Biochemistry Chapter 3
Dec 29, 2015
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?