chapter 2 (revised jan10)

8/3/2019 Chapter 2 (Revised Jan10)

1/31

Chapter 2: The Molecules of LifeOrganic Compounds


2/31

Introduction Are you aware that

most of your body is

composed of mostlywater? No? Well, itis. As a matter offact, the human

body is composed of60%-80% water.


3/31

This also holds true for all living organisms. Wateris the main inorganic compound found in allliving organisms. If you were to remove all the

water from a body, the remaining dry weightwould be composed of carbon atoms. (animatezombie walking)

=


4/31

Can you name the organic

compounds found in thehuman body??

Ans: proteins, carbohydrates,lipids, and nucleic acids.


5/31

PROTEINS

Proteins are the most abundant organic

compound found in all living things and accountfor as much as 15% of the bodys dry weight.


6/31

These proteins are made up of a chain ofessential building blocks called amino acids.There are 20 essential amino acids that serve as

building blocks for the different proteins, all ofwhich are listen in table 2-3 in this chapter ofyour book. (make molecule rotate)


7/31

There are three components or groups that makeup an amino acid. Can you name the three?

Ans: Amino group (NH2), carboxyl

group (COOH), and a hydrocarbonside chain called an R group (refer tofig 2-7 of your book)


8/31

Animal cells are capable of producing

some of the amino acids required toform necessary proteins, but not all ofthem.

(moving cell)


9/31

For the amino acids that they cannot synthesize,they acquire them either directly or indirectlyfrom other plant and food sources.


10/31

Therefore, a wellbalanced diet isessential to obtainall the necessary

amino acids tomanufacture theproteins required

for proper bodyfunction


11/31

We both know that meat and fish are good sources

of amino acids. What other foods are goodsources of amino acids?


12/31

Enzymes are proteins that accelerate chemical

reactions. Your body undergoes variouschemical reactions which requires energy in theform of heat to take place. Most of theseprocesses require high temperatures which

could prove fatal. It is the enzymes in the bodythat make these processes possible at lowtemperatures


13/31

What are the four characteristics ofenzymes? Enzymes are highly specific

Enzymes are required in minute amounts

Temperature affects enzyme reactions

pH affects enzyme reactions


14/31

Enzymes are highly specific. Aparticular enzymecan catalyze only a specific chemical reaction.


15/31

They are also required in minute amounts only.Enzymes are so potent that one molecule ofcatalase can catalyze the breakdown of 5 millionmolecules of hydrogen peroxide in one second.


16/31

Temperature also affects enzyme reactions.

Some enzymes only function at normal bodytemperature but are inactive at very lowtemperatures. Different enzymes also requireoptimum working temperatures


17/31

Enzymes also react to different pH levels. For

exampleA

mylase works best at a neutral pH andbecomes denatured at highly acidic or alkalinesolutions


18/31

Whenever you get sick,

your body isprotected by a type ofprotein calledantibodies. Your

antibodies protectyou by destroying thedisease causing cellsor by aggregating the

cells.


19/31

Carbohydrates

These are the organic

compounds that serveas your bodys mainenergy source.Carbohydrates,

together with proteinsalso function asstructural componentsof living cells.


20/31

What three elements make up carbohydrates?

Carbon

Oxygen

Hydrogen


21/31

The composition of carbohydrates requires ahydrogen to carbon and oxygen ratio of two is to

one. Construct a carbohydrate molecule basedon this ratio.

Ans: C(H2O)


22/31

What are the three main groups of

carbohydrates??

Monosaccharide

Disaccharides

Polysaccharides


23/31

Monosaccharides are simple sugars with only

one sugar unit (mono means one).


24/31

Disaccharides arecomplex sugars made

up of two molecules ofmonosaccharideschemically joinedtogether (di means

two).


25/31


26/31

These are organic substances that

include fats and fat-like substancessuch asphospholipids, waxes,

steroids, sphingolipids and others.

Ans: Lipids


27/31

Like carbohydrates,lipids are also madeup of carbon,

hydrogen, and oxygen.But contains lessoxygen in proportionto hydrogen


28/31

What functions do lipids serve?

Ans: -Source and storage of energy

-E

ssential parts of cell structures (cellmembranes)

-Insulating material to prevent heat loss

-Solvent for fat-soluble vitamins and

hormones-Prevents water loss from skin surface (oil

secreted by sebaceous glands)


29/31

These are organic compounds that

function for the storage of genetic

information

Ans: Nucleic acids


30/31

What are the two types of nucleicacids found in all living things?

Deoxyribonucleic acid (DNA) and ribonucleicacid (RNA)


31/31

Both types of nucleic acids are made up of abasic building block called nucleotides. Anucleotide is made up of a five-carbon sugar, aphosphate group, and a nitrogenous base.

The differences of DNAand RNAare discussedin Table 2-4 located on page 46 of your book

chapter 2 (revised jan10)

Documents