CIE AS Biology - Biological Molecules

Monosaccharides

What is a carbohydrate made up of

(CH2O)n

General formula of a monosaccharide

Beta Glucose

Hydroxyl group on C1 is above ring structure

Alpha Glucose

Hydroxyl group on C1 is below ring structure

Source of energy in respiration

Role of Alpha Glucose in living organisms

Building block for larger molecules

Role of Beta Glucose in living organisms

Condensation Reaction

Reaction whereby a molecule of H2O is produced

Hydrolysis

Adding water to break a bond

Glycosidic bond

The bond that forms due to a condensation rxn

Fructose + Glucose

Sucrose

Glucose + Galactose

Lactose

Glucose + Glucose

Maltose

Amylose

Long unbranched alpha glucose chain (1.4 linkages)

Amylopectin

Long branched chains of alpha glucose (1.6 linkages)

Starch

Mixture of amylose and amylopectin builds large ______ grains

Glycogen

Chains of 1.4 linked alpha glucoses with 1.6 linkages forming branches

More branched than amylopectin

Clumps together to form granules

Cellulose

Beta glucose molecules

Linked at 180 degrees to one another

Makes up 20%-40% of the cell wall

Microfibrils

60/70 cellulose molecules that become tightly cross linked

Fibres

Bunches of microfibrils held tightly together

Lipids

Molecule of glycerol and fatty acids

Buoyancy, nutrition, water repellant, hormones, physical protection, electrical insulation

Uses of lipids

Unsaturated Fatty Acids

Double bonds between neighboring carbon atoms

Plant lipids occur as oils

Polyunsaturated Fatty Acids

More than one double bond between neighboring carbon atoms of lipids

Monounsaturated Fatty Acids

One double bond between neighboring carbon atoms

Triglycerides

Most common lipid

Phospholipids

One of three fatty acid tails is replaced by a phosphate group

Hydrophilic head

Hydrophobic tails

Allows molecules to form membranes

Characteristics of phospholipids

Peptide Bond

Condensation reaction between two amino acids forms a ________ bond. The bond can be broken by hydrolysis.

Primary Structure

The sequence of amino acids

Secondary Structure

Polypeptide chain is folded in one or more ways, most commonly an alpha helix. H binds between C double bond and NH group of every 4th peptide.

Tertiary Structure

Helical structure of a polypeptide folds on itself (supercoiling). This produces a 3D structure which is maintained by a series of interactions between R-groups. it is highly specific.

Quaternary Structure

Several tertiary level polypeptides fitted together, eg. Hemoglobin.

Weak Intermolecular Forces

The forces holding tertiary and quaternary structures of proteins together

Globular Proteins

Ball shaped proteins that are usually soluble and have a precise shape that is key to their functioning, eg. hemoglobin

Fibrous Proteins

Proteins that form long strands, not usually soluble in water, and mostly have structural roles.

Opsin

Fibrous protein that is part of a pigment called rhodopsin that is found in the rod cells of the retina.

Collagen

Fibrous protein found in connective tissues. made up of three long strands coiled into a triple helix. every third amino acid is glycine.

Carrier Proteins, Recognition proteins, Clotting of blood.

Functions of proteins.