UNIT 2 Flashcards
EXAM 2 (50 cards)
In bacteria, DNA will be found in ________.
the nucleoid
Which of the following is a major difference between prokaryotic cells and eukaryotic cells?
Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not.
In which of the following organelles would you expect to find digestive enzymes?
lysosome
Which structure is common to plant and animal cells?
mitochondria
An antibiotic that blocks protein synthesis in a bacterium most likely targets which of the following?
ribosomes
A cell with a predominance of rough endoplasmic reticulum is most likely ________.
producing large quantities of proteins for secretion
Which of the following is the most common pathway taken by a newly synthesized protein that will be secreted by a cell?
rough ER → Golgi → transport vesicle → plasma membrane
The evolution of eukaryotic cells most likely involved ________.
endosymbiosis of an oxygen-using bacterium in a larger bacterial host cell-the endosymbiont evolved into mitochondria
Which of the following statements about the cytoskeleton is true?
The cytoskeleton is dynamic and constantly changing
Cyanide is a strong poison that interferes with the production of ATP. If a cell is exposed to cyanide, in which organelle would you expect to find the cyanide?
mitochondria
Which of the following structures form cytoplasmic channels that connect adjacent plant cells through the cell walls?
plasmodesmata
Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large, complex, undigested lipids. Which cellular organelle is most likely defective in this condition?
the lysosome
According to the fluid mosaic model, a membrane ________.
is composed of a fluid bilayer of phospholipids with embedded amphipathic (having both hydrophilic and hydrophobic parts) proteins
An animal cell lacking carbohydrates on the external surface of its plasma membrane would likely be impaired in which function?
cell-cell recognition
Winter wheat is a variety of wheat commonly grown during the colder months because it is very resistant to cold temperatures. The membranes of winter wheat are able to remain fluid when it is extremely cold by ________.
increasing the proportion of unsaturated phospholipids in the membrane
Which of the following statements about diffusion is true?
It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
Which of the following would diffuse through the lipid bilayer of a plasma membrane most rapidly?
CO2
The force driving simple diffusion is ________, while the energy source for active transport is ________.
a concentration gradient; ATP hydrolysis
Facilitated diffusion is a form of passive transport. When ions move across the plasma membrane via facilitated diffusion they often use
A channel protein
Which of the following statements describes a characteristic feature of all carrier proteins in a plasma membrane?
It specific for a particular molecule.
A sodium-potassium pump ________.
moves three sodium ions out of a cell and two potassium ions into a cell using energy from ATP hydrolysis
The phosphate transport system in bacteria imports phosphate into the cell even when the concentration of phosphate outside the cell is much lower than the cytoplasmic phosphate concentration. Phosphate import depends on a H+ gradient across the membrane that must first be established by the hydrolosis of ATP. In this bacterial cell, phosphate transport is an example of ________.
secondary active transport
The difference between pinocytosis and receptor-mediated endocytosis is that ________.
pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity
Which of the following statements correctly describes osmosis?
In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration.
