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Surface area to volume ratio : the amount of surface area per unit volume of
an object or collection of objects.
The higher the SA: V ratio , the more effective the process of diffusion.
The respiratory system provides a large surface area to volume ratio to
ensure efficient…

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The fluid mosaic model describes the plasma membrane of animal cells. It is
mosaic is structure because it is embedded with proteins of all different sizes.
It is considered fluid because it doesn't have an entirely rigid structure.

Component Structure/Description Function
Phospholipid hydrophilic phosphate forms bilayer
heads impermeable barrier…

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Osmosis: the movement of water molecules from an area where they are in
high concentration to an area of lower concentration through a partially
permeable membrane .
Water molecules form hydrogen bonds with solutes, reducing the movement
of water molecules.
Through phospholipid bilayer.
Passive, no energy required.

Passive transport:…

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ATP supplies energy to change the shape of a carrier protein molecule when
substances are moved against the conc. gradient.

Endocytosis bulk transport of substances into a
cell by the creation of a vesicle.
Exocytosis bulk transport of substances out of
the cell.
vesicles fuse with the cell surface

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RNA the pentose sugar is called ribose and the base uracil replaces the base
There are 3 different types of RNA:
mRNA (messenger RNA) ­ it acts as a copy of a gene by having a
sequence complementary to one strand of DNA and identical to the
other strand.…

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The genetic code in the DNA making up the chromosomes acts as a code for
protein synthesis .
It dictates the order of the amino acids required to make the protein and the
order in which they should be bonded together.
3 bases code for 1 amino acid and…

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Fibrous and Globular

Fibrous Globular
Repetitive regular sequences of Irregular amino acid sequences.
amino acids
Actual sequences may vary slightly Sequence highly specific and never
between 2 examples of same varies between 2 examples of same
protein. protein.
Polypeptide chains form long parallel Polypeptide chains folded into a
strands. spherical…

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Extracellular reactions: reactions occurring outside a cell.

Increase in temperature (increase in kinetic energy to molecules), increases
likelihood of collisions between enzyme and substrate molecule. Hence rate
of reaction increases. Beyond the optimum temperature , the increased
vibration of the atoms in the protein molecule break the bonds maintaining…

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each old strand serves as a template for a new strand. Two new double
helices result, each containing one new strand and one old strand.
Sometimes, the DNA does not replicate properly ­ an incorrect base may slip
into place = a gene mutation .
If it occurs in…

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In humans, recessive mutations of single genes result in:
o Cystic Fibrosis : mucus which is too viscous.
o Thalassaemia : abnormal haemoglobin formation.
o Albinism : lack of pigment production.

Gregor Mendel initiated the study of genetics using the garden pea. He
established patterns of inheritance of a number…







where are you?

tony farag


Im here son, dont worry **



these are great thanks so much

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