Question

Metabolism and Energetics Anatomy: Mention at least 3 structures, parts and/or organelles of the cell involved in metabolic processes. Physiology: Describe Glycolysis; Kreb Cycle/Citric Acid Cycle/Tri-Carboxylic Acid (TCA) Cycle; Electron Transport Chain • Fluid, Electrolyte & Acid-Base Balance Anatomy: What is the percentage distribution of fluids between males versus females? What is the percentage distribution of fluids between intracellular versus extracellular fluids? Mention the percentage distribution of the specific varied Cations and Anions within the intracellular versus extracellular fluids. Physiology: What is a Buffer? Describe at least three buffer systems of the body.

Answer 1

Anatomy:

• Three anatomical structures involved in majority of metabolic activities are:

Liver, muscles, pancreas.

• Organelles include:

1. Mitochondria:

• The mechanism of oxidative phosphorylation occurs in mitochondria of live cells.

2. Peroxisomes:

• Fatty acid metabolism occurs in mitochondriamatrix and peroxisomes.

3. Ribosomes:

• Ribosomes participate in process of translation and help to synthesize proteins

Physiology:

1. Gycolysis:

• During glycolysis, from each molecule of glucose- 2 molecules of pyruvic acids are produced.
• Two molecules of pyruvic acids undergo oxidation in aerobic pathway to form two molecules of Acetyl co A.
• Thus, from 6 molecules of glucose 2 x 6 = 12 molecules of Acetyl co A will be produced.

Glucose -->2 Pyruvate—Oxidation à 2 Acetyl Co-A

Pyruvate thus generated, undergoes oxidation and with the help of enzyme pyruvate dehydrogenase complex is converted to acetyl co-A.

2 Pyruvate ---> 2 Acetyl Co-A

CHROH CHRON 6.44 chool Glucose OH Oth OH CAT? Herokinase ADP он 6 011 CHRON 1. 614 Go phosphate it anADE tapi CHROH Кон 04 1 Sucroses suerase Glucose 6- Phosphate K Но Phosphogluco CH2-OP 02- Fructoset I someone 041 Foructose - 6- Phosphate Phosphofructo • ATP OH kinase-l 4 ADP Fructosey, 6-bisphosphate Aldolase 04 H Dihydroxyacetone phosphate / Foiose phosphate So mepare chool - can 13. Phosphate Orc 1 0 1 HO Ho c-o-p-8- Irudo HQ NADHT kinase RH cerate eHeropogeo Claro Cheat Ou Ho/bH Ciao الله Glyceraldehyde と。 ópog? O 1 1 C- Dely drogenaselt Phosphate gyeletesen 1 RADP RAPP 2- OPO3 Ho CHRoho phoglycenate 11 c-enė -H OPO A بي -p-o- 3- Phosphoglycepate Phospho-gl @ 2- Enolase muraglycero DH H2H phosphoglycer pate oi-caeh OH Phosphoe nolpur molbyruvate 4 oë- ezért Pynun iruvate Kinase BADP OPO QATP Pyruvate 11

2. TCA:

• Krebs cycle is also called citric acid cycle or tricarboxylic acid cycle. It includes step wise cyclic process, in which pyruvate (from glycolysis), is oxidised to ultimately form water and carbon dioxide. The products formed during the cycle, include CO2, electron carriers- NADH and FADH2, which are used to generate ATP.
• The phases of Krebs cycle include:

Phase I of Krebs cycle:

• Entry of Acetyl Co-A- combines with 4- carbon Oxaloacetate.
• 6 carbon Citrate is produced

Phase II of Krebs cycle:

• Citate is converted to iso-citrate.
• Isocitrate is oxidized to 5- carbon α-Ketogluterate.
• Reduces NAD+ to NADH + H (step 3)
• α-Ketogluterate is converted to Succinyl CoA, also NADH + H is produced.
• Succinate converted to fumerate, also generates FADH2.

Phase III of Krebs cycle:

Malate is oxidized to Oxaloacetate to reinitiate the cycle. NAD is reduced to NADH+H (step 8).The enzyme Succinate dehydrogenase is part of TCA cycle as well as electron transport chain.

Acetyl CoA Citrate 2 9 Oxalo acetate noe NAO +H > . Iso citrate NADH THt 8 Malate 7 Funerate 4 a- keto glaterrate ok Succinyl CoA NAD NADH THt 6 Succinate FADH₂ HSGA GP Gortpi

3. ETC:

• The mechanism of oxidative phosphorylation occurs in mitochondria of live eukaryotic cells.
• Electrons are transported across various components of electron transport chain (ETC), resulting in series of oxidation-reduction reactions within the membrane bound complexes in mitochondria (complex I, II, III, IV).

Complex I: NADH dehydrogenase:

Complex II: Succinate dehydrogenase

Complex III: Ubiquinol cytochrome C oxidoreductase

Complex IV: Cytochrome C oxidase

• Electrons are transported across various components of electron transport chain (ETC), resulting in series of oxidation-reduction reactions. NADH and FADH2 are electron donors; their oxidation creates high concentration energy from electrons. This energy is used to pump proton from matrix to inter membrane space. Flow of protons creates and electrochemical gradient, which is used to generate ATP.

• ATP synthase complex, designated as F0F1- ATP synthase, is located within the mitochondrial cristae.

• They help in back flow of proton, creating free energy to generate ATP.

  ATP synthase is composed of two parts:

  a) Coupling factor 1 (F1)- which contains the catalytic subunit of ATP synthase.

  b) Coupling factor 0 (F0) – which act as a proton channel between mitochondrial matrix and intramembranous mitochondrial space. F1undergoes conformational changes and binds to ADP and Pi.