2. Organic compounds – chemicals synthesised by living things.
Contain carbon.
The basis of cells
◦ The big 4:
Carbohydrates
Lipids
Protein
Nucleic acid
& vitamins
Inorganic compounds (ie nutrients)
mineral salts, water, gases
3. All cells use nucleic acids (DNA) to store
information
All cells use proteins as catalysts (enzymes) for
chemical reactions
All cells use lipids for membrane components
All cells use carbohydrates for cell walls (if
present), recognition, and energy generation
All cells use nucleic acids (RNA) to access
stored information
4. WATER: 90% of the chemical reactions, solvent,
protoplasm regulate temperature
Medium for transport
Mineral salts: dissolved in cytoplasm and
Synethsis of macromolecues and
and vacuoles in plant cells body tissues
Assist Enzyme function (co-
enzymes)
Na+ and Cl- assist in water balance
n cells and the function of nerve and
muscle cells
Gases (CO2 H20) dissolved in CO2: Photosynthesis
protoplasm or produced Respiration produc
Regulates pH
O2: releases energy during
respiration
Product of photosynthesis
5. ◦ Monomers joined together
◦ Macro = BIG
◦ DNA
◦ Proteins
◦ Lipids & Carbohydrates (indirectly)
◦ See table 2.2
6. Monosacharides can be joined to one another to form
disaccharides, trisaccharides, ……..polysaccharides
◦ Saccharide is a term derived from the Latin for sugar (origin = "sweet
sand")
Carbohydrates classified according to the number of
saccharide units they contain.
◦ A monosaccharide contains a single carbohydrate,
over 200 different monosaccharides are known.
◦ A disaccharide - two carbohydrate units A
polysaccharide - many carbohydrates on hydrolysis,
examples are starch and cellulose.
7. All have general formula CnH2nOn (hydrates (H2O) of
carbon)
Simple sugars (glucose) are a source of quick
energy in cells to produce ATP in the mitochondria
Glucose + oxygen ATP
Stored as polysaccharides, in some plant cells
maybe dissolved in vacuoles
8. ◦ Cell structure:
Cellulose, LPS, chitin
Chitin in exoskeleton
Cellulose in plant cell walls Lipopolysaccharides (LPS)
in bacterial cell wall
10. Don’t dissolve in water – too big
Cellulose
Most abundant carbohydrate on the planet!
◦ Structural component of plant cell walls
◦ Indigestible by animals
Starch
◦ Energy storage molecule in plants
◦ Can be digested by animals
Glycogen
◦ Animal energy reserve
◦ Found primarily in liver and muscle
11. Cellulose is a linear
polysaccharide in which some
1500 glucose rings link together.
It is the chief constituent of cell
walls in plants.
Human digestion cannot break
down cellulose for use as a
food, animals such as cattle and
termites rely on the energy
content of cellulose. They have
protozoa and bacteria with the
necessary enzymes in their
digestive systems. Only animals
capable of breaking down
cellulose are tunicates.
12. Starches are carbohydrates in
which 300 to 1000 glucose units join
together. It is a polysaccharide used
to store energy for later use. Starch
forms in grains with an insoluble
outer layer which remain in the cell
where it is formed until the energy is
needed. Then it can be broken
down into soluble glucose units.
Starches are smaller than cellulose
units, and can be more readily used
for energy. In animals, the
equivalent of starch is glycogen,
which can be stored in the muscles
or in the liver for later use.
14. Lipids
◦ Fatty acids (Polymers of CH2 units), few oxygen atoms
◦ Insoluble in water, greasy, oily
◦ Animals = fats, plants = oils
◦ Triglyceride = I glycerol molecule & 3 fatty acids
15.
16. Function
◦ Energy Storage, stored in cytoplasm. Carbohydrates can be
converted to fats in times of food abundance
◦ Structural function: Cell membranes and cell compartments
◦ Bi-layer structure
Outer or plasma membrane
Nuclear membrane
Internal structures
Er, Golgi, Vesicles, etc.
Structural parts of hormones
18. Proteins serve many essential roles in the cell
◦ Are made up of polymers of amino acids,
one chain is called a poly peptide
◦ Peptide bond holds amino acids together
◦ One or more polypeptides can be twisted
together forming a protein
◦ The sequence and arrangement of amino
acids determines the type of protein – just
like the alphabet
◦ 20 naturally occurring amino acids
The large number of amino acids allows
huge diversity in amino acid sequence
Cannot be stored, excreted as nitrogenous
waste
19. Structure- form structural components of the cell including:
◦ Cytoskeleton / cell membranes
Enzymes - control reactions
Movement - Coordinate internal and external movement of cells,
organells, tissues, and molecules.
◦ Muscle contraction, chromosome separation, flagella………
Transport-regulate transport of molecules into and out of the cell /
nucleus / organelles.
Communication-serve as communication molecules between
different organelles, cells, tissues, organs, organisms.
◦ Hormones
20. Chemical properties of
the amino acids yield
properties of the protein!
21. The 3-D shape and properties of the protein
determine its function.
Shape and properties of protein determined by
interactions between individual amino acid
components.
Four “levels” of protein structure
◦ Primary (Io), secondary (IIo), tertiary (IIIo), and quaternary
(IVo) (sometimes).
22. All nucleic acids are made up of
nucleotides (monomers)
Made up of: a simple sugar, a
base, a phosphate
It is the sequence of bases which
differs, providing the genetic code
DNA –deoxyribonucleic acid
RNA –ribonucleic acid
So what’s the difference?
◦ RNA is one strand, DNA is 2
23. DNA RNA
Controls cells Messanger RNA – passes on
information stored in DNA,
transports a transcribed copy
from the nucleus to the
cytoplasm.
Transmits inherited Assist the message to be
information translated into proteins
Main component of chromatin
24. Information for all proteins stored in DNA
in the form of chromosomes or plasmids.
Chromosomes consist of two strands of DNA wrapped
together in a left handed helix.
The strands of the helix are held together
by hydrogen bonds between the individual
bases. The “outside” of the helix consists of
sugar and phosphate groups, giving the DNA
molecule a negative charge.
25. Chromosomes are composed of DNA and
proteins.
◦ Proteins serve a structural role to compact the
chromosome.
◦ Chromosomes can be circular, or linear.
Both types contain an antiparallel double helix!
◦ Genes are regions within a chromosome.
Like words within a sentence.
For an animation of the organization of a human chromosome see:
http://www.dnalc.org/ddnalc/resources/chr11a.html
Editor's Notes
This image shows the primary structure of glycophorin A , a glycoprotein that spans the plasma membrane ("Lipid bilayer") of human red blood cells. Each RBC has some 500,000 copies of the molecule embedded in its plasma membrane. Fifteen carbohydrate chains are "O-linked" to serine (Ser) and threonine (Thr) residues. One carbohydrate chain is "N-linked" to the asparagine (Asn) at position 26. Two polymorphic versions of glycophorin A, which differ only at residues 1 and 5, occur in humans. These give rise to the MN blood groups The M allele encodes Ser at position 1 (Ser-1) and Gly at position 5 (Gly-5) The N allele encodes Leu-1 and Glu-5 Genotype to Phenotype Individuals who inherit two N alleles have blood group N. Individuals who are homozygous for the M allele have blood group M. Heterozygous individuals produce both proteins and have blood group MN . Glycophorin A is the most important attachment site by which the parasite Plasmodium falciparum invades human red blood cells.
