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Biology 235 > Chapter 25: Metabolism And Nutrition > Flashcards

Chapter 25: Metabolism And Nutrition Flashcards

1
Q

Metabolism

A

Refers to all of the chemical reactions that occur in the body.
2 types: catabolism and anabolism.
Produce nonvolatile acids

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2
Q

Catabolism

A

Or decomposition
Chemical reactions that break down complex organic molecules into similar ones.
These reactions are exergonic: produce more energy than they consume, releasing the chemical energy stored in organic molecules.

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3
Q

Anabolism

A

Or synthesis
Chemical reaction that combine simple molecules and monomers to form the complex structural and function components.
Example: formation of peptide bonds between amino acids.
Are endergonic reaction: consume more energy than they produce.

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4
Q

ATP-Adenosine Triphosphate

A

Molecule that participates most often in energy exchanges in living cells.
Couples energy relabeling catabolic reactions to energy requiring anabolic reactions.
Contains 3 prostate groups
Greatest amount of emergency stored in ATP is in the 3rd phosphate group
Provides energy for formation of peptide bonds between amino acids to form a peptide

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5
Q

Coupling of Catabolism and Anabolism by ATP

A

ATP couples catabolic (decomposition) reactions with anabolic (synthesis) reactions.
Catabolic (Energy released) is used to drive anabolic reactions.
Energy from complex molecules in catabolic reactions to combine ADP and a phosphate group to resynthesize ATP.
ADP+P+ energy=ATP
40% of energy released in catabolism is for cellular functions. The rest (60%) is converted to heat to maintain body temp.

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6
Q

Oxidation

A

Also known as: dehydrogenation
Is the removal of electrons from an atom or molecule.
Results is a decrease in potential energy of the atom or molecule.
Reaction is: exergonic

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7
Q

Dehydrogenation Reactions

A

Most biological oxidation reactions involve the loss of hydrogen atoms.

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8
Q

Reduction

A

Opposite of oxidation.
Is an addition of electrons to a molecule.
Results in an increase in the potential energy of the molecule.

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9
Q

Nicotinamide Adenine Dinucleotide (NAD)

A

A coenzyme that is commonly used by animal cells to carry hydrogen atoms.
Derivation of the B vitamin niacin.

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10
Q

Flavin Adenine Dinucleotide (FAD)

A

Coenzyme commonly used by animal cells to carry hydrogen atoms.
Derivative of vitamin b2 or riboflavin

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11
Q

Oxidation-Reducation

A

Or redox reactions
Are always coupled. Each time one substance is oxidized another is simultaneously reduced.

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12
Q

Phosphorylation

A

Addition of a phosphate group to a molecule to increase its energy potential.
Forms: substrate, oxidative, photo

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13
Q

Organism use 3 Mechanism of Phosphorylation to Generate ATP

A
  1. Substrate level phosphorylation: generate ATP by transferring a high energy phosphate group from a substrate directly to ADP. Occurs in cytosol.
  2. Oxidative phosphorylation: removes electrons from organic compounds and passed them through a series of electron acceptors called electron transport chain to molecules of O2. Occurs in mitochondrial membrane.
  3. Photophosphorylation: occurs only in chlorophyll-contained plant cells or in certain bacteria that contain other light absorbing pigments.
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14
Q

Glucose

A

Bodies prefers source for synthesizing ATP.
Complete oxidation includes: water, CO2, ATP, O2

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15
Q

ATP Production: Glucose

A

Body cells that require immediate energy, glucose is oxidized to produce ATP.

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16
Q

Amino Acid Synthesis: Glucose

A

Excessive amino acids are converted into glucose
Cells throughout the body can use glucose to form several amino acids which can be incorporated into proteins.

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17
Q

Glycogen Synthesis: Glucose

A

Hepatocytes and muslce fibers can perform glycogensis. Storage of glycogen: 125 g in liver, 375 g in skeletal muscles.

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18
Q

Triglyceride Synthesis: Glucose

A

When glycogen storage ares are filled up, hepatocytes can transform the glucose to glycerol and fatty acids by lipogenesis.
Triglycerides are deposited in adipose tissue.

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19
Q

Glucose Movement into Cells

A

Occurs by facilitated diffusion
A high level of insulin in the body increase the insertion of one type of GluT called GluT4 into plasma membranes of most body cells there by increasing the rate of facilitated diffusion of glucose into cells.

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20
Q

Glycolysis

A

Chemical reactions spilt 6 carbon molecules of glucose into 2 3-carbon molecules of pyruvic acid.
Key Regulator for Rate: phosphofrutokinase
Thyroid hormone promotes this process
Occurs in: cytosol
Does not require O2 so it can occur under aerobic or anaerobic conditions.
ATP: 2 from substrate level phosphorylation

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21
Q

Pyruvic Acid

A

Produced by glycolysis.
Used in metabolic crossroads
Its fate depends on the availability of O2.
If O2 is scare: pyruvic acid is reduced via anaerobic pathway by the addition of 2 hydrogen atoms to form lactic acid.
2 pyruvic acid+ 2 NADH+2H= a lactic acid + 2 NAD.

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22
Q

Coenzyme A (CoA)

A

Derived from pathothenic acid a B vitamin.
Enzyme required in oxidation of glucose.
Used in cellular respiration.

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23
Q

The Krebs Cycle

A

Oxidation of acetylcholine CoA to produce CO2, ATP, NADH + H and FADH2
Most abundant product: reduced coenzymes
ATP production: 1
Reactions: 8
Reaction occurs in matrix of mitochondria.
Once pyruvic acid has undergone decarboxylation and remaining acetyl group has attached to CoA, resulting compound acetyl CoA enters this cycle.
Reduction reactions and decarboxylation reactions that release co2.
Oxidation-reduction reactions transfer chemical energy in form of electrons, 2 coenzymes, NAD and FAD.

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24
Q

Electron Transport Chain

A

Is a series of electron carries, integral membrane proteins in the inner mitochondrial membrane.
Membrane fold into Cristal that increase surface area accommodating thousands of copies of the transport chain in each mitochondria.
Each carrier in chain is reduced, picks of electrons and oxidized as it gives up electrons.
Electrons passing through chain, exergonic reactions releases energy used to form ATP.
ATP production: 26-28

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25
Chemiosmosis
Produces ATP is when hydrogen ions diffuse back into the mitochondria matrix. An accumulation of large amount of H between inner and outer mitochondria membranes occurs.
26
Glycogen
ATP combines with molecules of glucose. Polysaccharide that is only form of carbohydrate in the body.
27
Glycogenesis
Synthesis of glycogen when body does not immediately need ATP. Occurs when stimulation of insulin from pancreatic beta cells stimulates hepatocytes and skeletal muscle cells to carry this reaction out. Body can store about 500g of glycogen, 75% in skeletal muscle fibers, 25% in liver cells.
28
Glycogenolysis
Is catabolic. Stimulated by: epinephrine Happens when body needs ATP. The process of splitting glycogen into its glucose subunits. Glycogen stored in liver is broken down into glucose and released into the blood to be transported to cells where is its catabolized by cellular respiration.
29
Gluconeogenesis
Process by which glucose is formed from noncarbohydrates sources. The glycerol part of triglycerides, lactic acid and certain amino acids are converted in the liver to glucose. Stimulates by cortisol.
30
Lipids
Are non polar, hydrophobic molecules. (Ie) triglycerides To be transported in watery blood they first must be made more water soluble by combining with proteins produced by the liver and intestines.
31
Lipoproteins
Lipid and proteins combination that is formed to make lipids transportable in watery blood. Spherical particles with an outer shells of proteins, phosolipids and cholesterol molecules, Outer shell is known as: apoprotiens (apo).
32
Chylomicrons
Transport dietary lipids to adipose tissue for storage. Form in mucosal epi cells of small intestine. Contains: 1-2% proteins 85% triglycerides 7% phosolipids 6-7% cholesterol Small amount of fat soluble vitamins
33
Very Low Density Lipoproteins (VLDLs)
Form in hepatocytes Contain mainly endogenous lipids. 50% of triglycerides Transport triglycerides synthesized in hepatocytes to adipocytes for storage.
34
Low Density Lipoproteins (LDL)
Carry about 75 % of total cholesterol in blood. 5% triglycerides Deliver it to cells throughout body for use in repair of cell membranes and synthesis of steroid hormones and bile salts. Contain single protein: apo B100.
35
High Density Lipoproteins (HDL)
Removes excess cholesterol from body cells and the blood. Transport it to the liver for elimination. 5-10% triglycerides
36
The Fate of Lipids
Lipids can be oxidized to produce ATP. If body does not need lipids (triglycerides) they are stored in adipose tissue in body and liver.
37
2 Essential Fatty Acids the Body cannot Synthesize
Linoleum acid Linolenic Acid
38
Triglyceride Storage
Major functions of adipose tissue: to remove triglycerides from chylomicrons nad VLDLS and stores them until they are needed for ATP production in other parts of the body. Triglycerides stored in adipose tissues constitutes 98% of all bodies energy.
39
Lipolysis
Catalyzed by enzymes called lipase. Fasting increase this process. Process is carried out by hepatocytes and adipose tissue Triglycerides must split into glycerol and fatty acids for muscle, liver, adipose tissue to oxidize the fatty acids derived from triglycerides to produce ATP.
40
Beta Oxidation
First stage in fatty acid catabolism. Fatty acids yield more ATP than glycerol. Found in matrix of mitochondria.
41
Ketone Bodies
Can enter the Krebs cycle or be used for ATP Formation of 3 substance from fatty acid catabolism: 1. Aceteoacetic acid 2. Beta-hydroxybutyric acid 3. Acetone Process of this formation is: ketogenesis Formed by hepatocytes Ketone bodies freely diffuse through plasma membranes, leave hepatocytes and enter bloodstream During fasting or starvation, these can be used for ATP production
42
Lipogenesis
Stimulated by insulin. Occurs when individuals consume more calories than are needed to satisfy their ATP needs. Synthesis of triglycerides Liver cells and adipose cells can synthesize lipids from glucose or amino acids.
43
Proteins
During digestion, proteins are broken down into amino acids. Not stored for future use. Used for: 1. oxidized to produce ATP 2. synthesize new proteins for body growth and repair.
44
Fate of Proteins
Active transport of amino acids into body cells is stimulated by IGFs and insulin. Once digested amino acids are reassembles into protein. Some function as enzymes, others in transport. Some serve as antibodies, clotting chemicals, hormones, contractile elements in muscle fibers.
45
Delamination
Occurs in hepatocytes. Produces ammonia. Before amino acids go through Krebs cycle, their amino group (NH2) must be removed.
46
Protein Anabolism (Synthesis)
Formation of peptide bonds between amino acids to produce new protiens. Carried out on the ribosomes of almost every cell in the body. Directed by cells of DNA and RNA. Stimulated by: insulin Growth like factors Thyroid horome Estrogen and testosterone
47
Essential Amino Acids
Of 20 amino acids, 8 are essential and must be present in our diet. Excess of amino acids are converted into glucose.
48
Complete Proteins
Contain sufficient amounts of all essential amino acids (Ie) beef, fish, poultry, eggs, milk
49
Incomplete Proteins
Does not contain all essential amino acids. (Ie) leafy green, legumes, grains.
50
Nonessential Amino Acids
Can be synthesized by body cells. Formed by transamination, the transfer of an amino group from an amino acid to pyruvic acid or to an acid in the Krebs cycle.
51
Metabolic Adaptation
Regulation of metabolic reactions depends both on chemical enviroment in body cells and signals from nervous systems and endocrine system. 2 States: 1. Absorptive State: ingested nutrients are entering the bloodstream. Glucose is available for ATP production. 2. Post absorptive State: absorption of nutrients from the GI tract is complete. Energy needs must be met by fuel already in the body.
52
Energy Balance
Refers to the precise matching of energy intake to energy expenditure over time.
53
Calorie (Cal)
Defined as the amount of energy in the form of heat required to raise the temp of 1 gram of water 1degree. Calories from proteins: 12-15% Calories from carbs: 50-60% Calories from simple sugars: less than 15% Calories from fats: less than 30% Calories from saturated fats: less than 10%
54
Kilocalorie (kcal)
Often used to express the energy content of food. 1 kcal = 1000 calorie When a food item contains 500 calories it is referring to kcal.
55
Metabolic Rate
Overall rate at which metabolic reactions use energy. Some energy is used to produce ATP, some is related to produce heat. The higher the metabolic rate the higher rate of heat production.
56
Several Factors Effect Metabolic Rate
1. Hormones: thyroid hormones are main regulator for basal metabolic rate. 2. Exercise: during exercise, the metabolic rate may increase to as much as 15 times the basal rate. 3. Nervous System: during stressful situations the sympathetic division is stimulated release epi and norepinephrine. 4. Body Temp: higher body temp, higher metabolic rate. 5. Ingestion of food: food raises metabolic rate 10-20% due to energy costs of digesting, absorbing and storing nutrients. 6. Age: metabolic rate of child in relation to size is double that of an elderly person related to growth. 7. other factors: gender (lower in females), climate(lower in tropical regions)and malnutrition (lower)
57
Basal State
Conditions within the body in a quiet, resting and fasting condition. How metabolic rate is measured under standard conditions.
58
Basal Metabolic Rate (BMR)
Measurement obtained under the basal state conditions.
59
Food Induced Thermogenesis
Is greatest after eating a high protein meal. Is less after eating carbohydrates and lipids.
60
Total Metabolic Rate (TMR)
Total energy expenditure by the body per union of time. 3 components contribute to TMR: 1. BMR: 60 % 2. Physical Activity: 30-35% 3. Food induced thermogenesis: 5-10%, heat produced while food is beingdigested, absorbed and stored.
61
Non-Exercises Activity Thermogenesis (NEAT)
Energy cost for maintaining muscle tone, posture while sitting or standing and involuntary fidgeting movements.
62
Satiety
Feeling of fullness accompanied by lack of desire to eat. Hypothalamus contains a cluster of neurons that regulates food intake.
63
Leptin
Hormone that helps to decrease adiposity: total body fat mass. Synthesized and secreted by adipocytes. Can pass through the brain blood barrier.
64
Neuropeptide Y
Neurontransmitter that is relapses when leptin and insulin levels are low. Stimulates food intake.
65
Ghrelin
Hormones involved in the regulation of food intake. Produced by endocrine cells in the stomach. Plays a roll in increasing appetites.
66
Heat
Is form of energy that can be measures in temperature. Factors that affect heat: Exercise Hromeone Nervous system Ingestion of food
67
Core Temperture
Temp in body structures deep to the skin and SC layer. Process that increase core temp: 1. Constriction of blood vessels of skin 2. Increase cellular respiration 3. Shivering 4. Thyroid hormone induced increase in metabolic rate If core temp is too high: kills by denaturing body proteins. If core temp is too low: causes cardiac arrhythmias that results in death.
68
Shell Temperture
Near the body surface in the skin and SC layer. Temp is 1-6 degrees lower than core temp.
69
Insensible Water Loss
Water loss that the body is not aware of from the skin and mucous membranes of mouth and resp system.
70
Hypothalamic Thermostat
Found in the the pre optic area: control center that functions as the bodies thermostat is a group of neurons in there anterior part of the hypothalamus Recieves input from thermoreceptors in skin and hypothalamus itself. Stimulates skeletal muscle activity Pre optic area progrades 2 areas: Heat losing center Heat promoting center These set int operation a series of response that lowers or raises body temp.
71
Thermoregualtion
Mechanisms that help conserve heat ANS increase heat production via negative feedback loop to raise body temperature back to normal 1. Vasoconstriction: heat promotion center stimulates sympathetic nerves that cause blood vessels of the skin to constrict to decreased flow of warm blood. 2. Releases of epi and norepinephrine: sympathy nerves of adrenal medulla stimulate releases of these hormones into blood to increase cellular metabolism. 3. Shivering: heat promoting stimulates parts of the brain to increased muscle tone and heat production. 4. Releases of thyroid hormone: thyroid glands responds to TSH by releasing more thyroid hormones into blood, increase metabolic rate.
72
Nutrients
Chemical substances in food that body cells use for growth, maintenance and repair. 6 main types: water, carbs, lipids, proteins, minerals and vitamins.
73
Essential Nutrients
Specific nutrients molecules that the body cannot make in sufficient quantity to meet its needs and thus must be obtains by diet. (Ie) amino acids, fatty acids, vitamins and minerals
74
Minerals
Inorganic elements that occurs naturally In body they appear in combination with one another, in combination with organic compounds act as ions.
75
Vitamins
Organic nutrient required in small amounts to maintain growth and normal metabolism. Vitamins do not provide emergency or serve as the body’s building materials.
76
Provitamins
Raw material or building blocks needed to assemble vitamins in the body.
77
Fat Soluble Vitamins
Vitamins A, D, E are absorbed along with other dietary lipids in small intestine and packages into chylomicrons.
78
Water Soluble Vitamins
Includes several vitamin B and C are dissolved in body fluids. Excess quantities of these vitamins are not stored and excreted in urine.
79
Antioxidant Vitmains
Vitamin C, E and Beta Carotene (pro vitamin). They inactivate O2 free radicals.
80
ADP- Adenosine Diphosphate
When the terminal phosphate is cut off ATP
81
Processes involved with Glucose Catabolism
Glycolysis Formation of CoA Krebs cycle Electron Transport chain
82
Pyruvate Dehydrogenase
Found in the mitochondria
83
Hepatocytes (Liver Cells)
Convert ammonia into urea
84
Absorptive State of Metabolic Reaction
Ingested nutrients are entering the bloodstream. Glucose is available for ATP production. Stores energy 50 % of glucose that enters the liver is converted to glycogen Insulin dominates this state Reactions include: Catabolism of glucose, amino acids, dietary fats Protein synthesis Glyogensis Lipogensis
85
Lactic Acid
Can produce ATP from cardiac muslces
86
Postabsorptive State of Metabolic Reactions
Absorption of nutrients from the GI tract is complete. Energy needs must be met by fuel already in the body. Involved in protein breakdown Primary hormone: cortisol Reactions include: Glycogenlysis Lipolysis Gluconeogenesis
87
Amino Acids
Once transported to the liver they: 1. Used for synthesis of fatty acids 2. Used for synthesis of glucose 3. Used for syntehsis of proteins 4. Used for ATP production in Krebs cycle
88
Total Energy Expenditure
Physical activity: 30-35% Food induced thermogenesis: 5-10% BMR: 60%
89
NADPH
Hydrogen and electron donator used in reeducation reactions for synthesize of fatty acids and steroid hormones. Is synthesized from glucose 6 phosphate as part of synthesis of Nucleic acid.
90
Phenylktonuria
Disorder produceted by a genetic error or protein metabolism Symptoms:L vomiting, rashes, seizures, growth deficiency and severe mental retardation.
91
ATP Production: 4 Different Steps
1. Glycolysis: 2 ATP 2. Acetylcholine Coenzyme A: 5 ATP 3. Krebs Cycle: 1 ATP 4. Electron Transport Chain: 26-28 ATP
92
Cholesterol Levels
Normal: under 200mg/dL Borderline high: 200-239 mg/dl Above high: 239 mg/dL
93
Radiation
Refers to heat loss of infrared rays between warmer objects and cooler objects without physical contact. In resting person loss is: 60%
94
Conduction
Heat exchange that occurs better 2 material that are in direct contact with eat other. At rest: 3% of heat is lost due to conduction
95
Convection
Is the transfer of heat by the movement of air or water between area of different temp. At rest: 15 % of body heat is lost
96
Evaporation
Is the conversation of a liquors to a vapor. 22% of heat loss occurs by evaporation. 700 ml of water/day 300 exhaled 400 from skin surface.
97
Hypothermia
When body temp falls below 35 degrees C Characterized by: Shivering Confusion Vasoconstriction Muscle rigidity Acidosis Hypotension Bradycardia Cardiac arrhythmias Coma then death
98
Deamination
The removal of the amino group from amino acid before they enter the Krebs cycle Occurs in hepatocytes Produces ammonia

Biology 235 (29 decks)

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