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1.1.1 Cell Organelles
(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 - 1500x



(b) explain the difference between magnification and resolution;

(c) explain the need for staining samples for…

Page 2

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Mosaic ­ There are glycoproteins, lipoproteins and proteins on the membrane make "patches"
which give it a mosaic appearance.

(d) describe the roles of the components of the cell membrane; phospholipids, cholesterol,
glycolipids, proteins and glycoproteins;

Phospholipids ­ Form a fluid barrier. Short chain and unsaturated fatty acids increase its…

Page 3

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(i) explain what is meant by osmosis, in terms of water potential. (No calculations of water
potential will be required);

(j) recognise and explain the effects that solutions of different water potentials can have upon
plant and animal cells (HSW3).

1.1.3 Cell Division

(a) state that mitosis occupies only a…

Page 4

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Telophase ­ Nuclear envelope reforms. Spindle breaks down. Chromosomes uncoil so can no
longer be seen in a light microscope. (2 cells in 2n)

(c) explain the meaning of the term homologous pair of chromosomes;

Homologous pair of chromosomes - Apairof chromosomeshaving the same genesequences
each derived from one…

Page 5

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(k) explain, with the aid of diagrams and photographs, how cells are organised into tissues, using
squamous and ciliated epithelia, xylem and phloem as examples;

(l) discuss the importance of cooperation between cells, tissues, organs and organ systems (HSW4).

1.2.1 Exchange surfaces and breathing

(a) explain, in terms of surface…

Page 6

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Cartilage ­ Is in C-rings to support the trachea and bronchi to hold them open. The C shape is to
allow movement and the expansion of the oesophagus when swallowing.

Cilia ­ Contain microtubules which slide over each other to make the cilia bend in a sweeping
action. They sweep…

Page 7

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(a) explain the need for transport systems in multicellular animals in terms of size, level of activity
and surface area:volume ratio;

(b) explain the meaning of the terms single circulatory system and double circulatory system, with
reference to the circulatory systems of fish and mammals;

Single circulatory system ­ Fish…

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(i) describe, with the aid of diagrams and photographs, the structures and functions of arteries,
veins and capillaries;



Very narrow lumen ­ Enables blood to be carried at a sustained high pressure.

Tunica intima ­ Endothelium layer that is very smooth to reduce friction of blood flow to…

Page 9

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Proteins Plasma proteins Proteins secreted by body Proteins secreted by body cells
and hormones cells and some small (cannot go through capillaries
hormones. into blood so must be carried
by lymph)
Fats Some transported None More than in blood such as
as lipoproteins. reconstituted fatty acids and
glycerol which are…

Page 10

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Candidates should be able to:

(a) explain the need for transport systems in multicellular plants in terms of size and surface
area:volume ratio;

Need for transport systems:

Diffusion is too slow ­ Not a large enough surface area if surface area to volume ratio is small

Layers of cells can…


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