Biology 1407 Exam 1 Questions with Correct
Answers
Does a DNA molecule contain Uracil?
False, DNA contains thymine instead of uracil.
What is starch composed of?
Starch is composed of branched amylopectin and unbranched amylose.
What characterizes biological membranes?
Phospholipids move laterally within the plane of the membrane.
What does the fluid mosaic model describe?
The membrane is composed of a fluid bilayer of phospholipids with embedded amphipathic
proteins.
Which molecules are least likely to have hydrophilic domains?
Cholesterol.
What is glycogen?
Glycogen is a storage polysaccharide found in animals, composed of alpha 1-4 and alpha 1-6
glycosidic bonds.
How do dehydration reactions and hydrolysis differ?
Dehydration reactions assemble polymers; hydrolysis reactions break polymers apart.
Which term does not describe a molecule of glucose?
A disaccharide.
, Why are cooking oil and gasoline not amphipathic?
They do not have a polar or charged region.
Which molecules diffuse through a cell membrane most readily?
Small hydrophobic molecules.
Which molecules are least likely to diffuse through the phospholipid bilayer?
Large hydrophobic molecules.
Which membrane activity requires energy from ATP hydrolysis?
The movement of Na+ ions from a lower concentration in a mammalian cell to a higher
concentration in the extracellular fluid.
What is a characteristic feature of a carrier protein in a plasma membrane?
It exhibits specificity for a particular type of molecule.
Why do celery stalks become limp in a 0.15 M salt solution?
The fresh water is hypotonic and the salt solution is hypertonic to the cells of the celery
stalks.
What happens to a red blood cell in pure water?
The cell will swell because the water in the beaker is hypotonic relative to the cytoplasm of
the RBC.
What drives simple diffusion and what is the energy source for active transport?
The force driving simple diffusion is a concentration gradient, while the energy source for
active transport is ATP hydrolysis.
What is facilitated diffusion?
Answers
Does a DNA molecule contain Uracil?
False, DNA contains thymine instead of uracil.
What is starch composed of?
Starch is composed of branched amylopectin and unbranched amylose.
What characterizes biological membranes?
Phospholipids move laterally within the plane of the membrane.
What does the fluid mosaic model describe?
The membrane is composed of a fluid bilayer of phospholipids with embedded amphipathic
proteins.
Which molecules are least likely to have hydrophilic domains?
Cholesterol.
What is glycogen?
Glycogen is a storage polysaccharide found in animals, composed of alpha 1-4 and alpha 1-6
glycosidic bonds.
How do dehydration reactions and hydrolysis differ?
Dehydration reactions assemble polymers; hydrolysis reactions break polymers apart.
Which term does not describe a molecule of glucose?
A disaccharide.
, Why are cooking oil and gasoline not amphipathic?
They do not have a polar or charged region.
Which molecules diffuse through a cell membrane most readily?
Small hydrophobic molecules.
Which molecules are least likely to diffuse through the phospholipid bilayer?
Large hydrophobic molecules.
Which membrane activity requires energy from ATP hydrolysis?
The movement of Na+ ions from a lower concentration in a mammalian cell to a higher
concentration in the extracellular fluid.
What is a characteristic feature of a carrier protein in a plasma membrane?
It exhibits specificity for a particular type of molecule.
Why do celery stalks become limp in a 0.15 M salt solution?
The fresh water is hypotonic and the salt solution is hypertonic to the cells of the celery
stalks.
What happens to a red blood cell in pure water?
The cell will swell because the water in the beaker is hypotonic relative to the cytoplasm of
the RBC.
What drives simple diffusion and what is the energy source for active transport?
The force driving simple diffusion is a concentration gradient, while the energy source for
active transport is ATP hydrolysis.
What is facilitated diffusion?
