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.