Its all about Science . This notes include Physics, chemistry, Biology. This are very easy and understanding notes .This notes include many points which are referred to past examination question's answers . This also includes basics that will help in understanding the concept even better. I a...
Life Processes :
1) Digestive, respiratory, circulatory, excretory and control systems, different external
and internal organs are performing their functions independently but through a
complete co-ordination.
2) To performing their functions, they need of continuous source of energy.
3) main sources of this energy : Carbohydrates, fats and lipids which are produced by
mitochondria present in each cell.
4) For energy production, both foodstuff & oxygen is necessary.
5) Circulatory system :
food stuffs and oxygen are transported up to the cell.
6) Besides, it is coordinated by the control system of the body.
7) Functioning of all these life processes also requires the energy.
8) foodstuff :
Plants are autotrophs.
They prepare their own food.
They utilize some of the food for themselves whereas remaining is stored in various
parts like fruits, leaves, stem, roots, etc.
Human and other animals consume all these various plant materials and obtain
different nutrients like carbohydrates, fats, proteins, vitamins, minerals, etc.
Living organism and Energy production :
In living organisms, respiration
occurs at two levels as body and
cellular level.
1) Respiration at body level :
Oxygen and carbon dioxide are
exchanged between body and
surrounding.
2) Respiration at cellular level :
In case of respiration at cellular
level, foodstuffs are oxidized
either with or without help of
oxygen.
, 02.
Cellular respiration :
1) Carbohydrates of the food that Human and other animals consume everyday are
mainly utilized for production of energy required for daily need.
This energy is obtained in the form of ATP (Adenosine triphosphate).
For this purpose, glucose, a type of carbohydrates is oxidized step by step in the cells.
This is called as cellular respiration.
2) Cellular respiration occurs among the living organisms by two methods.
A) aerobic respiration (oxygen is involved)
B) anaerobic respiration (oxygen is not involved)
A) aerobic respiration (oxygen is involved) :
In aerobic respiration, glucose is oxidized in three steps.
a) Glycolysis : (EMP pathway)
scientists Gustav Embden, Otto Meyerhof, and Jacob Parnas
1) Process of glycolysis occurs in cytoplasm.
2) A molecule of glucose is oxidized step by step in this process and two molecules of
each i.e. pyruvic acid, ATP, NADH2 (Nicotinamide adenine dinucleotide) and water are
formed.
3) Molecules of pyruvic acid formed in this process are converted into molecules of
Acetyl-Coenzyme-A.
4) Two molecules of NADH2 and two molecules of CO2 are released during this process.
b) Tricarboxylic acid cycle : (Cyclic chain of reactions) or (Kreb’s cycle)
1) Both molecules of Acetyl-Coenzyme-A enter the mitochondria.
Cyclic chain of reactions called as tricarboxylic acid cycle is operated on it in the
mitochondria.
2) Acetyl part of Acetyl-Coenzyme-A is completely oxidized through this cyclical
process and molecules CO2, H2O, NADH2, FADH2 ( Flavin adenine dinucleotide ) are
derived.
3) The cyclical reactions of tricarboxylic acid cycle were discovered by Sir Hans Kreb.
Hence, this cyclical process is also called as Kreb’s cycle.
c) Electron transfer chain reaction :
1) Molecules of NADH2 and FADH2 formed during all above processes are participate
in electron transfer chain reaction.
2) Due to this,
3 molecules of ATP are obtained from each NADH2 molecule and
2 molecules of ATP from each FADH2 molecule.
3) Besides ATP, water molecules are also formed in this reaction.
4) Electron transfer chain reaction is operated in mitochondria only.
5) Thus, a molecule of glucose is completely oxidized in aerobic respiration and
molecules of CO2 and H2O are produced along with energy.
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