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The molecules of cells Carbohydrates, lipids,
nucleic acids

• Inside the cell. NIH publication No. 05-1051
  http//www.nigms.nih.gov
• Cooper G. M, Hausman R. E. The cell. A molecular
  approach, 4th addition, ASM Press, 2007

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Professors
Vladimir Berezin
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The chemical composition of cells
? Water
? Inorganic ions
? Carbon-containing (organic) molecules -
Carbohydrates - Lipids - Nucleic acids -
Proteins
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Water
Water constitutes about 70 by weight of most
living cells. As a result, most cellular
components are essentially in an aqueous
environment.
States of water
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Water

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Carbohydrates

• The carbohydrates contain a carbon backbone and
  many hydroxyl (-OH)
• groups marking them very soluble in water

• Simple carbohydrates (mono- and-disaccharides)
  are simple sugars, such as
• glucose, and sucrose respectively

• Polysaccharides consist of many small, ring-like
  sugar molecules (monomers)
• attached to one another by glucosidic bonds in
  a linear or branched array to
• form the sugar polymer

• Functions of carbohydrates
• - Nutrients of cells a source of energy and
  the starting material for the synthesis of
  other constituents
• - Storage forms (polysaccharides)
• - Structural components of the cells
• - Markers for a variety of cell recognition
  processes (cell adhesion, modulators of cell
  adhesion, sorting and transport of proteins)

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Monosaccharides
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Disaccharides
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Polysaccharides
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Lipids

• Fatty acids

• Triacylglycerols or fats

• Phospholipids
• - Glycerol phospholipids
• - Sphingomyelin

• Glycolipids

• Cholesterol

• Functions of lipids
• - An important form of energy storage
• - Major components of cell membranes
• - Cell signaling (steroid hormones)

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Fatty acids
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Unsaturated fatty acids
Elaidic acid is a trans unsaturated fatty acid
often found in hydrogenated vegetable oils.
Oleic acid is a cis unsaturated fatty acid that
comprises 55-80 of olive oil.
Eating trans fats increases the risk of coronary
(atherosclerotic) heart disease.
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Triacylglycerols (fats)
Fats are a more efficient form of energy storage
than carbohydrates, yielding more that twice as
much energy after breakdown.
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Phospholipids
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Phospholipids
Phospholipids are amphipathic molecules, part
water-soluble and part water-insoluble.
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Glycolipids and cholesterol and steroid hormones
Cholesterol is extremely important biological
molecule that has roles in membrane structure as
well as being a precursor of the steroid hormones
and bile acids.
More than half of the cholesterol in the body
comes from the external sources.
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Nucleic acids

• Purine and pyrimidine bases

• Nucleosides and nucleotides

• Deoxyribonucleic acid (DNA)

• Ribonucleic acid (RNA)
• - Messenger RNA (mRNA)
• - Ribosomal RNA (rRNA)
• - Transfer RNA (tRNA)

• Functions of nucleotides and nucleic acids
• - Carriers of energy and reactive chemical
  groups
• - Signaling second messengers (cAMP, cGMP)
• - DNA and RNA are the principal information
  molecules of the cell
• - Protein synthesis (mRNA, rRNA, tRNA)
• - Catalysis (RNA)

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Nucleotides
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Polymerization of nucleotides
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Complementary pairing between nucleic acid bases
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Summary

• The chemical composition of cells includes
  water, inorganic ions and
• carbon-containing (organic) molecules
  carbohydrates, lipids, nucleic
• acids and proteins.

• Water constitutes about 70 of most living
  cells. Most cellular
• components are in an aqueous environment.

• Carbohydrates (simple sugars and
  polysaccharides) function as
• nutrients of all cells, storage forms,
  structural components and
• markers for a variety of cell recognition
  processes.

• Nucleic acids are the principal information
  molecules of the cell
• (DNA, RNA) coding for protein sequences and
  functioning in protein
• synthesis (mRNA, rRNA and tRNA) and catalysis
  (RNA).
• Nucleotides are carriers of energy and reactive
  chemical groups (ATP,
• GTP) and the source signaling second
  messengers (cAMP, cGMP).