Biochemistry

Chapter 3

Chapter 3 Vocabulary

• Monomer• Polymer• Condensation reaction• Hydrolysis• Adenosine

triphosphate• Carbohydrate• Monosaccharide

• Disaccharide• Polysaccharide• Protein• Amino acid• Substrate• Fatty acid• Triglyceride• Steroid

Carbon Compounds

• Two broad categories of compounds– Organic– Inorganic

• Organic compounds – made primarily of carbon atoms

• Most matter in living organisms is made up of organic compounds

Functional Groups

• Functional groups - is the portion of an organic molecule that is active in a chemical reaction and that determines the molecule's properties. – Clusters of atoms– Influence the characteristics of molecules

Functional Groups

Large Carbon Molecules

• Monomers – small, simple molecules• Polymers – monomers bonded to one another

to form repeated, linked units• Macromolecules – large polymers

Formation of Large Carbon Molecules

• Condensation reaction – when monomers link to form polymers, resulting in the release of a water molecule

• Hydrolysis – when water is used to break down a polymer. The reverse of a condensation reaction.

Energy Currency

• Life’s processes require a constant supply of energy.

• Energy is available in certain compounds• ATP (adenosine triphosphate) is an important

energy supplier• ATP used by the cell to drive the chemical

reactions that allow the cell to function.

Macromolecules

• You are responsible for explaining the type of macromolecule to the class– Carbohydrates– Lipids– Nucleic Acids– Proteins

Self Quiz

• How do carbon molecules form?• How do they break down?• What are the 4 functional groups we discussed

in class?• What do they look like?• What is ATP?

Molecules of Life

Carbohydrates

• Carbohydrates – organic compounds composed of carbon, hydrogen, and oxygen.

• Ratio 1:2:1 (C:H:O)• Source of energy• Structural materials

Carbohydrates

• Three types:– Monosaccharides– Disaccharides– Polysaccharides

Monosaccharides

• Simple sugar• Contains carbon, hydrogen, and oxygen• General formula (CH2O)n

• Most common are:– Glucose– Fructose– Galactose– Have same chemical formula but different

structures, known as isomers

Disaccharides and Polysaccharides

• Disaccharide – a double sugar– Fructose + glucose = sucrose

• Polysaccharide – a complex molecule of three or more monosaccharides– Glycogen – the form of glucose that animals store– Starch – the form of glucose that plants store• Cellulose – a large polysaccharide that gives plant cells

strength and rigidity.

Proteins

• Proteins – organic compounds composed mainly of carbon, hydrogen, oxygen, and nitrogen.

• Formed from monomers called amino acids

Amino Acids

• 20 different amino acids (a.a.)• Share a basic structure– Central carbon– 4 functional groups

Dipeptides and Polypeptides

• Dipeptide – two amino acids bonded• Peptide bond – formed by a condensation

reaction. Two amino acids form a covalent bond.

• Polypeptide – long chains of amino acids

Enzymes

• Enzymes – RNA or protein molecules that act as biological catalysts

• Are essential for the functioning of the cell• Many enzymes are proteins

Enzyme Reactions

• Depend on physical fit between enzyme and substrate

• Substrate – the reactant being catalyzed• Active site – where the substrate fits on the

enzyme• Enzymes are substrate specific• Link of enzyme and substrate causes slight

change in enzyme shape

Lipids

• Lipids – large, nonpolar organic molecules• Lipids do not dissolve in water• Types of lipids:– Triglycerides– Phospholipids– Steroids– Waxes– Pigments

Fatty Acids

• Fatty acid – unbranched hydrocarbon chains that make up most lipids

• Hydrophilic and hydrophobic ends• Saturated and unsaturated– Saturated – only single bonds, carbons full– Unsaturated – double bonds, carbons not full

Triglycerides

• Triglyceride – composed of three molecules of fatty acid joined to one molecule of glycerol– Saturated• Ex. butter

– Unsaturated• Ex. Plant seeds

Phospholipids

• Phospholipids – have two fatty acid chains attached to glycerol and a phosphate group attached to the glycerol.

• Phospholipid bilayer – makes up the cell membrane

Waxes and Steroids

• Wax – a type of structural lipid– A long fatty acid chain joined to a long alcohol

chain.– Waterproof, protective coating

• Steroids – composed of four fused carbon rings with various functional groups– Cholesterol is an important one

Nucleic Acids

• Nucleic acids – very large and complex organic molecules that store and transfer information in the cell

• Two major types– DNA – deoxyribonucleic acid– RNA – ribonucleic acid

DNA and RNA

• DNA contains information that determines the characteristics of an organism

• RNA stores and transfers information from DNA.• Some RNA molecules can act as enzymes• DNA and RNA are polymers composed of

nucleotides• Nucleotide – Phosphate group– Five-carbon sugar– Nitrogenous base

Self Quiz

• What are the three components of a nucleotide?

• How many amino acids are there?• What are the three types of carbohydrates?• What does it mean that enzymes are substrate

specific?• What are the two main types of nucleic acids?