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TOPIC 1 AND 2…read more

Slide 2

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· Structure of water
Water is made up of on oxygen atom and 2 hydrogen atoms
joined together by shared electrons.
Because hydrogen atoms only have one electron this is pulled
towards the oxygen atom to share electrons.
This results in the oxygen side of water having a slight
negative charge and the hydrogen end having a slight
positive charge.
This makes water a dipolar molecule.
Properties of water making it a good transport
· Water is a particularly good solvent because of its dipole
nature. This is because many substances are ionic meaning
they are made from one positive or negative atom. Therefore
the positive end of the water will be attracted to the negative
ion, and will completely surround the ion. This will make the
ion dissolve very quickly. When substances are dissolved
they cause less friction so are easier to transport.
· Water is also very cohesive. This means that molecules of the
same type attract each other, so water molecules sort of stick
together. This helps water "flow".…read more

Slide 3

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Monosaccharides- carbohydrates such a glucose are monosaccharaides.
They are joined together using GLYCOSIDIC bonds in condensation reactions to
form Disaccharides.
Two glucose molecules join to make Maltose.
The hydrogen atom of one glucose bonds to the
hydroxyl (OH) group of another. The disaccharide
can also be broken apart in hydrolysis. In glucose
the bond is known as a 1,4 bond.
LACTOSE is another disaccharide made up of glucose and
galactose with a 1,4 glycosidic bond.
The last is SUCROSE made from glucose and fructose joined
with 1,2 glycosidic bonds.…read more

Slide 4

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· A polysaccharide is formed when "many" monosaccharide join
together, These are some polysaccharides:
· Starch
· The main storage molecule in plants, when energy is needed
the plant slowly breaks the starch down releasing glucose.
· Starch is made from amylose and amylopectin.
· Amylose is Glucose with 1,4 bonds and coils up so is very compact and really good
for storage because a lot can fit into a small space.
· Amylopectin is Glucose with 1,4 and 1,6 bonds so has side branches. This allows
enzymes to break down the bonds faster so releasing the glucose faster.
· Starch is also insoluble so doesn't cause water to enter the cells via osmosis.
· Glycogen
· The main storage molecule in animals, which is broken down to release energy.
· It is made up of glucose joined using 1,4 and 1,6 glycosidic bonds, but it has even
more side branches than amylopectin meaning energy can be released very quickly.
· Like starch it is also compact and insoluble so is a good storage molecule.…read more

Slide 5

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Triglycerides are fat lipids.
head The 3 fatty acid tails are
They are also HYDROPHOBIC
(water repelling)
How are triglycerides formed? They make the lipid insoluble.
Like carbohydrates, they are formed using condensation reactions. Three fatty
acids and a glycerol molecule are joined using ESTER bonds.
Ester bond
The tails can also be shown with an R
= Triglyceride + Water
There are 2 types of lipids- SATURATED and UNSATURATED. The difference between
these two lipids is their tails. Saturated lipids have no double bonds between the carbon
atoms in their tails whereas unsaturated ones do. This means unsaturated lipids kink and
melt at lower temperatures they are also more healthy and are usually found in plants…read more

Slide 6

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· A Dipeptide is made of 2 amino acids, a polypeptide of more
than 2, and a protein is made up of 1 or more polypeptide
· The general structure for an amino acid is:
The green part is the carboxyl group,
The Yellow is the amino group,
And the blue is the variable R group.
· Like lipids and carbohydrates, they are joined together in
condensation reactions with PEPTIDE bonds.…read more

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