1.The structural and functional unit of all living organisms is the A)ribosome.
2.Which of the following could be used to study general features of cells? A)a magnifying glass
B)scanning electron microscope
C)transmission electron microscope
3.In order to study in detail, the anatomy of internal cell parts, it would be best to use A)x-rays.
C)a transmission electron microscope (TEM).
E)a scanning electron microscope (SEM).
4.The plasma membrane
A)separates the nucleus from the rest of the cell.
B)is a rigid protein membrane.
C)is not permeable.
D)has a single layer of phospholipids.
E)regulates movement of materials into and out of the cell. Answer: e
5.The environment outside the plasma membrane is most appropriately referred to as A)intracellular.
E)none of the above.
6.The fluid-mosaic model of the plasma membrane suggests that A)cholesterol forms the outermost layer of the membrane.
B)proteins form a "liquid" sea in the membrane.
C)phospholipids form a single lipid layer in the center of the membrane. D)the membrane is neither rigid nor static in structure.
E)proteins are not a part of the membrane.
7.According to the most current model of the plasma membrane A)cholesterol forms the innermost layer of the membrane
B)proteins are free to move about with a double layer of phospholipids C)phospholipids and cholesterol form a single lipid bilayer D)the membrane is a rigid unchanging structure
E)the membrane is impermeable to all other molecules.
8.Which of the following activities is a function of the plasma membrane? A)digestion of unneeded cell organelles
B)recognition of bacterial cells by the immune system
C)transport of products from the nucleus to the endoplasmic reticulum D)cell metabolism
9.Plasma membrane phospholipids
A)have polar (charged) tails.
B)are arranged in a single layer.
C)have tails that face the exterior of the membrane.
D)are 95% cholesterol.
E)have a hydrophilic head and hydrophobic tails.
10.Which of the following is correctly matched with its function? A)channel proteins - are part of an intercellular communication system B)marker molecules - are primarily steroids
C)receptor molecules - attach to ligand molecules.
D)peripheral proteins - penetrate the lipid bilayer from one surface to the other. E)nongated ion channels - are always closed.
11.In general, water-soluble molecules diffuse through the ______ ______; and lipid-soluble molecules diffuse through the ______ ______. A)protein channels; protein channels
B)protein channels; bilipid layer
C)bilipid layer; protein channels
D)bilipid layer; bilipid layer
E)none of the above
12.Cell membrane phospholipids
A)have nonpolar fatty acid tails.
B)form a bilayer.
C)have polar phosphate heads.
D)create a selectively permeable barrier.
E)all of the above
13.When a sperm cell comes into contact with an egg cell, there is a change in the electrical charge across the plasma membrane and various channel proteins close. These channels would be called A)open-gated channels.
E)nongated ion channels.
14.Communication between cells occurs when chemical messengers from one cell bind to _____ on another cell. A)channel proteins