Unit 2

BIO.1B.1 - The Four Macromolecules

Need to know

Be able to do

• Identify a macromolecule from its drawn structure: repeating sugar rings indicate a carbohydrate; a long hydrocarbon chain with a carboxyl group indicates a lipid; amino-acid features indicate a protein; and a sugar, phosphate, and nitrogen base indicate a nucleic acid.
• Choose the correct function from choices that may describe other macromolecules.
• Evaluate a complete chart row containing a macromolecule, monomer, and function, rejecting it if any part is wrong.
• Identify the traits shared by collagen, lipase, and hemoglobin: they are composed of amino acids and contain nitrogen.

Watch out for

• Lipids do more than store fat; they also form the bilayer in cell membranes.
• Know the functions of all four macromolecules so you can eliminate mismatched choices.

BIO.1B.2 - Enzyme Investigations

Need to know

• Enzymes are proteins that speed up the rate of chemical reactions.
• The three tested conditions are temperature, pH, and concentration.
• Past the optimum, extreme temperature or pH changes an enzyme's shape so the substrate no longer fits and activity drops.
• A substrate-concentration plateau means every enzyme is already busy. Concentration is the only one of the three conditions that does not damage the enzyme.

Be able to do

• Name the independent variable, which is the condition changed, and the dependent variable, which is relative activity or reaction rate. Relative activity is on the y-axis.
• Read the peak of a curve as the optimum range.
• Tell the three curve shapes apart: temperature and pH rise to a peak and then fall, while concentration rises and then levels off.
• Read a multiline graph by checking its key before interpreting the curves.
• Conclude that an enzyme's optimum for one variable can shift when a second variable changes.
• Complete missing procedural steps and identify controlled variables in an enzyme investigation.

Watch out for

• A plateau is not the same as a drop. A plateau indicates saturation, not enzyme damage.
• Always read the key before interpreting a multiline graph.