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Section 3-3
Chemical Compounds
in Cells
Elements and Compounds
• Element – most basic of all substances
• Atoms – smallest part of an element
– Made of three parts: protons (+), neutrons (0),
electrons (-)
• Compound – combo of two or more elements
• Molecule – smallest particle of a compound
Organic and Inorganic Compounds
• Organic – contains carbon
– Important organic molecules – carbohydrates,
lipids, proteins, nucleic acids (DNA)
• Inorganic – no carbon
– Important inorganic molecules – water (H2O), salt
(NaCl)
Carbohydrates
• energy rich compounds made of carbon,
hydrogen, and oxygen
• Small pieces are sugars
• Includes sugars, starches (bread, rice,
potatoes)
Lipids (Fats)
• Energy rich compounds made of H, C, and O
– Small pieces are fatty acids and glycerol
• Examples: Fats, Waxes, Oils
Proteins
• Large molecules made of carbon,
hydrogen, oxygen, nitrogen, sulfur
• Amino Acids
– Small molecules that make up
proteins, there are only 20
• Make up membrane of cell,
organelles, etc.
• Enzyme
– Type of protein that speeds up
chemical reactions
• Examples: Meat, eggs, nuts, beans
Nucleic Acids (DNA)
• Made of C, O, H, N, P
–Small pieces are
nucleotides
• Two types
–DNA – instructions
for all life functions
–RNA – used to
make proteins
Water
• Used to dissolve substances so chemical
reactions can take place
• Gives cells shape
• Regulates temperature
• Important in chemical reactions