Cell Structure Flashcards
Three main ideas of cell theory
• All living organisms are made up of one or more cells
•Cells are the basic functional unit in living organisms
• New cells are produced from pre-existing cells
All cells:
surrounded by a membrane
contains genetic material
have chemical reactions occur within the cell that are catalysed by enzymes
Define magnification
How many times bigger the image of a specimen observed is compared to its actual size
Convert mm to micrometers
x1000
convert micro meters to nm
x 1000
convert nano meters to micro metres
divided by 1000
How to use a scale bar
1) use a ruler and measure length of scale bar convert to mm
2) convert measurements to same units as used on scale bar
3) put in formula
measured length of scale bar / scale bar labelled
Define Resolution
The ability to distinguish between objects that are close together
Factors of light microscope
• Uses light to form an image
• maximum resultion 0.2 micro metres
• cannot be used to observe smaller organelles
• maximum magnification x1500
Factors of electron microscope
• Uses electrons to form an image
• maximum resolution 0.0002 micrometers
• can be used to observe smaller organelles
• maximum magnification x1500000
• specimens needs to be dead
Explain immunofluorescence
involves the use of antibodies that have been prepared with fluorescent dyes which bind with target molecules , allowing specific molecules to be detected
Explain freeze - fracture
a sample rapidly frozen using liquid nitrogen and then physically broken apart in a vacuum
Explain Cryogenic electron microscopy
• Involves flash freezing solutions
• Frozen solutions exposed to electrons to produce images of molecules
What ribosomes do prokaryotic cells have
70E
Ribosomes Function
Binding and Reading of mRNA during translation to produce proteins
Plasma membrane functions
Controls what enters and exits the cell
Function of cell wall
protection and maintains shape
What are the key structures animal and plant cells share ?
membrane -bound organelles
larger ribosomes (80S)