Passive Transport:

VOCABULARY REVIEWExplain the relationship between the terms in each of the following pairs of terms.

  1. Concentration gradient, diffusion:
  1. osmosis,aquaporin:
  1. hypertonic, hypotonic:

MULTIPLE CHOICE

_____1. If a solution outside a cell is more concentrated so that the cell loses water to its environment,
the external solution is said to be ______to the cell contents.
(a.) hypertonic (b.) in equilibrium (c.) isotonic (d.) hypotonic

______2.Phospholipid molecules in a membrane are arranged with their ____ on the exterior and their ____ on the interior.
(a.) hydrophobic heads ... hydrophilic tails

(b.)nonpolar heads ... polar tails

(c.)hydrophilic heads ... hydrophobic tails

(d.) hydrophobic tails ... hydrophilic heads

(e.) hydrophilic tails ... hydrophobic heads

______3.In osmosis, water always moves toward the ____ solution: that is, toward the solution with the ____ solute concentration.

(a.) isotonic ... greater

(b.) hypertonic ... greater

(c.)hypertonic ... lesser

(d.)hypotonic ... greater

(e.) hypotonic ... lesser

______4.The movement of molecules from an area of higher concentration to an area of lower concentration is called _____.(a.) diffusion(b.) endocytosis
(c.) phagocytosis(d.) active transport(e.) osmosis

______5.Which term is used to describe thecarryingof molecules across a membrane
that does not require energy?(a.) osmosis(b.) facilitated diffusion
(c.) active transport(d.) diffusion

SHORT ANSWER:Answer the questions in the space provided.

1.What happens to the movement of water molecules at equilibrium (isotonic)?

2.How do carrier proteins transport substances across cell membranes?

3.Critical Thinking:How does the interaction between a carrier protein and the substance it transports resemble the interaction between an enzyme and its substrate?

STRUCTURES AND FUNCTIONS: Identify if the cell is isotonic, Hypertonic, or hypotonic solution.

Active Transport:

VOCABULARY REVIEWDefine the following terms.

  1. Active Transport:
  1. Endocytosis:
  1. Vesicle:

4.Phagocytosis:

MULTIPLE CHOICE

_____ 1. Which mechanism requires energy? (a.) Facilitated diffusion (b.) osmosis (c.) diffusion (d.) active transport

_____2.Which statement best describes phagocytosis?

(a.)Cells use this process to export products such as insulin or thyroxine.
(b.) A cell engulfs a particle by wrapping pseudopodia around it and
packaging it within a vacuole.

(c.) Small droplets of extracellular fluid and
all the dissolved solutes enter the cell by this process.
(d.) Only specific extracellular ligands enter the cell in this fashion.
(e.) After entry, the endocytotic vesicle migrates to and fuses with the
Golgi apparatus.

______3.The secretion of neurotransmitters out of the nerve cell, from small vesicles at the
end of the axon, can be considered an example of(a.) exocytosis(b.) endocytosis
(c.) phagocytosis(d.) pinocytosis(e.) osmoregulation

______4. The rate of transport of a substance into a cell is drastically reduced when the formation of ATP is blocked. The transport system must be a form of

(a.) active transport (b.) simple diffusion (c.) facilitated diffusion
(d.) both active transport and simple diffusion (e.) both simple and facilitated diffusion

______5.Which cell process is represented by the diagram below?

(a.)pinocytosis(b.)osmosis(c.)endocytosis(d.)exocytosis

SHORT ANSWER

1.Why is the sodium-potassium transport mechanism called a “pump”?

2.Explain how a phagocyte destroys bacteria.

3.Describe how a cell produces and releases proteins.

4.Critical Thinking Why is it important that ions being transported across a cell membrane be shielded from the interior of the lipid bilayer?

STRUCTURES AND FUNCTIONS

1.On which side of the membrane are Na+ ions released from the pump?

2.On which side of the membrane are K+ ions released from the pump?

3.Put the actions of the sodium potassium pump in order.