Chapter 5 Homework
A cell has a mutation that prevents it from breaking down unwanted proteins present in vesicles. Which cellular structure is most likely to be disrupted by this mutation?
lysosomes
RNA molecules are transported from the nucleus to the cytoplasm in eukaryotes through:
nuclear pores.
Which choice is considered an integral membrane protein?
a protein with its amino-terminus in the cytoplasm and its carboxy-terminus in the extracellular space
Which statement is true about the presence or absence of plasma membranes?
All cells have a plasma membrane
A beaker contains two solutions of salt dissolved in water. The two solutions have different concentrations of salt (measured by molarity, M) and are separated by a membrane that is permeable to both salt and water. The salt and water will move through the membrane by diffusion. Which statement is true about the diffusion of these solutions?
There will be a net movement of salt from side B to side A and net movement of water from side A to side B.
During translation, the new polypeptides are often directed to specific parts of the cell by the presence or absence of short sequences of amino acids called signal sequences. Which sequence would you expect to find in the signal sequences that will eventually become enzymes important in photosynthesis?
an amino-terminal signal sequence
In order for phospholipids to form bilayers spontaneously in an aqueous environment, the pH should be:
approximately neutral.
What would be found in the cells of a blade of grass but not in the cells of an insect feeding on that grass?
chloroplasts
In intestinal epithelial cells, a transport protein moves the bulky, polar glucose molecules through the membrane into the cytoplasm, while simultaneously transporting Na+ through the membrane into the cell down its electrochemical gradient. Which example correctly describes this cotransport of glucose and sodium?
secondary active transport by a symporter
Which of the structures are part of the endomembrane system?
the nuclear envelope
