Download Diapositiva 1 - Scuola Media di Piancavallo

Chemicals inside us and around us
PROTEINS
Proteins are a large molecules made up of one or more chains of
amino acids.
Amino acids are joined together by a peptide bond.
Union of a few amino acids is a peptide.
Chains of many amino acids is a polypeptide.
Proteins that contain other kinds of
molecules are called Conjugated proteins.
The structures of proteins
The primary structure of proteins is determinated by the
sequence of amino acids.
The secondary structure of proteins depends on
whether the protein chains are straight or folded
up in a particular pattern.
Functions of proteins
- Structure (i.e. myosin, keratins)
- Catalysis (enzymes)
- Control (insulin)
- Energy (albumin, casein)
- Transport (haemoglobin)
- Protection (antibody)
Denaturation of proteins
Denaturation occurs when the normal bonding patterns are
disturbed causing the change of the protein shape .
This can be caused by changes in temperature, pH or salt
concentration.
If the protein is not severely denaturated, it may regain its normal
structure.
CARBOHYDRATES
Carbohydrates are organic compounds and they have the
general formula Cx(H2O)y.
Sugars are the simplest
carbohydrates.
Monosaccharides
Simple sugars
Disaccharides
Two monosaccharides linked together
Oligosaccharides
Few monosaccharides linked together
Polysaccharides
Long chains of monosaccharides
Functions of carbohydrates
- Intermediates for the conversion of food into energy
- Energy storage molecules in plants
- They form cell walls in plant cells
- They are structural components in the body shells of many invertebrates
- They occur in the surface coat of animal cells and in bacteria cell walls
Carbohydrates are produced during photosynthesis.
Photosynthesis is the process by which green plants produce carbohydrates
from CO2, O2 and H20 using the energy from sunlight.
LIPIDS
Lipids are organic compounds that are insoluble in water but soluble in
organic solvents.
Simple lipids are esters of fatty acids and various alchols.
Functions of lipids
- Storage form for metabolic energy (triglycerides)
- Components of membranes
- Messagers (prostaglandis, steroid hormones)
CLASSIFICATION OF LIPIDS
Fat and oils
Compoud lipids
Waxes
Esters of fatty acids and alcohols containing
addictional groups ( i.e. phospholipids and
glycolipids)
Some important vitamins are lipids.
Vitamins are substances used by living cells to aid
enzyme reactions.
NUCLEIC ACIDS
DNA
RNA
(Deoxyribonucleic acid)
(ribonucleic acid)
DNA and RNA store and transfer genetic information
DNA is the genetic material and contain the informations
necessary for the synthesis of proteins.
Before protein can be synthesized, the instructions in DNA must
first be copied to messenger RNA.
Structure and composition of nucleic acids
Nucleic acids are composed of units called nucleotides linked together.
Each nucleotide contains a base, a sugar (deoxyribose in DNA and
ribose in RNA) and a phosphate group.
DNA is composed of two
strands that are twisted
forming a configuration
that is called double
helix.
THE FLOW OF GENETIC INFORMATION
DNA
Replication
Transcription
RNA
Translation
Proteins
BIBLIOGRAPHY
P. Briano – A Matter of life - English for Chemistry, Biology and
Biotechnology – Edisco
P. Vaudo – On the Lab – Ed. Yuvenilia
D. L. Nelson, M. M. Cox – Introduzione alla Biochimica di Lehninger – Ed.
Zanichelli
Author: Gabriele