Unit 6 Self-Test Bio156

Front 1

What does it mean if the plasma membrane exhibits selective permeability?

Back 1

some substances can cross the membrane more easily than other substances.

Front 2

Which of the following is the main structural component of plasma membranes?

Back 2

phospholipids

Front 3

Which of the following describes a phospholipid molecule?

Back 3

polar head, hydrophobic tail

Front 4

In an aqueous environment, phospholipids tend to organize into a bilayer because the formation of a bilayer:

Back 4

shields the hydrophobic tails from water

Front 5

What type of molecuels pass most easily through plasma membranes?

Back 5

nonpolar molecules because they are soluble in lipids

Front 6

Which of the following has the greatest effect on the ability of polar molecules to pass through membranes?

Back 6

the protein carriers that are present in the membrane

Front 7

Which of the following best describes the plasma membrane?

Back 7

fluid mosaic

Front 8

How do proteins in the plasma membrane help hold the membrane in place?

Back 8

A and B only- they many be linked to the cytoskeleton inside the cell-they may be linked to the extracellular matrix outside the cell

Front 9

What type of organism has cholesterrol in it's membranes?

Back 9

animals

Front 10

What is the role of cholesterol molecules that are embedded in the membranes of some living things?

Back 10

only B and C- help stabilize the phospholipids at body temperature-keep the membrane fluid at lower temperatures

Front 11

Which of the following function as cell indentification tags that can be recognized by other cells?

Back 11

glycoproteins and glycolipids

Front 12

Which of the following are functions of membrane proteins?

Back 12

All of the Above- Aome proteins are involved in attaching the membrane to the cytoskeleton and external fibers-some proteins help in providing identification tags-some proteins help form junctions between adjacent cells

Front 13

Which of the folowing are functions of membrane proteins?

Back 13

All of the Above- some proteins are enzymes involved in catalytic reactions-some proteins function as receptors for chemical messengers from other cells-some proteins receptors involved in signal transduction-some proteins are involved in transport, and help move substances across the membrane

Front 14

The movement of molecules from higher concentration to lower concentration is called:

Back 14

diffusion

Front 15

Which of the following requires the use of energy in the form of ATP?

Back 15

active transport

Front 16

Which of the following can move across membranes by passive transport?

Back 16

All of the Above-oxygen-carbon dioxide-water

Front 17

Which of the following can move across membranes by diffusion?

Back 17

All of the Above-Oxygen-Carbon Dioxide-Water

Front 18

Which of the following is the difusion of water molecules across a selectively permeable membrane?

Back 18

osmosis

Front 19

If the solution outside of a cell h as a greater concentration of solutes than the solution inside the cell, the solution outside the cell is ___ in relation to the cell

Back 19

hypertonic

Front 20

If the solution outside of a cell has a lower concentration of solutes than the solution inside the cell, the solution outside the cell is ____ in relation to the cell.

Back 20

hypotonic

Front 21

If the solutions both inside and outside of a cell have an equal concentration of solutes, the solution outside the cell is ___ in relation to the cell.

Back 21

isotonic

Front 22

If the salt concentration insdie a cell is 0.9%, and the salt concentration outside a cell is 9%, in whcih direction will there be a net movement of water by diffustioin?

Back 22

out of the cell

Front 23

If the salt concentration inside a cell is 0.9%, and the salt concentration outside a cell is 9%, in which direction will there be a net movement of salt by diffusion?

Back 23

there will be no movement since salt cannot cross the membrane by diffusion

Front 24

If a cell is in equilibrium with its environment

Back 24

the environment is probably isotonic to the cell

Front 25

Which of the following will happen to an animal cell if placed in a hypotonic environment?

Back 25

the cell will become larger, and may burst

Front 26

What is osmoregulation?

Back 26

the control of water balance

Front 27

In a hypertonic environment, a plant cell will:

Back 27

shrivel, and the cell membrane will pull away from the cell wayy

Front 28

In a bypotonic enviroment, a plant cell will become:

Back 28

turgid

Front 29

In a plant cell, if there is a net inflow of water keeping pressure exerted against the inside of the cell wall, the cell must be in ____ environment.

Back 29

a hypotonic

Front 30

Which of the following cells have contractile vaculoes for osmoregulation?

Back 30

Paramecium

Front 31

If the contractile vacuoles in a single-celled organism are actively contracting, the organism is likely to be in ____ environment.

Back 31

a hypotonic

Front 32

A plant cell is placed into a solution whose solute concentration is twice as great as the concentration of the cell cytoplasm. The cell membrane is selectively permeable, allowing water but not all the solutes to pass through. What will happen to the cell?

Back 32

the cell will shrivel because of osmosis

Front 33

Red blood cells shrivel when placed in a 10% sucrose solution. When first placed in the solution, the solute concentration of the cells is ____ the concentration of the sucrose solution. After the cells shrivel, their solute concentration is ____ the concentration of the sucrose solution.

Back 33

less than.... equal to

Front 34

In facilitated diffusion, a molecule cannot cross a biologcial membrane unless ___ is present.

Back 34

a transport protein

Front 35

Which of the following requires specific transport proteins?

Back 35

only B and C- facilitated diffusion, active transport

Front 36

Which of the following moves molecules against their concentration gradient?

Back 36

active transport

Front 37

Which of the following is an endergonic process?

Back 37

active transport

Front 38

Which of the following is a difference between active transport and facilitated diffusion?

Back 38

active transport requires energy from ATP and facilitated diffusion does not

Front 39

The export of macromolecules out of the cell by means of a membrane enclosed vesicle moving to the plasma membrane is called:

Back 39

exocytosis

Front 40

The import of macromolecules into the cell using a vesicle is called:

Back 40

endocytosis

Front 41

If a hormone is produced inside a cell, it can be released out into the environment by:

Back 41

exocytosis

Front 42

"cellular eating" is called:

Back 42

phagocytosis

Front 43

"cellular drinking" is called:

Back 43

pinocytosis

Front 44

In which of the following does the product of protein synthesis never have to cross a membrane?

Back 44

exocytosis

Front 45

A white blood cell is capable of producing and releasing thousands of antibody molecules every second. Antibodies are large, complex protein molecules. How would you expect them to leave the cell?

Back 45

exocytosis

Front 46

If a person has an excessive cholesterol level in the blood even without producing more cholesterol than other people, that person probably:

Back 46

lacks sufficient LDL receptors in plasma membranes

Front 47

Sodium ions require energy to move across a plasma membrane. The movement of sodium ions across a membrane:

Back 47

only A and B- is by active transport-requires a transport protein

Front 48

Which best describes the general structure of a cell membrane?

Back 48

proteins embedded in two layers of phospolipid

Front 49

The total solute concentration in a red blood cell is about 2%. Sucrose cannot pass through the membrane, but water and urea can. Osmosis would cause such a cell to shrink the most when immersed in which of the following?

Back 49

a hypertonic sucrose solution

Front 50

The calcium concentration in a cell is 0.3%; the concentration in the surrounding fluid is 0.1%. How could the cell obtain more calcium?

Back 50

Any of the above-passive transport-diffusion-active transport-osmosis