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Cell structure

a) State the resolution and magnification that can be achieved by a light microscope, a
transmission electron microscope and scanning electron microscope.

Magnification Resolution
Light microscope 2 000 x 200 nm
Scanning electron 500 000 x 0.5 nm
Transmission electron 100 000 x…

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- Nucleus - Controls cellular activity
- Nucleolus - Makes the RNA and ribosomes
- Nuclear - Has nuclear pores that allows large molecules to
envelope pass through
- Rough and - Transport proteins made in the ribosomes
smooth attached to the rough ER

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i) Compare and contrast with the aid of diagrams and electron micrographs the structure of
prokaryotic cells and eukaryotic cells

Prokaryotes Eukaryotes
No membrane bound Have membrane bound
organelles organelles
Slippery layer called
DNA not in membrane but Have a true nucleus
in nucleoid

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Cell membranes

a) outline the roles of membranes within cells and at the surface of cells

They control the entrance/exit of molecules into the cell through the means of active and
passive transport. They also maintain a difference in charge between the inside/outside of
the cell.…

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f) explain the term cell signalling

It is the response of cell to their environment based on molecules that may affect the cell's
functions. It is also the communication of cell amongst one another through the means of
chemical molecules such as hormones.

g) explain the…

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Cell Division, Cell Diversity and Cellular organisation

a) State that mitosis occupies only a small percentage of the cell cycle and that the remaining
percentage includes the copying and checking of genetic information;

Mitosis is only a small percentage of the cell cycle. The remaining

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d) explain the significance of mitosis for growth, repair and asexual reproduction in plants and

Mitosis allows growth and repair of the organism's body as it produces identical cells.
Mitosis makes the daughter cells genetically identical therefore ensuing that the daughter
cells can perform the…

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Neutrophils has many lysosomes to kill
retained their nucleus ER and Golgi
apparatus to produce enzyme and

Epithelial cells have cilia that propel mucus
has a large surface area
Have many mitochondria to produce
ATP for cilia propulsion.

Sperm cells has many mitochondria to…

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a)explain, in terms of surface area: volume ratio, why multicellular organisms need specialised
exchange surfaces and single-celled organisms do not (HSW1);

Multicellular organisms have a smaller surface area to volume ratio compared to single celled
organisms. This means that the surface area of the organism is…

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During expiration:

The pressure
The diaphragm inside the lungs The change in
The volume of the
is higher than the pressure drive s
and intercostal chest cavity
the air out of the
muscles relax decreases pressure outside

g)explain the meanings of the terms tidal volume…





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