Chapter 3 Homework Questions PDF

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Homework Questions and Answers - Professor Wilson ...

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Chapter 3 Homework Questions:

Identify all the general similarities between Bacteria and Archaea. -

Lack membrane-bound organelles Lack membrane-bound nucleus

Historically, prokaryotes were differentiated from eukaryotes by ______. -

The absence of a nucleus

Which of the following describes the controversy concerning the use of the term "prokaryote?" -

Biochemical, genetic, and genomic analysis have shown that Bacteria and Archaea are distinct taxa.

Which genus gets its name due to the cellular arrangement of spherical cells found in clusters, like a bunch of grapes? -

Staphylococcus

Match the following common bacterial cellular components with their function. -

Cell wall - protection against osmotic stress Cell membrane - selectively permeable barrier Capsule - protective layer and sometimes aids in adhesion Ribosomes - site of protein synthesis

Which of the following shares a basic body plan with bacteria? -

Archaea

What term is used to describe the plasma membrane and all layers external to it? -

Cell envelope

Prokaryotes were not fully described until 1962 when scientist grouped them together based on ___________. -

what they lacked compared to eukaryotes

Which of the following terms describes the way in which lipids and proteins behave in a membrane? -

Fluid mosaic model

Which of the following organisms appears to blur the lines between prokaryotes and eukaryotes? -

Archaea

Which term describes the cellular arrangement of spherical cells linked in a chain? -

Streptococcus

Plasma membranes are organized by having ______. -

two lipid layers

Which of the following cellular components are commonly found in most bacterial cells? -

Ribosomes Capsule Flagella Cell wall Slime layer

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

Cell envelope

Bacteria growing at higher temperatures have phospholipids with _____. -

more saturated fatty acids

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

Fluid mosaic model

Which describes a bacterial hopanoid? -

Sterol-like compounds

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

Which of the following is true regarding macronutrients and micronutrients? -

Macronutrients are substances needed in large quantities.

The lipid composition of a plasma membrane varies with the environmental temperature. The structural changes to the phospholipids occurs in the _____ -

Hydrocarbon chains

Bacterial plasma membranes contain ____, rigid planar lipids similar to cholesterol found in eukaryotic cell membranes. -

Hopanoids

Macroelements include which of the following? -

Carbon, sulfur, oxygen, hydrogen and a few others

Elements required in low concentrations for cell growth are called ______. -

Micronutrients

Compounds such as essential amino acids are considered _____.

-

Growth factors

Compounds considered to be growth factors ______. -

are acquired from the environment

Zinc, cobalt, molybdenum, nickel, and copper are examples of ______. -

Micronutrients

Which three of the following are growth factors? -

Vitamins Some amino acids Some nucleotides

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 active transport

The lipid composition of a plasma membrane varies with the environmental temperature. The structural changes to the phospholipids occurs in the _____ -

Hydrocarbon chains

True or false: Bacterial cells uptake nutrients that are dissolved. -

True

Compounds that must be acquired from the environment for cell survival are called _______. -

Growth factors

Which of the transport mechanisms relies only on concentration gradients to provide the "force" to move materials across the plasma membrane? -

Passive diffusion

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

High/low

Bacterial cells acquire nutrients that are ____. -

Dissolved

Zinc, cobalt, molybdenum, nickel, and copper are examples of ______. -

Micronutrients

Substances like oxygen, carbon dioxide and water move across a bacterial cell membrane by _____. -

Passive diffusion

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 active transport

The "energy-free" movement of molecules across a membrane with the aid of a transporting protein is called ______. -

facilitated diffusion

A cell is placed into a slightly hostile environment where the temperature is not ideal for the cell but tolerable. Which of the following transport mechanisms would probably work the fastest? -

Passive diffusion because it is unaffected by the hostile conditions

Proteins characterized as channels and carriers are ______. -

Transport proteins

Which three of the following substances cross a membrane by passive diffusion?

-

Water Oxygen Carbon dioxide

Which of the transport mechanisms relies only on concentration gradients to provide the "force" to move materials across the plasma membrane? -

Passive diffusion

As you add more and more solute, facilitated diffusion by carriers will __________. -

reach a maximum rate of transport

Which of the following describes proteins that aid in the movement of materials across a membrane? -

Channels and carriers

Substances like oxygen, carbon dioxide and water move across a bacterial cell membrane by _____. -

Passive diffusion

A carrier protein that transports solute molecules by facilitated diffusion has _____ configuration(s) because _____. -

two; it needs to bind solute outside the cell and then release it in the cytoplasm

When facilitated diffusion reaches a maximum rate (arrow), this indicates that ____. -

carrier molecules have been saturated by solutes

Which of the following statements regarding carrier-mediated facilitated diffusion is false? -

The carrier protein moves solute molecules against a concentration gradient.

As you add more and more solute, facilitated diffusion by carriers will __________.

-

reach a maximum rate of transport

The use of ATP to power the movement of substance across a membrane is commonly referred to as ____ transport. -

Primary active

Active transport and facilitated diffusion are similar because they both ____. -

use proteins to move materials across a membrane

If the concentration of solute drops, what happens to facilitated -

It slows down

In active transport, the "active" refers to ____. -

the use of energy to power the movement of molecules across a membrane...