Respiration

Matter has energy, whether potential or kinetic energy. Matter requires energy to perform various processes. Energy can be used to transform matter, and matter can store energy. e.g. kinetic particle theory.
 * 1. What is the relationship between energy and matter?

2. How is energy significant to biological system? The biological system needs energy to survive, to carry out life processes like respiration (the build up of proteins from amino acids to build muscles), daily activities –> the transfer of chemical energy from one organism to another up the food chain

3. Can an organism survive without the exchange of matter with its environment? No. All living things need to respire and give out waste, thus an organism is bound to need exchanging gas and other substances with its environment. Photosynthesis also requires the exchange of materials.

4. Are all matters living and all living organisms made of matter? Not all matters are living, as there are many objects or things around us that are non-living, for example, tables, water. All living organisms are made of matter - they have mass and occupy space, made up of macromolecules!

5. Can living organisms create and destroy energy? No. According to Newton's law of energy, energy cannot be created or destroyed but only transferred, converted, gained or lost. Hence, living organisms can only transfer, gain or lose energy through life processes and its interaction with the environment, and convert the stored energy inside them to other forms such as kinetic energy, heat energy.

6. Can living organisms create and destroy matter?** No. According to the law of conservation of matter, matter cannot be created or destroyed, but merely changed from one form to another.

- macromolecules - photosynthesis: the process whereby light energy is converted to chemical energy in the form of ATP (example of matter where energy is stored in a high energy bond –> broken bond –> formation of ADP –> tremendous release of energy. build simple molecules to end with complex molecules: anabolism - respiration - break down complex molecules to simple molecules: catabolism, reverse reaction from photosynthesis
 * MATTERS, SYSTEMS and ORGANISATION**

ENDURING UNDERSTANDINGS:
 * 1) Change in the form of any matter involves energy.
 * 2) Survival of the biological system depends on the conversion of energy from one form to another.
 * 3) Changes in the organism are dependent on its environment.
 * 4) Living organisms require matter and energy to maintain its complexity and organisation.
 * 5) Energy flow in biological processes obeys the laws of thermodynamics.

UNIT ESSENTIAL QUESTIONS: - Why do we need to respire? - Do the structure and organisation of the living system change when energy is released from them? - How are respiratory systems of animals organised efficiently to carry out its functions? - Can there be any metabolism without enzymes? (enzymes lower activation energy –> able to speed up reactions)

ENDURING UNDERSTANDINGS:
 * 1) Living organisms release energy within the biological molecule into forms they can use to carry out life processes.
 * 2) Process of the release of energy is affected by external environment.
 * 3) The structure and organisation of the respiratory system is dictated by the function that it serves. IMPORTANT!
 * 4) Metabolic pathway is a __sequence__ of enzyme-controlled reactions. (must go step by step, cannot jump from one step to a far away step)

**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__ //(specific)// //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.

YEAST EXPERIMENT - yeast respires - foam produced: carbon dioxide (determined by white precipitate formation in limewater) - warm temperature glucose (about 40 degree celsius) –> faster reaction (yeast is tolerant to heat) - baking bread: flour has complex structure –> hard to break down –> sugar added to speed up reaction - how to test rate of respiration in yeast? test tubes of water, glucose, sucrose, flour etc with yeast to compare amount of carbon dioxide produced –> measure height of foam –> must keep volume of substance, amount of yeast, temperature, time constant - oxidation: losing electrons (OLE), reduction: gaining electrons (RGE). methylene blue is an indicator used to see whether the chemical is reduced or oxidised - reduced: turn colourless, oxidised: turn blue. blue methylene blue is reduced to a colourless methylene blue –> can be oxidised back to blue. - when yeast is mixed with water, it forms a cloudy yeast suspension in water - yeast breaks down from granular state to release individual yeast –> increased surface area for faster rate of respiration - vigorous shaking of yeast with methylene blue will introduce oxygen and decolourise it - boiled yeast: blue - no oxidative reaction occurring in dead yeast cells; live yeast: decolourised, gained electrons - yeast cells lose electrons and methylene blue gains - microscope - yeast cells have different intensities of blue - remains dark blue: dead; decolourised/decolourised over time: alive. reason: methylene blue can pass through yeast cell membrane –> once inside cell, it will decolorise due to the reduction reaction that is taking place inside the yeast - besides this experiment to test if yeast is alive, can grow yeast in agar

- sac within a sac. inner sac is folded to increase surface area - inter-membrane space - reservoir for hydrogen ions - inner chamber: matrix - ADP synthesised - carbon dioxide diffuses out of mitochondrion as waste product - must know how to draw and label parts of the mitochondrion!
 * Mitochondrion**

- Systems are so interconnected, cannot separate them. Digestive system works with respiratory system, both work with circulatory system to carry the two important raw materials (oxygen and glucose) to cells - aerobic respiration of glucose: glucose + oxygen –> carbon dioxide + water + large amount of energy: C6H12O6 + 6O2 –> 6CO2 + 6H2O + energy (can change "energy" to ATP) - not all its stages of respiration requires oxygen –> glycolysis –> anaerobic - must know: what are the reactants? where do they come in?

- cellular respiration – 3 stages: 1. **Glycolysis** (cytoplasm) - break down glucose - break down 6C into 3C and 3C (pyruvate) - not oxygen dependent - 2. **the Krebs Cycle** (mitochondrial matrix) - named after Krebs - 2 pyruvate enter the cycle. 1 cycle requires 1 pyruvate. 1 molecule of glucose can generate 2 Krebs Cycle - transfer electrons to cristae to generate more ATP - process where carbon dioxide is given off - generates hydrogen - AcetylCoA //- each cycle generates 2, so it generates 4 with 1 glucose molecule (???)// - products: 2 times (2 ATPS 6 NADH2 2 FADH2) - 6 NADH2: 6 times 2 ATPs - 2 FADH2: 2 times 2 ATPs

3. **Electron Transport Chain & oxidative phosphorylation** (inner membranes of mitochondrion) - oxygen needed. oxygen combines with hydrogen to produce water. - helps to drive Krebs Cycle – forward reaction. because of this, oxygen is needed in Krebs Cycle too - 90% of respiration occurs here –> aerobic is efficient while anaerobic is not - ATP synthase - proton carrier - transport H+ ions

2 types of carrier: NADH and FADH2 ATP: O-P-P-P basal metabolic rate

- ** produces lactic acid - when running, lactic acid builds up. muscle using energy –> breaking down glucose in muscle to produce energy, not enough oxygen transported to muscle, pyruvate acid is converted into lactic acid (1 glucose molecule –> 2 lactic acid) - accumulation of lactic acid –> cramps, muscle aches. disperse lactic acid, which must be converted back to
 * Anaerobic respiration

- Myoglobin makes muscles red in colour, similar to haemoglobin in blood - take oxygen from myoglobin during exercise - oxygen debt - when running fast, want to take oxygen straight from muscles, but body will go into oxygen debt (owe myoglobin oxygen) –> lactic acid - when panting, you're returning oxygen debt - if never run for a long long time, legs will feel itchy as blood goes to places it hasn't been in a long time - muscles have no mechanisms to convert lactic acid –> go to liver –> convert to carbon dioxide and water
 * why need myoglobin?**

- trachea –> bronchia –> bronchiole –> air sacs (alveoli) –> air enters alveoli –> into capillaries in alveoli –> oxygen diffuses into water –> haemoglobin binds to oxygen - even carbon dioxide reacts to form bicarbonate –> blood is slightly acidic - we have nitrogen and other gases diffused in bloodstream too, but nothing really happens to them when you drown, what causes death? - too little oxygen, alveoli cannot expand and contract due to water breathe in water concentrated with oxygen that allow diffusion to occur when sudden change in air pressure, dissolved nitrogen become air bubbles –> divers bend: joints cannot bend as air bubbles stuck in capillaries, and brain will be injured

1. large surface area to volume ratio 2. thin membrane - for faster diffusion 3. moisture - oxygen diffuses into water in blood plasma first before binding to haemoglobin 4. efficient transport system so as to establish and maintain concentration gradient 5. ventilation system ** muscles come and work in bunches sternum is made of cartilage –> elastic –> ribs can expand and move up although attached to vertebra at the back lungs are made up of lobes: left lung has one less lobe than right lung to make space for heart at no time is any muscle fully relaxed as muscles always work in pairs tuberculosis destroys cells in alveoli –> white patches seen in lungs during x-ray trachea - tube - already have air inside. principle of straw and blowing balloon trachea has c-shaped bands of cartilage with gaps in between, to allow esophagus to expand when swallowing bolus of food face has chambers, cavities to allow voice to resonate. These cavities also allow mucus to flow – sinus happens when mucus is unable to drain contraction of intercostal muscles and diaphragm increases volume of thoracic cavity –> pressure in lungs drops, pressure outside higher –> air rushes in relaxation of intercostal muscles air expelled pressure is inversely proportionate to volume – increasing volume results in decreasing pressure alveoli sacs contain millions of alveoli cells alveolar space: space in alveoli blood capillaries are surrounding alveoli 95% of oxygen taken by haemoglobin oxy-haemoglobin - red deoxy-haemoglobin - purple blue partial pressure of oxygen - level of dissolved oxygen graph of percent saturation against partial pressure is a curve. 50% partial pressure - 85% percent saturation. carbon dioxide can be transported faster through the system when in bicarbonate form so it can be gotten rid of quickly. in the lung, bicarbonate reaction is reversed Chemoreceptors - detect temperature and chemical changes (pH) - pH of blood dropping due to carbon dioxide –> brain thinks oxygen is insufficient –> send signal to intercostal muscles and diaphragm to expand and contract more –> panting. The mechanism for control of breathing is controlled by the amount of carbon dioxide. Brain cannot detect presence of oxygen but can do so for carbon dioxide. Acidic diet –> breathe faster. some acidic medicine –> 'hyperventilating' carbon monoxide poisoning – same properties as oxygen –> will bind with haemoglobin (brain thinks it's oxygen) –> form permanent bond and will not dissociate or release easily –> more and more haemoglobin occupied with carbon monoxide –> oxygen cannot bind –> body will feel sleepy due to lack of oxygen –> die. have to give flush of oxygen, much higher percentage than in atmosphere to resuscitate person
 * Properties of Gas Exchange Surfaces