7.1 process respiration

8/4/2019 7.1 Process Respiration

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7.1

THE RESPIRATORY PROCESS

IN ENERGY PRODUCTION



Respiration

• A vital living process carried outby all living organisms.

• Living organisms require energy

for various activities and livingprocesses.



Energy is required for:

• Excretion of waste products

• Muscle contraction which enableslocomotion

• Cell division in which new cells are

produced for growth and development

• Transmission of new impulses



• Absorption of digested food through

active transport

• Active transport of biochemical

substances

• Maintaining the body temperature (in

warm-blooded animals)

• Synthesis of lipids, hormones, proteinsand enzymes.



Respiration can be divided into 2

stages:

• External respiration/

Breathing

•

Internal respiration/ Cellularrespiration



External Respiration

• Breathing

•A mechanical process that maintainscontinuous exchange of gases betweenthe respiratory surfaces of an organismand its environment



Internal Respiration

• Cellular respiration

•

The biochemical process in which energyis made available to all living cells.

•

This process involves the oxidation oforganic molecules to release thechemical energy stored within these

molecules.



What is the main substratefor cellular respiration

•Glucose



2 types Cellular respiration:

aerobic respiration anaerobic respiration

Aerobic respiration is a process

that requires a continuous supply ofoxygen obtained from the air or water

surrounding the organism.

Energy Production in

Aerobic Respiration



Aerobic respiration

• Involves the oxidation of glucose in thepresence of oxygen to carbon dioxide, waterand energy.

C6H12O6 + 6O2 → 6CO2+ 6H2O+ 2898kJ

Glucose oxygen carbon water energy

dioxide• Releases all the available energy stored

within the glucose molecules.



ATP

• ATP is an direct source of energy andthe main energy supply for all living cells.

• A large portion of energy is used tosynthesis adenosine triphosphate (ATP)from adenosine diphosphate (ADP) and

inorganic phosphate.

ADP + phosphate + energy → ATP



ATP Production during

Aerobic Respiration



• Each ATP molecule consists of 3

phosphate groups and thephosphate bonds can be easilybroken down to release energy.

• ATP → ADP + phosphate + energy



Anaerobic Respiration in Cells

• Is a process that breaks down glucosewhen there is very little or no moreoxygen.

• Generates little energy for the cell

•

Organisms that require anaerobicallyknown as anaerobes.

• Eg. Bacteria and certain types of yeast.



Two forms of anaerobic

respiration:

• Anaerobic Respiration in Human

Muscles

•

Anaerobic Respiration in Yeast



Anaerobic Respiration in

Human Muscles

• During periods of prolonged physicalactivity, the muscles are forced to dowork without enough oxygen supply.

•

The cells are using ATP at high rate andthe lungs and the circulatory systemcannot deliver sufficient oxygen to thecells for cellular respiration.

http://www.lakemichigancollege.edu/dept/Arts-Sciences/bio/pics/mus_ant1.jpg




Anaerobic Respiration in

Human Muscles

• During periods of prolonged physicalactivity, the muscles are forced to dowork without enough oxygen supply.

•

The cells are using ATP at high rate andthe lungs and the circulatory systemcannot deliver sufficient oxygen to thecells for cellular respiration.





• Muscle cells undergo adifferent type ofrespiration- anaerobicrespiration, in whichmuscle cells continue to

generate energy (ATP) inthe absence of oxygen.

• Initially, during vigorousexercise, the musclesrespire aerobically.



• Soon, the muscles use up all the

available oxygen. The blood cannotsupply oxygen fast enough to meettheir requirements.

•

The muscles are in a state of oxygendeficiency, and an oxygen debt isincurred.

• the muscles obtain the extra energyfrom anaerobic respiration.



• During anaerobic respiration, the glucose

molecules break down partially into lacticacid, instead of carbon dioxide.

C6H12O6 → 2C3H6O3 + 150 kJ

glucose lactic acid energy

• Because glucose is not completely brokendown, the energy released is much lessthan the energy during aerobic respiration.



• For every molecule of glucose,anaerobic respiration releases only 2molecules of ATP /150kJ.

C6H12O6 → 2C3H6O3 + 150 kJ

glucose lactic acid energy



• The accumulation of lactic acid may reach

a level of concentration which is highenough to cause muscle cramps

→

tiredness→

breathe in deeply andrapidly to inhale more oxygen→ used by

the body to oxidise the accumulated lactic

acid to carbon dioxide and water.



Oxidation of Lactic Acid

•

Lactic acid + O2→

CO2 + water + energy

• A portion of the lactic acid is oxidised

to produce energy.

• The remaining is converted into

glycogen and stored in the muscle cells.

• The oxygen debt is paid off when all of

the lactic acid is removed.



Anaerobic Respiration in Yeast

• Yeast carries out anaerobic respirationunder anaerobic conditions.

• Also known as fermentation and iscatalysed by the enzyme zymase.

• C6H12O6 → 2C2H5OH + 2CO2 + 210 kJGlucose ethanol carbon energy

dioxide



Question:

Is there any commercial value of the endproduct of fermentation

• Ethanol produced during fermentationcan be used in wine and beer making.

Comparison between Aerobic and



Comparison between Aerobic and

Anaerobic Respiration

Aerobic Respiration Anaerobic Respiration

Similarities

• Cellular respiration

• Involve the break down of glucose

• Release energy that is stored in the ATP molecules

• Are catalyzed by enzymes

Differences

O2 is present. Availability of O2 O2 is absent.

Complete oxidation Oxidation of glucose Incomplete

of glucose. oxidation of

glucose

CO2 water and energy Products of Respiration Lactic acid &



CO2, water and energy Products of Respiration Lactic acid &energy

38 molecules of ATP Number of ATP molecules 2 molecules of ATP

produced

Large amount of energy Amount of Energy Small amount:

(2898 kJ) per mole of glucose 1) 210kJ (during

fermentation)

2) 150kJ(during

anaerobic

respiration in

muscle cells)

In all organisms: Chemical Equation In muscle cells:C6H12O6 + 6O2 → C6H12O6 → 2C3H6O3 + 150 kJ

6CO2+ 6H2O+ 2898kJ

Mitochondria Place where the Cytoplasm

process takes place

7.1 process respiration

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