Biology- Chapter 5 Quiz

The plasma membrane is composed of a phospholipid bilayer and associated proteins. What else is commonly found in the plasma membranes of animal cells?

cholesterol

Which statement is true about the presence or absence of plasma membranes?

All cells have a plasma membrane

Which particles are pumped across the lysosomal membrane by a transport protein to create a special internal environment in the lysosome?

protons

Some plant cells create a high concentration of protons outside the cell to move solutes, such as sucrose, across the plasma membrane into the cell where the sucrose concentration is already relatively high. This type of transport is an example of:

secondary active transport

The sodium-potassium pump is an example of:

an antiporter

In order for phospholipids to form bilayers spontaneously in an aqueous environment, the pH should be:

approximately neutral

Which substance could most easily cross a synthetic membrane composed of phospholipids but not proteins?

oxygen(O2)

Phospholipids spontaneously form a variety of structures in aqueous solution. Which choice best describes this property?

All of these choices are correct

If a mutation rendered the signal recognition particle nonfunctional, what would be the most obvious effect on the cell?

All proteins normally secreted by the cell would remain in the cytosol

If a mutation blocked the function of the signal recognition particle, making it unable to bind signal sequence, what would result?

All proteins would be translated on free ribosomes in the cytoplasm

Which molecule would most likely require a transport protein to cross the plasma membrane of a red blood cell?

C6H12O6

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

The plasma membranes of some plant cells use transport proteins to move protons out of the cell against their concentration gradient. This is an example of:

active transport

Some diseases result from defective transport across the membrane. For example, cystic fibrosis results when a chloride ion transporter does not function. What is affected when this transporter does not function?

both the chloride concentration gradient and the electrical gradient of the cell

Which sequence accurately describes the path traveled by a new protein from when it first starts to be translated to its release from the cell?

cytosol-->ER-->Golgi-->vesicle-->plasma membrane-->external environment

The beaker in the illustration contains two solutions of salt with different concentrations (measured by molarity, M). The two solutions are separated by a membrane that is permeable to water but not to salt.What will occur in this container?

diffusion of water from A to B but no diffusion of salt

The protein-assisted movement of a polar molecule across the membrane that does not require ATP or the input of energy occurs through:

facilitated diffusion

Purified phospholipids mixed in water will only form membranes if the appropriate enzyme is present.

false

Which component of a phospholipid is found in the interior of a lipid bilayer?

fatty acids

The active maintenance of a constant internal environment is referred to as:

homestasis

Some transmembrane proteins are embedded in patches of plasma membrane with a specialized, non-random assortment of phospholipids, sphingolipids and cholesterol. These patches are referred to as:

lipid rafts

The first cells were surrounded by a membrane composed largely of lipids synthesized by intracellular proteins.As life on earth was starting, from what were the first membranes most likely formed?

lipids mixing in the watery environment

Which proteins would be synthesized on the rough endoplasmic reticulum and processed in Golgi apparatus?

lysosomal enzymes that break down proteins in the lumen of the lysosome

The beaker in the illustration contains two solutions of salt with different concentrations (measured by molarity, M). The two solutions are separated by a membrane that is permeable to both salt and water. What will occur in this container?

net diffusion of water from A to B and of salt from B to A

RNA molecules are transported from the nucleus to the cytoplasm in eukaryotes through:

nuclear pores

Which choice describes the hydrophilic component of cholesterol?

the hydroxyl head group

Which component is not considered part of the cytoplasm?

the nucleus