Ch 4 Lab study set

Which of the following directly affect the rate of diffusion in an aqueous solution?

-Temperature of the solvent -Molecular weight of the solute -Viscosity of the solvent

Which of the following will occur if the concentration of membrane-impermeable solutes in the intracellular fluid of a cell is higher than the concentration of such solutes in the extracellular fluid?

-There will be a net movement of water INTO the cell. -There will be a net movement of solutes OUT OF the cell and water INTO the cell.

Paired organelles that are used to organize the mitotic spindles that attach to chromosomes during mitosis

Centrioles

Genetic material within the nucleus; consists of DNA and associated proteins in an uncoiled form

Chromatin

Includes cellular organelles and cytosol; cytosol contains enzymes that mediate many cytosolic reactions such as glycolysis and fermentation

Cytoplasm

Composed of protein filaments called microtubules, intermediate filaments, and microfilaments; provides structural support for the cell

Cytoskeleton

Site where proteins are modified, packaged, and sorted for delivery to other organelles or to the plasma membrane of the cell

Golgi apparatus

Membrane-enclosed sacs that contain oxidative enzymes (e.g., catalase)

Peroxisomes

Provides a selectively permeable barrier between the intracellular and extracellular environment of the cell

Plasma membrane

Chromatin coils into chromosomes, which become visible when viewed with a light microscope

Prophase

Neurons contain large amounts of rough endoplasmic reticulum. Neurons are cells that need to be able to transport numerous ions into and out of the cell. They accomplish this task by synthesizing many ion channels to insert in the plasma membrane. Knowing this, what function of rough endoplasmic reticulum makes it so important to neurons?

Protein synthesis

Sites of protein synthesis; may be bound to the ER ("bound") or found within the cytoplasm ("free")

Ribosomes

Certain cells within the pancreas function in the synthesis and secretion of the hormone insulin, which is a protein. Based on this function, what organelle(s) do you predict these cells would contain large numbers of?

Rough endoplasmic reticulum

Synthesizes new proteins destined for the plasma membrane, for lysosomes, or for secretion from the cell

Rough endoplasmic reticulum (RER)

One major function of liver cells (hepatocytes) is to detoxify alcohol. Based on this function, what organelle do you predict hepatocytes would contain a large number of?

Smooth endoplasmic reticulum

Chromosomes are located at opposite ends of the cell; a cleavage furrow may be visible

Telophase

To determine if dialysis tubing is permeable to glucose, you fill the dialysis tubing with a glucose solution and place it in a beaker filled with distilled water. After allowing time for diffusion, what would be the best next step to determine if the dialysis tubing is permeable to glucose?

Test for glucose in the beaker with Benedict's solution.

In an experimental set up, starch is placed in dialysis tubing and suspended in water. When iodine is added to the water it turned yellow. Over time the starch solution in the bag turned purple, while the color of the water remained yellow. Which of the following most likely occurred?

The starch stayed in the bag and the iodine leaked into the bag and reacted with it, turning the solution purple.

Synthesizes ribosomes

nucleolus

The movement of water across a semipermeable membrane

osmosis

Which of the following will pass through a cell membrane most easily?

small nonpolar molecules

The dissolved substance in a solution

solute

A solution into which another substance dissolves

solvent

Facilitated diffusion is used to transport

sugars and amino acids

When sugar is mixed with water, equilibrium is reached when

the dissolved sugar molecules are evenly distributed throughout the solution.

A 5% urea solution is hypotonic to a 10% urea solution.

true

An increase in temperature causes solute particles in a solution to move more rapidly and increases the rate of diffusion.

true

Diffusion is one of the processes whereby materials are exchanged between a cell and its environment.

true

Facilitated diffusion requires a specific transporter for a specific molecule.

true

If a cell is placed in an isotonic medium, there will be no net movement of water.

true

Osmosis is best defined as the movement of

water molecules across a membrane from an area of high water concentration to an area of lower concentration.

Contains the cell's genetic material (DNA)

Nucleus

Which component of a human cheek cell contains a dark-staining body?

Nucleus

Facilitated diffusion requires

carrier proteins

The rate of diffusion is affected by which of the following?

concentration gradient, membrane permeability, temperature, and pressure

A __________ gradient drives the movement of solutes for diffusion, whereas a __________ gradient drives the movement of fluid for filtration.

concentration; pressure

An increase in viscosity of the solvent will increase the diffusion rate.

false

Unlike simple diffusion, facilitated diffusion requires energy expenditure by the cell.

false

Solutes with a __________ molecular weight require __________ energy to move a given distance and therefore diffuse more slowly.

higher; more

a solution that has higher osmotic pressure than intracellular fluid

hypertonic

A solution that has a lower osmotic pressure than intracellular fluid

hypotonic

Facilitated diffusion occurs

in either direction depending on the concentration gradient of the molecule

Chemotherapy treatments are given to cancer patients in an attempt to halt or slow the growth of a tumor, which is composed of rapidly dividing cells. Certain chemotherapy drugs exert their actions by interfering with mitosis. For example, some drugs act to prevent microtubules from lengthening or shortening. Microtubules are protein filaments that attach to chromosomes and centrioles, forming the mitotic spindle, which moves the chromosomes during mitosis. Based on this role of microtubules during mitosis, with which stage(s) of mitosis would these drugs most likely interfere?

Anaphase

Chromosomes are being pulled toward the opposite poles of the cell

Anaphase

Uncoiled chromatin exists within the nucleus of the cell; chromosomes are not visible when viewed with a light microscope

Interphase

Which of the following types of solutions should be used when preparing a wet mount?

Isotonic

While on vacation, your brother runs out of contact lens solution. In an attempt to improvise, he uses tap water to hydrate his contact lenses. Immediately upon application of the contact lenses to his eyes, he starts complaining of pain in his eye. The pain is bad enough that he removes the contact lenses and is afraid he will not be able to wear them for the rest of the vacation. Why did tap water cause such significant discomfort to your brother's eyes?

It was a hypotonic solution that caused the eye to dry out.

Membrane-enclosed sacs that contain digestive enzymes and extracellular components; function in the breakdown of intracellular molecules

Lysosomes

Chromosomes line up at the center of the cell along the equatorial plate

Metaphase

You are in the laboratory observing a wet mount of fresh erythrocytes under the microscope. In an attempt to make the erythrocytes easier to see, you decide to dilute the sample. Following dilution you make another wet mount, but you are unable to find any cells when you observe the slide under the microscope. What happened to the erythrocytes?

You accidentally diluted the sample with distilled water and caused the cells to lyse.

A red blood cell placed in a hypertonic medium will

a red blood cell will lose water and undergo crenation (shrivel)

When preparing a wet mount of human cheek cells, methylene blue is a(n) __________ dye that is most attracted to __________ components of the cell.

basophilic; eosinophilic

To determine the effects of osmosis on human cells, an experiment is performed by placing red blood cells into solutions of differing concentrations of sodium chloride [NaCl] in a pipette. Each pipette is the placed into a spectrophotomoeter and the transmittance of light is recorded. In this experiment, the concentration of NaCl is the __________, the transmittance of light is the __________, and the stock solution of blood is the __________.

independent variable; dependent variable; control

A solution that has the same osmotic pressure as intracellular fluid

isotonic

A patient enters the emergency department with considerable blood loss from blunt force trauma. The physician attending to the patient needs to increase the volume of the patient's bodily fluids so the patient's blood pressure and systemic perfusion of tissues can be maintained. The physician quickly administers an intravenous solution of NaCl. To avoid causing more harm to the patient, the tonicity of the intravenous solution should be _________________.

isotonic to bodily fluids

Simple diffusion is defined as the movement of

molecules from areas of higher concentration to areas of lower concentration.