Midterm Study Guide KEY p. 2
Enzymes
Vocabulary:
 Catalyst – a molecule that starts a reaction
 Substrate – molecule that reacts with an enzyme
 Active site – area on an enzyme where reactions take place
 Activation energy – energy necessary in order for a reaction to occur
 Induced fit model – perfect fit between a substrate and its enzyme (like a lock and key)
 Denaturation – deactivation of an enzyme due to drastic change in temperature or pH
Questions
1. What is the function of an enzyme?
Enzymes can speed up a reaction. Enzymes can start a reaction (catalyze). Enzymes can
lower the activation energy.
2. In the picture below, which reaction most likely involves an enzyme?
Reaction 3
Macromolecules
Macromolecule
Monomer/Polymer
Elements/Components
involved
Examples
Protein
Amino
Acid/Polypeptide
C, H, O, N /
Carboxyl group, Amino
group, R group
Meats
Lipids
Fatty acids/
Triglycerides,
Phospholipids, Waxes,
Steroids
C, H /
Glycerol, Fatty acids,
Phosphate group
(phospholipids)
Oils
Carbohydrates
Monosaccharide/
Polysaccharide
C, H, O /
Sugars
Bread
Nucleic Acids
Nucleotide/DNA or
RNA
C, H, O, N, P /
Sugar, Phosphate group,
Nitrogenous base
DNA
Questions
1. What reagents are used to test for each of the macromolecules?
a. Lipids
Paper  Positive result: Transparent, Negative result: Opaque
b. Carbohydrates
Benedict’s solution  Positive result: Green/Orange, Negative result: Blue
c. Proteins
Biuret  Positive result: Purple, Negative result: Blue
d. Starch
Iodine  Positive result: Black, Negative result: Red/orange
The Cell
Vocabulary  identify the structure and function of the following organelles
 Mitochondria – organelle that creates energy
 Vacuole – organelle that stores water, wastes, and salts
 Plasma membrane – organelle that surrounds cell and regulates what can enter and leave
 Nucleus – organelle that holds genetic information
 Cell wall – ridged organelle that surrounds plasma membrane and provides strength and
structure to plant and bacteria cells
 Golgi apparatus – organelle that packages and ships molecules in the cell
 Ribosomes – organelle that makes proteins
 Nuclear envelope – membrane that surround the nucleus
 Rough endoplasmic reticulum – organelle that aids in transport of molecules with ribosomes
attached to its membrane
 Smooth endoplasmic reticulum – organelle that aids in transport of molecules
 Chloroplast – organelle where photosynthesis takes place (plant cells only)
 Chromosomes – condensed form of DNA
Questions
1. List the scientists involved with early cell discoveries and identify their contribution.
Robert Hooke  Saw cork cells under microscope
Anton van Leeuwenhoek  Made first light microscope and saw first cells
2. How is surface area relevant to cell size?
Cell size is limited by its surface area. As cell size decreases, surface area increases.
3. What are the differences between prokaryotes and eukaryotes?
Prokaryotes
Smaller
Bacteria/Archaea
No membrane bound nucleus (nucleoid)
Eukaryotes
Larger
Plants/Animals
Membrane bound nucleus
4. What are the differences between plant and animal cells?
Plant
Nucleus is off centered
Chloroplasts
Cell wall
Central vacuole
Animal
Nucleus in center
Centrioles
Lysosomes