Exam 2 Review

Question 1

One reason for a cell to use a signal transduction pathway is to be able to “amplify” the original chemical signal that it received. True or false.

Answer 1

True

Question 2

Many molecules (both the ligand and initial receptor molecule, as well as a series of relay molecules) will be involved in a signal transduction pathway. True or false.

Answer 2

True

Question 3

All of the cells in your body will respond to the same incoming chemical signal with an identical signal transduction pathway. True or false.

Answer 3

False

Question 4

Which of the following enzymes would add a phosphate group to a relay molecule inside a cell, switching it “on?”
a. a protein kinase
b. a protein phosphatase
c. both
d. neither

Answer 4

a. protein kinase

Question 5

Ligands are capable of causing ion channels to be opened or closed, controlling the amount of ions allowed across the outer cell membrane. True or false.

Answer 5

True

Question 6

A G protein-linked (protein-coupled) receptor would be found inside of a cell (and bind to a ligand once it has already crossed the outer cell membrane), rather than being present on the outer cell membrane, itself. True or false.

Answer 6

False

Question 7

Which of the following would be used for “long-distance” chemical signaling in the human body?
a. paracrine signaling
b. hormone signaling
c. both
d. neither

Answer 7

b. hormone signaling

Question 8

Which of the following would occur first in a signal transduction pathway?
a. the binding of a ligand to a cell membrane receptor
b. a change in shape occurring in a cell membrane receptor
c. the use of a relay molecule
d. It depends upon the signal transduction pathway being used.

Answer 8

a. the binding of a ligand to a cell membrane receptor

Question 9

A protein component of a cell membrane that extends through the membrane to the outside environment on both sides would contain amino acids with:
a. hydrophilic R-groups
b. hydrophobic R-groups
c. hydrophobic R-groups at the ends and hydrophilic R-groups in its outer midsection
d. hydrophilic R-groups at the ends and hydrophobic R-groups in its outer midsection

Answer 9

d. hydrophilic R-groups at the ends and hydrophobic R-groups in its outer midsection

Question 10

A cell is capable of “recycling” an old, worn-out organelle by merging the organelle with a lysosome. True or false.

Answer 10

True

Question 11

Phagocytosis (“cell eating”) involves a very large molecule/particle being engulfed and “taken in” by a portion of a cell membrane. This scenario would provide a good example of exocytosis in action. True or false.

Answer 11

False

Question 12

When a protein moves two types of molecules across a cell membrane at the same time in opposite directions, against both of their concentration gradients, which of the following is taking place?
a. active transport using an antiporter
b. facilitated diffusion using an antiporter
c. active transport using a cotransporter (symporter)
d. facilitated diffusion using a cotransporter (symporter)

Answer 12

a. active transport using an antiporter

Question 13

Which of the following types of transport does not involve direct energy input (in the form of ATP), but, rather, is coupled with the energy-releasing diffusion of another substance across a membrane (along its concentration gradient)?
a. primary active transport
b. secondary active transport

Answer 13

b. secondary active transport

Question 14

Ions and small, polar molecules (like water) often travel across cell membranes via the use of channels. True or false.

Answer 14

True

Question 14

There is a low concentration of a (large-sized) sugar molecule inside a cell, and there is a high concentration of the same sugar molecule in the surrounding environment. Which of the following processes would be the most likely way that sugar would move into the cell?
a. passive diffusion
b. facilitated diffusion
c. active transport

Answer 14

b. facilitated diffusion

Question 14

In the example above, which of the following would describe the environment in which your cells would find themselves (before any movement of molecules has occurred)?
a. hypotonic
b. hypertonic
c. isotonic

Answer 14

b. hypertonic

Question 15

What would drinking distilled water (pure water, with a lower solute concentration than your body cells) do to the cells in your digestive tract?

Answer 15

They would take up water molecules from the distilled water, possibly lysing them

Question 16

Which of the following could be expected to travel through a cell membrane most rapidly through the use of passive diffusion, alone?
a. a large, uncharged molecule
b. a large, charged molecule
c. a small, uncharged molecule
d. a small, charged molecule

Answer 16

c. a small, uncharged molecule

Question 17

Glycoproteins and glycolipids involve carbohydrates that are bound to cell membrane components, usually for the purposes of either identifying a cell or receiving signals from other parts of the body. True or false

Answer 17

True

Question 18

Which type of protein would be found only on one side of a cell membrane or the other (not extending into the phospholipid “tail” interior of the membrane)?

Answer 18

peripheral

Question 19

Which type of fatty acid tails would tend to create a more “loosely-packed” phospholipid membrane?

Answer 19

unsaturated

Question 20

Cholesterol molecules can have an insulating effect upon the fluidity of cell membranes under fluctuating temperature regimes, keeping membranes more fluid at low temperatures and more cohesive at high temperatures. True or false.

Answer 20

True

Question 21

In order for a phospholipid molecule to cross from one side (leaflet) of a phospholipid bilayer to the other, both a flippase enzyme and a source of energy are required. True or false.

Answer 21

True

Question 22

Why was the evolution of the phospholipid bilayer so important in the history of life on Earth?
a. It allowed cells to maintain homeostasis.
b. It allowed cells to monitor incoming and outgoing materials.
c. It provided cells with “waterproofing.”
d. all of the above

Answer 22

d. all of the above

Question 22

The phospholipids in a cell membrane are usually free to move, both “in place” (individually) and through “swapping” positions with other phospholipids on the same membrane surface (leaflet). True or false.

Answer 22

true

Question 23

Which of the following allows neighboring animal cells to be attached in a way that is completely waterproof?
a. plasmodesmata
b. tight junctions
c. desmosomes
d. gap junctions

Answer 23

b. tight junctions

Question 24

Which of the following allows the cytosol of neighboring plant cells to be joined?
a. plasmodesmata
b. tight junctions
c. desmosomes
d. gap junctions

Answer 24

a. plasmodesmata

Question 25

It is the dynamic formation and breakdown of cytoskeletal fibers that makes overall cytoplasmic movement (like cytoplasmic streaming and pseudopodia) possible.

Answer 25

True

Question 26

Motor proteins that are capable of “walking” along cytoskeletal fibers use ATP as their source of energy. True or false.

Answer 26

True

Question 27

Which of the following cytoskeletal components represents the largest type of protein filament/fiber?
a. microtubules
b. intermediate filaments
c. microfilaments (actin filaments)

Answer 27

a. microtubules

Question 28

Which of the following are short protein fiber structures (usually found in high numbers on the eukaryotic cells in which they occur) that allow “wave-like” cell movement?
a. flagella
b. cilia

Answer 28

b. cilia

Question 29

Which of the following organelles breaks down wastes/toxins, but creates hydrogen peroxide as a byproduct that it is also capable of breaking down?
a. peroxisome
b. lysosome
c. mitochondria
d. smooth ER

Answer 29

a. peroxisome

Question 30

What is the purpose of the mitochondria in a cell?

Answer 30

to create energy from the breakdown of sugar

Question 31

Which of the following organelles are referred to as “semiautonomous” due to the fact that they contain their own DNA?
a. rough ER
b. mitochondria
c. chloroplasts
d. b and c only
e. all of the above

Answer 31

d. b and c only

Question 32

Which of the following organelles could be used to help a protist cell rid itself of excess water?
a. peroxisome
b. lysosome
c. central vacuole
d. contractile vacuole

Answer 32

d. contractile vacuole

Question 33

Which organelles are capable of producing a set of hydrolases that can be used in the breaking down of unwanted materials during both the process of autophagy and the process of phagocytosis?

Answer 33

lysosomes

Question 34

While rough ER creates proteins, smooth ER is involved in the creation of lipids. True or false.

Answer 34

True

Question 35

Which of the following is the path that a protein will take (via a series of vesicles) when it is destined to be exported from a cell?
a. Golgi apparatus (Golgi body) to rough ER to outer cell membrane
b. smooth ER to Golgi apparatus (Golgi body) to outer cell membrane
c. rough ER to Golgi apparatus (Golgi body) to outer cell membrane
d. smooth ER to rough ER to Golgi apparatus (Golgi body) to outer cell membrane

Answer 35

c. rough ER to Golgi apparatus (Golgi body) to outer cell membrane

Question 36

Bound ribosomes are located on the rough ER, and serve as tiny “protein workshops” to create the proteins that a cell needs. True or false.

Answer 36

True

Question 37

Ribosomes are created within the nucleolus region of a eukaryotic cell’s nucleus. True or false.

Answer 37

True

Question 38

Which of the following would be found in a eukaryotic cell, but not in a prokaryotic cell?
a. a nucleoid
b. a nucleus
c. ribosomes
d. All of the above would be found in a eukaryotic cell, but not in a prokaryotic cell.

Answer 38

b. a nucleus

Question 39

During the process of cell fractionation, lighter subcellular structures (such as ribosomes) would be expected to come out of solution sooner (and at a lower speed) than heavier subcellular structures (like nuclei). True or false.

Answer 39

False

Question 40

If you are interested in looking at the detailed surface structure/sculpturing of something as small as a bacterial cell, which of the following would be the best tool to use?

Answer 40

scanning electron microscopy

Question 41

Organisms that are closely related (in the evolutionary tree of life) would be expected to have more similar genetic sequences than organisms that are less closely related. True or false.

Answer 41

True

Question 42

Which nitrogenous bases have a structure that consists of a single carbon ring?

Answer 42

pyrimidines

Question 43

Which of the following nitrogenous bases would be found in an RNA molecule, but not in a DNA molecule?
a. adenine
b. cytosine
c. guanine
d. uracil
e. thymine

Answer 43

d. uracil

Question 44

DNA’s double helix “ladder” has “sides” that are formed by covalently-bonded pentose sugars and phosphate groups, with “rungs” that are formed by hydrogen-bonded nitrogenous bases. True or false.

Answer 44

True

Question 45

ACCTTA would turn into…

Answer 45

TGGAAT

Question 46

A nucleotide is composed of a phosphate group, a nitrogenous base, and glucose. True or false.

Answer 46

False

Question 47

The majority of proteins are able to function optimally across a wide range of temperatures and pH levels, since their structural integrity is not impacted by heat or the presence of excess ions. True or false.

Answer 47

False

Question 48

. You see a diagram of a protein “superstructure” composed of three polypeptide strands that fit together to create a single functional unit. Which of the following levels of protein structure does the diagram represent?
a. primary structure
b. secondary structure
c. tertiary structure
d. quaternary structure

Answer 48

d. quaternary structure