Nutrition Exam 3
What is the net ATP of glycolysis?
- 2 ATP used - 4 ATP produced - Net = 2 ATP
Each complete turn of the citric acid cycle produces:
- 2 molecules of CO2 - 1 potential ATP in the form of 1 molecule of guanosine triphosphate (GTP) - 3 molecules of NADH + H 1 molecule of FADH2
How is ATP regenerated?
- A phosphate is added back to AMP and ADP - The energy released during catabolism permits Pi (inorganic phosphate) to re-form a high energy bond with AMP and ADP, thereby regenerating ATP **this recycling of ATP is essential for survival**
Individuals who abuse alcohol are at increased risk of developing mineral deficiencies. The most common mineral deficiencies include:
- calcium - magnesium - zinc - iron
In addition to protein deficiencies, deficiencies of vitamins and minerals are likely and can result in further complications. These deficiencies are usually the result of:
- decreased intake - impaired absorption - altered metabolism - alcohol-related tissue damage in the GI tract, liver, and pancreas
Alcohol abuse and alcoholism pose serious risks for many individuals. Alcohol abuse is characterized by a pattern of drinking accompanied by at least 1 of which problems?
- failing to fulfill major responsibilities at work, school, or home because of heavy drinking - drinking with it is physically dangerous, such as while driving a car - having recurring alcohol-related legal problems, such as physically hurting someone while drunk - having social or relationship problems that are worsened by alcohol intake
The factors linked to developing alcohol-related problems include?
- genetics - gender - age of drinking onset - ethnicity -parental and peer attitudes favoring excessive drinking - presence of mental health disorders, such as depression and anxiety disorder
Whereas glycolysis requires only the B-vitamin niacin as NAD, the pyruvate dehydrogenase complex that converts pyruvate to acetyl-CoA requires coenzymes from 4 B-vitamins:
- thiamin, riboflavin, niacin, and pantothernic acid **CoA is made from the B-vitamin pantothenic acid; CHO metabolism depends on an ample supply of these vitamins**
What are three pathways of alcohol metabolism?
1) Alcohol dehydrogenase pathway (ADH) 2) Microsomal ethanol oxidizing systems (MEOS) 3) Catalase pathway
Glycolysis has 2 roles:
1) Break down CHO to generate energy 2) Provide building blocks for synthesizing other needed compounds
What are the 3 stages of catabolism that produce energy for body cells?
1) Digestion: breakdown of complex molecules to their component building blocks 2) Conversion of building blocks into acetyl-CoA (or other simple intermediates) 3) Metabolism of acetyl-CoA to CO2 and formation of ATP
What are the 4 stages of aerobic cellular respiration of glucose?
1) Glycolysis --> 2 pyruvate - glucose --> 2 pyruvate 2) transition reaction - pyruvate --> acetyl CoA 3) Citric acid cycle - acetyl CoA --> NADH + H + FADH2 + ATP 4) Electron transport chain - water and ATP
The safest and most logical approach to maintaining a healthy weight is to:
1) Watch calorie intake 2) Exercise regularly 3) Get problem eating behaviors under control
The body uses energy for 3 main purposes:
1) basal metabolism 2) physical activity 3) digestion, absorption, and processing of ingested nutrients
The key metabolic functions of the liver are (7):
1) conversions between various forms of simple sugars 2) fat synthesis 3) production of ketone bodies 4) amino acid metabolism 5) urea production 6) alcohol metabolism 7) nutrient storage
Some of the most common inborn errors of metabolism are (3):
1) phenylketonuria (PKU) 2) Galactosemia 3) Glycogen storage disease
A standard drink is usually defined as the size that provides approximately ____ grams of alcohol.
14 grams of alcohol **equates to: 12 oz. beer; 8-9 oz. of malt liquor; 10 oz. wine cooler; 5 oz. glass of wine; 1.5 oz. hard liquor (80 proof spirits; whiskey, rum, gin, vodka, tequila, etc.)**
The amount of alcohol in breast milk peaks about ___ to ___ minutes after the mother ingests it, then declines.
30 to 60
Researchers found that ___% of adolescents who drink before the age of 14 go on to develop alcohol dependency, compared with ___% of those who wait until age 21 years or later to begin drinking.
45%; 10%
A social drinker who weights about 150 lbs. (~70 kg) and has normal liver function metabolizes about ___-___ g of alcohol per hour.
5-7 g
Alcohol is an energy-rich substance that supplies _____ kcals per gram
7 kcals per gram
Each fatty acid carbon results in about ____ ATP, whereas glucose oxidation results in _____ ATP per carbon
7;5
The key to alcohol metabolism lies in one's ability to produce the enzymes used in the alcohol dehydrogenase pathway because this pathway metabolizes about ____% of the alcohol consumed.
90%
Inborn errors of metabolism occur when:
A person inherits a defective gene coding for a specific enzyme from one or both parents
Why are alcoholics at increased risk of developing niacin deficiency?
Alcoholics are at increased risk of developing niacin deficiency because alcohol metabolism requires large quantities of this vitamins
Why is the recommended limit for alcohol use lower for women than for men?
An equivalent amount of alcohol is more concentrated in women -- they are smaller and have more fat and less body water than men. Women cannot metabolize alcohol a quickly as men, due to lower activity of the alcohol dehydrogenase in the stomach, so blood alcohol concentrations remain elevated for longer periods.
What is an example of an anabolic pathway?
Anabolic pathways use small, simpler compounds to build larger, more complex compounds. For example: - glucose + glucose --> glycogen - glycerol + fatty acids --> triglycerides - amino acids + amino acids --> protein **energy must be used for anabolic pathways to take place**
Oxidized compounds tend to be high reactive; they seek electrons from other compounds to stabilize their chemical configuration. How do antioxidants fit into this picture?
Antioxidants, such as vitamin E, donate electrons to these highly reactive compounds, making them less reactive. **the term antioxidant is typically used to describe a compound that can donate electrons to oxidized, putting them into a more reduced (stable) state.
______________ can be determined by measuring the amount of alcohol excreted through the lungs because the alcohol content of exhaled air and blood are directly related.
Blood alcohol concentration (BAC)
What is an example of catabolic pathway?
Catabolic pathway break down compunds into small units. For example: - glycogen --> glucose + glucose - triglycerides --> glycerol + fatty acids - protein --> amino acids + amino acids **energy is released when catabolic reactions take place**
Excessive alcohol intake can result in deficiencies of the fat-soluble vitamins A, D, E, and K. Why is this?
Chron alcohol abuse damages the liver and pancreas, which impairs the liver's ability to secrete bile and the pancreas's ability to secrete enzymes that digest fats. Decreased bile and pancreatic lipase secretions in turn, lead to poor absorption of fat and fat-soluble vitamins
_____ is a chronic degenerative disease, caused by poisons (e.g. alcohol) that damage liver cells, that results in a reduced ability to synthesize proteins and metabolize nutrients, drugs, and poisons.
Cirrhosis
T or F: A nutritious diet may help prevent some of the complications associated with alcoholism and alcoholic liver disease.
False
T or F: Drinking a little wine or beer before breastfeeding will allow the mother to relax and the baby to suckle longer.
False
T or F: Excessive alcohol intake adversely affects the liver but not other organs in the body.
False
T or F: Just like CHO, protein, and fat, alcohol requires digestion and specific transport mechanisms or receptors to enter cells
False
__________ is the accumulation of triglycerides and other lipids inside liver cells.
Fatty liver **causes may include excessive alcohol intake, malnutrition, and obesity**
The anaerobic glycolysis pathway encompasses:
Glycolysis and conversion of pyruvate to lactate
It takes 2 turns of citric acid cycle to process 1 glucose molecule because:
Glycolysis and transition reaction yield 2 acetyl-CoA
A big difference between glucose and fatty acids is?
Most fatty acids have far more carbons and, thus, can go around the citric acid cycle many more times than glucose.
Second, coenzyme A and aldehyde dehydrogenase convert acetaldehyde to acetyl-CoA and yield ___________.
NADH + H
Without oxygen, metabolism stops and death occurs. Why is this?
NADH + H and FADH2 produced during the citric acid cycle can be regenerated in to NAD+ and FAD only by the eventual transfer of their electrons and hydrogen ions to oxygen, as occurs in the electron transport chain. The citric acid cycle has no ability to oxidize NADH + H and FADH2 back to NAD+ and FAD.
A fatty acid eventually degrade 2 carbons at a time into acetyl-CoAsome of the chemical energy contained in te fatty acids in transferred to _____ and ______
NADH + H; FADH2
Why is adenosine triphosphate (ATP) the main form of energy that the body uses?
Only the energy in ATP and related compounds can be used directly by the cell to synthesize new compounds (anabolic pathways), contract muscles, conduct nerve impulses, and pump ions across membranes
What is carnitine's role in fatty acid oxidation?
The fatty acids that have been taken into the cells from the bloodstream are shuttled from the cell cytosol into the mitochondria by a carrier called carnitine In healthy people, cells produce the carnitine needed, and carnitine supplements provide no benefit
Who should not consume alcoholic beverages?
Those who cannot restrict their alcohol intake to moderate levels; women who are or may be pregnant; anyone younger than the legal drinking age; individuals taking medications that can interact with alcohol; those with specific medical conditions; those who will be engaging in activities that require attention, skill, or coordination (driving or operating machinery)
T or F: The most severe damage occurs during the first 12 to 16 weeks of pregnancy, when organs are undergoing major developmental steps.
True
Many vitamins and minerals are needed for metabolic pathways to operate. Most notable: (List of vitamins and minerals)
Vitamins: B-vitamins (thiamin, riboflavin; niacin; pantothenic acid; biotin; vitamin B6; folate; vitamin B12) Minerals: iron and copper
Chronic alcohol abuse often leads to a severe form of thiamin deficiency called ____
Wernicke-Korsakoff syndrome
The largest drinking population in North America consists of?
Young, White college students, many of whom are not yet of legal drinking age
First, alcohol is converted in the cytosol to ______ by the action of the alcohol dehydrogenase enzyme and the NAD+ coenzyme. NAD+ picks up 2 hydrogen ions and 3 electrons from the alcohol to form NADH +H and produces the intermediate acetaldehyde.
acetaldehyde
Most ketone bodies are converted back into ________ in other body cells, where they then enter the citric acid cycle and can be used for fuel. (Acetone leaves the body via the lungs, giving the breath of a person in ketosis a characteristic, fruity smell)
acetyl-CoA
The first step in transferring the energy in a fatty acid to ATP is to cleave the carbons, 2 at a time, and convert the 2-carbon fragments to ______
acetyl-CoA
Typically fatty acids cannot be turned into glucose because those with an even number carbons -- the typical form in the body -- break down into ________
acetyl-CoA molecules
When oxygen is readily available, cellular respiration may be ________. When oxygen is not present, ________ pathways are used.
aerobic; anaerobic **Aerobic respiration is far efficient than anaerobic metabolism at producing ATP. -- aerobic respiration of a single molecule of glucose will result in a net gain 30 to 32 ATP -- The anerobic metabolism of a single molecule of glucose is limited to a net gain of 2 ATP**
In middle-aged and older adults, moderate alcohol use has been shown to lower the risk of cardiovascular disease and overall mortality in comparison with nondrinkers. What are the factors that help reduce heart disease?
alcohol can: - lower serum low-density lipoproteins (LDL) levels - increase protective high-density lipoprotein (HDL) levels - decrease platelet aggregation (blood cell accumulation)
The ________ pathway is the main way alcohol is metabolized.
alcohol dehydrogenase (ADH)
The alcohol-related health consequences are known collectively as ______
alcohol spectrum disorders (FASD) **may experience range of effects, including facial malformations, growth retardation (including smaller than normal brain), birth defects, lifelong learning disabilities, short attention spans, and hyperactivity**
The catabolism of amino acids, primarily from the liver, yields amino groups, which then are converted to _________.
ammonia
All the pathways that take place within the body can be categorized as either ____ or _____
anabolic; catabolic
Why is oxygen essential to many life forms?
because it is a final acceptor of the electrons and hydrogen ions generated from the breakdown of energy-yielding nutrients
Fatty acid oxidation is also called
beta-oxidation
During the first few days of a fast, _______ is broken down rapidly -- in fact, it supplies about 90% of needed glucose, with the remaining 10% coming from glycerol.
body protein
Calorie values can be derived by directly measuring calorie content using a device called a __________.
bomb calorimeter
Removal of the amino group (of an amino acid) produces _________, most of which enter the citric acid cycle.
carbon skeletons
The citric acid cycle is a series of chemical reactions that cells use to convert the _______ of an acetyl group to _______ while harvesting energy to produce ATP.
carbons; carbon dioxide
Enzyme synthesis and rate of activity are controlled by:
cells and by the products of the reactions in which the enzymes participate
ATP is generated through ______
cellular respiration
The breakdown product of both glucose and fatty acids -- acetyl-CoA -- enters the _______
citric acid cycle
When a person consumed a low CHO diet, oxalocetate may be inadequate, causing _____________ activity to decrease. However, lipolysis continues, which means acetyl CoA production from fatty acids also continues, and results in buildup of acetyl CoA because ___________ is not available to allow it to enter the citric acid cycle. Because acetyl CoA cannot enter in the citric acid cycle, these molecules join together and form _________.
citric acid cycle; oxaloacetate; ketone bodies
Dehydrogenases
class of enzymes that remove hydrogens from energy-yielding compounds or their breakdown products **these hydrogens are eventually donated to oxygen to form water. In the process, large amounts of energy are converted to ATP**
intermediates
compounds formed in any of the many steps in a metabolic pathway
Oxidative phosphorylation requires the minerals _______ and ________
copper; iron
Glycolysis takes place in?
cytosol portion of the cell
What are impacts of binge drinking on college campuses?
death; injury; assault; sexual abuse; unsafe sex; academic problems; health problems/suicide attempts; drunk driving; vandalism; property damage; police involvement; alcohol abuse and dependence
High ATP concentration
decrease energy-yielding reactions such as glycolysis increase anabolic reactions, such as protein synthesis, that use ATP
If the concentration of ketone bodies rises too high in the blood, they spill into the urine, pulling the electrolytes sodium and potassium with them. Eventually, severe ion imbalances occur in the body. The blood also becomes more acidic because 2 of the 3 forms of ketone bodies contain acid groups. The resulting condition, ________, can induce coma or death if not treated immediately.
diabetic ketoacidosis
_____ and _____ remain the most important steps in the treatment of alcoholism.
early identification; intervention
The synthesis of ATP from ADP and Pi involves the exchange of _____, mostly in the form of hydrogen ions (H+), from energy-yielding compounds (CHO, fat, protein, alcohol).
electrons
Regarding energy balance, what is the difference between energy equilibrium, positive energy balance, and negative energy balance?
energy equilibrium: energy intake = energy expenditure = weight maintenance positive energy balance: energy intake > energy expenditure = weight gain negative energy balance: energy intake < energy expenditure = weight loss
Form of alcohol we consume is:
ethanol (supplied mostly by beverages such as beer, wine, and distilled spirits, liqueurs, cordials, and hard cider) **sometimes used as an ingredient in food**
The further breakdown of fatty acids for energy production is called ________ because the donation of electrons from fatty acids to oxygen is the net reaction in the ATP-yielding process.
fatty acid oxidation
Because of the toxic effects of alcohol and acetaldehyde, the metabolism of alcohol takes priority over continuation of the citric acid cycle. Thus, most of the acetyl-CoA is directed toward ______ and ______ synthesis, resulting in the accumulation of fat in the liver (called ______).
fatty acid; triglyceride; steatosis
This fall in blood insulin then causes _________ to flood into the blood stream and eventually form ketone bodies in the _______.
fatty acids; liver
The alcohol we consume is produced by:
fermentation
The most serious FASD is known as _______
fetal alcohol syndrome (FAS)
Anyone who consumes more kcals from any of the energy-yielding nutrients than what the body can use will _________
gain weight
Any part of the carbon skeleton that can form pyruvate or bypass acetyl CoA and enter the citric acid cycle directly are called _______ because these carbons can become the carbons of glucose.
glucogenic amino acids
The lactate generated during high intensity exercise is transported from the muscles to the liver, where it is converted to ______, which can then be returned to the muscles.
glucose
The pathway to produce _______ from certain amino acids -- gluconeogenesis -- is present only in liver cells and certain kidney cells.
glucose
The ________ portion of triglyceride is the part that can become glucose.
glycerol
Metabolic pathway
group of biochemical reactions that occur in progression from beginning to the end
Worldwide, nearly ____ of men and ____ of women do not drink.
half; two-thirds
Binge drinking
having 4+ drinks for females and 5+ drinks for males on a single occasion **binge drinking increases the risk of alcohol poisoning**
Excessive consumption of alcohol contributes significantly to 5 of the 10 leading causes of death in North America -- which are:
heart failure; certain forms of cancer; cirrhosis of the liver; motor vehicle and other accidents; suicides
Ketone bodies
incomplete breakdown products of fat, containing 3 or 4 carbons Most contain a chemical group called a ketone
Low levels of _______ in the blood promote gluconeogenesis, protein breakdown, and lipolysis.
insulin
When a person is in a state of semistarvation or fasting, the amount of glucose in the body falls, so ________ production falls.
insulin
Any parts of carbon skeletons that become acetyl-CoA are called ________ because these carbons become acetyl-CoA and, if insulin levels are low, they can become ketones.
ketogenic amino acids
After several weeks of fasting, half or more of the nervous system's energy needs are met by _______; nonetheless, some glucose must still be supplied via the catabolism of lean body mass.
ketone bodies
The heart, muscles, and some parts of the kidneys then use ______ for fuel. After a few days of ketosis, the ______ also begins to metabolize ketone bodies for energy.
ketone bodies; brain
A condition of having a high concentration of ketone bodies and related breakdown products in the bloodstream and tissues is called ____________
ketosis
When oxygen is absent, pyruvate that is produced through glycolysis is converted into _______
lactate or lactic acid
Compared with men, women produce ___ of the alcohol dehydrogenase enzyme in the cells that line their stomach.
less; as a result, women absorb about 30-35% more unmetabolized alcohol from the stomach directly into the bloodstream
The pathways for the synthesis of fat from excess CHO or protein intake, called __________, are found primarily i the cytosol of liver cells.
lipogenesis
The breaking down of triglycerides into free fatty acids and glycerol is called ________
lipolysis
Protein metabolism takes place primarily in the _______. Only branched-chain amino acids are metabolized mostly at other sites -- in this case, the ________.
liver; muscles
The metabolism of alcohol occurs predominantly in the _______, although approximately 10 to 30% of alcohol is metabolized in the _________.
liver; stomach
To prevent the toxic effects of alcohol and acetaldehyde, the body utilizes a 2nd pathway, called the ______, to metabolize the excess alcohol
microsomal ethanol oxidizing system
Gluconeogenesis begins in the _________ with the production of oxaloacetate.
mitochondira
Cells that lack ______ are not capable to aerobic respiration.
mitochondria
Fatty acid oxidation takes place in the
mitochondria
The final pathway of aerobic respiration is the electron transport chain located in the ________
mitochondria
Protein consumed in excess of need does not promote ________
muscle development
Alcohol
narcotic, an agent that reduces sensations and consciousness, and a central nervous system depressant **most commonly abused drug in North America (third leading cause of preventable death in the US)** **Too much alcohol damages almost every organ in the body; the liver and brain are particularly vulnerable to its toxic effects**
Although most cells can use fatty acids for energy, the ______ and __________ use only glucose for energy.
nervous system; red blood cells
Two B-vitamins, _____ and _____, assist dehydrogenase enzymes and play a role in transferring the hydrogens from energy-yielding compounds to oxygen in the metabolic pathways of the cells.
niacin (nicotinamide adenine dinucleotide (NAD) is the oxidized form and NADH is the reduced form); riboflavin (flavin adenine dinucleotide (FAD) is the oxidized form and FADH2 is the reduced form
Alcohol slows _____ and ______ delivery to the fetus, thereby retarding growth and development.
nutrient; oxygen **alcohol may also displace nutrient dense foods in the mother's diet**
As fatty acids create acetyl-CoA, carbohydrates are needed to keep the concentration of pyruvate high enough to resupply _______ to the citric acid cycle.
oxaloacetate
The metabolic process, called ______, is the way in which energy derived from the NADH + H and FADH2 is transferred to ADP + Pi to form ATP.
oxidative phosphorylation
A substance is _____ when it loses 1 or more electrons.
oxidized
The process of cellular respiration ______ food molecules to obtain energy (ATP).
oxidizes
In oxidation-reduction reactions, electros are transferred in series of reactions from energy-yielding compounds eventually to ______
oxygen
For hard liquor (distilled spirits), alcohol content is listed by ____ rather than percentage.
proof (twice the percentage of alcohol content) **ex: 80-proof vodka or gin is 40% alcohol**
Alcohol moves easily through the cell membranes, and as it does, it damages _____ in the membranes.
proteins
Acetyl-CoA can never re-form into _________
pyruvate
When oxygen is present, the pyruvate dehydrogenase enzyme complex converts _______ into a 2-carbon compound called acetyl-CoA.
pyruvate
The lactate produced by cells (e.g. red blood cells) is released into the bloodstream, picked up primarily by the liver, and used to synthesize:
pyruvate, glucose, or some other intermediate in aerobic respiration
A substance is ______ when it gains 1 or more electrons.
reduced
Some studies suggest that the heart disease prevention benefits are predominately associated with red wine consumption and a phytochemical it contains called _______
resveratrol
The effects of alcohol are intensified by the offspring _____ and prolonged because the fetus is unable to _______ the alcohol and must wait for maternal blood to carry it away.
small size; metabolize
High ADP concentrations
stimulate energy-yielding pathways
In the first few hours of a fast, the body fuels itself with:
stored liver glycogen fatty acids from adipose tissue
The energy used by all the cells of the body initially come from the ______
sun
Metabolism refers to:
the entire network of chemical processes involved in maintaining life **it encompasses all the sequences of chemical reactions that occur in the body**
How is energy released from ATP?
to release the energy in ATP, cells break a high-energy phosphate bond, which creates adenosine diphosphate (ADP) plus Pi, a free (inorganic) phosphate group **hydrolysis of ADP results in the compound adenosine monophosphate (AMP)
distill
to separate 2 or more liquids that have 2 different boiling points. Alcohol is boiled off and the vapors are collected and condensed. Distillation produces a high alcohol content in hard liquor.
Ultimately, the fatty acids and glycerol are used to synthesize _________, which are subsequently delivered by very-low-density lipoproteins via the bloodstream to adipose tissues for storage.
triglycerides
The liver prepares the amino groups for excretion in the urine with the _______
urea cycle
During the urea cycle, 2 nitrogen groups -- 1 ammonia group and 1 amino group -- react through a series of steps with carbon dioxide molecules to form _____ and ________
urea; water
The factor that determines whether an amino acid is glucogenic or ketogenic is?
whether part of all of the carbon skeleton of the amino acid can yield a "new" oxaloacetate molecule during metabolism, 2 of which are needed to form glucose
Moderate alcohol intake for: women: men:
women: < or equal to 1 drink per day men: < or equal to 2 drinks per day
