Unit 1: Chemistry of life
What type of bond forms between two water molecules?
Hydrogen bond
Which organelle modifies and packages proteins?
Golgi apparatus
What is the main energy-carrying molecule in cells?
ATP
Which cell structure receives a chemical signal on its surface?
Receptor protein
Which property of water allows it to move upward through plant xylem?
Cohesion (and adhesion)
What organelles are in charge of protein synthesis?
Rough ER and ribosome
What enzyme is responsible for producing ATP during chemiosmosis?
ATP synthase
What type of signaling is used for short distances?
Paracrine signaling
Name the macromolecule that contains nitrogen, has peptide bonds, and performs enzymatic functions.
Protein
Why are cells small? Also relate your answer to surface area-to-volume ratio.
Smaller cells have a higher surface area-to-volume ratio, increasing efficiency of nutrient/waste exchange.
Where in the chloroplast does the Calvin Cycle take place?
Stroma
During which phase of the cell cycle is DNA replicated?
S phase of interphase
Describe the dehydration synthesis reaction that forms a disaccharide.
Two monosaccharides join, releasing a water molecule.
What would happen to an animal cell placed in a hypotonic solution?
Water would enter the cell, possibly causing it to swell or lyse.
Explain how temperature affects enzyme activity. Draw a sketch of the general pattern.
Increases rate to an optimal point, then activity drops due to denaturation.
A drug prevents phosphorylation of proteins during transduction. Predict the outcome for signal response.
Signal transduction would fail, so the cell would not initiate a response.
Design an experiment to test the effect of salinity on water potential in potatoes. Include your independent and dependent variables.
Soak identical potato pieces in solutions of varying NaCl concentrations.
Independent variable: NaCl concentration
Dependent variable: Change in mass of potato pieces
A muscle cell and a pancreatic cell both contain nuclei, but one has more smooth ER and the other more rough ER. Explain the reason for this difference.
Muscle cells rely on smooth ER for calcium storage and lipid metabolism, so they have more smooth ER.
Pancreatic cells produce digestive enzymes (proteins for export), so they have more rough ER for protein synthesis and secretion.
In an experiment, oxygen consumption in mitochondria increases when ADP is added. What does this indicate?
ADP stimulates cellular respiration; more oxygen is used for oxidative phosphorylation.
During which phase of mitosis do sister chromatids separate, and what ensures they’re pulled apart correctly?
Anaphase; spindle fibers attached to kinetochores shorten and pull chromatids to opposite poles.