Biological Macromolecules

What are Polymers built from?

Monomers

What is a Polymer?

Long molecule consisting of many similar building blocks

How many classes of life’s organic molecules are polymers?

3/4

How do Monomers join together?

Condensation, 2 monomers bon through loss of a water molecule

How are Polymers returned to Monomers?

Hydrolysis

What is the general structure of an Amino Acid?

Carboxyl, Amino Group, R group, Central Carbon

Why do amino acids differ in properties?

Differing side chains (R groups)

How do the side chains of Amino Acids differ?

• Non polar - Hydrophobic

• Polar - Hydrophilic

• Electrically charged - Positive or Negative

How are Amino Acids linked?

By peptide bonds

What is the Structure of a Functional Protein?

Polypeptide twisted, folded and coiled into unique shape

How is a protein’s 3D structure determined?

By sequence of amino acids

How does a protein’s structure relate to its function?

Structure determines function

What is the Primary Structure of Proteins?

Sequence of amino acids in a protein determined by inherited genetic info

What is the Secondary Structure of Proteins?

H bonds cause coils and folds between repeating constituents of polypeptide into alpha helix and beta pleated sheet

Describe an Alpha Helix

Coil

Describe a Beta Pleated Sheet

Folded structure

What is the structure of Spider Silk?

Structural protein containing Beta Pleated Sheets

Describe the Beta Pleated Sheets in Spider Silk

Mainly non-polar, stabilised by disulphide bonds w/in cysteine residues

What are Fibrils formed from?

Repeating motifs separated by spacer sequences

What is the Quaternary Structure of Proteins?

Aggregation of 2 or more polypeptides

What is the BRAF gene?

Kinase that regulates a signal transduction pathway

Where is the signal transduction pathway used?

• CD

• D

• A

Controlling cell division, differentiation, apoptosis

What do mutations in the BRAF Gene cause?

Conformational change causing constitutive kinase activity and uncontrolled cell growth

How is X-Ray Crystallography used to help understand Protein Structure?

Determine protein’s structure

How do Virus Capsids compare to other protein assemblies?

Many are more/less athletic

What is a Receptor Protein?

Response of cell to chemical stimuli eg nerve cell receptors

What is the unifying feature of Lipids?

Little/no affinity for water

Why are Lipids Hydrophobic?

Consist mostly of hydrocarbons

What is the Main Function of Lipids?

Energy storage

Where do Humans and other Mammals store their fat?

Adipose cells

What is Adipose tissue’s other functions?

Cushioning vital organs & insulates

How are Proteins/Lipids Characterised?

By a carbon skeleton consisting of 4 fused rings

What is Cholesterol?

Important steroid, component in C cell membrane3 C

What is Glycerol?

3 C alcohol w/ a hydroxyl group attached to each C

How do Cis Double Bonds affects unsaturated fats?

Causes bending

Describe the tails of Phospholipids

2 Hydrophobic Fatty Acid Tails

How are the Phospholipid Tails joined?

Joined to a hydrophilic head containing glycerol, phosphate, polar group

What is the simplest carbohydrate?

Monosaccharide

What is the usual molecular formula of Monosaccharides?

C_nH_2nO_n

What is the most common Monosaccharide?

Glucose

What are Isomers?

Same formula but different arrangement of atoms

How are chemical properties of sugars different in Isomers?

Minor changes

Why can Isomers have important biological effects?

Recognised by enzymes and other proteins

How are Disaccharides formed?

Dehydration between 2 monosaccharrides

What is the Covalent Bond between Disaccharides?

Glycosidic linkage

What is Starch?

Storage polysaccharide in plants, only glucose

How do Plants store surplus starch?

As granules within chloroplasts and other plastids

What is Glycogen?

Storage polysaccharide in animals

How do humans and other vertebrates store glycogen?

Mainly in liver and muscle cells

What is the effect of Glycogen Hydrolysis?

Releases glucose into useable form in the body

What is Cellulose?

Major component of tough wall of plant cells

Describe B glucose polymers

Straight, form unbranched B glucose molecule

How are Cellulose molecules held together?

Unbranched cellulose molecules held together by H bonds between OH groups on parallel strands

How are Parallel Cellulose Molecules held?

Grouped into microfibrils, form strong building materials for plants