Select the feature that best describes cell membranes

Match the following items 1. rr 2. rr 3. identical alleles 4. unlike alleles 5. rr ()homozygous, recessive ()homozygous definition ()heterozygous, dominant cell ()heterozygous definition () homozygous, dominant cell

Lactase is essential for digesting lactose in milk. this enzyme is specific for this sugar. why? molecules and active sites vary in size; only properly sized molecules can fit. there is a precise compatibility between the active site and the lactose molecule. specificity refers to the action of the enzyme, such as hydrolysis, and relatively few molecules can be hydrolyzed. reaction-specific enzymes assume a fit by folding around the most numerous substrate molecules.

The part of the eye that closes and opens to let light in is .