Microbiology Chapter 3

Which of the following best describes peripheral membrane proteins? Peripheral proteins are not easy to extract from membranes. Peripheral proteins are not water soluble. Peripheral proteins span the membrane. Peripheral proteins are on the surface of a membrane.

Peripheral proteins are on the surface of a membrane.

The minimum unit of a cell membrane is the _____. nucleotide amino acid glycerol phospholipid

Phospholipid

Which type of lipids compose a cell membrane? Phospholipid Integral protein Rationale: Realize that proteins and lipids are very different compounds. Cholesterol Hopanoid

Phospholipid

Which type of lipids compose a cell membrane? Cholesterol Integral protein Phospholipid Hopanoid

Phospholipid

Which of the following structures is absolutely required for something to be considered a living organism? Nucleus Plasma membrane Capsule Cell wall Flagella

Plasma Membrane

Which of the following structures is found in all living organisms? Nucleus Flagella Plasma membrane Capsule Cell wall

Plasma Membrane

What cellular structure is closely associated with the cell's cytosol? Slime layer Capsule Cell wall Plasma membrane

Plasma membrane

Which of the following terms describes a bacterial cell that is variable in shape and lacks a single characteristic form? Spiral Bacillus Coccus Pleomorphic

Pleomorphic

Drs. Singer and Nicholson proposed a model to describe how lipids behave in a membrane called ___________ _____________ model.

fluid mosaic

Which of the following terms describes the way in which lipids and proteins behave in a membrane? Permeable mosaic model Endosymbiotic hypothesis Rigid mosaic model Fluid mosaic model

fluid mosaic model

Lipids in membranes arrange __________. tails toward the water side heads toward the water side both heads and tails toward the water side (i.e., they lay flat, "side-ways")

head toward the water side

Lipids in membranes arrange __________. tails toward the water side both heads and tails toward the water side (i.e., they lay flat, "side-ways") heads toward the water side

heads toward the water side

Molecules crossing a plasma membrane from a ____ concentration to a ____ concentration without energy use is an example of passive diffusion. low / low high / low high / high low / high

high / low

The lipid composition of a plasma membrane varies with the environmental temperature. The structural changes to the phospholipids occurs in the _____ hopanoids glycerol portion polar hydrophilic head hydrocarbon chains

hydrocarbon chains

The tails of a phospholipid are nonpolar. Their insolubility in water is described by the term _________

hydrophobic

The tails of a phospholipid are nonpolar. Their insolubility in water is described by the term ___________

hydrophobic

Lipids in membranes arrange __________. hydrophilic head to hydrophobic tail hydrophobic tail to hydrophobic tail hydrophilic head to hydrophilic head

hydrophobic tail to hydrophobic tail

A(n) _______ _________ is a layer of lipid macromolecules that surround the cell's cytoplasm.

plasma membrane

Bacterial cells that are variable in shape and lack a single characteristic form are called __________ unavailable correct in shape.

pleomorphic

Which of the following describes how the phospholipid tails interact with water? Hydrophilic Neutral Amphipathic Hydrophobic

Hydrophobic

Which three of the following substances cross a membrane by passive diffusion? Amino acids Oxygen Carbon dioxide Water Sugars

Oxygen Carbon dioxide Water

Which three of the following are macronutrients? Oxygen Zinc Nickel Cobalt Sulfur Carbon

Oxygen, Sulfur, and Carbon

Bacterial membranes are lipid bilayers within which proteins float. What is the relative proportion of these two components? 90% lipid + 10% protein 70% lipid + 30% protein 20% lipid + 80% protein 50% lipid + 50% protein

50% lipid + 50% protein

Which term is used to describe the asymmetric character of the lipids found in membranes? Selectively permeable Amphipathic Hydrophobic Hydrophilic

Amphipathic

What term is used to describe the plasma membrane and all layers external to it? Flagella Outer membrane Capsule Cell envelope Cell wall

Cell envelope

Which of the following describes proteins that aid in the movement of materials across a membrane? Adhesin Flippases Channels and carriers Integrases

Channels and carriers

Which of the transport mechanisms relies only on concentration gradients to provide the "force" to move materials across the plasma membrane? Group translocation transport Secondary transport Primary active transport Facilitated diffusion

Facilitated diffusion

Which of the following terms describes the way in which lipids and proteins behave in a membrane? Fluid mosaic model Permeable mosaic model Rigid mosaic model Endosymbiotic hypothesis

Fluid mosaic model

Which of the following best describes integral membrane proteins? Integral proteins are on the external surface of a membrane. Integral proteins are on the cytoplasmic surface of a membrane. Integral proteins span the membrane. Integral proteins can easily be removed from membranes.

Integral proteins span the membrane.

Which of the following is true regarding macronutrients and micronutrients? Macronutrients are substances that can be synthesized by the cell. Macronutrients are substances needed in large quantities. Micronutrients are substances needed in large quantities. Micronutrients are substances that can be synthesized by the cell.

Macronutrients are substances needed in large quantities.

Which of the following transport mechanisms relies on concentration gradients of one substance to power the translocation of a different substance across a membrane? Secondary transport Primary active transport Facilitated diffusion

Secondary Transport

Which two of the following are differences between spirochetes and spirilla? Spirochetes have one or more flagella at one or both the ends, spirilla have a unique internal flagellar arrangement. Spirochetes have a unique internal flagella arrangement, spirilla have one or more flagella at one or both the ends. Spirochetes are more rigid spiral shaped structures, spirilla are more flexible, spiral shaped structures. Spirochetes are more flexible, spiral shaped structures, spirilla are more rigid spiral shaped structures.

Spirochetes have a unique internal flagella arrangement, spirilla have one or more flagella at one or both the ends. Spirochetes are more flexible, spiral shaped structures, spirilla are more rigid spiral shaped structures.

How many lipid layers are found in a bacterial plasma membrane? (Note: a lipid layer consists of a series of phospholipids arranged side to side with hydrophilic heads all facing one direction and hydrophobic tails facing the other direction) Two Three Four One Varies for bacteria

Two

Which term describes a bacterial cell that is a slightly "bent rod" shape, also called comma-shaped?

Vibrio

The bacterial shape known as bacillus is different from coccus because bacillus is __________. motile smaller larger a rod shape a spherical shape

a rod shape

The _______ ________ is defined as the plasma membrane and all surrounding layers external to it (e.g., cell wall and/or capsule).

cell envelope

The two most common bacterial cell shapes are _____ and _____, both shown here.

cocci, bacilli

Bacteria growing at higher temperatures have phospholipids with _____. more saturated fatty acids shorter hydrocarbon chains longer hydrocarbon chains fewer saturated fatty acids

more saturated fatty acids

Substances like oxygen, carbon dioxide and water move across a bacterial cell membrane by _____. group translocation facilitated transport passive diffusion active transport

passive diffusion

The unaided energy-free movement of molecules across a membrane is called _______. passive diffusion active transport group-translocation transport facilitated diffusion

passive diffusion

The amphipathic character of phospholipids found in plasma membranes implies that ______. the lipid is long the lipid is fluid the lipid is rigid the lipid is asymmetric

the lipid is asymmetric

Plasma membranes are organized by having ______. one lipid layer and a cell wall three lipid layers two lipid layers one lipid layer and a capsule

two lipid layers

Active transport and facilitated diffusion are similar because they both ____. use proteins to move materials across a membrane transport solutes using energy provided by ATP are independent of solute concentration use diffusion to move materials across a membrane

use proteins to move materials across a membrane