Biology Chapter 5 test

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.

transport proteins, down

Which of the following processes can move a solute against its concentration gradient?

Active transport

What's the difference between Endocytosis and Exocytosis?

Endocytosis is the movement of large molecules into the cell. Exocytosis is the movement of large molecules out of the cell

Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles tells you that the environment...

Is hypotonic to the protozoan

Diffusion does not require the cell the expend ATP. Therefore, diffusion is considered a type of...

Passive transport

The molecules responsible for membrane transport are..

Proteins

Which of the following statements are true for all types of passive transport?

The concentration gradient is the driving force.

Osmosis can be defined as

The diffusion of water

Using the concepts we have learned about osmosis explain why our salad gets soggy when it sits in dressing for too long.

The salad dressing is a hypotonic environment. Water from the dressing moved into the plant cells making the salad more rubberized/ soggy with water.

Which of the following is a typical feature of an ATP- driven active transport mechanism?

The solute moves against the concentration gradient

The fluid mosaic model describes the plasma membrane as consisting of

diverse proteins embedded in a phospholipid bilayer

When two water-based solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will..

exhibit a net movement to the side with lower concentration

Membrane phospholipids..

have hydrophobic tails that face each other creating a bilayer

Plasma membranes are selectively permeable. This means that...

the plasma membrane allows some substances to enter or leave a cell more easily than others

Which of the following statements regarding membrane function is FALSE?

the plasma membrane is the control center of the cell. That's false because the nucleus is the control center of the cell.

What makes the "fluid mosaic" description of a plasma membrane accurate?

It is fluid meaning the outside is flexible and can rearrange. It is also a mosaic because it is made of a variety of lipids and proteins.

What do you predict would happen if I soaked carrot in highly concentrated salt water overnight? Explain your prediction using a scientific explanation.

The salt water is a hypertonic environment. Water from the inside of the carrot will move out of the carrot into the salt water.

In the lab, you use a special ballon that is permeable to water but not sucrose to make an "artificial cell." The ballon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur?

Water will leave the balloon. because the percentage of water decreases