B1.1 Carbohydrates and Lipids

SI Units

• SI units are used to ensure scientists from different parts of the world have the same standard system of measurements.

• IB Biology students should be able to convert between different SI units using the SI prefixes. 

  Prefix	Abbreviation	Power of 10
  kilo-	k	x 103
  centi-	c	x  10-2
  milli-	m	x 10-3
  micro-	µ	x 10-6
  nano-	n	x 10-9

Carbohydrates

• macromolecules of carbon

• Carbohydrates are a large group of organic compounds occurring in foods and living tissues including sugars, starch, and cellulose.

• They contain hydrogen and oxygen in the same ratio as water (2:1) and typically can be broken down to release energy in the animal body.

• Carbohydrates are classified based on the number of sugar monomers in the molecule.

 

	# of sugar molecules	Examples
Monosaccharide	1	Glucose, ribose, fructose
Disaccharide	2	Sucrose, maltose, lactose
Polysaccharide	Many	Starch, glycogen, cellulose, chitin

Lipids

• Lipids are a diverse range of organic compounds which all have chains of hydrocarbons.

• Lipids are hydrophobic, as they are all nonpolar compounds.

• Lipids dissolve in other nonpolar compounds, but will not dissolve in water.

• Lipids include

  • Triglycerides - Fats and Oils

  • Steroids

  • Waxes

  • Phospholipids

Covalent Bonds

• bonds formed by the sharing of electrons rather than the transfer of electrons

• weaker than polar bonds

• The covalent bonds can be single bonds or a combination of single and double bonds.

• Covalent bonds form when valence electrons are shared between two non-metal elements. 

• carbon can form up to 4

Macromolecules

Monomers

Polymers

Polysaccharides

Polypeptides

Nucleic Acids

Condensation Reactions

Hydrolysis Reactions

Monosaccharides

Polysaccharides

Pentose Sugars

Hexose Sugars

Starch

Amylose

Amylopectin

Cellulose

Glycogen

Cellulose Microfibrils

Glycoproteins

Antigens

Amphipathic

Hydrophobic

Hydrophilic

Triglycerides

Phospholipids

Fatty Acids

Saturated Fatty Acids

Unsaturated Fatty Acids

Monounsaturated Fatty Acids

Polyunsaturated Fatty Acids

Steroids

Fats

Oils