Unit 4: Cell Structure, Metabolism and the Nutrients that Support Metabolism
The Cell
Cell is basis of human _________________________
Function of the cell
Requires ________________, adenosine triphosphate (_______)
Requires ____________________
Three major areas of cell
Cell ______________
Cytoplasm with _________________
_____________________
Parts of the Cell
1. Cell (________________) Memebrane
Controls what goes ____ and ___________ of the cell
______________________
2. _________________ and ___________________ (little organs)
Fluid matrix that suspends the organelles of the cell
______________________: Powerhouse of cell
Organelles
Endoplasmic Reticulum: _____________________ of the cell
_________________ ER (rER): contains ribosome
Participates in _______________ synthesis
___________________ ER (sER): does not contain ribosomes
Participates in _______________ sysnthesis and detoxification
__________________: Packaging site for protiens and lipids
__________________: cell’s digestive system, contains enzymes
3. ________________: Control center of Cell
Nuclear _________________: controls what goes in and out of nucleus
________: code book for reproduction and protein synthesis
__________________: Where RNA and ribosomes are made
Chapter 7
Metabolism: From Food to Life
What is Metabolism?
Metabolism is sum of _____ chemical and physical processes by which the body _____________ down and
_______________ up molecules
The specifice types of metabolic reactions _____________ or __________________ energy
For example
Anabolism
_______________________ is the process of making larger, chemically complex molecules from
smaller ones
Critical for ____________, ______________, maintenance and synthesis of body tissue
_________________ energy
Catabolism
_______________________ is the breakdown or degradation of larger, more complex molecules to
smaller, more basic molecules
Occurs during digestion of macromolecules
Old tissues or cells are ________________ down for repair or replacement
_________________ energy
Metabolic reactions are usually linked.
What are the molecules important for these chemical reactions?
Adenosine Triphosphate (ATP)
ATP is an organic compound used by cells as a source of energy
How is it used?
Enzymes, cofactors and coenzymes
________________
Molecules that ____________________ chemical reaction
Is it simply just speeding up these chemical reactions?
Enzyme Action
What about the cofactors and coenzymes?
Helpers for enzymes
Cofactors
____________________
____________________ (Iron, Magnesium, and Zinc)
Coenzyme
_____________________
_____________________ (Vitamin B-Complex)
Metabolic Pathways
Metabolic pathways are clusters of chemical reactions that occur __________________________ to achieve
a particular goal
Occur in a specific part of a _______________
May be limited to specific organs or tissues
____________________________ is the site of energy production in the nucleus of the cell
Additional chemical reactions
___________________________ (_____________________) is an anabolic process
Water is ____________________ as a by-product
A—OH + H—B  A—B + H2O
____________________ is usually a catabolic process
A large molecule is broken apart with the ____________________ of water
A—B + H2O  A—OH + H—B
______________________ is the addition of phosphate group to a compound
When the 2 high-energy phosphate bonds in ATP are hydrolyzed
energy is ____________________
_______________________ is transferred to other molecules
Oxidation-Reduction Reactions
Molecules exchange electrons (________________)
__________________ – lose of one or more electrons
__________________ – gain of one or more electrons
Exchange reactions occur together
Molecule donating an electron is _____________________
Its electron is removed by ________________
Molecule acquiring an electron is ___________________
In gaining an electron, it becomes more _______________________ charged
Since most chemical reactions or pathways will involve the use of energy how do we exact make our energy
currency?
What is our energy currency?
Energy from Carbohydrates
When glucose is transported to the liver, it is
Phosphorylated and metabolized for _______________ or stored as ____________________
Released into circulation for other cells to use as ________________ or _____________ as glycogen (muscle
tissue)
Converted to fatty acids, if glucose exceeds caloric needs, and ___________ as triglycerides in adipose tissue
Fructose and galactose are ______________ to __________________ in the liver and follow the same process
Let’s first focus on how to extract energy from the carbs we eat.
Summary of Glucose Oxidation
___________________ Pathway
Requires ______
3 Major Stages
__________________
Breaks down glucose (6-C) to two _____________________ (3-C)
Occurs in the _________________
Requires 2 ATPs
Produces a total of 4 _________ and 2 _____________
Anaerobic reaction?
In the Absence of Oxygen…
In the Presence of Oxygen…
________________/_____________________ Step
Convert ______________________ to ______________________
Loss of 2___________ from the pyruvates
_________________ is produced in the process
Occurs in the __________________________
______________________________ Acid Cycle
a.k.a. _______________ Cycle
Acetyl CoA is broken down completely to _____________.
cells use carbon skeletons of intermediates to produce other organic molecules (amino acids).
energy harvested per acetyl CoA:
___ ATP
___ NADH
___ FADH2
______________________ Transport Chain
Series of proteins & electron carriers embedded in the inner mitochondrial membrane.
_________ is the final electron acceptor
_________ is the final product
Summary of Glucose Oxidation
What about Energy from Fat?
________________: dietary and adipose triglycerides are broken down by lipase to yield glycerol and three
free fatty acids
_______________ is converted to pyruvate, then to acetyl CoA for entry into the TCA cycle
______________________________ are used for energy or stored (-oxidation)
_______________________ of Fatty Acids
Attached to ____________________, fatty acids are transported to working cells in need of energy
(muscle or liver cells)
Fatty acids must be activated by Coenzyme A before being shuttled across the mitochondrial membrane by
carnitine
Long-chain fatty acids are broken down into two-carbon segments to form acetyl CoA
What about Energy from Proteins?
______________________: dietary proteins are digested into amino acids or small peptides
Amino acids are transported to the liver
Made into _____________
_______________ into the blood for uptake by other cells for building and repair functions
The body _____________ using carbohydrates and fat for energy
Protein are used for fuel primarily during ____________ total energy or carbohydrate intake
Energy from Protein
Excess dietary protein
used for energy or ______________ to __________ acids for storage as triglycerides
Alcohol Oxidation
Alcohol is oxidized primarily in the liver by enzymes:
Alcohol dehydrogenase (ADH)
Aldehyde dehydrogenase (ALDH)
Microsomal ethanol oxidizing system (MEOS)
First-pass metabolism: small amount of alcohol is ______________ in the stomach, before being absorbed
into the bloodstream
Gastric ADH activity
Reduces alcohol absorption
Genetic differences in amount of activity
Alcohol Absorption
Most is absorbed into the blood and transported to be ________________ by the liver
Liver typically oxidizes alcohol at a constant rate (about 1 drink per hour)
This rate varies with the individual's genetic profile, state of health, body size, use of medication, and
nutritional status
Excess alcohol goes back into the ________________
Now let’s look at metabolism during feeding, fasting, and starvation
But before we do so let look at Synthesizing Macronutrients
Synthesizing Macronutrients
________________________: making glucose from nonglucose substrates
Primarily from glucogenic __________________
Vital ________________- proteins (skeletal and heart muscles and organ proteins)
Small amount from ___________ (triglyceride)
Maintains blood glucose during sleep, fasting, trauma, and exercise
____________________ catabolism for glucose production can draw on vital tissue proteins (skeletal and
heart muscles and organ proteins)
Fatty Acids Cannot form Glucose
There is ___________________ to convert acetyl CoA to pyruvate
Since acetyl CoA cannot be converted to glucose, fatty acids cannot be converted to glucose
Therefore you get ketogenesis
Ketoacidosis
____________ are by-products of fat catabolism
____________ occurs when ketones (acidic) inappropriately lower blood pH
_________________ occurs when blood pH falls, further resulting in severe dehydration
___________________ (de novo synthesis): making fat from nonfat substances such as carbohydrates, amino
acids, and alcohol
When consuming _______________ calories, acetyl CoA units form fatty acid chains
Fatty acids _____________ with glycerol to form triglycerides
Mostly occurs in liver cells
Amino acid synthesis
The body makes the carbon skeleton of nonessential amino acids (_______)
Amine group comes from ________________________
Synthesis of NEAA occurs ________ when the body has enough energy and nitrogen
Since essential amino acids cannot be synthesized,they must be consumed
Metabolism during Feeding
__________________ state: bloodstream is enriched with glucose, fatty acids, and amino acids
Glucose is stored as _______________________
When glycogen stores are saturated, remaining glucose is stored as triglycerides
Fatty acids are stored as triglycerides mostly in adipose tissues
Amino acids are deaminated and carbon skeletons are converted to fatty acids for storage as triglycerides
Metabolism during Fasting
Liver glycogen is broken down, releasing ____________ into the blood
Most cells can switch to using fatty acids as fuel to conserve glucose for brain and other cells that rely on
glucose as fuel
__________________ form as acetyl CoA units are blocked from entering TCA cycle
__________________ synthesis from glucogenic amino acids and glycerol
Metabolism during Starvation
The body switches to ______________________________
Blood glucose is maintained to support brain and red blood cells
Activity, body temperature, metabolism decline
Fatty acids become the primary fuel
Brain cells start to use ketone bodies as fuel
Muscle protein supplies glucose
Nutrients Involved in Energy Metabolism
Vitamins vs Minerals
Vitamins
______________ molecules that assist in regulating body processes
______________
Minerals
_____________ substances required for body processes.
Vitamins and Metabolism
Do not ________________ provide energy
Are needed for generating energy from ___________________
B-vitamins are particularly important in assisting energy metabolism
Often function as _________________
Let’s first focus on Vitamins and Metabolism
__________________: a protein that accelerates the rate of a chemical reaction.
Enzymes are _____________- for all metabolic reactions.
_________________: a molecule that combines with an enzyme to facilitate enzyme function.
___________ metabolic reactions require coenzymes.
Vitamins and Metabolism
B-complex Vitamins
The B-complex vitamins are especially important for energy metabolism.
_______________ (vitamin B1)
Food Source:
Function:
Coenzyme thiamin pyrophosphate (_______) required for metabolism of carbohydrate and
branched-chain amino acids and production of DNA and RNA and synthesis of
neurotransmitters
Deficiency
____________________ – thiamin deficiency results in muscle wasting and nerve damage
Occurs where polished rice is the only staple
________________ neuropathy
Impaired sensory, motor and reflex
Have difficulty rising from squatting position
Occurs within ___days on a thiamin deficient diet
Toxicity
_______________________ (vitamin B2)
Food Source:
Good source: milk, enriched foods, meat
Light _____________ (use opaque milk cartons)
Function:
component of 2 coenzymes involved in oxidation-reduction reactions in metabolism
__________ and ___________
part of antioxidant enzyme glutathione peroxidase
Deficiency
___________________ – riboflavin deficiency; sore throat, swollen mucous membranes
Toxicity
__________________
Nicotinamide and nicotinic acid
Food Source:
Good sources: meat, fish, poultry, enriched bread products
Can be made from amino acid ________________
Function:
Required for oxidation–reduction reactions of carbohydrates, proteins, and fats
_______ and ________
Deficiency
________________ – severe niacin deficiency
Occurs in 50-60 days
Prevented with an adequate protein diet
Consequences of deficiency
Diarrhea, Dementia, Dermatitis
Toxicity
Toxicity can result from ____________________
Flushing of skin, Itching, Nausea, and Liver damage
Vitamin B6 (___________________)
Food Source:
Good sources: enriched cereals, meat, fish, poultry, starchy vegetables
Function:
Group of 3 related compounds
______________, Pyridoxine, Pyridoxamine
Coenzyme for over _____ enzymes in amino acid metabolism
Decarboxylation of amino acid
Transamination reaction
Deficiency
_____________________________
Seborrheic dermatitis
Convulsion, depression, confusion
Toxicity
Toxicity from ________________ can result in nerve damage, skin lesions
_______________ (_____________ acid)
Food Source:
Good sources: Liver, fortified breakfast cereals, grains, legumes, foliage vegetables
Function:
Works with enzymes are critical for ______ synthesis, cell differentiation, amino acid metabolism,
and repair of damaged cells
Plays a special role in embryo development
Coenzyme tetrahydrofolate (_______) involved in DNA synthesis and amino acid metabolism
Involved in the metabolism of ____________________
Deficiency
_________________ anemia
Similar signs and symptoms of vitamin B-___deficiency
___________________ defects
Toxicity
A masking of symptoms of vitamin B-12 deficiency
___________________ damage
Vitamin B12 (_____________________)
Food Source:
Good sources: Organ meat, Seafood, Eggs, Hot dogs, Milk
Function:
Includes a number of compounds that have a _______ center surrounded by a ring structure
Works with coenzymes to assist ______ synthesis; essential for nervous system functioning
Part of _____________ that assists with formation of blood and homocysteine metabolism
Deficiency
________________ anemia
______________ degeneration, weakness
Tingling/numbness in the extremities (__________________)
Paralysis and death
Toxicity
____________________ acid
Food Source:
Good sources: chicken, beef, egg yolk, potatoes, oat cereals, tomato products
Function:
Component of coenzymes for fatty acid metabolism
___________________________
Required for _________________ cholesterol, steroids, and detoxification of drugs
Deficiency
___________
Listlessness, fatigue, headache, sleep disturbance, nausea, abdominal distress
______________ at risk
Usually in combination with other deficiencies
Toxicity
_________________
Food Source:
Biotin content has been determined for very few foods
Cauliflower, yolk, liver, peanuts, cheese
______________ synthesis of biotin
Function:
Part of coenzymes involved in ___________________ of carbohydrates, fat, and proteins
A component of coenzymes used for fatty acid synthesis, ______________________
Deficiency
Deficiency seen in large consumption of ______________ egg whites over time
Symptoms: hair thinning, hair color loss, red rash
Toxicity
_________________ is a vitamin-like substance
Food Source
Good sources: milk, liver, eggs, peanuts
Function
Assists in ____________________ metabolism
Accelerates the synthesis of __________________, a neurotransmitter
Fat and cholesterol metabolism/transport
Deficiency
Deficiency can lead to fat ___________________ in the liver
Toxicity
Toxicity can result from supplements
_______________ body odor
Vomiting
Excess salivation
Sweating
Diarrhea
Low Blood Pressure
Minerals and Metabolism
_____________ (__)
Iodine is a ____________- mineral.
Food Source
Good sources: saltwater fish, shrimp, iodized salt, milk and dairy products
Function
Critical for the synthesis of _____________ hormones
Thyroid hormones _____________ body temperature and resting metabolic rate
Important for healthy reproduction and growth
Deficiency
Iodine deficiency disorders (IDDs)
_____________ –thyroid enlarges to capture more iodine
________________ – mental retardation from iodine deficiency during embryonic development
________________ – low thyroid hormone results in low body temperature, cold intolerance, weight
gain, fatigue
_________________ -high levels of thyroid hormone caused by Graves' disease
Weight loss, increased heat production, muscular tremors, nervousness, racing heartbeat, and
protrusion of the eyes
Toxicity
Interferes with thyroid function
Over consumption of seaweed
Chromium (____)
Chromium is a _____________ mineral.
Food Source
Good sources: mushrooms, prunes, dark chocolate, nuts, whole grains
Function
Assists __________ to transport __________ from the bloodstream into the cells
Important for RNA and DNA metabolism
Supports normal growth and immune function
Deficiency
Chromium deficiency uncommon
Induced in labs: raises blood glucose and insulin
Toxicity
High-dose supplementation safety is unknown
Manganese (___)
Manganese is a ___________ mineral.
Food Source
Good sources: whole-grain foods, brown rice, pineapple, pine nuts, okra, spinach
Function
A _________________ in protein, fat, and carbohydrate metabolism, gluconeogenesis, cholesterol
synthesis, and urea formation
Part of the antioxidant enzyme _____________________________
Deficiency
Toxicity
Toxicity impairs the nervous system causing spasms and tremors
Sulfur (___)
Sulfur is a ______________ mineral.
Food Source
Found in a few amino acids
Function
Component of ____________ and _______________
Part of amino acids: methionine, cysteine
Required for detoxification of alcohol and drugs by the liver
Assists in maintaining acid–base balance
Deficiency
Sufficient sulfur is synthesized from the protein in our ______________
Toxicity
B-vitamin Status
Diets high in unenriched processed foods provide inadequate levels of B-vitamins
Some B-vitamins lost in milling of grains are replaced by the enrichment process
Poor B-vitamin status impacts exercise
Limited studies show poor work performance: lower intensity and duration