BIOL 1408 Ch. 5

Why can't cells get as large as golf balls?

A cell that large would not have enough surface area to use in exchanging materials.

_____ aid in the coordination of the activities of adjacent animal cells.

Gap (communicating) junctions

Hypertonic

Having a higher concentration of solute outside the cell.

A cell has no membrane proteins at all. Which substance will diffuse across the membrane fastest?

Oxygen

Which direction is water most likely to move if there is a membrane or concentration difference between two regions?

Water will move out of a hypotonic solution into a hypertonic solution. Water is more likely to move from low solute concentration to high solute concentration.

Which of the following is most like a gap junction?

a nuclear pore

Desmosomes

are more like the cytoskeleton because both provide structural support

Phospholipids

can be recognized by the presence of a head and two tails.

Glycoprotein

composed of both a carbohydrate and a protein.

The primary role of _____ is to bind animal cells together.

desmosomes

Which membrane proteins increase the rate of chemical reactions?

enzymatic proteins

What is the word for membrane proteins that have carbohydrates attached to them?

glycoprotein

Cholesterol

helps to stabilize the structure of the plasma membrane.

You know that this cell is in a(n) _____ solution because it _____.

hypertonic solution ... lost water A cell will lose water when placed in a hypertonic solution.

You know that this cell is in a(n) _____ solution because the cell _____.

hypotonic ... swelled. A cell will gain water when placed in a hypotonic solution.

Endocytosis moves materials _____ a cell via _____.

into ... membranous vesicles

When molecules move down their concentration gradient, they move from where they are _____ to where they are _____.

more concentrated... less concentrated

What name is given to the process by which water crosses a selectively permeable membrane?

osmosis

Diffusion across a biological membrane is called

passive transport

Facilitated diffusion is a type of _____.

passive transport During facilitated diffusion, the cell is not expending energy to move the particles across the membrane; therefore, facilitated diffusion is a form of passive transport.

A white blood cell engulfing a bacterium is an example of _____.

phagocytosis. Phagocytosis occurs when a cell engulfs a large particle.

You can recognize the process of pinocytosis when _____.

the cell is engulfing extracellular fluid

What simple property causes molecules to diffuse from high concentration toward a lower concentration?

the continuous random motion of molecules

Which of these cell junctions form a barrier to the passage of materials?

tight junctions