# 2.1 Biological macromolecules

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## Biological macromolecules

A biological macromolecule is one that is found in living organisms. Biological macromolecules include molecules such as carbohydrates, proteins and nucleic acids. Lipids are also biological macromolecules. They are essential for all known forms of life to survive.

Biological macromolecule

A biological macromolecule is a polymer that occurs naturally in living organisms. These molecules are essential to the survival of life.

## Carbohydrates

Carbohydrates include the sugars and their polymers. One key characteristic of the carbohydrates is that they contain only the elements carbon, hydrogen and oxygen. In the carbohydrate monomers, every carbon except one has a hydroxyl group attached to it, and the remaining carbon atom is double bonded to an oxygen atom to form a carbonyl group. One of the most important monomers in the carbohydrates is glucose ( [link] ). The glucose molecule can exist in an open-chain (acyclic) and ring (cyclic) form.

Glucose is produced during photosynthesis , which takes place in plants. During photosynthesis, sunlight (solar energy), water and carbon dioxide are involved in a chemical reaction that produces glucose and oxygen. This glucose is stored in various ways in the plant.

The photosynthesis reaction is as follows:

$6{\mathrm{CO}}_{2}+6{\mathrm{H}}_{2}\mathrm{O}+\mathrm{sunlight}\to {\mathrm{C}}_{6}{\mathrm{H}}_{12}{\mathrm{O}}_{6}+6{\mathrm{O}}_{2}$

Glucose is an important source of energy for both the plant itself, and also for the other animals and organisms that may feed on it. Glucose plays a critical role in cellular respiration , which is a chemical reaction that occurs in the cells of all living organisms. During this reaction, glucose and oxygen react to produce carbon dioxide, water and Adenosine Triphosphate (ATP). ATP is a molecule that cells use for energy so that the body's cells can function normally. The purpose of eating then, is to obtain glucose which the body can then convert into the ATP it needs to be able to survive.

The reaction for cellular respiration is as follows:

$6{\mathrm{C}}_{6}{\mathrm{H}}_{12}{\mathrm{O}}_{6}+{60}_{2}\to 6{\mathrm{CO}}_{2}+6{\mathrm{H}}_{2}\mathrm{O}+\mathrm{ATP}$

We don't often eat glucose in its simple form. More often, we eat complex carbohydrates that our bodies have to break down into individual glucose molecules before they can be used in cellular respiration. These complex carbohydrates are polymers, which form through condensation polymerisation reactions ( [link] ). Starch and cellulose are two example of carbohydrates that are polymers composed of glucose monomers.

• Starch Starch is used by plants to store excess glucose, and consists of long chains of glucose monomers. Potatoes are made up almost entirely of starch. This is why potatoes are such a good source of energy. Animals are also able to store glucose, but in this case it is stored as a compound called glycogen , rather than as starch.
• Cellulose Cellulose is also made up of chains of glucose molecules, but the bonding between the polymers is slightly different from that in starch. Cellulose is found in the cell walls of plants and is used by plants as a building material.

## Interesting fact

It is very difficult for animals to digest the cellulose in plants that they may have been feeding on. However, fungi and some protozoa are able to break down cellulose. Many animals, including termites and cows, use these organisms to break cellulose down into glucose, which they can then use more easily.

are you sure u wantd to ask tht or u wantd to say " how many bonds are there in alkane nd their names?" ?
I also think that's what she meant 'coz I don't really understand her question
LINDOKUHLE
yeah nd if that's th case , there are only single bonds wch I could say one of em tht I know is methane
Frank
I mean methane,ethane they end up to what
Sylvia
well I also assume ths is wah u lookin for .. methane , ethane , propane, butane, pentane, hexane , Heptane, octane , nonane , decane . is ths wah u wanted ?
Frank
how many alkane are there n there names
what's the difference between work and power ?
Greetings Science Geniuses what is involved in fractional distillation of air?
what are the types of van der waals forces
weak van Der Waal forces 1.London forces 2.Dispersion forces 3.weak dipole dipole strong van Der Waal forces 1.hydrogen bonding 2.strong dipole-dipole forces
Zethu
compounds which there's no bonds between hydrocarbon atoms
Ruth
compounds which don't have double bonds or triple bonds between them
Hlengiwe
and they can be divided into two equal parts
Hlengiwe
what does the air in the atmosphere
How to calculate a frictional force if not given in the information?
what is not given in the problem?
Jhandy
Determine first the force between the surface and the object (N) then find the coefficient of friction with respect to the surface. Then multiply those two (N and Coefficient of Friction)
Jhandy
re read the statement there must something to use for calculation in the statement
Tandiswa
is it necessary to draw an arrow over vector quantities?
Yes. Because vector quantities consist of magnitude and direction. The arrow, which must include its head, tells you the direction of your quantity/es.
Jhandy
What is the monomer
it is a molecule that can be bonded to other identical molecules to form a polymer
Kwanda
need help in paper 2
yes
Zethu
what do you need?
Zethu
The four molecules of life are proteins, carbohydrates, lipids and nucleic acids. ... Without any of these four molecules, a cell and organism would not be able to live. All of the four molecules of life are important either structurally or functionally for cells so they are important in most cases
Nozipho
so it always has to be four molecules
Mbali
Hey guys i need help wit paper one
Mpho
why mass not change
because it is irreversible
Jiluis
Hi Allan the reason why mass never change Is because of its interaction with Higgs field never change.
LUTHO
what is different between work and power in details
When a force is exerted to an object and causes it to move in the direction of the force the work is done whereas power is the rate at which work is done.
ISRAEL
Hlayiselo
i also want to be helped
Tobeka
work occurs when force causes an object to move a certain distance while power is the work done at that specific time ..
Elago
and the difference can be simply simply that " work is in jouls while power is in walts
Elago
Why is alcohol flameable?
What is interconversion reaction for? ... under substitution reaction
Moloto
alcohol is flammable because the electrons in the CH and CC bonds are high energy compared to the electrons in OH and CO bonds of the product
Zethu
is carboxylic acid or alcohol need more heat to over come intermolecular forces?
Mpeh
carboxylic acid has higher boiling point compared to alcohol . carboxylic acid are two sited for H- bonds and alcohol is one sited for H- bonds. carboxylic acid needs more energy to break it's intermolecular forces compared to alcohol.
Zethu
heat under reflux .....it suitable for which type of reaction....btwn Addition,Elimination n Substitution reactions...?
Sqiniseko