02: Molecular Biology Sections 2.1 – 2.3

2.1: Molecules to Metabolism Essential Idea: Living organisms control their composition by a complex web of chemical reactions. 2.1: Molecules to Metabolism

Molecular biology explains living processes in terms of the chemical substances involved. Carbon atoms can form four covalent bonds, which allows a diversity of stable compounds to exist. Understandings

Life is based on carbon compounds: carbohydrates, lipids, proteins and nucleic acids. Metabolism is the web of all enzyme-catalyzed reactions in a cell or organism.

Anabolism is the synthesis of complex molecules from simpler molecules, including the formation of macromolecules from monomers by condensation reactions. Catabolism is the breakdown of complex molecules into simpler molecules including hydrolysis of macromolecules into monomers.

Carbon atoms have four valence electrons Carbon atoms have four valence electrons. This means that a carbon atom can form four covalent bonds. This characteristic allows for a variety of molecular shapes and structures.

Ring

Branched Chain

Straight Chain

These different structures allow for the creation of macromolecules These different structures allow for the creation of macromolecules. Macromolecules are, quite obviously, large molecules. Name the four macromolecules and provide two examples of each. Describe the structure and function of each. Task #1

Why are enzymes necessary for metabolic processes to take place? Metabolism is a web of reactions that occur in a series of small steps and takes place in cell cytoplasm. It is controlled by enzymes. You can break up metabolism into two distinct processes: catabolism and anabolism. Why are enzymes necessary for metabolic processes to take place?

Define and describe the processes of catabolism and anabolism, and provide examples. Compare and contrast the processes and what type of reaction is required for each. Task #2

More Artwork! You need to be able to recognize and draw four structures: glucose, ribose, an amino acid, and a simple lipid. For the lipid, you must be able to distinguish between saturated and unsaturated fats. Task #3

Essential Idea: Water is the medium of life

Water molecules are polar and are made of hydrogen bonds Water molecules are polar and are made of hydrogen bonds. Hydrogen bonding and polarity explan water’s cohesive, adhesive, thermal and solvent properties. Substances can be hydrophobic or hydrophilic. Understandings

Why is water so important? Water contains two hydrogen ions and an oxygen ion. H+ is used for active transport, photosynthesis and respiration. O-2 is used for aerobic respiration. Water has a pH of 7, which makes it neutral. Water is polar because of the unshared pairs of electrons on the oxygen ion. This allows the formation of hydrogen bonds. Why is water so important?

Create a concept map/graphic organizer describing the properties of water: cohesion, adhesion, thermal, and solubility, including examples. Why is it essential for nutrients to be water- soluble? What does this mean for molecule transport? Task #4

Essential Idea: Compounds of carbon, hydrogen and oxygen are used to supply and store energy. 2.3: Carbs & Lipids

Monosaccharides monomers are linked together by condensation reactions to form disaccharides. Fatty acids can be saturated, monounsaturated, or polyunsaturated. Understandings

Unsaturated fatty acids can be cis or trans isomers Unsaturated fatty acids can be cis or trans isomers. Triglycerides are formed by condensation from three fatty acids and one glycerol.

Monosaccharides are simple sugars Monosaccharides are simple sugars. Disaccharides are a combination of two monosaccharides. Polysaccharides are chains of sugars. Molecules are built or deconstructed via condensation reactions or hydrolysis. These are the processes by which carbs are processed by the body. Saccharides

Describe the difference between monosaccharides, disaccharides and polysaccharides. List three examples of each. What is the difference between hydrolysis and condensation reactions? Task #6

Fatty acids are long chains of hydrocarbons with a methyl group at one end and a carboxyl group at the other end. They function as long term energy storage. Fatty acids can be saturated, unsaturated, or polyunsaturated. The difference between these saturation levels is the presence of double bonds in the hydrocarbon chain. Lipids & Fatty Acids

Lipids are fats and oils composed of a glycerol molecule and a fatty acid tail. Triglycerides are a glycerol combined with three fatty acids. It is an insoluble molecule. In terms of dietary needs, why are triglycerides considered “bad?”

Create a Venn Diagram comparing and contrasting lipids vs Create a Venn Diagram comparing and contrasting lipids vs. carbohydrates. List three functions of lipids & fatty acids. Task #7

“Cis” means same and “trans” means opposite “Cis” means same and “trans” means opposite. When fats are hydrogenated (meaning a hydrogen atom is added), it alters the structure of the molecule. Naturally curved fatty acids are cis fatty acids and hydrogenated straightened ones are trans fatty acids.

To Be Continued…