Energy Transformation: Energy Transformation: Cellular RespirationCellular Respiration

Leila A. Allado-Ombat, PhDBiology Department

College of Arts and SciencesCaraga State University, Butuan City

Learning ObjectivesLearning Objectives

At the end of this session, the learner be able to:1.differentiate aerobic from anaerobic respiration (STEM_BIO11/12-IIa-j-6).2.explain the major features and sequence the chemical events of cellular respiration (STEM_BIO11/12-IIa-j-7).3.distinguish major features of glycolysis, Krebs cycle, electron transport system, and chemiosmosis (STEM_BIO11/12-IIa-j-8).4. describe reactions that produce and consume ATP (STEM_BIO11/12-IIa-j-9).5.describe the role of oxygen in respiration and describe pathways of electron flow in the absence of oxygen (STEM_BIO11/12-IIa-j-10).6.compute the number of ATPs needed or gained in photosynthesis and respiration (STEM_BIO11/12-IIa-j-11).

REVIEW OF PREVIOUS TOPICREVIEW OF PREVIOUS TOPIC

1. What is ATP?2. What does ATP do for you?3. How do we get energy from ATP?4. How ATP re-made?5. When is ATP made in the body?

AnswerAnswer

• What is ATP?

AnswerAnswer• What does ATP do for you?

It supplies you energy.

AnswerAnswer• How do we get energy from ATP?By breaking the high energy bonds between the

last two phosphates in ATP through hydrolysis (adding of water)

• How the breaking of bond happens?

ATPase

With the aid of ATPase (enzyme)

AnswerAnswer

• How ATP re-made?ADP uses energy and gain an extra

Phosphate and is recharged back to ATP with the help of ATP synthetase (an enzyme)

ATP-ADP CycleATP-ADP Cycle

ATPase

ATPsynthetase

AnswerAnswer

• When is ATP made in the body?

During a Process called Cellular Respiration that takes place in both Plants & Animals

Physical exercise for 10 minutesPhysical exercise for 10 minutes

Question to Answer:Question to Answer:

1. What do you call the gas inside the bag?2. Aside from the gas, what else inside the bag?3. What other things you observed in your body

after you exercise?4. How those things are produce by your body?5. What do you call the process of producing

carbon dioxide, water and energy in your body?6. What cell organelle is responsible for that

process?7. Are all living organisms have mitochondria?

Cellular RespirationCellular Respiration

• Includes pathways that require oxygen• Glucose is oxidized and O2 is reduced• Glucose breakdown is therefore an

oxidation-reduction reaction• Breakdown of one glucose results in 36 to

38 ATP molecules

Overall Equation of Cellular Respiration

Raw Materials Product

6CO6CO22 + 6H + 6H220 + e0 + e-- + +

36-38ATP’s36-38ATP’sCC66HH1212OO6 6 + 6O+ 6O22

What Type of Reaction is What Type of Reaction is Cellular Respiration?Cellular Respiration?

• An Oxidation-Reduction Process or An Oxidation-Reduction Process or REDOX ReactionREDOX Reaction

• Oxidation of GLUCOSE --> COOxidation of GLUCOSE --> CO22 + H + H22O (O (ee-- removed from Cremoved from C66HH1212OO66))

• Reduction OReduction O22 to H to H22O (O (ee-- passed to O passed to O22))

What Carries the electron?What Carries the electron?

• NADNAD++ ((nicotinadenine nicotinadenine dinucleotidedinucleotide) ) acts as acts as the energy carrierthe energy carrier

• NADNAD++ is a coenzymeis a coenzyme• It’s Reduced to It’s Reduced to NADH NADH

when it picks up two when it picks up two electrons and one electrons and one hydrogen ionhydrogen ion

Are there any Electron Carrier?Are there any Electron Carrier?

Yes the FAD – another co-enzyme• FAD+FAD+ (Flavin (Flavin

adenine adenine dinucleotide)dinucleotide)

• ReducedReduced to to FADHFADH22

Where Does Cellular Respiration Where Does Cellular Respiration Take Place?Take Place?

It actually takes place in It actually takes place in two parts of the cell:two parts of the cell:

•Glycolysis occurs in the Glycolysis occurs in the CytoplasmCytoplasm

•Krebs Cycle & ETC TakeKrebs Cycle & ETC Take place in the place in the MitochondriaMitochondria

Review of Mitochondrion AnatomyReview of Mitochondrion Anatomy

• Smooth outer Membrane

• Folded inner membrane

• Folds called Cristae• Space inside cristae

called the Matrix

Cumulative Process of Cumulative Process of Cellular RespirationCellular Respiration

• Glycolysis (Anaerobic)– Breaks down glucose into two molecules of

pyruvate in cytoplasm• The citric acid cycle (Aerobic)– Completes the breakdown of glucose in the

matrix of mitochondrion• Oxidative phosphorylation– Is driven by the electron transport chain in

inner mitochondrial membrane– Generates ATP

An Overview of Cellular An Overview of Cellular RespirationRespiration

Overall process of cellular respirationOverall process of cellular respiration

Video on cellular respiration

In the CytoplasmIn the Cytoplasm

• Glycolysis consists of two major phases– Energy investment

phase– Energy payoff phase

Energy Investment Phase Energy Pay off Phase

FermentationFermentation

• In the absence of O2 (e.g. in plant roots in flooded soil), fermentation regenerates the NAD+ needed for glycolysis.

- glycolysis can then be the main source of energy

Transition between glycolysis andTransition between glycolysis andKreb’s CycleKreb’s Cycle

Before the citric acid cycle can begin– Pyruvate must

first be converted to acetyl CoA, which links the cycle to glycolysis in the mitochondrion

Kreb’s Cycle/TCA/Citric Acid CycleKreb’s Cycle/TCA/Citric Acid Cycle

Reactions and enzymes of the Citric Acid Cycle

Electron Transport System (ETC)Electron Transport System (ETC)

• Catalyzes a flow of electrons from NADH to O2

• Electron transport is coupled with formation of proton gradient → used for ATP synthesis

• Consists of 5 complexes:– Complex I (NADH dehydrogenase)– Complex II (succinate dehydrogenase)– Complex III (Cytochrome bc1 complex)– Complex IV (Cytochrome c oxidase)– Complex V (ATP synthase)

Electron Transport ChainElectron Transport Chain

• Plant mitochondria contain additional enzymes (in green), which do not pump protons.

Number of ATPs produced per GlucoseNumber of ATPs produced per Glucose

• There are three main processes in this metabolic enterprise

Consumption of ATPConsumption of ATP

ATP powers most energy-consuming activities of cells, such as: anabolic (synthesis) reactions, such as:

joining transfer RNAs to amino acids for assembly into proteins synthesis of nucleoside triphosphates for assembly into DNA and RNA synthesis of polysaccharides synthesis of fats

active transport of molecules and ions conduction of nerve impulses maintenance of cell volume by osmosis addition of phosphate groups (phosphorylation) to different proteins

(e.g., to alter their activity in cell signaling) muscle contraction beating of cilia and flagella (including sperm) bioluminescence

Extracellular ATP•In mammals, ATP also functions outside of cells. ATP is released in the following examples:from damaged cells to elicit inflammation and painfrom the carotid body to signal a shortage of oxygen in the bloodfrom taste receptor cells to trigger action potentials in the sensory nerves leading back to the brainfrom the stretched wall of the urinary bladder to signal when the bladder needs emptying

THANK YOU….THANK YOU….