anabolism, that is, the making of new organic molecules.
Protein function: ____ __________- receptors, cell identity, pumps
cell membranes
Lipids: Chemical precursors: a precursor of steroids, bile salts, and vitamin D
cholesterol
Vitamins are _______, meaning they attach to enzymes and help them work.
coenzymes
Minerals are _______, meaning they attach to enzymes and help them work.
cofactors
_____ ______ that have all essential amino acids are usually derived from soy or animal sources
complete proteins
Chlorine:
component of stomach acids (HCl), produces chemical gradients
The hydrolysis of ATP that often occurs simultaneously with the synthesis of many compounds is an example of
coupled reactions
What does chemiosmosis do
couples ETC to ATP synthesis
Chemiosmosis in respiration
coupling of the redox reactions of the electron transport chain to ATP synthesis
Peptide YY and CCK:
create sensations of satiety and cessation of eating
Location of the Electron Transport Chain (ETC)
cristae of the mitochondria
Location of Glycolysis
cytoplasm of the cell
An overabundance of protein can lead to ______ during exercise/sweating and _______ ____ in urine which can lead to kidney stones/osteoporosis.
dehydration; calcium loss
Type I Diabetes (insulin _______) happens when the body is not producing adequate amounts of insulin and when the body burns ____ instead of sugars for energy.
dependent; fats
Gut hormones ___ hunger. Glucagon and epinephrine ____ hunger.
depress; stimulate
Jake is getting ready for spring training and is sitting down to a dinner of half a chicken, a rib-eye steak, black beans, and 5 slices of bacon. He has been eating typical dinners like this for about a month and has since gained 7 pounds, while exercising only briefly. When Jake asks why he doesn't see an increase in his biceps or abs, the proper response should be
dietary protein alone does not contribute to muscle accretion
Name 2 ways enzymes are different from each other.
each acts on a specific substrate; each has its own specific structure
main parts of ATP SYNTH
each made up of multiple polypeptides, A rotor in the inner mitochondrial membrane. A knob that protrudes into the mitochondrial matrix. An internal rod extending from the rotor into the knob. A stator, anchored next to the rotor, which holds the knob stationary.
Mineral salts:
electrolytes; govern function of nerve and muscle cells; regulate distribution of body water
FADH2
electron carrier (coenzyme) produced during the Krebs cycle
Small intestine: ________ by bile salts from liver increases surface area of fat globules.
emulsification
Lipids are the body's stored _____.
energy
Iron:
essential for hemoglobin and myoglobin
All of the following are features of the metabolism of surplus dietary carbohydrate in human beings except a. excess glucose suppresses fat oxidation. b. excess glucose is oxidized only very slowly. c. excess glucose is first used to fill glycogen reserves. d. conversion of excess glucose to fat occurs only to a very limited extent.
excess glucose is oxidized only very slowly.
Glycogenesis:
excess glucose is stored as glycogen
The effects on metabolism from starvation are similar to those from
fasting
All of the following may serve as precursors for oxaloacetate synthesis except a. fat. b. starch. c. glucose. d. protein.
fat
Production of excessive amounts of acetyl CoA molecules leads to the synthesis of
fatty acids only
Protein function: _________ _________- (collagen, keratin) for structural purposes (example tissues)
fibrous proteins
Order of molecules of chain
first flavoprotein (named because it has a prosthetic group called flavin mononucleotide), then iron-sulfur protein, then ubiquinone (Q), only member of chain that is not a protein (mobile charier shuttles electrons and receives). Most of the remaining electron carriers between Q and oxygen are cytochroms
The electron transport chain
generates no atp directly. a collection of molecules embedded in the cristae, the folded inner membrane of the mitochondrion. The folding of the cristae increases its surface area, providing space for thousands of copies of the chain in each mitochondrion. Most components of the chain are proteins bound to prosthetic groups, nonprotein components essential for catalysis. Electrons drop in free energy as they pass down the electron transport chain.
Protein function: ______ _____- (antibodies, myoglobin, enzymes) functional. (immune system!)
globular proteins
Alpha (a) cells produce ______ (during _______).
glucagon; fasting
Lipolytic glycerol
gluconeogenesis, and glycolysis
Liver metabolized carbohydrates: Acts as _____ ______. Lowers blood glucose by converting it to storage form, glycogen, through ____________.
glucose buffer; glycogenesis
Glycolysis:
glucose converted to ATP
The glycemic index classifies carbohydrate containing foods according to their potential to raise your blood _______ _____.
glucose level
Glycolysis is the conversion of
glucose to pyruvate
Liver metabolizes fats: hepatocytes break triglycerides into ______ and ____ ____ ___(___)
glycerol and free fatty acids (FFA)
The series of reactions involving the conversion of glucose to pyruvate is known as
glycolysis
The electrons carried by FADH2
have lower free energy and are added at a lower energy level than those carried by NADH. The electron transport chain provides about one-third less energy for ATP synthesis when the electron donor is FADH2 rather than NADH.
In the adult body, food energy not stored as fat or glycogen is lost as
heat
Liver metabolizes proteins: liver builds proteins collectively referred to as ____ ____. (List the 4)
hepatic proteins: albumin, trnsport proteins such as transferrin, apoproteins, clotting factors such as fibrinogen.
Elizabeth has been fasting for 4 days in observance of her religious beliefs. You note that her breath smells "fruity." This is most likely due to
her body's shift to a state of ketosis
What do low levels of LDL indicate?
high LDL correlates with cholesterol deposition in arteries; opposite with low
Adverse side effects of typical low-carbohydrate diets include all of the following except a. fatigue. b. nausea. c.constipation. d.high blood pressure.
high blood pressure
Hormone's effect on lipogenesis
high insulin level increases FA synth
The _______ _____ gives fat chemical characteristics.
hydrocarbon chain.
The number of ATP molecules that can be produced from a molecule of protein, fat, or carbohydrate is generally related to the number of atoms of
hydrogen
Saturated fats are made by adding _______ to unsaturated fats by _________. This makes ____ fats.
hydrogen; hydrogenation; trans fats
Ketosis causes
hypoglycemia (need glucose to effectively use fats) results in: ****Dec oxaloacetate (inc in lipolytic activity b/c few Acetyl CoA can contribute to TCA) Inc FFA Inc Acetyl CoA, which leads to... Inc Ketones Inc Insulin
Type I diabetes is due to ________ of insulin; Type II is due to _______.
hyposecretion; hypoactivity
Where is ATP synthase located
in the inner membrane of the mitochondria
Ferm and cellular resp differ
in their mechanism for oxidizing NADH to NAD+ In fermentation, the electrons of NADH are passed to an organic molecule to regenerate NAD+. In respiration, the electrons of NADH are ultimately passed to O2, generating ATP by oxidative phosphorylation.
Nurient signals: _____ nutrient levels in the blood ____ eating.
increased; supress
What do high levels of HDL indicate?
indicates cholesterol is being removed from the arteries
To maintain the proper energy balance and weight, must match _____ to _______.
input to output
Carbs cause the pancreas to secrete large amounts of _______, leading to _______ resistance as seen in type 2 diabetics.
insulin
Blood glucose is carefully regulated by ____ and _______.
insulin and glucagon
Beta (B) cells produce _______ (during ______).
insulin; eating
Absorptive state is regulated by _____ secreted in response to elevated blood glucose and amino acid levels and the hormones ___,__,and ___.
insulin; gastrin, secretin, and cholecystokin
What is the highly folded space between membranes
intermembrane space
A feature of catabolic reactions is that they
involve release of energy
What does it mean for glucose to be completely oxidized?
it means that all the energy from the original glucose molecule has been released and gathered by the cell
A person said to have acetone breath most likely has the condition known as
ketonemia
Ketonemia is defined as an elevation of
ketones in the blood
A person with fruity odor on the breath demonstrates evidence of metabolic
ketosis
When a person is performing intense physical exercise and begins to feel fatigue and a burning pain in the muscles, the response of the muscles is to synthesize more
lactate
Your roommate Demetrius is participating in a weightlifting course and complains of a burning pain during workouts. You explain to Demetrius that the rapid breakdown of glucose in his muscles produces large amounts of pyruvate, which leads to a fall in pH within the muscle and that the muscle responds by converting excess pyruvate to
lactate
The Cori cycle involves the interconversion of
lactate and glucose
Fasting CHO
leads to insufficient insulin--> FA flood the liver--> most acetyl CoA produces Ketones, and few contribute to TCA
vita
life
Glucagon's major target is the _____, where it promotes the release of glucose into the blood.
liver
Excess alcohol intake leads to a reduction in the synthesis rate of
liver glucose
Short term effects of low-carb diets:
lose weight quickly
Adipose Tissue
major storage site for TG
Matter (___) and ___ are the same thing in different forms.
mass; energy
What is glycolysis?
means the splitting of sugars; does not require oxygen; it is the oxidation of glucose to pyruvic acid with the production of some ATP and energy containing NADH; the first stage of carbohydrate catabolism
Hypothalamus secretes ______, an appetite supressant
melanocortin
A typical cell contains "powerhouses," which is another name for the
mitochondria
Hyperglycemia:
more glucose in bloodstream than necessary
Protein function: ________ ________- movement of body, cells, and cell structures.
muscle contraction
Type II Diabetes (___-______ dependent) occurs when the cells are insulin resistant. (do not respond to insulin).
non-insulin
To be able to metabolize, we need to have _____ ***
nutrients
A feature of ketosis is that it
occurs when fats are partially oxidized
Vitamins are ______, meaning they have carbon.
organic
genesis
origin
oxidation-reduction (redox reaction)
oxidation is the removal of electrons (e-) from an atom or molecule (produces energy). Reduction is adding electrons(e-) to an atom or substance. These reactions are always paired; does not involve oxygen
To make energy, cells require 2 things
oxygen & nutrients
An aerobic reaction is one that requires
oxygen.
Lipids: Structural: ________ and _______ are components of plasma membrane and myelin.
phoshpholipids and cholesterol
Phosphorus:
phospholipids, ATP, buffers, nucleic acids
Protein function: ___ ____- blood osmolarity and viscosity
plasma proteins
Where can essential fatty acids be found?
polyunsaturated oils such as corn and safflower
Vitamins act as coenzymes and are ________ of coenzymes.
precursors
All of the following are among the functions of the liver except a. synthesis of urea. b. synthesis of glycogen. c. production of red blood cells. d. conversion of fructose to glucose.
production of red blood cells
Cytochrome
protein, The prosthetic group of each cytochrome is a heme group with an iron atom that accepts and donates electrons.The last cytochrome of the chain, cyt a3, passes its electrons to oxygen, which is very electronegative.
Cholesterol travels in the body in packages with __________.
proteins (Lipoproteins)
Chemiosmotic hypothesis entails what
proton motive force
Purpose of fermentation
provides a mechanism by which some cells can oxidize organic fuel and generate ATP without the use of oxygen.
Purpose of cellular metabolism
provides the energy needed to maintain homeostasis.
What do transport proteins in the membrane do
pump H+ across inner membrane to intermembrane space
alcohol fermentation
pyruvate is converted to ethanol in two steps. First, pyruvate is converted to a two-carbon compound, acetaldehyde, by the removal of CO2. Second, acetaldehyde is reduced by NADH to ethanol. Alcohol fermentation by yeast is used in brewing and winemaking.
lactic acid fermentation
pyruvate is reduced directly by NADH to form lactate (the ionized form of lactic acid) without release of CO2. Lactic acid fermentation by some fungi and bacteria is used to make cheese and yogurt.Human muscle cells switch from aerobic respiration to lactic acid fermentation to generate ATP when O2 is scarce. The waste product, lactate, may cause muscle fatigue, but ultimately it is converted back to pyruvate in the liver.
Metabolism
refers to all the chemical reactions that occur in the body.
After digestion and absorption, an amino acid not used to build protein will first be subjected to
removal of its amino group.
RNA
ribonucleic acid, a nucleic acid present in all living cells; role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins
_______ fatty acids have the maximum number of hydrogen's bonded to the carbons.
saturated
krebs cycle
second stage of cellular respiration, in which pyruvic acid is oxidized into carbon dioxide in a series of energy-extracting reactions with the production of some ATP, energy containing NAHD, & another reduced electron carrier FADH2
The site of lipid synthesis in the cell is the
smooth endoplasmic reticulum
The basic units derived from food include all of the following except
starches
Ghrelin:
stimulates hunger and induces eating
The metabolism of alcohol begins in the
stomach
When protein consumption is in excess of body needs and energy needs are met, the excess amino acids are metabolized and the energy in the molecules is
stored as glycogen and fat
2 other metabolic roles of liver: 1. _____ for variety of substances. 2. _____ body of wastes, drugs, and toxins.
storehouse clears
glykus
sweet
Glucogenesis:
synthesis of glucose from non-carb sources (lactic acid and amino acids.)
Name 4 ways an enzyme can be altered.
temperature, pH, enzyme inhibitors, substrate concentrate
List the factors that influence enzyme activity
temperature, pH, substrate concentration, inhibitors
What is the fate of NADH in a fermentative organism?
the NADH from glycolysis is oxidized to pyruvic acid (which is reduced) and recycled back as NAD+ so that glycolysis can continue
An immediate consequence of a cellular deficiency of oxaloacetate is a slowing of
the TCA cycle
chemiosmosis
the energy released when a substance like a hydrogen atom (H+) moves across a gradient (ex: membrane) and is used to synthesis ATP.
BASAL METABOLIC RATE
the minimum, RESTING energy expenditures of an awake, alert person.
Location of the Kreb's Cycle
the mitochondrial matrix
Chronic excess alcohol intake leads to all of the following effects on folate except a. the small intestine recycles more folate. b. the liver releases more folate into the blood. c. the kidneys excrete more folate via the urine. d. the small intestine absorbs less folate from the diet.
the small intestine recycles more folate.
What is the 'nutrient pool'? Carbs first; Lipids second choice; Amino acids seldom broken down if other sources available...
the source of organic molecules for both catabolism and anabolism. Cells tend to conserve materials needed to build new compounds & tend to break down the rest. Cells continuously replace membranes, organelles, enzymes, & structural proteins. These anabolic activities require more amino acids than lipids & few carbohydrates. Catabolic activities, however, tend to process these organic molecules in the REVERSE order. In general, when a cell with excess carbohydrates, lipids, and amino acids needs energy, it will break down: Carbohydrates first. Lipids are the second choice as an energy source, and amino acids are seldom broken down if other energy sources are available.
Define metabolism & describe the fundamental differences between anabolism & catabolism
the sum of all chemical reactions within living systems. Catabolism is the breakdown of complex organic compounds into simpler ones; enzyme regulated reactions that release energy; usually hydrolysis reactions; Anabolism is the building of complex molecules from simpler ones; enzyme regulated reactions that require energy; are dehydration reactions;
Factors for regulation of food intake include _____ and _____.
thermoreceptors and chemoreceptors
The Wernicke-Korsakoff syndrome in people with chronic alcohol abuse stems primarily from a deficiency of
thiamin.
katabole
throwing down
Function of ETC
to break the large free energy drop from food to oxygen into a series of smaller steps that release energy in manageable amounts.
Explain the overall function of metabolic pathways.
to break-down larger components through a series of oxidation-reduction reactions to extract energy from organic compounds and store it in ATP.
What is the purpose of NADH
to pass electrons to ETC
The electron transport chain is made up of mostly
transport proteins
_________ fatty acids have less than the maximum number of hydrogen's bonded to the carbons.
unsaturated
Products from the electron transport chain pathway include all of the following except a. CO2. b. urea. c. water. d. energy.
urea
