3_Cellular_respiration_notes

INTRODUCTION

You will need to know that: 1. Breathing and cellular respiration are different processes of respiration. 2. Mitochondrion is site for the release of potential energy in cellular respiration. 3. Enzymes are crucial in the control of metabolic pathways. 4. Glucose is the main respiratory substrate. 5. Oxygen is the final electron acceptor and the formation of water. 6. Aerobic respiration releases a much greater amount of energy per glucose molecule than anaerobic respiration. 7. Respiratory system is adapted for its function as a mechanism to obtain oxygen for respiration and to excrete waste carbon dioxide. 8. The complexity of gaseous exchange system in various organisms is directly proportion to the size of the organism and its habitat.

You will be able to:

1. State the uses of energy in the body of humans: muscle contraction, protein synthesis, cell division, active transport, growth, the passage of nerve impulses and the maintenance of a constant body temperature. 2. Define //aerobic respiration// in words or symbols. 3. Describe the roles of enzymes in the control of respiratory pathways, illustrated by oxidoreductases and hydrolases. 4. Identify the main steps of cellular respiration: glycolysis, Kreb cycle and electron transport chain. 5. Describe the conversion of monosaccharides to pyruvate during glycolysis; the phosphorylation of hexose molecules; breakdown to glycerate 3-phosphate (GP); production of reduced coenzyme (NADH + H+) and chemical potential in ATP during oxidative phosphorylation in the electron transport chain. //(Details of intermediate compounds and reactions, other than those specified, are not required)// 6. Describe the role of oxygen as the final electron acceptor and the formation of water 7. Indicate on a diagram or micrograph of a mitochondrion, where each stage of the cellular respiration occurs. 8. Define //anaerobic respiration// in humans and yeast in words or symbols. 9. Explain the formation of lactic acid in muscle; formation of ethanol in yeast when pyruvate do not undergo complete oxidation in the absence of oxygen. 10. Describe the effect of lactic acid in muscles. 11. Compare and explain the differences in the yields of ATP from complete oxidation of glucose and from the fermentation of glucose to lactic acid or ethanol. 12. Explain that aerobic respiration releases a much greater amount of energy per glucose molecule than anaerobic respiration. 13. Appreciate how different organisms are adapted for efficient gaseous exchange. 14. Explain how the human respiratory system is adapted for its function as a mechanism to obtain oxygen for respiration and to excrete waste carbon dioxide. (Include reference to the larynx, trachea, bronchi, bronchioles, alveoli and associated capillaries.) //15.// Design and perform an experiment to investigate the effect of external factor on the respiration in yeast. 16. Tabulate results, analyse data and state a conclusion of each investigation. 17. Identify problems at the end of the experiment and make recommendations for future improvement.

Use BIOZONE


 * __CELLULAR RESPIRATION__**


 * Energy making process**

The raw materials for energy making process eventually arrive at the body cells, known as RESPIRATION. (link between circulatory system)

Each living cell is provided with the food and oxygen to generate energy

OXYGEN AND FUEL respiration and digested food -> ENERGY


 * Input, process, output**

Carbon dioxide - waste product, removed by circulatory system


 * Cellular respiration**

The process by which organisms break down energy rich molecules e.g. glucose to release the energy in the ATP form.


 * Uses of energy**

- muscle contraction - protein synthesis - cell division - active transport - building up of protoplasm for growth - transmission of nerve impulses - maintenance of a constant body temperature


 * Stages**

1. Glycolysis

occurs in cytoplasm (6 carbon) break down glucose into smaller molecules (forming pyruvate - 3 carbon x2)

no oxygen required (anaerobic) 2ATP+ 2NADH + 2H produced

2. The Krebs Cycle

mitochondrial matrix glucose broken down to CO2 - decomposes a derivative of pyruvate to carbon dioxide - citric acid cycle - produces: NADH, FADH2 and ATP

hydrogen atoms from both stages form ATP NADH and ATP - chemicals used to transfer energy

3. Electron Transport and oxidative phosphorylation

last stage - generates about 90% of total ATP inner membranes of mitochondrion (cristae)

ATP - Adenosine Triphosphate

AEROBIC - requires oxygen

When oxygen is not sufficient, the body will automatically start anaerobic respiration, but it is a less efficient process and produced a waste product, lactic acid


 * USE A FLOW CHART TO REVISE**

Reference: http://moodle.rgs.edu.sg/moodle/mod/resource/view.php?inpopup=true&id=5002 http://moodle.rgs.edu.sg/moodle/mod/resource/view.php?inpopup=true&id=5004

http://moodle.rgs.edu.sg/moodle/mod/resource/view.php?inpopup=true&id=5091


 * Gaseous Exchange**

Practical - holding our breath
 * Respiration**

Myoglobin and haemoglobin haemoglobin binds to oxygen Myoglobin causes the muscles to be red and needs energy Oxygen debt - happens when myoglobin does not have enough oxygen, causing anaerobic respiration -> 1 glucose to 2 ATP compared to 34 - insufficient energy without oxygen. Build up of lactic acid -> body sending signals to take in oxygen -> stops the muscles from contracting/expanding Panting to replace oxygen When energy is made again, lactic acid will go to the liver and be converted into CO2 and water.

Cellular respiration creates a constant demand for oxygen and a need to eliminate Carbon Dioxide gas. Oxygen is DISSOLVED in our bloodstream We breathe in **air**, the aveoli in the lungs help to FILTER the air such that only oxygen is taken in and enters the bloodstream. By diffusion

How does drowning occur? If we use dissolved oxygen, why do we still drown? It cannot happen as we have too much water in our lungs, weighing it down and preventing us from ventilation.

If we have air bubbles in our bloodstream, the pressure will cause them to burst - blood vessels burst, pain/stroke

Do we have dissolved nitrogen in our bloodstream? Yes, but we do not really need it.

see biozone for examples of different types of respiration systems

- Thin membrane (quick diffusion) - Large Surface Area : Volume Ratio - Moisture (dissolve gas) - Efficient transport system (circulatory) so as to establish concentration system - Ventilation system -> two-way to circulate air
 * Properties of Gas Exchange surfaces**

nose-> nostril larynx (prevent food from entering) trachea cartilage bronchus lung heart sternum Pleural membrane rib Intercostal muscle Lymph vessels along bronchiolet bronchiole -> split to aveolar ducts/sacs alveolus diaphragm
 * Parts of Human respiratory system**

Aveoli - Rich blood supply - many capillaries - Thin membrane - easy diffusion - Large surface area - space to diffuse - Moist - gases can dissolve

Site where gases are dissolved and exchanged Dissolving while diffusing into capillaries from aveoli red blood cells containing haemoglobin - carry oxygen by binding to oxygen and releasing it at places in the body which need it

chemical equation for carbon dioxide, CO2 + H2O ->(enzyme)-> HCO3 + H carbonic acid is formed (pH of our blood is actually less than 7) reversed when it is back to the lung if oxygen is insufficient, CO2 increases, carbonic acid increases and pH increases - brain receptor makes us breathe more mechanism of controlling breathing is determined by amount of carbon dioxide (not oxygen)

inhaling (inspiration) and exhaling (expiration) is done by the intercostal muscle and diaphragm contracting and relaxing as the pressure changes as volume changes. in order to reach equilibrium: volume increases - pressure decreases

