biological molecules mrs chenery

What is a monomer

A small molecule that joins with other monomers to make a polymer

What isa polymer

A large molecule made of many monomers chemically joined together

Give two examples of monomers

Monosaccharides and nucleotides

What do u have to do to join monomers together?

Condensation reaction while taking out a molecule of water

What do u have to do to separate a polymer into its monomers, explain?

Hydrolysis Which is hydrolysing the covalent bonds between the monomers by using water

What is the structure of glucose? And what types are there?

Alpha and beta

What type of molecule is glucose?

A monosaccharide

What type of molecule is maltose?

Disaccharide

What type of molecule is starch

Polysaccharide

How do u make maltose?

Two alpha glucose

What is a glycosidic bond?

When two monosaccharides covalently bond in a condensation reaction

Give three examples of disaccharides?

Maltose,lactose,sucrose

What are polysaccharides mainly uased for?

Energy store and structured components of cells

Give an example of energy store and structure components of cells?

Starch in plants for energy store and Cellulose for structured components

What is a reducing sugar? Give an example

A sugar that can reduce another substance Such as glucose reducing Benedict’s reagent

How do u test for a reducing sugar?

Add Benedict’s and heat and it should go orange or red

How do u test for a non reducing sugar?

-add HCL and heat

-neutralise by adding sodium hydrogen carbonate

-add Benedict’s and should then colour change to orange, red or yellow

Why do u add HCL?

To break the glycosidic bonds between the molecules of sucrose

What do the sucrose molecules get split into?

Glucose and fructose

Why do we neutralise the solution now?

Because the solution is acidic and Benedict’s does not work in acid

What ph do we want it to be at?

PH 8

What is an isomer?

A compound with the same chemical formula but a different chemical structure

Give an example of an isomer?

Alpha and beta glucose

What is a polysaccharide?

A polymer containing many monosaccharides joined together by glycosidic bonds formed with condensation reactions

Name three polysaccharides

Starch, cellulose, glycogen

What is starch made from?

Long chains of alpha glucose linked by glycosidic bonds by condensation reactions

What are the two types of starche chains

Amylose and amylopectin

What is amylose

Amylose is long unbranched chains of alpha glucose And the angles of the glycosidic bonds give it a coiled shape

What does the coiled shape help with?

Being compact so good for storage and fit more in a small space

What is amylopectin?

Branched chain of alpha glucose

What do the branches allow?

Allows enzymes to hydrolyse the glycosidic bonds at multiple points meaning that glucose can be released quicker

Hydrolyisis only works on the ……….

Ends of a polymer

Why is starch a good energy store? (4)

Insoluble

large So can’t leave the cell

compact

Fast hydrolysis with branches

What is starch major in?

Carbohydrate storage molecule in plants

What do animals store carbohydrates as?

Glycogen

What is glycogen stored as in animals?

Small granules

What are the monomers of glycogen?

Alpha glucose joined by glycosidic bonds

Glycogen chains are more…….

Branched

What is cellulose made from?

unbranched chains of beta glucose

How do u join beta glucoses together?

U must rotate alternate glucoses by 180 degrees for them to align correctly to form the glycosidic bond

Where does the strength of the cell wall come from?

From cellulose microfibrils

Give three examples of monosaccharides

Glucose, fructose and galactose

Explain how cellulose gives cotton its strength/ (3)

Beta glucose molecules join by a glycosidic bond forming long unbranched chains

Hydrogen bonds form between the adjacent cellulose chains holding the chains together

The chains are held together in microfibrills giving it high strength and turgidity

What are lipids insoluble and soluble in?

Insoluble in water

Soluble in organic solvents such as alchohol

What do lipids contain?

Carbon hydrogen and oxygen

What are the main groups of lipids

Triglycerides and phospholipids

Give 5 roles of lipids

• Cell membranes

• Energy source

• Water proofing

• Insulation

• Protection

Why are tryglycerides essential for animals in the dessert?

Triglycerides release water when oxidised

Why are triglycerides called triglycerides?

They consist of three fatty acids and one glycerol

How do the fatty acids bond with the glycerol

Each fatty acid forms an ester bond with glycerol in a condensation reaction

What chemical group does fatty acids have attached too them?

Carboxyl group

What makes trygylcerides good storage molecules

They have low mass to energy ratio

What is the advantage of being insoluble in water?

Does not effect the water potential in them

What are saturated fatty acids?

Only have single bonds between carbon atoms

What are unsaturated fatty acids?

Have a double bond between carbons

What do the double bonds of carbon do in the chain

Kinks

How do u do the emulsion test (3)

• addd ethenol to the sample and shake

• Add distilled water and shake

• Should form cloud white emulsion

Phospholipids are the major part of……….

Plasma membrane

What are phospholipids made from?

Two fatty acids and glycerol

What replaces the emtpy space between the fatty acids?

A phosphate group

Describe the head of a phospholipid?

where the phosphates group and glycerol are

It is hydrophilic and polar

Describe the tail

Has the fatty acids

Hydrophobic and non polar

What do unsaturated fatty acids have?

Kinks

How do phospholipids arrange themselves in water

In a phospholipid bilayer

Why are glycerides not polymers?

Because they do not have a chain of repeating monomer units

Why are lipids good for long term energy store?

They have high energy per gram and are compact so efficient to store

Why is insulation important?

Because fats are a poor conductor of heat so reduces heat loss and maintaining a consultant body temp

How is protection of organs connected to lipids

Fats act as a cushioning around organs perotecting them from physical impact

The phospholipid bilayer acts as………

Partially permeable barrier where it controls what goes in and out of cell

What are proteins made of?

Polypeptides

What are the 4 different chemical groups attached to the central carbon atom in an amino acid?

Carboxyl group

Amino group

Hydrogen atom

R group

What is the amino group?

NH2

How can amino acids join together?

Condensation reaction between the OH of the Carboxyl group and the H from the amino group from another amino acid

What kind of bond is this called?

Peptide

What are many amino acids joined together called?

Polypeptide

What is the primary structure of proteins?

Many amino acids that bond to form a polypeptide

How many types of amino acids are there?

20

What happens in the secondary structure of protiens?

Twisted into an alpha helix

What causes the twisted shape

It is when hydrogen bonds form between the Carboxyl and amino group causing the twisted shape

What happens in the teritiary structure?

The alpha helix are twisted and folded even more to form a unique 3D shape

What bonds could the 3D shape be held by?

Ionic

Disulphide

Hydrogen

Why is the 3D shape important to how the protein functions?

Makes each protein distinctive and allows it to be recognised by other molecules so it can interact with them

What happens in the quaternary structure of proteins?

There is more than pone kind of polypeptide chain in the protein

Give examples of a quaternary protein

Haemoglobin

What happens if the temperature is too high for the protein?

Kinetic energy increases so molecule vibrates more making the intermolecular forces break, and denaturing enzymes

What happens to the shape of the protein when bonds are broken?

3D shape is lost

What are the conditions that denature a protein?

High temp

High ph

What does the sequence of amino acids determine?

Where bonds form

And their unique 3D shape

Shape of active site

What might Cause a change in the amino acids sequence?

Mutations

What do their 3D shaped determine?

Their function

Name two types of shapes of protiens

Globular protiens

Fibrous protiens

Give an exmaple of globular and their function

Haemoglobin - carry out metabolic functions

Example of fibrous protiens and their function

Collagen

Carry out structural functions

Describe globular

Is spherical

And soluble in water

Why are they soluble in water?

They have hydrophobic R groups on the inside and hydrophilic R groups on the inside

What shape are fibrous proteins

Long chains of polypeptides that run parallel to each other linked by hydrogen bonds and form very stable molecules

Are they soluble or insoluble and explain

Insoluble - they have lots of disulphode bonds make them more resistant to an attack

What manages them insoluble?

Have hydrophobic R groups and have strong bonds in between chains making it harder for it to dissolve

What are the two biological molecules are the main respiratory substances?

Carbohydrates and lipids

What are the structure of the chains in cellulose

Straight and unbranded