(Module 1) Cells and microscopes Flashcards
Microscope table
Image size
_____________
Actual Size X Magnification size
A plant cell in a photograph measures 15mm across. If the actual size of the cell is 0.015mm, what is the magnification.
15 X 0.015 = 1000
The nucleus of a cell in a photograph measures 3mm. If the magnification on the photograph is X 500, what is the actual size
3 / 500 = 0.006
How strong is the light microscope
It has a magnification strength X 2000
How strong is an electron microscope
It uses a beam of electrons to magnify X 2000000
Factors of a prokaryotic cell
Single celled organisms - e.g bacteria
No nucleus
About 0.2 - 2 um
No membrane bound organelles (except ribosomes)
Factors of a Eukaryotic cell
Multicellular organisms e.g animals, anything but bacteria
Have a nucleus
Approximately 10um - 100 um in length
Membrane bound organelles
Parts of a Prokaryotic cell
Circular DNA Cell wall Ribosome Plasma membrane Slimy capsule Cytoplasm Flagellum (tail)
What did Robert Hooke do
Discovered Plant cells
What are the three types of cell movements
Diffusion
Osmosis
Active transport
What is diffusion
Diffusion is the net random movement of particles from an area of high concentration to an area of low concentration e.g a deodorant being sprayed in a room.
Gas exchange at the alveoli of the lungs to the lungs.
Factors that affect cell movement
Concentration gradient
Temperature
Surface area (of the membrane)
What is osmosis
Osmosis is the net random movement of water molecules from an area of high water potential to an area of low water potential across a partially permeable membrane
What is a dilute solution - what is a concentrated solution
More water, less solute
Less water, more solution
Different types of solution
Hypertonic - high concentration of solute e.g lots of sugar
Hypotonic - lower concentration of solute e.g less sugar
Isotonic solution - equal concentrations of water and solute
Different levels of plant cell water levels
Plasmolysed cell- this is where there is too little water- un fixable
Flaccid cell - equal solute concentrations inside and out the cell
Turgid cell - this is a plant cell with pure water outside.
What is active transport
The movement of substances from an area of low concentration to higher concentration against the concentration gradient. E.G taking in vitamins through the small intestine
Why is active transport different
Energy (from respiration in the mitochondria)
Give an example of active transport in plants
Root hair cell
Surface area to volume ratio
Cells are more efficient at exchanging substances when they have a large surface area to volume ratio - the smaller the cube, the bigger the ratio.
Example of surface area to volume ratio
The alveoli
