Cell Structure and Function (Mid 2)

Question 1

As your muscles undergo cellular respiration during exercise (or even everyday life), they deplete the oxygen in and around the muscle cells. Oxygen will therefore be expected to move from ______ concentration in the blood to ______ concentration in muscle cells

a
Higher; lower

b
Lower; higher

c
Same; same

d
Higher; higher

e
Lower; lower

Answer 1

a
Higher; lower

Question 2

If a nurse were to mistakenly give you an I.V. bag full of pure water, what would you expect to happen to your blood cells?

Multiple answers:
Multiple answers are accepted for this question

a
They will neither gain nor lose water

b
They would gain water

c
They would lose water

d
They would swell in size

e
They would stay the same

f
They would shrink in size

g
Your blood plasma (fluid) would be hypertonic to the inside of your blood cells

h
Your blood plasma (fluid) would be isotonic to the inside of your blood cells

i
Your blood plasma (fluid) would be hypotonic to the inside of your blood cells

Answer 2

b
They would gain water
d
They would swell in size
i
Your blood plasma (fluid) would be hypotonic to the inside of your blood cells

Question 3

You take a dosage of milk of magnesia, which causes a high salt concentration in the fluids of your intestinal lumen (inside of intestines, where feces are formed). If increases or decreases in water in the intestinal lumen can affect the consistency of feces, then you would expect that:

a
Milk of magnesia likely helps cure diarrhea

b
Milk of magnesia likely helps cure constipation

c
Milk of magnesia would have no effect on feces consistency

Answer 3

b
Milk of magnesia likely helps cure constipation

Question 4

Celery stalks that are immersed in freshwater for several hours become stiff. Similar stalks left in a 0.15 M salt solution become limp. From this, we can deduce that the freshwater:

a
and the salt solution are both hypertonic to the cells of the celery stalks

b
and the salt solution are both hypotonic to the cells of the celery stalks

c
is isotonic and the salt solution is hypertonic to the cells of the celery stalks

d
is hypertonic and the salt solution is hypotonic to the cells of the celery stalks

e
is hypotonic and the salt solution is hypertonic to the cells of the celery stalks

Answer 4

e
is hypotonic and the salt solution is hypertonic to the cells of the celery stalks

Question 5

Just based on size, which do you think would lose/diffuse heat to the environment the fastest: my axolotl (<0.5 lb), my dog (~75 lbs), or me? (Think about the effects of surface area to volume ratio and size in your answer)

a
Axolotl

b
Dog

c
Me

d
All would lose heat at the same rate

Answer 5

a
Axolotl

Question 6

A normal cell has a low concentration of sodium on the inside and a high concentration on the outside. Yet, the net movement of sodium is out of the cell. Which of the following must be involved?

a
Osmosis

b
Facilitated diffusion

c
Active transport

d
Simple diffusion

e
Multiple of the above could be true

Answer 6

c
Active transport

Question 7

Which of the following is true comparing prokaryotes and eukaryotes? (select all that apply)

a
Prokaryotes are smaller than eukaryotes

b
The majority of organisms on Earth are eukaryotes

c
Eukaryotes have more organelles (are more compartmentalized) than prokaryotes

d
All of the above are true

e
Two of the above are false

Answer 7

c
Eukaryotes have more organelles (are more compartmentalized) than prokaryotes

a
Prokaryotes are smaller than eukaryotes

Question 8

One of the most important functions of the plasma membrane is its ability to be selective about what it is letting into and out of the cell. Based on what we have discussed so far, in order to get into or out of the cell, a molecule:

a
Always go directly between the phospholipids of the bilayer

b
Always go through a transport protein

c
May go between the phospholipids if it is small/hydrophobic or may go through a transport protein

d
Must go through an enzyme

Answer 8

c
May go between the phospholipids if it is small/hydrophobic or may go through a transport protein

Question 9

Which of the following is present in eukaryotes, but not found in prokaryotes?

a
Ribosomes

b
Nucleus

c
Plasma Membrane

d
DNA

e
All of the above are found in both eukaryotes and prokaryotes

Answer 9

b
Nucleus

Question 10

Red blood cells (RBCs) transport oxygen from the lungs to the rest of the body. Mammalian RBCs are odd in that mature RBCs lack almost all organelles. They are essentially a sac (plasma membrane) filled with hemoglobin, the protein that binds to oxygen to transport it. (Note: the hemoglobin in RBCs was made before the RBC was fully matured and lost its nucleus). Based on this, which of the following should RBCs be able to do?

a
Translate DNA into RNA

b
Make new proteins

c
Convert energy in macromolecules into usable energy for the cell

d
Control what comes into and out of the cell

e
All of the above

Answer 10

d
Control what comes into and out of the cell

Question 11

Which function(s) is/are specific to chloroplasts?

a
Detoxifies poisons and toxins

b
Converts light into chemical energy

c
Converts chemical energy in macromolecules from food into chemical energy in ATP

d
Packages/modifies proteins

e
Multiple of the above are specific to chloroplasts

Answer 11

b
Converts light into chemical energy

Question 12

What does the Mitochondria do?

Answer 12

converts energy in macromolecules into usable energy for the cell

Question 13

What does the Nucleus do?

Answer 13

contains most of the cells’ DNA

Question 14

What does the Ribosome do?

Answer 14

synthesizes proteins

Question 15

What does the endomembrane system do?

Answer 15

main site of manufacturing and modification of proteins and lipids (especially those destined to leave the cell)

Question 16

What does the Plasma membrane do?

Answer 16

surrounds the cell only letting certain things in or out

Question 17

What does the Lysosome do?

Answer 17

disposal of bacteria; damaged organelles; and cellular debris

Question 18

How and why certain proteins get into the nucleus is extremely important for understanding certain diseases. For example, the HIV virus, like all viruses, uses a host cell’s machinery and energy to produce new viral particles. Unlike most viruses, HIV is a retrovirus, which means that it re-encodes its RNA into DNA and then inserts that DNA into the host cell’s DNA. The genome of HIV encodes a very small number of proteins including: GP41 and GP120 (both used to attach to and get inside the host cell), reverse transcriptase (used to encode the HIV RNA into DNA), integrase (used to integrate this new DNA into the host’s DNA), and protease (used to cut one of the viral proteins to the right length). Based on these functions, which of the HIV proteins is most likely to have a nuclear localization signal?

a
Protease

b
GP41

c
Reverse transcriptase

d
Integrase

e
GP120

Answer 18

d
Integrase

Question 19

Cells that line your intestines are known to possess a large number of membrane proteins that transport small molecules and ions across the plasma membrane. Which of the following cell structures would you expect to be required for this function of the cells?

a
Lysosomes

b
Peroxisomes

c
Extra nuclei

d
Endoplasmic reticulum

e
Cell wall

Answer 19

d
Endoplasmic reticulum

Question 20

Researchers tried to explain how vesicular transport occurs in cells by attempting to assemble the transport components. They set up microtubular tracks along which vesicles could be transported and they added vesicles and ATP (because they knew the transport process requires energy). Yet, when they put everything together, there was no movement or transport of vesicles. What necessary part were they missing?

a
endoplasmic reticulum

b
motor proteins

c
contractile filaments

d
a flagellum

e
They weren’t missing anything, this should have worked

Answer 20

b
motor proteins

Question 21

Spherocytosis is a human blood disorder associated with a defective cytoskeletal protein in the red blood cells (RBCs). What do you suspect is the consequence of such a defect?

a
abnormally shaped RBCs

b
adherence of RBCs to blood vessel walls, causing plaque formation

c
an insufficient supply of ATP in the RBCs

d
an insufficient supply of oxygen-transporting proteins in the RBCs

Answer 21

a
abnormally shaped RBCs

Question 22

What do the cell walls of plants and the extracellular matrix of animal cells have in common?

a
They form very rigid structures that provide structural support for cells and limit their expansion

b
They are largely composed of phospholipids and glycoproteins

c
Their proteins are usually made by ribosomes in the rough ER, instead of by free ribosomes

d
They limit the passage of small molecules

e
None of the above are characteristic of both plant cell walls and the extracellular matrix of animals

Answer 22

c
Their proteins are usually made by ribosomes in the rough ER, instead of by free ribosomes

Question 23

Pemphigus vulgaris is an autoimmune disorder in humans in which antibodies are produced against proteins in desmosomes. The blistering of the skin and mucous membranes characteristic of this disorder is probably a result of:

a
inadequate production of cytoskeletal proteins

b
a loss in cell–cell adhesion

c
a decrease in flexibility of the cell membrane

d
an inadequate number of hormone receptors

Answer 23

b
a loss in cell–cell adhesion

Question 24

Sponges are extremely simple animals. Some species of sponge can be put into a blender and re-form from individual, unconnected cells. Consider the following experiment: you mix cells of two different sponge species and find that the sponges reassemble into individuals of the two separate species. That is, the cells from one species do not interact or form associations with the cells of the other species. How do you explain these results?

a
The molecules responsible for cell—cell adhesion differed between the two species of sponge

b
The molecules responsible for cell—cell adhesion were irreversibly destroyed during the experiment

c
One cell functioned as the nucleus for each organism, thereby attracting only cells of the same species

d
The two species of sponge had different enzymes that functioned in the reassembly process

Answer 24

a
The molecules responsible for cell—cell adhesion differed between the two species of sponge