Cell Sizes and Diffusion Flashcards
(23 cards)
What tool is used to see most cells?
A light microscope.
What unit are most cells measured in?
Micrometers (µm).
How many micrometers are in a millimeter?
1,000 µm = 1 mm.
What unit is used to measure very small cells and viruses?
Nanometers (nm).
How many nanometers are in a millimeter?
1,000,000 nm = 1 mm.
What type of microscope is needed to see things measured in nanometers?
An electron microscope.
How do cells obtain nutrients and remove waste?
By diffusion.
What is diffusion?
Movement of molecules from high to low concentration.
Is diffusion an active or passive process?
Passive (does not require energy).
What does diffusion transport into and out of cells?
Nutrients (like food and oxygen) in, wastes (like CO₂) out.
Name five factors that affect the rate of diffusion.
Temperature, concentration gradient, surface area, volume, molecule size.
How does temperature affect diffusion rate?
Higher temperature increases diffusion rate.
How does concentration gradient affect diffusion rate?
A steeper gradient increases diffusion rate.
How does surface area affect diffusion?
Larger surface area increases diffusion rate.
How does cell volume affect diffusion?
Larger volume slows diffusion rate.
Why are cells small?
To increase their SA:V ratio and allow fast diffusion.
What does a high SA:V ratio mean for a cell?
Faster diffusion and faster growth.
What does a low SA:V ratio mean for a cell?
Slower diffusion and reduced efficiency.
How do you calculate surface area of a cube-shaped cell?
SA = 6 × length × width.
How do you calculate volume of a cube-shaped cell?
V = length × width × height.
What shape do cells tend to be to maximize diffusion?
Thin and flat.
How does shape affect SA:V ratio?
Thinner, flatter shapes increase SA:V ratio.
Why are cell shapes adapted to have high SA:V ratios?
To promote a faster rate of diffusion.
