Foundations in Biology - Biological molecules

Water is a metabolite. What does this mean?

It's used in metabolic reactions such as condensation and hydrolisis

Name the types of metabolism

Catabolism- breaking down large into small

Anabolism- molecular build up from small to large

What is the advantage of waters high specific heat capacity?

Lots of energy os required to heat it therefore it doesn't go through massive temperature fluctuations

What is a macromolecule

Made from smaller subunits whereas polymer is made from always repeating subunits

how does sweating cool down the body?

Sweet is released on the skin and due to waters high latent heat of vaporisation it provides a cooling effect upon evaporation.

How does ice being less dense than water affect organisms?

In winter ice is formed on water and as ice is less dense than water due to semi crystalline structure it floats to the surface this provides an insulation affect meaning aquatic life is safer as it near impossible to freeze a body of water all the way through.

Why is water a good solvent

It has negatively charged o2 and positively H+ so it’s polar and interacts with charged regions to dissolve the substance (other polar molecules)

What is the difference between alpha and beta glucose?

The hydroxyl group on carbon 1 of alpha glucose is below the ring whereas the hydroxyl group on beta glucose is above the ring.

What elements make up carbohydrates?

carbon, hydrogen, oxygen

What elements make up protein base structure?

carbon, hydrogen, oxygen, nitrogen

What elements make up lipids?

carbon, hydrogen, oxygen

What are examples of monosaccharides?

glucose, fructose, galactose

What are examples of disaccharides?

sucrose, lactose, maltose

What are the Monomers of Maltose?

glucose and glucose

What are the Monomers of sucrose?

glucose and fructose

What are the Monomers of Lactose?

glucose and galactose

What is the structure of Amylose?

It's an unbranched chain of glucose joined by 1,4 glycosidic bonds as a result it's coiled

What is the structure of Amylopectin

It's branched and joined together by 1,4 glycosidic bonds however its branches join with 1,6 glycosidic bonds. Due tot he presence of branches it is digested rapidly

What is the structure of cellulose?

It's a long, unbranched chain of beta glucose joined by glycosidic bonds. Hydrogen bonds hold multiple chains together forming microfibrils.

What is the structure of glycogen?

It's a highly branched straight chain of alpha glucose joined with 1,4 and 1,6 glycosidic bonds. It's extremely large but very compact.

What is a saturated lipid and where is it found?

Saturated lipids are found in animal fat and contain no CC double bond.

What is an unsaturated lipid and where is it found?

Unsaturated lipids are found in plant oils and DO contain a CC double bond

What is a lipids function

Buoyancy

Protection for vital organs

Insulation

Storage of energy via adipose tissue

What is the structure of a phospholipid?

One phosphate head attached to a glycerine which has two fatty acids attached.The phosphate group is hydrophilic

What is the function of H+ in the body?

It determines the pH of certain areas

What is the function of Fe2+ in the body?

It's a component of haemoglobin which carry's oxygen in red blood cells

What is the function of Na+ in the body?

It is involved in the co-transport of glucose and amino acids

What is the function of Phosphate ions in the body?

They are components in DNA and ATP.

Outline the primary structure of proteins

A straight chain of amino acids bonded with polypeptide bonds.

Outline the secondary structure of proteins

It's the shape an amino acid chain takes either alpha helix or beta pleated sheet. They are held together by hydrogen bonds.

Outline the tertiary structure of proteins

It's is the 3D structure a protein takes it can either be globular or fibrous they are held together by Disulfide bridges, hydrogen bonds, ionic bonds and hydrophobic interactions.

Outline the quaternary structure of proteins

A quaternary structure is formed when two or more polypeptide chains associate to form a single protein.

How do amino acids act as buffers ?

The carboxyl and amine groups ionise. The carboxyl acts like an acid and loses a H+ whereas the amine gains a H+, acting like a base

It is amphoteric as it has both acidic and base properties

Desc H bonds in a protein.

Between polar groups, electronegative of CO- and electro positive of OH or NH

Desc disulphide bonds in a protein

Strong covalent bonds

Between Sulfur containing R groups (cysteine)

Form strong links to strengthen the tertiary structure

Desc ionic bond in a protein

Between ionised R groups that have become negative or positive and so are attracted to eachother

Desc globular protein

Metabolic role

Ball shape

Soluble

Eg haemoglobin ( has 4 pp: 2 alpha 2 beta with haem group at centre of each with iron inside that)

Desc a fibrous protein

Structural role

Long strands

Insoluble

Eg collagen in skin teeth bones so very essential for structure

Draw alpha glucose structure

Draw lipid structure

Draw phospholipid structure

Draw protein structure

What is the test for proteins

Biuret- add a couple drops, turns from blue to purple

Test for lipids

Emulsion test - add ethanol, then distilled water as lipids insoluble in water but soluble in ethanol

Starch test

Iodine drops

Reducing sugar test

Benedict’s- add drops

Boil in water bath for 3-5 mins

Non reducing sugar test (dis)

take last result

Boil in dilute Hcl to hydrolyse the sugar

Nuetralise by adding sodium bicarbonate

Repeat Benedict’s

Difference between deoxybribose and ribose

Deoxy had hydrogen atom at c2 ribose has OH

What is a purine

Larger, double carbon nitrogen ring (A and G)

What is a pyrimidine

Single carbon nitrogen ring

C and T

Desc semi conserve replication

1. DNA gyrase unwinds

2. DNA helices unzips breaking H bonds and leaving two single strands with exposed bases

3. Free DNA nucleotides line up via complementary base pairing

4. DNA polymerase catalyses their addition in 5-3’ directions

5. Leading strand made continuously lagging has to be joined by dna ligase (Okazaki fragments)

What is degenerate code

More than one codon for an AA

What is universal code

Same codons same AA in all organisms

What is non overlapping code

Bases are only read once

What is DNA transcription + method

Copying DNA into mRNA as dna too large to leave nucleus

1. Dna helices unzips, making a sense and an antisesnse strand (template) and sense strand

2. RNA nucleotides attach to exposed bases Free DNA

3. RNA polymerase joins forming phosphodiester bonds

4. Dna returns to double helix

Desc DNA translation

1. Small subunit of ribosome binds at start codon

2. tRNA with complementary anticodon attaches held via hydrogen bonds

3. tRNA attaches again joining peptide bond and catalysed by peptidyl transferase, part of rNA

4. Another tRNA comes and the first gets released