UNIVERSITY OF GUYANA FACULTY OF NATURAL SCIENCES

CHEMICAL KINETICS &ELECTROCHEMISTRY (CHM

2202)*ASSIGNMENT NO.1*

APPLICATION OF ELECTROCHEMISTRY PRINCIPLE

&THE FUNCTIONING OF THE HEART

The human heart is an organ that pumps blood throughout the body via the circulatory system,

supplying oxygen and nutrients to the tissues and removing carbon dioxide and other wastes.

THE HEART CAN BE TERMED: 1.A Muscle 2.A Pump

2.A MUSCLE – The heart is considered a muscle because it contracts and relaxes (beats), with these movements the fluid (blood) is moved. In order for the heart to

contract – relax ; energy is required.

1.A PUMP - The heart is considered a pump because it moves a fluid (blood), which is what a pump does, from one place to another. In order for this fluid to move it uses muscular power as energy intake.

WHAT IS THE NAME OF THE ENERGY

SOURCE?

WHERE DOES THIS ENERGY SOURCE

COME FROM?

WHAT IS THE NAME OF THE ENERGY SOURCE?

ATP WHERE DOES THIS ENERGY SOURCE

COME FROM?ATP is synthesized during “Cellular Respiration”

Within heart cells (cardiomyocytes). The numerous amounts of Cardiomyocytes combine

to form the heart muscle.

Cellular Respiration is also called aerobic respiration due to the presence of oxygen. The main purpose of Cellular Respiration is to make usable energy for the cell in the form of a compound; Adenosine Triphosphate (ATP).

•Glycolysis  •Krebs cycle

•Oxidative phosphorylation

CELLULAR RESPIRATION

From these three steps combined

approximately 36 molecules of ATP is

produced from one (1) Glucose molecule.

Cellular Respiration takes place under three steps:

BEHIND THE SCENES TOUR OF CELLULAR

RESPIRATION To follow along during our behind the scenes tour of cellular respiration familiarity with REDOX reactions is required. Redox Reactions is a common “Electrochemistry Principle”

Redox reactions involve losing or gaining electrons.• In oxidation, an atom loses an

electron

• In reduction, an atom gains an electron 

LEO the lion says GER.

LEO is short for Loss of Electrons is Oxidation

&GER is short for Gain of Electrons is Reduction.

GLYCOLYSIS STEP 1 – One phosphate from the two ATP molecules is added to the glucose molecule.

STEP 2 – The phosphate glucose molecule splits into 2 sugars.

STEP 3 – The 3-carbon phosphate sugar each lose an electron (oxidized), and the NAD+ becomes NADH after gaining an electron (reduced)

STEP 5 – The two phosphates that were added to the oxidized sugars is removed an added to the 2 ADP molecules hat were formed in STEP 1. Thus forming 2 ATP molecules.

STEP 6 – The remaining phosphates on the 3-carbon sugar are taken off to make two more ATP. The two remaining molecules “Pyruvate”

STEP 1 – Pyruvate is converted to acetyl coenzyme(acetyl CoA).

STEP 2 - The acetyl coenzyme drops the acetyl group ( 2 carbons), which combines with a 4-Carbon compound forming “Citric Acid”

STEP 3 – Citric acid is oxidized and loses two carbon atoms one at a time. The electrons citric acid loses, goes on to reduce NAD+ to NADH. This process happens twice hence 2 NADH is formed. STEP 4 – One ATP molecule is Formed

STEP 5 – The 4-Carbon compound is oxidized by losing two Hydrogens. The hydrogens then reduce FAD+ to FADH2.

.

CITRIC ACID CYCLE (KREB’S CYCLE)

OXIDATIVE PHOSPHORYLATION

1. NADH (complex I) & FADH2 (complex II) is oxidized, and their proton (H+) is released into the intermediate space

2. The electrons from NADH & FADH2 makes their way through the protein complexes

(I – IV) 3. Oxygen (O2) is reduced to H2O, since it

is the terminal electron acceptor4. Due to the movement of electrons through complexes I - IV H+ ions is pumped into the intermembrane space, and an electrochemical gradient is formed.5. The H+ ions generated pass through specialized proton

channel proteins (complex V); the energy derived from this movement of protons is used to synthesis ATP from ADP & Pi

NADH --> NAD+ + H+ +  2e-

FADH2 --> NAD+ + 2H+ +  2e-

1/2 O2 + 2H+ + 2e- --> H2O

CROSS BRIDGE CYCLE• The ATP molecules produced within the heart and that will be continuously produced, is used in the “Cross Bridge Cycle”.

• The Cross Bridge Cycle highlights the way in which muscles contract and relax, and the molecules/ compounds necessary for these contractions/relaxations to occur.

• In this case it would be showing how the heart contracts and relaxes, since the heart itself is considered a muscle.

Without ATP, ADP & Pi cannot be produced,

therefore ATP plays a role in muscle contraction

Actin slides across the myosin

Without ATP, the muscle would not relax

CROSS BRIDGE CYCLE CONT’D

• From the previous slide it is observed that, when

ATP attaches to the myosin head the cross bridge detaches.• ATP is critical for muscle contractions

because it breaks the myosin – actin cross bridge, freeing the myosin for the next contraction.

Therefore :

Without ATP, their would be no molecule to

provide ADP & Pi which is necessary for muscle

contraction

If the heart does not contract, this may lead to asystole (flat line) a form of

cardia arrest.

1

Without ATP, heart muscles would remain in their contracted state,

rather than their relaxed state.

Unable to release contraction, all the muscles in the heart remain tense,

causing rigor mortis.

2

CONCLUSION • Without NAD+ & FAD being reduced, NADH & FADH2 will not be formed.

• NADH & FADH2 is a necessity in the electron transport

chain. They are oxidized (lose electrons) so as to donate their electrons to the transport chain, and they first contribute to the proton (H+) gradient in the intermembrane space

• Without the H+ ions ATP cannot be synthesized since the energy generated by the proton gradient aids in the synthesis of ATP.

• The heart cannot function without ATP since it plays a role in both contraction and relaxation.

• The combination of contraction and relaxation, aids in the heart beat we feel.

• If either of these actions does not function as per normal, problems will arise in terms of the heart functioning efficiently.

CONCLUSION