Biochemical energy production

Metabolism

• Sum of all chemical reactions in living organism

• Provides energy needed for activities like thinking, moving etc

• Supplies energu for cellular processes like protein synthesis, RNA transcription, DnA replication and membrane transport

Types of metabolic pathways

1. Linear pathway

2. Cyclic pathway

Catabolism

• All metabolic reactions where large biochemical molecules are broken down into smaller ones

• Ex: oxidation of glucose

Release energy

Catabolism

Anabolism

• Small biochemical molecules are joined to form larger ones

• Synthesis, forms

• Ex: synthesis of protein

Requires energy

Anabolism

Prokaryotic

• Single compartment

• No nucleus; found in bacteria

• Single circular DNA molecule located near the center of the cell

Eukaryotic

• Multi-compartment

• DNA is enclosed membrane-bound nucleus

• 1000 larger than bacterial cells

• Has distinct cellular organelles

Nucleus

DNA replication and RNA synthesis

Plasma membrane

Cellular boundary

Cytoplasm

Water-based material of a eukaryotic cell

Mitochondria

Generates most of the energy needed for the cell

Lysosome

Contain hydrolytic enzyme needed for rebuilding, repair and degradation

Ribosomes

Sites for protein synthesis

Outer membrane

• permeable to small molecules

• 50% lipid 50% protein

Inner membrane

• Highly impermeable to most substances

• 20% lipid 80% protein

• Folded to increase surface area

Site of ATP synthesis

Inner membrane

Cyclic monophosphate (cAMP)

Cyclic structure of phosphate

Monophosphate

Structural component of RNA

ADP and ATP

Key components of metabolic pathways

Uridine triphosphate (UTP)

Involved in carbohydrates metabolism

Guanosine triphosphate (GTP)

Involved in protein and carbohydrate metabolism

Cytidine triphosphate (CTP)

Involved in lipid metabolism

Ribitol

Reduced form of ribose sugar

Flavin Adenosine Dinucleotide (FDA)

A coenzyme required in numerous metabolic redox reactions

Flavin subunit

it is the active form that accepts and donates electrons

Energy

Needed to run human body is obtained from food

Stage 3 of energy production

Citric acid cycle

Stage 1 of energy production

Digestion

Stage 4 of energy production

Electron transport chain and oxidative phosphorylation

Stage 2 of energy production

Acetyl group formation

ATP is high

Citric acid inhibits citrate synthase

When ATP low

ADP citrate synthase

Citric acid is controlled by

ATP AND NADH LEVELS

NADH

Acts as an inhibitor

ADP

Acts as an activator

Electron transport chain

Facilitates the passage of electrons trapped in FADH2 and NADH during citric acid cycle

ETC

Ultimately receiver of electrons in molecular oxygen

Complex I: NADH—Coenzyme Q reductase

• NADH is the source of electrons for this complex

• Contains >40 subunits includes FMN and several FesP

• Several intermediate reactions are involved in this electron transfer

Complex II: Succinate- coenzyme Q reductase

• Smaller than complex I

• Contains 4 subunits include two FesP

• succinate converted to fumarate

• Generates FADH2

Coenzyme Q

Final recipient of electrons from FADH2