BIOL 1001: Chapter 5

Structure B is a ____. (purple thing)

transport protein

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

Gap (communicating) junctions

Vibrio cholerae causes severe diarrhea in its victims. How might it cause this to occur?

It tricks the cells of the intestines into secreting ions.

How does the plasma membrane stop most substances from crossing it?

The non-polar fatty acid tails form a barrier to polar substances.

What do channel proteins, aquaporins, and carrier proteins have in common?

They all perform facilitated diffusion. (No energy is expended when these membrane proteins allow their target molecules through.)

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 scenarios is most similar to desmosomes?

cement between bricks in a wall

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

desmosomes

Vocab: Pinocytosis is one form of ________, the movement of large materials into a cell by an infolding of the plasma membrane.

endocytosis

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 (Glycoproteins are a protein with a carbohydrate group attached.)

Vocab: A(n) _____ solution has a higher concentration of dissolved particles than an adjacent solution.

hypertonic

Vocab: A(n) _________ solution has a lower concentration of dissolved particles than an adjacent solution.

hypotonic

Endocytosis moves materials _____ a cell via _____.

into ... membranous vesicles

Vocab: A(n) ________ solution has the same concentration of dissolved particles as an adjacent solution.

isotonic

Which of these is hydrophobic like the interior of the plasma membrane?

lipid soluble molecule

Where can the phosphate portion of the phospholipids in a membrane be found?

on the surfaces of the bilayer, facing the outside liquid or the cytoplasm inside

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

osmosis (Osmosis is the passive transport of water.)

This is an animation of _____. (brown debris)

phagocytosis (Phagocytosis involves the engulfing of large particles.)

You know that this process is _____ because _____. (extracellular fluid)

pinocytosis ... the cell is engulfing extracellular fluid

This is an animation of _____. (receptor protein)

receptor-mediated endocytosis

Which method of transport can a cell use to bring in molecules without allowing them to pass through the plasma membrane?

receptor-mediated endocytosis (The end-result of this process pulls the membrane itself into a vesicle. The molecule never passes through the membrane.)

Structure A is a ____. (white balls)

solute

What is the function of cholesterol?

stabilization of the phospholipids

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

tight junctions

Vocab: Embedded within the phospholipid bilayer surrounding a cell are _______, which regulate the movement of hydrophilic molecules from one side of the plasma membrane to the other.

transport proteins

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. (The larger the cell, the more nutrients it needs to pull in and the more waste in needs to expel. The volume outgrows the available surface area quickly.)

Which of these is TRUE with regard to this animation? (active transport)

An electrochemical gradient forms across the plasma membrane.

How does a freshwater Paramecium counteract osmosis (and avoid becoming too swollen with water)?

It pumps salt into a contractile vacuole, drawing excess water in to be squeezed out of the cell. (Pumping salt into the contractile vacuole causes water to flow into it and be pumped out of the cell when the vacuole squeezes.)

Vocab: _______ is the movement of large materials into a cell by wrapping extensions of the plasma membrane around the material and engulfing it by fusing the extensions together.

Phagocytosis

What causes a plant to wilt?

The cells lose turgor pressure. (Plant cells with too little water in them shrink away from the cell wall due to loss of turgor pressure.)

Which of the following is most like a gap junction?

a nuclear pore

Vocab: ________ is the movement of materials out of a cell through the fusion of a transport vesicle with the plasma membrane.

exocytosis

This is an animation of _____. (vesicle)

exocytosis (A membranous vesicle is fusing with the plasma membrane and releasing its contents into the extracellular fluid.)

Which type of transport requires assistance from membrane proteins, but no energy?

facilitated diffusion (This form of passive transport requires a transport protein, but since it only works if you can move the substance down a concentration gradient, it does not require energy (such as ATP).)

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

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