Grade 12 Biology: Macromolecules

Carbohydrates Function:

-Are the primary source of energy in living things but have many other structural functions.

-Quick energy source.

-Commonly known as sugars, starches, and fiber (indigestible roughage).

-Made up of saccharide units.

Monomers of Carbohydrates:

Monosaccharides

Monosaccharides:

-3 to 7 carbons in length.

-Also known as a simple sugar.

-Aldoses (aldehydes)

-Ketoses (Ketones)

-Further classified based on the number of carbons:

3 - tri, 4 - tetr, 5 - pent, 6 - hex, 7 hept, etc.

Common Monosaccharides:

Glucose, fructose, galactose

Glucose:

-Formula: C6H12O6

-Isomers are fructose, galactose, and mannose.

-Straight chain.

-aldohexose

Fructose:

-Commonly called fruit sugar as it is a principle sugar in fruits.

-Ketohexose.

Disaccharides:

-Linked by C - O - C glycosidic bonds.

-General Formula: C12H22O11

Common Disaccharides:

-Maltose (glucose + glucose) alpha glycosidic bond

-Lactose (galactose + glucose) beta glycosidic bond

-Sucrose (glucose + fructose) alpha glycosidic bond

Polymers of Carbohydrates:

Polysaccharides

Polysaccharides:

-Complex carbohydrates of 100 - several 1000 monosaccharides joined by glycosidic bonds.

2 Functions of Polysaccharide:

1) Energy and energy storage.

2) Structural Component

Energy and Energy Storage: 1) Starch

-Storage energy molecule found on plants.

-Composed of two different polysaccharides: Amylose and Amylopectin.

Amylose:

-Simplest form.

-Composed entirely of alpha (1-4) glycosidic links.

-Unbranched or linear.

Amylopectin:

-More complex and branched.

-Main chain of alpha glucose bonded by alpha (1-4) links.

-Has branched points forming alpha (1-6) linkages.

Energy and Energy Storage: 2) Glycogen

-Is an energy storage molecule used by animals.

-Stored in liver and muscle cells of vertebrates.

-Similar to amylopectin but more highly branched.

The main chain is alpha (1-4) linkages with branches of alpha (1-4).

Structural Component: 1) Cellulose

-Fiber

-The most abundant organic compound on earth.

-Made up of beta glucose monomers

-Linkage is beat (1-4) glycosidic bond.

-Major component of plant cell walls.

Structural Component: 2) Chitin

-Beat (1-4) glycosidic bonds between glucose derivatives (modified with amino).

-Main component of cell walls of fungi and the exoskeleton of crustaceans and insects.

*Enzymes have a difficult time breaking down beat (1-4) linkages.

Lipids Function:

-Provide energy and energy storage.

-Help maintain. structural integrity of the cell membrane.

-Thermal insulation in animals.

Types of Lipids:

1) Fats and Oils (triglycerides)

2) Phospholipids

3) Steroids and Waxes

Monomers of Lipids:

Glycerol and Fatty Acids.

Glycerol:

-3 carbon alcohol with each carbon bearing a hydroxyl group (-OH).

Fatty Acids:

-Long hydrocarbon chains ending in a carboxyl group.

Two Types of Fatty Acids:

Saturated and Unsaturated fats

Saturated Fats:

-All single C-C bonds.

-Animal Fats.

-Solid at room temperature.

Unsaturated Fats:

-Double C=C bonds.

-Plant oils.

-Double bonds cause kinks in the chains.

-Liquid at room temperature.

-Two types: Cis and Trans fat.

Polymers of Lipids:

Triglycerides (fats and oils) and Phospholipids.

Fats and Oils:

-Fats (solid)

-Oils (liquid)

-Called triglycerides.

-Composed of glycerol and fatty acids.

Tryglycerides:

-Insoluble in H2O.

-Insoluble in non-polar.

Phospholipids:

-Major component of cell membrane.

-Made up of glycerol, 2 fatty acids, and phosphate group.

Other: Steroids

-Mostly used as hormones (chemical signals)

-Made up of 4 fused hydrocarbon rings and other functional groups.

Other: Waxes

-Hydrophobic

Proteins Function:

-Structural building blocks.

-Enzymes (biological catalysts).

-Enable movement.

-Transport substances.

-Regulate cell processes.

-Defend against disease.

Monomers of Proteins:

Amino acids

Amino Acids:

-There are 20 important amino acids.

-8 are essential (not produced by the body therefore obtained by food).

-12 are non essential (produced by the body).

-Proteins are formed by bonding amino acids together through peptide bonds.

Polymers of Proteins:

Polypeptides (peptide bonds)

Polypeptides (peptide bonds):

-Composed of of repeating amino acid units and are the building blocks of proteins.

Levels of Protein structure:

-Protein shape = biological activity

-Shape is determined by the sequence of amino acids.

Primary structure:

-Refers to the unique amino acid sequence in a protein.

-Primary structure ultimately determines the shape and therefore the function of the protein.

Secondary Structure:

-As the chain grows it coils or folds at various locations.

-H bonds are formed between amino acids to maintain its shape.

Two basic forms of secondary structure:

Alpha helix and Beat pleated sheet

Alpha helix:

-Contains a hydrogen bond.

-Found in hair, wool, claws, beaks, and feathers.

Beta pleated sheet:

-H bonding between 2 polypeptide chains that are parallel to each other.

-Found in fingernails and silk.

Tertiary Structure:

-Polypeptide chain bends back and forth into a 3-D globular structure.

-Maintained by the interactions between the amino acids variant group and its surroundings.

Types of Interactions:

-Hydrogen bonding

-Ionic bonding

-London dispersion forces

-disulfur bridges

Quaternary Structure:

-Complex structure formed by the interaction of 2 or more polypeptide chains.

Denaturary Proteins:

-Protein loses shape therefore doesn't function.

-Caused by change in the temperature or pH.

Nucleic Acids Function:

-Used by organisms to store and transmit genetic/hereditary information.

Two main types:

DNA

-ATP (adenosine triphosphate)

-Remains as a single nucleotide.

RNA

-Formed by monomers called nucleotides.

3 Components of a Nucleotide:

1) 5 carbon sugar (pentose)

2) Phosphate group

3) Nitrogenous base

Pentose Sugars:

Ribose and Deoxyribose

Nitrogenous Bases:

Purines:

-Double rings

-Adenine (A)

-Guanine (G)

Pyrimidines:

-Single rings

-Thymine (T) / Uracil (U)

-Cytosine (C)

DNA:

-Contains the genetic information.

-Sugar: deoxyribose

-Bases: A,G,C,T

-Location: nucleus

-Strands: 2

-Types: 1

RNA:

-Interprets and carries out the instructions specified by DNA for making proteins.

-Sugar: Ribose

-Bases: A,G,C,U

-Location: Cytoplasm (ribosomes)

-Strands: 1

-Types: Several (mRNA, tRNA, rRNA)