BIO - Unit 3 Quiz Questions

Which of the following is NOT an example of a variable in the human body that is regulated by homeostasis?

Exercise

Why is a cell's size limited?

Homeostasis is disrupted by a cell that is too large. Volume increases faster than surface area does.

What does the "fluid mosaic model" mean about the cell membrane?

It looks like a flexible pattern.

When glucose levels in the blood rise, your brain sends a signal to your pancreas. The pancreas releases insulin, which opens channels in cell membranes to allow glucose to enter the cell, lowering blood sugar levels.

Negative Feedback Loop

When you are hot, your body sweats to cool you down. This means your temperature went above normal and your body sweats to counteract that change to bring you back to normal. What kind of feedback loop would this be?

Negative Feedback Loop

How does a cell maintain homeostasis?

Regulates what enters and leaves the cell

Temperature, exercise, hydration, sugar levels, nourishment, and diseases all affect homeostasis.

True

What is the structure of a phospholipid in the cell membrane?

a "water-loving" head and two "water-fearing" tails

A failure of the body to maintain homeostasis can result in

a chronic disease. a temporary illness aging of the body.

When Streptococcus pneumoniae are exposed to an antibiotic, the bacteria try to pump the antibiotic out of their cells. Which of the following mechanisms is most likely used by the Streptococcus pneumoniae to pump the antibiotic out of their cells?

active transport

Which means of particle transport requires input of energy from the cell?

active transport

Water is important to life because it

acts as a solvent is found inside the cell surrounds all cells

Diffusion is the net movement of molecules from

an area of high concentration to an area of low concentration.

You are doing an experiment on osmosis. You take some dialysis tubing (a semi-permeable membrane) and fill it with a 50% sugar solution. Sugar molecules are very big and cannot pass through the membrane. If you want to make the cell get bigger (swell), which beaker should you place it into?

beaker of water

Which of the following structures serves as the cell's boundary from its environment?

cell membrane

Both active and facilitated diffusion involve

channel proteins

During diffusion, when the concentration of molecules on both sides of a membrane is the same, the molecules will

continue to move across the membrane in both directions

A molecule that diffuses down a concentration gradient goes from an area of ______ concentration into an area of ______ concentration.

high , low

In a lipid bilayer, ______ tails point inward and form a region that excludes water.

hydrophobic

If the environment gets cold, we will often shiver in order to:

increase body temperature

Homeostasis

is the maintenance of a relatively stable internal environment and often incorporates a form of feedback regulation

When the concentration of molecules on both sides of a membrane is the same, the molecules will

move across the membrane in both directions.

When something in the body changes from "normal" a ______________________ will return the variable back to normal.

negative feeback loop

The passive transport of water across a selectively permeable membrane is called

osmosis.

The cell membrane contains channels and pumps that help move materials from one side to the other. What are these channels and pumps made of?

proteins

The plasma membrane contains channels that help move materials from one side to the other. What are these channels made of?

proteins

Feedback loops responsible for homeostasis generally consist of three components that follow which of these patterns?

receptor, control center, effector

Which of the following is a function of the cell membrane?

regulates the movement of materials into and out of the cell

Which of the following is a function of the plasma membrane?

regulates which materials enter and leave the cell

The cell membrane of the red blood cell will allow water, oxygen, and carbon dioxide to pass through. Because other substances are blocked from entering, this membrane is called

semi-permeable

As a cell increases in size, it loses efficiency because

the surface area-to-volume decreases.

An animal cell that is surrounded by fresh water will burst because osmosis causes

water to move into the cell.