State the definition of resolution:
the degree to which a lens or photographic emulsion is able to define the details of an image.
Explain why electron microscopes have a better resolution that light microscopes.
Light microscopes are limited in resolution by the wavelengths of visible light (400-700 nm).
Electrons have a much shorter wavelength (2 - 12 pm) therefore electron microscopes have a much higher resolution
Light microscopes are usually limited to 1000x because, due to the resolution, nothing is gained by increasing the
magnification - try zooming in on an image on your laptop or phone after a certain point there is no benefit to zooming
in as the image becomes pixelated
.State what is meant by the term Ultrastructure.
Ultrastructure is all the structures of a biological specimen that are at least 0.1nm in their smallest dimension
State one thing that electron microscopes can see, but light microscopes cannot.
Electron microscopes can see viruses (0.1?m diameter) , but light microscopes cannot
Prokaryotes have a simple cell structure.
a. Define the term prokaryote.
A prokaryote is a single-celled organism that lacks a membrane-bound nucleus (karyon), mitochondria, or any other
membrane-bound organelle.
Outline the process of binary fission.
Binary fission in a prokaryote
1. The bacterium before binary fission is when the DNA is tightly coiled.
2. The DNA of the bacterium has uncoiled and replicated.
3. The DNA is pulled to the separate poles of the bacterium as it increases size to prepare for splitting.
4. The growth of a new cell wall begins to separate the bacterium.
5. The new cell wall fully develops, resulting in the complete split of the bacterium.
6. The new daughter cells have tightly coiled DNA rods, ribosomes, and plasmids, these are brand new organisms.
Is the process asexual or sexual? Compare the genetic content of the two daughter cells with the parent cell.
Asexual; the genetic code is identical
. Plant and animal cells are eukaryotic.
a. Define the term eukaryote.
an organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained
within a distinct nucleus. Eukaryotes include all living organisms other than the eubacteria and archaebacteria.
Outline the benefits compartmentalization provides to eukaryote cells compared when with prokaryotes
There are several advantages in being compartmentalized:
Efficiency of metabolism - enzymes and substrates can localized and much more concentrated
Localized conditions - pH and other such factors can be kept at optimal levels. The optimal pH level for one
process in one part of the cell
Toxic / damaging substances can be isolated, e.g. digestive enzymes (that could digest the cell itself) are
stored in lysosomes
Numbers and locations of organelles can be changed dependent on the cell's requirements.