biochemical metabolism

                                                                    بسم الله الرحمن الرحيم

Metabolic flow is based on anabolic and catabolic reactions. Metabolism begins with the

ingestion of food that is foreign to the organism (containing a varying amount of smaller

and larger compounds), which is broken down in the digestive tract to smaller molecules

by hydrolysis.

An anabolic phase occurs when the smaller molecules are taken up into the organism’s

bloodstream and become part of the organism. Catabolic reactions constantly break down

the organism again for its functional needs.

We will demonstrate the connections of processes in organs and organisms as well as the

interconnectedness of organisms within the whole of living nature.

1-Anabolic:
In the anabolic stream of metabolism, larger
compounds are formed from smaller ones.
Chemical reductions play a predominant role
in these reactions. An example is the
formation of complex carbohydrates from
lactate or carbon dioxide. 

2. Catabolic:
Catabolism is the opposite type of process,
the breakdown of more complex compound
into smaller ones. Chemical oxidation

Anabolic reactions incorporate bond energy into the larger compounds, which are in turn

part of cellular or tissue structures, for instance cellular membranes, connective tissue

fibers, or glycogen in the liver. Catabolic reactions effectively free up this energy. The

structuring substances of organisms therefore have the additional function of being a

source of potential energy in situations of need.

In trauma, or extreme situations like hunger states, the needs of the organism are met by
breaking down more and different structural compounds. Eventually the substance of
every organism ends up in its surrounding again, either in the form of energy, for instance
as the effect of muscular action, the fluorescent light of certain fishes, etc., or as
substance, as excretory products or when the living organism finally dies.

QUESTION: Are different types of bonds prototypical for
different types of compounds? Are different types of energy
stored in the different types of bonds?

QUESTION: Where does the energy come from that we use for
mental processes like thinking, emotions, or intentions? Is that
also released from structures in the organism that are broken

Biochemical cycles in metabolism

Anabolism and catabolism are opposite processes, and yet one is not simply the reverse of
the other. Usually several key reactions of the anabolic pathway need different enzymes
and/or produce different intermediate compounds than those used in catabolism.
Anabolism and catabolism can take place in the same cell, but they often take place in

1-A biochemical cycle in the organism as a
whole

The metabolism in anaerobic exercise
provides an example of a metabolic cycle
between organs. The so-called Cori cycle
comprises glycolysis in the exercising
muscle and gluconeogenesis in the liver.
In strenuous exercise, glucose in the
skeletal muscle is broken down
anaerobically to lactate (glycolysis) for
extra directly available energy. The blood
transports lactate to the liver. In the liver,
glucose can be built back up from lactate
(gluconeogenesis). This can be stored as
glycogen or transported back to the muscle
by the blood to be used as an energy
source for muscle contraction again.

Anabolic and catabolic metabolism can
alternate cyclically between organs in the
human organism.

2-A biochemical cycle in nature

A carbohydrate metabolic cycle occurs

between organisms in nature.

Green plants reduce carbon dioxide and

water to carbohydrates and oxygen in the

process called photosynthesis. They build

up their organism with the carbohydrates

formed in photosynthesis and release

oxygen. This is a reductive, anabolic process

in the plant using external sunlight as the

energy source.

The oxygen and the plant carbohydrates produced in photosynthesis are used up by

higher organisms in oxidative processes that break down the carbohydrates in the

digestive process. The metabolic cycle that exists between plants on the one hand, and

humans and animals on the other, involves different organisms in nature.

The overall role of animal and human metabolism in nature is catabolic. Plant metabolism

plays a prototypically anabolic role in nature and provides the energy required by the

overall catabolic metabolism of higher organisms

3-The citric acid cycle
The aerobic part of metabolism begins in the mitochondrion. In the eight steps of the
citric acid cycle, which takes place in the mitochondrion, the metabolites of carbohydrates,
proteins and lipids are finally oxidized to carbon dioxide and water. This catabolic process
results in the formation of large amounts of biochemical energy in the form of adenosine
triphosphate (ATP). To complete this process, some energy-carrying compounds that are
formed in the citric acid cycle have to go through oxidative phosphorylation in the inner

mitochondrial membrane to convert the
energy to ATP with the help of the reduction
of O2 to H2O. These are for instance NADH
(the reduced form of nicotinamide adenine
dinucleotide) and FADH2 (the reduced form
of flavin adenine dinucleotide). The citric
acid cycle is also the starting point for
gluconeogenesis. And it provides intermediates
for the synthesis of proteins and
lipids and for the heme group of
hemoglobin. In the citric acid cycle anabolic
and catabolic pathways connect. Cycles
interconnect with other cycles with the citric
acid cycle at the center.
Acetyl-CoA and the citric acid cycle
Acetyl-CoA is the molecule that starts the citric acid cycle by binding to its ”end” product
oxaloacetate. All metabolites of carbohydrates and lipids enter this cycle as acetyl-CoA,

and it is the link to ultimate oxidative breakdown for many amino acids.

Metabolic processes
The metabolic process of the human organism normally starts with breakdown products
from the intestines that become available for anabolic or catabolic reactions. Anabolic
reactions build up the substances of the organism. Anabolic reactions enable the
organism to ‘get substance’ and take form. The organism becomes visible like a standing
wave in a creek.
Larger compounds contain bond energy that holds together the compounds’ structure.
This energy can be made available by catabolic reactions for those functions of the
organism, which require directly available energy. The metabolic flow of living organisms
ends with the catabolism of its substance, which frees energy for the organism’s functions
(such as anabolic biochemical processes, bio-electrical, bio-mechanical and active
transport needs).
The citric acid cycle, which takes place in mitochondria, is at the center of oxidative
breakdown and can also be the starting point for the reductive synthesis of large
compounds in the organism. Acetyl-CoA plays a major role at this center of metabolic
activity.
The metabolic cycle in plants begins with the breakdown of water. Green plants obtain
their energy from breaking down water with the help of solar energy. The oxidation of
water provides the energy required in the plant to build up its organism. Plants in turn are
an important part of the food cycle in nature. They supply animals and humans with

metabolic