MCQ Paper Flashcards
Electron Microscope Wavelength
1 nanometre
Light Microscope Wavelength
400 to 700 nanometres
Electron Microscope lenses are made of
Electromagnet Lenses
Light Microscope lenses are made of
Glass Lenses
Light Microscope maximum magnification
x1500
Electron Microscope maximum magnification
x500,000
Light Microscope best resolution
200 nanometres
Electron Microscope best resolution
0.5 nanometres
Nucleus Size
5µm to 10µm
Chloroplasts Size
0.5 - 2 µm wide and 10 µm in length
Mitochondria Size
1 µm in length
Lysosomes Size
0.1-0.5 µm
Cell Surface Membrane Thickness
7nm
Centrioles Size
0.5 µm
Virus Size
Ranges in size (20–300 nm)
Prokaryote cell size
0.1–5.0 µm
Eukaryotic cell cize
10–100 µm
Maltose, lactose, sucrose
Maltose => α-glucose + α-glucose
Lactose => β-glucose + galactose
Sucrose => α-glucose + fructose
Early prophase
1) Centrioles replicate just before prophase
2) Chromosomes start to appear as the chromatin condenses and coils up, becoming shorter
3) Intact nuclear envelope
Late prophase
1) Chromosomes are seen to consist of two identical chromatids; each chromatid contains one DNA molecule
2) Centrioles move to opposite ends of nucleus where they form poles of the spindle
3) Nuclear envelope disappears (it breaks up into small vesicles which are not visible with light microscope)
4) Nucleolus disappears (forms part of several chromosomes)
Metaphase
1) Nuclear envelope disappears
2) Each centriole reaches a pole
3) Spindle (microtubules) is completely formed by centrioles
4) Chromosomes continue to condense
5) Spindle fibres attach to the cetromeres of the chromosomes
6) Spindle fibres pull on the centromeres, arranging them at the equator
Anaphase
1) Links between sister chromatids break
2) The centromeres of sister chromatids move apart, pulled by the spindle fibres to the poles of the cell
Telophase
1) Sister chromatids (now separate chromosomes) reach opposite poles
2) The chromosomes decondense
3) Nuclear envelope begin to form around the chromosomes at each pole
4) The spindle disappears
Cytokinesis
The cell divides into 2 cells, either by the infolding of the cell surface membrane in animal cells, or by the formation of a new cell wall and cell surface membrane in plants
Strength of bonding in proteins (strongest to weakest)
1) Disulfide bonds
2) Ionic bonds
3) Hydrogen bonds
4) Hydrophobic interactions
Interphase stages
- G1: cell makes RNA, enzymes, proteins for growth and at end of G1 the cell becomes committed to dividing or not dividing
- S: DNA replication - each chromosome replicates to have two identical chromatids
- G2: cell continues to grow and new DNA checked for any errors repaired before proceeding to mitosis
