A certain type of specialized cell contains an unusually large amount of rough endoplasmic reticulum
.Which of the following functions is this cell type most likely specialized to perform?
The production and secretion of proteins
Correct. The cytosolic surface of the rough
is covered by ribosomes that synthesize proteins that are then transported into the rough
, then to the Golgi complex, and finally out of the cell.
The fluid mosaic model of cell membranes describes proteins and steroids associated with a phospholipid bilayer. Which of the following membrane components affect membrane stability?
Steroids, such as cholesterol, give membranes more stability.
Cholesterol directly affects the membrane stability of animal cells.
A scientist is studying the various prokaryotic and eukaryotic species found floating in a sample of water taken from a marine ecosystem.
Which cellular component will be found in the widest range of organisms in the sample?
The ribosome, since all organisms need to synthesize proteins.
Correct. Ribosomes are found in all forms of life, allowing for comparison of the widest possible range of plankton species.
In an experiment, researchers provided a radiolabeled amino acid to living plant cells. After one hour, the researchers determined the amount of the radiolabeled amino acid that was in each of several subcellular compartments. The results of the experiment are represented in the table.
RELATIVE AMOUNTS OF RADIOLABELED AMINO ACID
Nucleus 2.1
Mitochondria 2.7
Endoplasmic Reticulum 1.9
Cytosol 1.0
Which of the following conclusions about the radiolabeled amino acid is best supported by the results of the experiment?
It was mostly incorporated into proteins that regulate and manage metabolic reactions.
Correct. Amino acids are the building block of proteins, and the data indicate that most of the radiolabeled amino acid was in the mitochondria. Therefore, the data best support the conclusion that most of the amino acid molecules were incorporated into proteins that regulate and manage the metabolic reactions that occur in mitochondria.
Which of the following statements accurately describes the facilitated diffusion of materials across a cell membrane?
Ions move down their concentration gradient across the membrane.
The antibiotic blasticidin S is a large molecule that can inhibit protein synthesis in mammalian cells. A researcher is investigating how blasticidin S enters mammalian cells. The researcher identified two proteins that might be associated with blasticidin S transport into the cell.
Which of the following claims most likely explains how the two proteins are directly involved in the antibiotic’s ability to enter the cell?
Responses
They are transport proteins that facilitate the movement of blasticidin S across the cell membrane.
Some cells, such as intestinal cells, exchange a lot of material with their surroundings. The surface-to-volume ratio of these cells affects the efficiency of material exchange.
The table provides measurements of four different eukaryotic cells.
cell 1 2 3 4
total surface area 40 60 80 100
total sugar 20 10 30 20
cell 2
