2.1 Biological Molecules Flashcards
what is resolution
The ability of an optical instrument to see or produce an image that shows fine detail and has ability to distinguish between 2 objects
Whats is magnification
The ability of an optical instrument to produce an image bigger than the original objects
what are the 2 types of microscopes
Optical
electron
advantages of optical microscope
Cheap
easy to use
portable
able to study whole living organisms
disadvantages of optical microscope
Poor resolution
low magnification due to the long wavelength of light
advantage & disadvantage of electron microscope
Advantages- high magnification and resolution.
Disadvantages-Expensive, specimen has to be dead, not portable
2 types of e-microscpes
TEM
SEM
How does TEM work
- extremely thin specimens are stained and placed in vacuum
- Electron guns produce a beam of electrons that pass through specimen
- Some parts of specimens absorb more electrons making them denser and making them appear darker
- Created 2d images
How does SEM work
- Specimen doesn’t need to be thin as electrons don’t pass through it as electrons beamed on the surface cause secondary electrons to bounce of surface + scatter and are focused on a screen
- 3d image formed
Max resolutions of all microscopes
(micrometers)
Light- 0.2
SEM- 0.003 - 0.001
TEM- 0.0005
Max magnifications of all microscopes
Lights - x1500
SEM - less than x1,000,000
TEM - More than x1,000,000
Units of measurements
Metre - m - 1
Millimetre - mm - 10 x -3
Micrometre - ym - 10 x -6
Nanometre - nm - 10 x -9
Picometre - pm - 10 x -12
Equation triangle
Image = Actual x Magnification
Actual = Image / Magnification
Magnification = Image / Actual
why do optical microscopes have low resolution & magnification
- Optical microscopes have the same wavelength as visible light (400-700nm)
- For this reason it can’t produce an image of object with a smaller wavelength than light
Rules for scientific drawings
- Include a title
- State magnification
- Use a sharp pencil for drawings and labels
- Use white, unlined paper
- Use as much paper as possible for the drawing
- Draw smooth, continuous lines
- Do not shade
- Draw clearly defined structures
- Ensure proportions are correct
- Label lines must be parallel to the top of the page and drawn with a ruler. They must not cross or have arrow heads.
Define organeles
Membrane bound compartment within the cell each providing distinct environments and therefore conditions for different cellular reactions
animal cell organelles that can be seen by light microscope
Cell Surface Membrane
Cytoplasm
Nucleus
Mitochondria
Centriole
Cytoplasmic Granules
plant cell organelles that can be seen by light microscope
Cell Wall
Cell surface membrane
Cytoplasm
Nucleus
Vacuole
Tonoplast
Mitochondria
Starch grains
Chloroplast
Animal Cell organelles that can be seen using electron microscope
Cell Surface membrane
Rough endoplasmic Reticulum (RER)
Nucleolus
Nucleus
Smooth Endoplasmic Reticulum (SER)
lysosome
Ribosome
Nuclear envelope with pores
Golgi apparatus
Cytoplasm
Mitochondria
Plant cell organelles that can be seen using electron microscope
Cell Surface membrane
Chloroplast
Rough endoplasmic Reticulum (RER)
Plasmodesmata
Nucleolus
Nucleus
Smooth Endoplasmic Reticulum (SER)
Ribosome
Nuclear envelope with pores
Golgi apparatus
Cytoplasm
Mitochondria
Vacuole
Cell Wall
Structure of Nucleus
(5)
- Nucleur envelope- surrounds the nucleus ad acts like a double membrane
- Nucleur Pores- Are hles in the nucleus that allows things to enter + leave
- Nucleur Plasm- A granular jelly like material
- Nucleolus- Small spheres where RNA + Ribbosommes are made inside
- Chromosomes- Are protein bound to nucleus and are linear DNA