Cell Theory & Cell Types
According to the Cell Theory, where do all new cells come from?
Existing / pre-existing living cells.
Osmosis is the passive movement of which specific molecule across a membrane?
Water
What does the word "homeostasis" mean?
Keeping internal body conditions steady and balanced.
What do blood vessels near the skin do when your body overheats: widen (dilate) or narrow (constrict)?
Widen/dilate (vasodilation).
Which organs control osmoregulation by filtering blood and balancing water and salt?
Kidneys
What is the main structural difference between a prokaryote and a eukaryote?
Eukaryotes have a nucleus (and organelles); prokaryotes do not.
What is the main rule of osmosis: does water move toward more dissolved salt or less dissolved salt?
Toward more dissolved salt (higher solute concentration).
What is the body's normal set point for core temperature?
98.6 degrees F
How does sweating cool down your skin?
Evaporative cooling (sweat absorbs body heat as it evaporates into air).
When a person is dehydrated, do the kidneys make clear, dilute urine or dark, concentrated urine?
Dark, concentrated urine (conserving water).
What is the primary job of ribosomes in a cell?
Making/assembling proteins.
What happens to a red blood cell placed into a beaker of 10% saltwater?
Water rushes out, causing the cell to shrivel up.
In a negative feedback loop, does the response push conditions further away from normal or reverse them back to the set point?
Reverses/opposes the change back to normal.
Why do skeletal muscles start shivering in freezing cold weather?
Rapid muscle contractions generate metabolic heat to warm the core.
When a person is overhydrated, do the kidneys make clear, dilute urine or dark, concentrated urine?
clear, dilute urine
Name the four cell structures shared by all living cells on Earth.
Cell membrane, cytoplasm, ribosomes, and DNA.
What word describes a solution that has an equal salt balance to human blood cells?
Isotonic
Which brain structure acts as the control center, comparing incoming signals to your set point?
The hypothalamus.
What is the term for narrowing skin blood vessels to trap warm blood deep inside your core?
Vasoconstriction
During hyponatremia (overhydration), why do brain cells swell dangerously?
Blood plasma turns hypotonic, forcing water into brain cells by osmosis.
Why is the cell membrane described as "semi-permeable"?
It lets some molecules pass through while blocking others.
A cell model gains weight after sitting in a beaker of liquid. Was that liquid hypertonic, isotonic, or hypotonic?
Hypotonic (water moved in).
Write the 5 stages of a negative feedback loop in correct, sequential order.
Stimulus --> Sensor --> Control Center --> Effector --> Response
At what dangerous core temperature does heat stroke start, causing vital cell proteins to unfold (denature)?
104 degrees F
In an exercise recovery loop, what specific organ acts as the effector that slows its contractions to return your pulse to resting baseline?
The heart