Download functional group

TOPIC 3.2
MOLECULES OF CELLS
ORGANIC and INORGANIC
MOLECULES
3.2.1
ORGANIC MOLECULES: molecules
containing C and H in their structure
INORGANIC MOLECULES : molecules
which do not have C in its structure.
A few chemical groups are key to the functioning of
biological molecules
• An organic compound has unique properties that
depend upon the
– size and shape of the molecule and
– groups of atoms (functional groups) attached to it.
• A functional group affects a biological
molecule’s function in a characteristic way.
• Compounds containing functional groups are
hydrophilic (water-loving).
© 2012 Pearson Education, Inc.
A few chemical groups are key to the functioning of
biological molecules
• The functional groups are
– hydroxyl group—consists of a hydrogen bonded to
an oxygen,
– carbonyl group—a carbon linked by a double bond
to an oxygen atom,
– carboxyl group—consists of a carbon doublebonded to both an oxygen and a hydroxyl group,
– amino group—composed of a nitrogen bonded to
two hydrogen atoms and the carbon skeleton, and
– phosphate group—consists of a phosphorus atom
bonded to four oxygen atoms.
© 2012 Pearson Education, Inc.
Table 3.2
A few chemical groups are key to the functioning of
biological molecules
• An example of similar compounds that differ
only in functional groups is sex hormones.
– Male and female sex hormones differ only in
functional groups.
– The differences cause varied molecular actions.
– The result is distinguishable features of males and
females.
© 2012 Pearson Education, Inc.
ORGANIC MOLECULES
3.2.2
Monomer: smallest unit of an organic
molecules e.g: glucose
Dimer: two monomers
Polymer: many monomers are linked to each
other to form macromolecules.
How are they linked to each other? condensation
How are they broken down? hydrolysis
CONDENSATION 3.2.5
HYDROLYSIS 3.2.5
3.2.2
CARBOHYDRATES 3.2.3
FUNCTIONS:
1- main energy source for cells
2- structural elements
STRUCTURE: consist of C, H,O
Monosaccharide, Disaccharides,
Polysaccharides
3.2.3. Monosaccharides
Hexoses (6C sugars)
Glucose
Fructose
Galactose
Pentoses (5C sugars)
Ribose
Deoxyribose
They are soluble in water. Why?
3.2.3. Disaccharides
Glucose + Glucose
Fructose + Glucose
Galactose + Glucose
Maltose
Sucrose
Lactose
They are less soluble than monosaccharides.
Polysaccharides 3.2.4
Starch
Glucose + Glucose + Glucose +.....
Glycogen
Cellulose
Chitin is a N containing polysaccharide which is
found in the exoskeleton of insects and cell wall
of fungi.
They are not soluble or slightly soluble.
3.2.4
Polymerization by dehydration
synthesis
monomers
+
+
polymer
+
enzyme
+
ATP
H2O
monosaccharide, amino acid or
polysaccharide,
protein
H2O
H2O
nucleotide
or polynucleotide
Polymerization
1. Happens by dehydration synthesis
2. Monomers are joined by covalent bonds to
form polymers
3 different covalent bonds can be formed:
Glycosidic bond between monosaccharides
Peptide bond between amino acids
Phosphodiester bonds between nucleotides
Polymerization
4. Enzymes are used
5. ATP is required
6. 1 H2O molecule is released for each bond
made between monomers
Depolymerization by hydrolysis
polymer
monomers
enzyme
H2O
H2O
+
+
H2 O
monosaccharide, amino acid or
polysaccharide,
protein
nucleotide
or polynucleotide
+
Depolymerization
1. Happens by hydrolysis
2. Polymers are broken down into monemers
by adding a water.
3. Energy is not used
4. Enzymes are required.
Example: digestion
LIPIDS 3.2.6
• Do all living things have lipids?
• Which elements do lipids contain?
• Are lipids hydrophilic?
What are the functions of lipids?
3.2.6
• Storage of energy
• Structural elements (cell membrane,
hormones, myelin sheat)
• Thermal insulation. How?
Fatty acids
Essential fatty acids
Saturated fats
vs.
Unsaturated fats
• 3.2.6
• Triglyceride (oil or fat)
Natural fats, found in the fat tissue of
animals, seed and fruit of plants.
• Phospholipids
Main component of the cell membrane
• Steroids
– Cholesterol, sex hormones
• Wax
Water proof material around fruits, leaves.
Triglycerides
Cholesterol
• Essential component of animal cell
membranes
• Precursor for the synthesis of vitamin D and
steroid hormones such as testosterone and
estrogen
• Important for the metabolism of fat soluble
vitamins (A, D, E, K)
Phospholipids