Biological molecules

Name the 9 properties of water

-High latent heat of vapourisation

-High specific heat capacity

-surface tension

-ice is less dense than water

-metabolic

-solvent

-cohesion

-liquid at room temperature

How does the iodine test work

Iodine forms triiodide ion that enters the middle of the amylose helix causing the colour change

Colour change in iodine test

Brown to blue black

Method for testing for lipids

Take sample and mix with ethanol

Lipid dissolves in ethanol

Filter

Pour solution into water

Cloudy white precipitate forms if positive result

Why do you filter the ethanol test

To remove the undissolved ethanol

How does the burnet test work

Colour formed by complex between nitrogen atoms in peptide chain and cu2+ ions

Method for testing for proteins

Add 5ml of biuret solution to sample

If protein is present colour changes from blue to lilac

Colour change in biuret test

Blue to purple

Colour change in reducing sugar

Blue-no colour change

Green-little glucose

Amber-some glucose

Red-lots of glucose

Iodine dissolved in potassium iodide solution when heated disappears but when cooled returns why

Bonds break when heated

Biosensors

Machines that tell you if a biological molecule is present

How do you estimate the amount of a sample without using a biosensor

Compare with standard solution

Two functional groups in an amino acid molecule

Amine

Carboxyl

R group

True or false

Sucrose is a polymer

FALSE SUCROSE IS NOT A POLYMER

Quaternary structure in insulin

Polypeptide chains that are linked by disulfide bonds

Quaternary structure in haemaglobin

Two alpha globin chains and two beta globin chains

1 only

Tertiary structure in insulin

Disulfide bonds between cysteine amino acids

What processes involve the formation of ester bonds

Synthesis of polynucleotides

Synthesis of triglycerides

Tertiary structure in haemaglobin

Disulfide bonds formed when alpha helix folds

Each chain is folded into a spherical shape

Name and describe the reaction that produces amino acids form polypeptides

Hydrolysis and peptide bonds are broken

Properties of collagen

Fibrous

Insoluble

Resistant to stretching

True or false

DNA and RNA are both polymers of nucleotides

True

True or false

Disulfide bonds are not involved in the secondary structure of a protein

True

Glycolipids

Glycolipids are lipids with a carbohydrate (sugar) attached, found on the outer surface of cell membranes that provide structural stability and facilitate cellular recognition

What do glycolipids contain

a lipid molecule (with a fatty acid backbone) and one or more carbohydrate groups linked by a glycosidic bond

What type of protein is haemaglobin

Globular

What is x

Haem group

Draw the structure of cysteine-amino acid

In form can lipids be used for energy storage

Triglycerides

Some hormones are also lipids.What anre they and they similar in structure to ….

Cholesterol molecules

Role of cholesteroll in cell surface membranes in the human body

Binds to phospholipid fatty acid tails increasing the packaging of the membrane

Reducing the fluidity of the membrane

What’s are the two general formulas of fatty acids

Name of triglyceride

Tripalmitin

Formula for tripalmitin

C55 H98 O6

How do you recognise a formulae of a triglyceride

It has a high ratio of hydrogen to oxygen

MS answer

Explain how the structure of phospholipids allows them to form the bilayer of a plasma membrane

Hydrophilic heads

Hydrophobic tails Repel water

Heads form Hydrogen bonds with water

Ester bond displayed formula

Triglyceride components

Glycerol

Fatty acids

What are the two types of insulation provided by triglycerides

Thermal

Electrical

Explain the relationship with hydrogens in formulae and melting points

The less hydrogens the more double bonds so the less uniformly packed together they are and the lower the melting point

What type of protein are channel proteins

Intrinsic protein

What bonds are present in a phospholipid

Ester bonds in fatty acid and glycerol

In phosphate group and glycerol joined by phosphoester bond

At what temperature are lipids that contain fatty acids liquid at room temperature

Room temperature

Are lipid polymers

No

Examples of 3 other polymers

Polysaccharides

Nucleic acids

Proteins

How do phospholipids increase the fluidity of cell membranes

Contain unsaturated fatty acids that can increase the fluidity of cell membranes

What happens to the phospholipid bilayer at high temperatures

At high temperatures the membrane is disrupted

Phospholipid bilayer breaks down

Membrane becomes very permeable

What is a polyunsaturated triglyceride

Contains more than one carbon double bond

Common point for a graph analysis question

Correlation doesn’t imply causation

Other factors affect the variable too

What is a property of cholesterol

Used to produce some hormones

True or false

Cholesterol is an unsaturated fatty acid as it contains carbon carbon double bonds

False

True or false

Triglycerides are polymers

False

Is glucose digested more rapidly than fat

Yes

What are carbohydrates

Polymers of glucose

Properties of carbohydrates

Large molecules

Insoluble

1-4 glycosidic bonds

Easy to make and break to release glucose

Compact

Is glycogen a type of carbohydrate

Yes

What are fats also called

Lipids

Properties of lipids in comparison to carbohydrates

Lipids have:

More carbon carbon bonds

More energy per molecule than carbohydrates

More energy stored in less space

Insoluble

Long carbon chains

Primary structure

Specific Sequence of amino acids

Tertiary structure

Disulfide

Can globular proteins change shape

Yes

C

No COOH group

What is the difference between the alpha glucose monomers in amylopectin and maltose

More than 2 monomer of alpha glucose monomers in amylopectin

What is amylopectin made of

Alpha glucose monomers

Is starch a polymer

Yes

Name of bond in amino acids chain and type fo reaction

Peptide bond

Condensation reaction

Conjugated protein definition

Protein that Contains a prosthetic group

Haemaglobin -what does it contain

Contain polypeptide chains

Contains cysteine

Contains iron ions

How many prosthetic groups does haemaglobin

4 prosthetic group

Monomers of collagen

Amino acid

Which are more dense

Lipids

Proteins

Proteins are more dense than lipids

Are all lipids soluble or insoluble in water

Insoluble

How are lipids transported around the body

In blood via lipoproteins

What is cholesterol used to synthesise

Steroid hormones

Bile

Hydrolysis in triglycerides

Adding water back to break 3 ester bonds between the units

What bond is in sucrose

Alpha glycosidic

Alpha glucose add fructose=sucrose

What ion is needed for the hydrolysis of starch by an enzyme

Cl-

Order these in order of solubility

Highest to lowest

Glucose

Ribose

Amylopectin

Amylose

What bond holds alpha glucose and fructose together

1-6 glycosidic bond

Why is it good that an energy store in compact

Able to store lots of energy

Beta glucose+galactose=lactose

What bond is in lactose

Beta glycosidic bond

How are the sugars layed out in lactose

Opposite direction

How are the sugars layed out in maltose

Same direction

Is galactose soluble and why

Yes

H/OH groups can form H bonds with water

Name 2 differences between eh structures of chitin adn glycogen

Glycogen has alpha glycosidic bonds

Chitin has nitrogen glycogen doesn’t

Cellulose

1-4 glycosidic only

Not branched

Straight chain

Is amylose soluble

No

Is amylose branched

No

Is amylose formed by condensation reactions

Yes

Is glucose a:

Polymer

Monomer

Monomer

Is amylopectin a:

Polymer

Monomer

Polymer

Is sucrose a:

Polymer

Disaccharide

Monomer

Disaccharide

Why can Maltase break down maltose into glucose

Contains 1-4 glycosidic bonds

What is the molecular formula of lactose

C12H24 O12

Sucrose is made of what two monosaccharides

Glucose

Fructose

Is glucose soluble

Yes