Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/50

Click to flip

50 Cards in this Set

  • Front
  • Back
What does it mean if the plasma membrane exhibits selective permeability?
some substances can cross the membrane more easily than other substances.
Which of the following is the main structural component of plasma membranes?
phospholipids
Which of the following describes a phospholipid molecule?
polar head, hydrophobic tail
In an aqueous environment, phospholipids tend to organize into a bilayer because the formation of a bilayer:
shields the hydrophobic tails from water
What type of molecuels pass most easily through plasma membranes?
nonpolar molecules because they are soluble in lipids
Which of the following has the greatest effect on the ability of polar molecules to pass through membranes?
the protein carriers that are present in the membrane
Which of the following best describes the plasma membrane?
fluid mosaic
How do proteins in the plasma membrane help hold the membrane in place?
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
What type of organism has cholesterrol in it's membranes?
animals
What is the role of cholesterol molecules that are embedded in the membranes of some living things?
only B and C- help stabilize the phospholipids at body temperature-keep the membrane fluid at lower temperatures
Which of the following function as cell indentification tags that can be recognized by other cells?
glycoproteins and glycolipids
Which of the following are functions of membrane proteins?
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
Which of the folowing are functions of membrane proteins?
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
The movement of molecules from higher concentration to lower concentration is called:
diffusion
Which of the following requires the use of energy in the form of ATP?
active transport
Which of the following can move across membranes by passive transport?
All of the Above-oxygen-carbon dioxide-water
Which of the following can move across membranes by diffusion?
All of the Above-Oxygen-Carbon Dioxide-Water
Which of the following is the difusion of water molecules across a selectively permeable membrane?
osmosis
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
hypertonic
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.
hypotonic
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.
isotonic
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?
out of the cell
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?
there will be no movement since salt cannot cross the membrane by diffusion
If a cell is in equilibrium with its environment
the environment is probably isotonic to the cell
Which of the following will happen to an animal cell if placed in a hypotonic environment?
the cell will become larger, and may burst
What is osmoregulation?
the control of water balance
In a hypertonic environment, a plant cell will:
shrivel, and the cell membrane will pull away from the cell wayy
In a bypotonic enviroment, a plant cell will become:
turgid
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.
a hypotonic
Which of the following cells have contractile vaculoes for osmoregulation?
Paramecium
If the contractile vacuoles in a single-celled organism are actively contracting, the organism is likely to be in ____ environment.
a hypotonic
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?
the cell will shrivel because of osmosis
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.
less than.... equal to
In facilitated diffusion, a molecule cannot cross a biologcial membrane unless ___ is present.
a transport protein
Which of the following requires specific transport proteins?
only B and C- facilitated diffusion, active transport
Which of the following moves molecules against their concentration gradient?
active transport
Which of the following is an endergonic process?
active transport
Which of the following is a difference between active transport and facilitated diffusion?
active transport requires energy from ATP and facilitated diffusion does not
The export of macromolecules out of the cell by means of a membrane enclosed vesicle moving to the plasma membrane is called:
exocytosis
The import of macromolecules into the cell using a vesicle is called:
endocytosis
If a hormone is produced inside a cell, it can be released out into the environment by:
exocytosis
"cellular eating" is called:
phagocytosis
"cellular drinking" is called:
pinocytosis
In which of the following does the product of protein synthesis never have to cross a membrane?
exocytosis
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?
exocytosis
If a person has an excessive cholesterol level in the blood even without producing more cholesterol than other people, that person probably:
lacks sufficient LDL receptors in plasma membranes
Sodium ions require energy to move across a plasma membrane. The movement of sodium ions across a membrane:
only A and B- is by active transport-requires a transport protein
Which best describes the general structure of a cell membrane?
proteins embedded in two layers of phospolipid
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?
a hypertonic sucrose solution
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?
Any of the above-passive transport-diffusion-active transport-osmosis