Biology Chapter 7.3 and 7.4 Practice Questions

away from the area where it is more concentrated

A substance that moves by passive transport tends to move

similar cells

A tissue is composed of a group of

endocytosis, exocytosis

Bulk transport involves the movement onto and out of the cell. When molecules move by bulk transport into the cell it is ______________. When molecules move by bulk transport out of the cell it is__________________________________.

Diffusion is the driving force behind the movement of substances across the cell membrane. If a substance is present in unequal concentrations on either side of the cell membrane, its particles will move toward the area where it is less concentrated until it is equally distributed. Once the concentration of the substance on both sides of the cell membrane is the same, equilibrium is reached. Diffusion depends on random particle movement requiring no additional energy. Diffusion is an example of passive transport.

Define the process of diffusion , including a detailed explanation of equilibrium

The dialysis tubing acted as a selectively permeable cell membrane allowing the iodine molecules to pass from the outside of the tube to the inside. The starch solution inside the tube reacted with the iodine to create the purple color. Yes. There was diffusion.

Explain what happened in the Diffusion Lab experiment. Why was the inside purple and not the outside? Was there diffusion? Explain.

Receptors help to maintain homeostasis by binding with chemical signals sent by various types of cells that are sent to cause important changes in cellular activity. A gap junction is a special connection that allows ions to carry an electrical signal from cell to cell. This type of junction can allow millions of cells to act at one time. {like with a heart beat} Other junctions hold cells together to prevent injury. (like when the force of a muscle contraction does not tear the muscle tissue)

How do cellular junctions and receptors help and organism maintain homeostasis?

Passive transport is the movement of materials across the cell membrane without using cellular energy. Examples are diffusion and facilitated diffusion. Active transport is the movement of materials against a concentration difference and it requires energy. Examples are endocytosis and exocytosis

How is active transport different from passive transport

Diffusion is the random movement of particles requiring no additional energy from the cell. Facilitated diffusion occurs when certain molecules cannot diffuse across the cellular membrane without the assistance of special protein channels that act as tunnels and allow the molecules to pass. It still is considered diffusion because it too does not require extra energy from the cell.

How is diffusion different from facilitated diffusion

Endocytosis is the process of taking material into the cell by means of infoldings, or pockets of the cell membrane. The pocket that results breaks loose from the outer portion of the cell membrane and forms a vesicle or vacuole within the cytoplasm. Exocytosis occurs when the membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell.

How is endocytosis different from exocytosis?

passive transport

If the movement of molecules across a membrane does not require any added energy and do not use the protein channel it is called ______________________

hypertonic

In this picture the section the arrow is pointing to has more particles on one side than the other side of the cell membrane. What type of solution is this?

hypotonic

In this picture with the arrow, one side of the permeable membrane has less particles than the other. This type of solution is called_______________________________

isotonic

In this picture, the section the arrow is pointing to has equal parts water and particles. What type of solution is this?

Passive

The molecules in this picture are are moving due to _____________________ energy

diffusion

The movement of particles from an area of high concentration to an area of low concentration

equilibrium

The movement will continue until there is an even distribution of molecules throughout. This even distribution is called ___________________________________

iodine

The starch indicator used in the diffusion lab was _________________________.

To maintain homeostasis, unicellular organisms grow, respond to the environment, transform energy, and reproduce. Cells of multicellular organisms become specialized for particular tasks and communicate with one another to maintain homeostasis.

What do unicellular and multicellular organisms maintain homeostasis?

In multicellular organisms, cell become specialized meaning that they each play a different role in maintaining the homeostasis if the organism. Some cells move, some react to the environment, and some produce substances that the organism needs.

What is cellular specialization?

Homeostasis is maintaining a relatively constant internal physical and chemical condition.

What is homeostasis?

True

When equilibrium is reached there is continued movement of the solute.

They all reproduce

Which of following is true of all single celled organisms?

If a person is an athlete who is sweating and replacing their water, but not replacing the salt they have lost by sweating, their blood can become hypotonic. Water is then drawn into the cells to help weaken the concentration and even out the number of electrolytes. This causes homeostasis, and swelling of the brain cells occurs. If this happens, the brain can signal the kidneys to stop removing salt from the blood stream. Homeostasis of the cells breaks down. Cells are damaged by the unregulated osmotic pressure. The result can be severe hyponatremia or death

Why could a person die from drinking too much water?

osmosis

the movement of water molecules across a selectively permeable membrane.