Chapter 24 - Metabolism Flashcards
What is a nutrient?
Substance in food needed for growth, maintenance and repair
What is a macronutrient?
three major nutrients that make up the bulk of ingested food - carbs, lipids, proteins
What is a micronutrient?
Two nutrients that are required, but only in small amounts - vitamins and minerals
What are the 3 major macronutrients?
Carbs, Lipids, Proteins
What is an essential nutrient?
45-50 Nutrients that must be eaten because the body cannot make/synthesize
What is a calorie?
essential nutrient
What is a Calorie?
energy value of food, sa
Which vitamins can be made up within the body?
Vitamin D (Skin) Vitamin B and K (Colon) Vitamin A (Converted from beta-carotene)
What are the fat soluble vitamins?
A, D, E, K
What is a mineral?
required in moderate amounts
Calcium Phosphorus Potassium Sulfur Sodium Chlorine Magnesium
What is a trace mineral?
Minerals required in trace accounts
What is the definition of metabolism?
All of the biochemical reactions inside of cells necessary to maintain life
What are the 2 types of metabolic reactions?
Anabolism
Catabolism
What is anabolism?
Synthesis of large molecules from smaller ones - ex) synthesis of protein from amino acids
What is catabolism?
Hydrolysis of complex structures to simpler ones - ex) break down of proteins to amino acids
What are the 1st stage of metabolism?
1) Digestion in the GI tract into absorbable form - products transported via blood to tissue cells
What is the 2nd stage of metabolism?
Anaolism and Catabolism of nutrients to form pyruvic acid w/in tissue cells
What is the 3rd stage of metabolism?
Oxidative breakdown of stage 2 products in mitochondria to get ATP - release CO2 and H20
What is the 3rd stage of metabolism?
Oxidative breakdown of stage 2 products in mitochondria to get ATP - release CO2 and H20
What is carbohydrate metabolism?
Oxidation of glucose
What is the reaction for carbohydrate metabolism?
glucose + oxygen –> water + carbon dioxide + ATP + heat
C6H12O6 + 6O2 –> 6H20 + 6CO2 + 32 ATP + Heat
What are three pathways to catabolize glucose?
Glycolysis
Krebs Cycle
Electron Transport Chain + Oxidative Phosphorlyation
Which pathway yields the most ATP?
ETC
What type of process is glycolysis?
Anaerobic, doesn’t need O2
Where does glycolysis take place?
Cytoplasm/Cytosol
What happens during glycolysis?
Glucose (6 carbon) broken down into 2 carbon pyruvate acid molecules (each with 3 carbons).
The 2 carbons then enter one of 2 pathways depending on O2 availability
In glycolysis, what are the 2 pathways carbon can enter?
Anaerobic or aerobic
What is the anaerobic glycolysis pathway?
lactic acid (mitochondria not involved)
What is the aerobic glycolysis pathway?
Krebs cycle, enters mitochondria
What is the net ATP production of one molecule of glucose in glycolysis?
2 ATP, fastest process but produces the least ATP
How are the krebs cycle and O2 related?
Doesn’t directly use O2, but O2 must be available for it to run
Where does the Krebs/Citric Acid/YCA process occur?
Mitchondria
In the krebs cycle, what molecules “enter” the cycle?
Coenzyme A hooked on to acetic acid
What are the products of the krebs cycle?
6 CO2
8 NADH + H+
2 FADH2
2 ATP
What goes “in” during the krebs cycle? And out?
3 carbon pyruvate go in
CO2, NADH+ H+ and FADH2 go out
What pathway requires oxygen?
ETC and Oxidative Phosphorylation
In ETC/Oxidative Phosphorylation how are hydrogen atoms delivered?
NADH+ H+ and FADH2
In ETC, where are H+ ions stored?
membrane space
Do cells store large quantities of ATP?
No
What happens when there are high levels of ATP in cells?
Glucose catabolism is inhibited, glyocen and fat formation are promoted
What is glycogenesis? Where does it occur?
Making glycogen, occurs mostly in liver and skeletal muscle
What is glycogenolysis?
Breaking down glycogen to make glucose
What is gluconeogensis? Where does it occur?
Making glycogen from non-carbohydrates such as protein and lipids; occurs in liver
When does glycogenolysis occur?
When blood glucose fall too low
When does glycogenolysis occur?
When blood glucose fall too low
What can the liver also use to make glucose?
protein and lipid
In lipid metabolism, what is the Kcal energy released from 1 gram of fat? And carbs and protein?
Fat - 9
Carbs/Protein - 4
How are fats transported?
In lymph as chylomicrons
What does fat digestion yield?
fatty acids plus glycerol
What are triglycerides a combo of
glycerol
3 fatty acids
What can lipids be broken down into?
Pyruvic acid and 2-carbon units of acetic acid and bound to COa (making acetyl CoA) - entering the krebs cycle
What do we use lipids for?
- Cell Membrane
2. Creation of phospholipids to make steroid hormones
What happens when excess protein is consumed?
Amino acids are oxidized for energy and converted to fat
What is transanimation
Amine group NH2 is removed to form keto acids - glutamic acid and keto acid
Where does keto acid go?
krebs cycle
Why is the amine group (NH2) converted? How is it excreted?
Converted to forms pyruvic or keto acid
Excreted thru kidney
Where does protein synthesis occur?
ribosomes
Who controls protein synthesis?
Hormones - growth hormone, thyroid hormone, sex hormones
What does protein synthesis require?
Complete set of amino acids
What are essential amino acids?
Proteins that must be supplied in the diet
What is a steady state?
Balance or equilibrium between catabolism and anabolism
The organic molecules in your body. are constantly being broken down and rebuilt - T/F
What’s the exception
True
DNA is the exception
What are the 3 interconvertible nutrient pools?
Amino Acids
Carbs
Fats
What is the absorptive state - controlled by, when does it occur, what is happening
1) The Fed State
2) Controlled by insulin 3) shortly after eating
4) Nutrient absorption where anabolism exceeds catabolism
What is being secreted during the absorptive state?
Insulin from the beta cells of the pancreas that are stimulated by elevated blood glucose
What is the post-absorptive state - status of GI tract, what is happening?
1) Fasting State
2) GI Tract is empty
3) Catabolism > Anabolism
In the post absorptive state, where does energy come from?
Energy supplied by breakdown of chemical reserves
When is Glucagon released? How?
1) Released to keep blood glucose up due to fasting or high amino acids
2) Glycogenolysis, Glycogenosis, lipolysis
What is energy balance?
Optimal state, input=output
How much energy is lost as heat?
60%
What is energy output?
Used to do work, driven by ATP
How is excess energy stored?
Stored as fat or glycogen which results in obseity
How do you calculate BMI?
wt (lb) x 705/height in^2
What is hyperthyroidism? What are the symptoms?
Oversecretion of thyroid hormone
Symptoms: increased hunger, weightloss
What is hypothyroidism?
Undersecretion of thyroid hormone
Symptoms: weight gain, slowed metabolism, diminished thought process
What is bad cholesterol?
LDL
What can high LDL indicate?
Likelihood of heart disease - artherosclerosis, CV disease, heart attack
How do you lower cholesterol?
Dietary management and exercise, statins
