Chapter 24) Metabolism and Nutrition Flashcards
1
Q
Nutrition
A
- Nutritent) A substance in food the body uses for growth, maintenace, and repair.
- Major Nutirents (Macronutrients)
- Buld of ingested food
- Carbs, Lipids and Proteins.
- Other Nutrients (micronutrients)
- Required in smaller ammounts
- Vitamins and minerals
- Water is important but not a nutrinent
- Food Gorups) Fruits, Vegtables, Grains, Protein, Dairy
- Essential Nutrients) nutrients that cannot be syntasized by the liver
- Around 40 molecules
- Non-essential nutrients viral to life as well.
2
Q
Proteins
A
- Complete Protiens
- Meet all the bodys protein requirments
- Eggs, Milk, Fish and most meats
- Incomplete proteins
- Nuts, Legumes, Beans, Cereals are protein rich but incomplete because they don’t contin all proteins needed for building
- can be complete if ingested together.
- All or None Rule) All amino acids need to be present to build a specific protein. If one is missing protein may not be built.
- Amino Acids are not stored.
3
Q
Vitamins
A
- Two Types
- Water-Soluable Vitamina
- B complex and C are absorbed with water
- B12 requires intrensic factor
- Any not used are excreted from the body within one hour; issues with accumulation are rare
- Fat-soluable Vitamins
- A, D, E. and K absorbed with lipid digestion products
- Sored in the body, except for vitamin K
4
Q
Metabolism
A
- Metabolism) Biochemical reactions inside cells involving nutrients
- Two reactions
- Anabolism) synthesis of large molecules from small ones
- ex) amino acids > Proteins
- Catabolsim) hydrolysis of complex strucures to simpler ones
- Ex) Proteins > Amino Acids.
- three major Stages
- Stage 1) Digestion and absorption in GI tract
- moves nutrients into blood then the tissue cells
- Stage 2) Occurs in the Cytoplasm of Tissue Cells
- Nutrients are build into lipids, proteins or glycogen by anabolic pathways or broken into smaller fragemnts by catabolic pathways
- Many end up as Pyruvic acid, a metabolic intemediate
- Stage 3) Occurs in Mitohondria
- Almost completely catabolic; requiures O2 and comlete breakdown of all stage 2 products.
- Most are converted into acetal CoA > CO2, ATP
5
Q
Cellular Respiration
A
- Group of catabolic reacations collecively called cellular respiration
- Glycolysis
- Citric Acid cycle
- Oxidative phosphorylation
- Catabolism of fuel from food is captured in the form of ATP in cells
- as ATP is hydrolyzed, Enymes shift high energy phosphate to other molecules (phospholrilztion)
- Phosphorylated molecules activated to preform cellular functions
- Goal > Trap chemical enrgy in ATP
- Energy is also stored in glycogen and fats
- Oxidation of Food for Fuel.
6
Q
Carb Metabolism
A
- oxidation of Glucose
- CH12O6 + 6O2 > 6H20 + 6CO2 + 32ATP + Heat
- Requires work of three pathways
7
Q
Glycolysis
A
- Glycolysis) “Sugar Splitting” (Glycotic pathway)
- 10 step pathway
- Convert glucose to two pyruvic acid
- All steps are fully reversable except for the first (can be converted back to gluose)
- Reaction keeps intercellular glucoce concentration low > continued glucose entry rrwuired
- Anerobic) occurs with or without the presence of O2
- Final Products of Glycolysis
- 2 Pyruvic Acid (C3H4O3)
- 2 NADH + H+
- Net gain of 2 ATP (2 in 4 out)
- NAD+ Must be present to acccept H+ atoms for glycolysis to continue
- NAD+ supply limited; NADH must dontate H+ to become NADH+ and for glycolysic to continue
- O2 Present) Occurs in midochondria in Eletron transport chain (ETC)
- No O2 present) NADH gives H+ to pyrivic acid and it becomes Latic Acid.
- Fate of Latic Acid
8
Q
Role of NADH/ production of Latic Acid
A
- NAD+ Must be present to acccept H+ atoms for glycolysis to continue
- NAD+ supply limited; NADH must dontate H+ to become NADH+ and for glycolysic to continue
- O2 Present) Occurs in midochondria in Eletron transport chain (ETC)
- No O2 present) NADH gives H+ to pyrivic acid and it becomes Latic Acid.
- Fate of Latic Acid
- Some laves cell > liver
- May be converted to Glucose-6-Phosphate for storage
- May be de-phosphorlyated and release glucose to the blood.
9
Q
Transitional Phase) Citric Acid Cycle (Krebs Cycle)
A
- Occurs in Mitochondrial Matrix
- Fueled by pyruvic acid from glycolysis and fatty acids from fat breakdown.
- Transitional Phase
- Occurs between glycolysis and Citric Acid Cycle
- Converts Pyruvic Acid to Acetyl CoA (Coenzyme A)
- Forms Molecule of CO2 and NADH
- Products of Each Turn of The Citric Acid Cycle
- 1 glucose > 2 Pyruvic acid > 2 turns of Krebs cycle
- Final Producets) 6NADH, 2FADH2, 4CO2, 2ATP,
10
Q
Electron Transport Chain and Oxidative Phosphorlation
A
- None of the reactions in the citric acid cycle use oxygen diretly
- ELectron Transport Chain) Carries out final catabolic reactions in mitochondrial membrane
- Reduced coenzymes produced in citric acid cycle are the substrates for the electron transfer chain
- Pathways are coupleled and aerobic (oxygen required)_
- Overview
- NADH + H+ and FADH2 (From glycolysis and Krebs Cycle) deliver H+ atoms
- H+ combines with O2 to form water
- Energy releases harnessed > Turned into ATP via Oxidative Phosphorlization
11
Q
Summary of ATP prodution
A
- Complete Oxifation of 1 Glucose
- Glycolysis + Krebs Cycle + Electron Transport Produces Co2, H20, and 32 molecules of ATP.
- Net result is about 30 ATP because of energy required to move NADH+ H+
12
Q
A
13
Q
Glycogenesis, Glycogenolysis, and Glucogenesis
A
- Glycolysis) Converts Glucose to Pyruvic Acid.
- Glycogenisis) Polymerizes glucose to form glycogen
- Liver and Skeletal mucles
- Glycogenolysis) Hydrolyzes glycogen to glucose monomers
- hepatocytes and some kindey and intestinal cells
- Gluconeogenisis) Forms glucose from noncarb precursors
- Formed in liver from glycerol and amino acids when blood glucose drops
- Protects agains hypoglycemia.
14
Q
Lipid Metabolism
A
- Greater Energy yield from glucose or proteins catabolism
- Chylomicrons) products of fat digestion transported in the lymph
- Hydrolyzed by endothelial enxymes into Fatty Acids and GLycerol
- Only Triglycerides are oxidixed for energy
- Two building blocks oxidized seperatly
- Glycerol Pathway
- Glycerol > Glyceraldhyde-3Phosphate (same as glycolysis)
- Enters the Krebs Cycle
- Yeilds about 1/2 the ATP of glucose (15 ATP per glycerol)
- Fatty Acid Pathway
- Pathway in which fatty acids are broken.
- Turns fatty acids into Acytel CoA
15
Q
Lypogenisis
A
- Diatary Glycerol and Fatty Acids not needed for energy > Stored as Triglerecided
- Tryglyceride Synthesis (Lipogenesis)
- Occurs when cellular ATP and glucose levels are high
- Glucose easily converted to fat because acetyl CoA
- Is intermediate in glucose catabolism
- Starting point for Fatty Acid Synthesis