Download Week 4 - Composition of Cells

WEEK 4:
Composition of Cells
LEARNING OUTCOMES
By the end of this week, you should be able to:
 Develop a knowledge and understanding of the
composition of cells.
 Describe the major groups of organic and
inorganic substances including carbohydrates,
proteins, lipids, nucleic acids, water, minerals,
vitamins.
 Describe the general role of these substances in
cell structure and function.
Chapter 3 Glossary
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Metabolism
Catabolism
Anabolism
Water
Cohesive
Hydrogen bonds
Hydrophilic
Hydrophobic
Monomers
Polymers
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Carbohydrates
Monosaccharide
Polysaccharide
Lipids
Trigylcerides
Phospholipids
Nucleic acids – DNA,
RNA
Proteins
Enzymes
Minerals
Vitamins
Organic Compounds
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Organic compounds all contain the
element carbon.
They usually also contain hydrogen
and oxygen in varying quantities.
They are often large molecules
(polymers), and are made of
smaller sub-units (monomers)
bonded together in various ways.
They all contain the elements C
carbon H (________)
hydrogen and O
(______),
oxygen
(_______).
Nitrogen (N) and sulphur (S) are
common in amino acids and
nucleotides.
Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur
Organic Compounds
MONOMER
POLYMER
EXAMPLES
Monosaccharides
(e.g. glucose)
Polysaccharides
Starch, glycogen,
cellulose
Fatty acids and
glycerol
Lipids
Fats, oils, waxes
Amino acids
Proteins
(polypeptides)
Enzymes, hormones,
structural proteins
Nucleic acids
Deoxyribonucleic acid
(DNA), ribonucleic acid
(RNA)
Nucleotides
Water
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2.
solvent in living
Water is the predominant ______
organisms.
cohesive
Water molecules are highly _______.
Draw and label a water molecule.
Add a couple more water molecules to your
diagram and illustrate how they stick together.
Carbohydrates
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1.
The different properties of carbohydrates relate
to the way the glucose monomers have been linked
together.
Copy table 3.3 from page 56 in your textbook.
Proteins
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1.
2.
Proteins contain nitrogen as well as C, H and O.
There are 20 naturally occurring amino acids
which make up the many different types of
proteins.
Amino acids join together with a peptide bond.
Two amino acids bonded together are called a
dipeptide.
More than two amino acids bonded together are
called polypeptides.
Draw a polypeptide.
Label a peptide bond and amino acid monomer.
Lipids
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Important in animals as they
contain about twice as much
energy as polysaccharides.
Hydrophobic.
Triglycerides are a common form –
they have one glycerol molecule
and three fatty acid tails.
Phospholipids are the main
constituent of plasma membranes.
They have a phosphate group
attached to the glycerol and two
fatty acid tails.
Biological Roles of Lipids
Mitochondrion
(false color TEM)
Lipids are concentrated
sources of energy and can
be broken down (through
fatty acid oxidation in the
mitochondria) to provide
fuel for aerobic respiration
Waxes and oils, when
secreted on to surfaces
provide waterproofing in
plants and animals.
Phospholipids form the
structural framework of
cellular membranes, e.g. the
plasma membrane (above).
Biological Roles of Lipids
The white fat tissue
(arrows) is visible in this ox
kidney
Fat absorbs shocks.
Organs that are prone to
bumps and shocks (e.g.
kidneys) are cushioned
with a relatively thick layer
of fat.
Lipids are a source of metabolic
water. During respiration, stored
lipids are metabolized for energy,
producing water and carbon dioxide.
Stored lipids provide
insulation in extreme
environments. Increased body
fat levels in winter reduce
heat losses to the
environment.
Nucleic Acids
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3.
Draw Figure 3.12 from page 59 of your
textbook.
Label the parts.
Write down three differences between DNA
and RNA.