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Module 1: Cells
1.1.1 Cell Structure
(a) state the resolution and magnification that can be achieved by a light microscope, a transmission electron
microscope and a scanning electron microscope

Light Microscope Transmission Electron Scanning Electron
Microscope (TEM) Microscope (SEM)
Radiation Source Light Electrons Electrons
Maximum Resolution 200nm 0.1nm 0.1nm

Page 2

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Module 1: Cells
object being viewed is completely transparent this makes the whole thing look white because the light
rays/electrons pass straight through. This problem is solved by staining the specimen. Different types of stains
bind to different specific cell structures :
Acetic Orcein stains DNA dark red
Genetian Violet…

Page 3

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Module 1: Cells

(f) outline the functions of the structures listed in (e)

Organelle Description Function
Nucleus Largest organelle 1020µm Contains chromatin mixture of DNA and
Roughly spherical associated proteins
Double membrane bound Controls protein synthesis makes mRNA

Nucleolus Area of dense chromatin within the nucleus Makes ribosomal RNA (rRNA)…

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Module 1: Cells
Contains chlorophyll: a photosynthetic

Cellulose On the outside of plant cells' plasma Supports the cell
Cell Wall membrane Helps maintain cell shape

Vacuoles A large membrane bound sac containing Storage of water and solutes
water and solutes Maintains cell turgidity

(g) outline the interrelationship between the…

Page 5

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Module 1: Cells

(i) compare and contrast, with the aid of diagrams and electron micrographs, the structure of prokaryotic cells
and eukaryotic cells
Eukaryotic Cells (means having a true nucleus) cells contain many organelles some of which are bound by a
membrane e.g. animals, plants and fungi

Prokaryotic Cells (means…

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Module 1: Cells
DNA Location In nucleus nucleus present Free in cytoplasm
no nucleus
Size of ribosomes Large 22nm (80S) Small 18nm (70S)

(j) compare and contrast, with the aid of diagrams and electron micrographs, the structure and ultrastructure of
plant cells and animal cells

Plant Cells Animal Cells


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