SBI4U – Grade 12 AP Biology – Biochemistry Test

Thanks, Bairavi Sripalan!

Main Ideas Labs Enyzmes  Water Properties


Chemical Reaction

Biological Consequence


Hydrogen Bonds (attractions)

 Holds together water molecules together, helps the transport of water against gravity in plants

Can travel through xylem from root to leaf

Moderation of temperature

Hydrogen Bonds

  •   Water absorbs heat from the wait and then releases heat into the cold air
  •   Can absorb/release a large amount of heat with only a slight change in its own temperature


Expansion upon freezing

Hydrogen Bonds

 The molecules re- arrange creating a gap. This makes the molecules take up more volume

Ponds preserve fish/wild life

Versatility as a solvent

Polar Covalent

  •   All living things use water in one form or another to transport nutrients and etc
  •   Dissolvability
  •   Transporting; moving

    substances from one place to another


 Carbon

Its properties include being able to make large molecules/chains because it is stable and has 4 possible bonds.

– 1 bond ex. Ethane = 2 bonds ex. Ethene ≡ 3 bonds ex. Ethine

Number of carbons in a molecule/chain

1. Methane 2. Ethane 3. Propane 4. Butane 5. Pentane 6. Hexane 7. Heptanes 8. Octane 9. Nonane 10. Decane

 Isomers
Are compounds with the same molecular formal but different structures and properties Structural Isomers

– Have different covalent arrangements of their atoms

Geometric Isomers
– Have the same covalent arrangements but different in spatial arrangements

– Isomers that are mirror images of each other

Functional groups

  • –  Are the components of organic molecules that are most commonly involved in chemical reactions
  • –  The number and arrangement of functional groups give each molecule it’s unique properties
  • –  Function groups give a carbonated chain certain properties, all compounds that have the same functional groups, share similar properties.

Polymer – a long molecule consisting of mainly similar building blocks
Monomers are small building block molecules
All living things are made up four classes: Carbohydrates, Lipids, Proteins and Nucleic Acids all of them are polymers but lipids.

Dehydration – when two monomers bond together through the loss of a water molecule (h2o)
Hydrolysis – when water is used to break up two monomers


  • –  includes sugars and polymers of sugars
  • –  the simplest carbohydrates are monosaccharides/single sugars
  • –  macromolecules are polysaccharides polymers composed of many sugar building blocks

    Disaccharides are formed when a dehydration reaction occurs and joins two monosaccharides This covalent bond is called a glycosidic linkage

– – – – – – – – –

are the one class of large biological molecules that do not form polymers
unifying feature of all lipids is that has little or no affinity for water
consists of fats, phospholipids and steroids
Hydrophobic – because they are mostly made up of non-polar covalent bonds
Fats- made up of two types of smaller molecules: glycerol and fatty acids
Glycerol : 3 carbon alcohol with a hydroxyl group attached to each carbon
Fatty Acid- consist of a carboxyl group attached to a carbon skeleton
Fatty Acids vary in length/number of carbons/locations of double and triple bonds Saturated fatty acids have the maximum number of hydrogen atoms possible, has no double bonds Example. Margarine, butter, lard
Unsaturated fatty acids have double bonds throughout the carbon skeleton example. Oils

– Are two fatty acids, a phosphate group that are attached to glycerol, the tails are a

hydrophobic and the head is hydrophilic Steroids

  • –  Are lipids characterized by a carbon skeleton consisting of four fused rings
  • –  Example. Cholesterol important component in animal cell membranes
  • –  Testosterone and estrogen are also steroids


There are many different types and functions for proteins

Enzymes – accelerate reactions Ex. Digestive enzymes

Structural – support Ex. Collagen

Storage – storage of amino acids Ex. Ovalbumn in egg whites

Transport- transportation of other substances Ex. Haemoglobin

Hormonal – coordination of organisms activities Ex. Insulin

Receptor – response of cell to chemical stimuli Ex. Nerve cells

Contractile and Motor – movement Ex. Actin and myosin

Defensive – protection against disease
Ex. Antibodies (combat bacteria and viruses)

Generic Formula for Protein (picture)

Protein Structures

Primary – Amino Acids join with peptide bonds and make a poly peptide. Ex. All proteins Secondary – folding of a polypeptide makes a β pleated sheet or α – helix. Ex keratin has a α- helix, collagen has β pleated sheets.
Tertiary – folds into a 3D structure because of attractions between polar-polar bonds, acid-bases and hydrogen bonds. Ex. Insulin

Quaternary – when two or more tertiary structures join together. Ex. Haemoglobin Factors that affect Proteins

pH – the acidic or basic parts of proteins are attracted to the solution
Salt concentration – ions attract parts of molecules
Temperature – nature of bonds are altered with dramatic temperature changes

 Enzymes
Catalysts speed up the rate of a reaction
lowers the energy required for a chemical reaction to happen; it is not a reactant so therefore remains unchanged at the end of the reaction

Enzymes are biological catalysts that control chemical reactions that take places in the cytoplasm Ex. Catalase

Enzymes are specific proteins which speed p reactions that are not used in the reaction and work best under optimum conditions

Allosteric – shape of enzyme and substrate fit (lock and key) Inhibitors

  • –  Causes a loss of catalytic activity
  • –  Changes the proteins structure
  • –  May be competitive or non-competitive
  • –  Some of these effects are irreversible

    Competitive Inhibitors

– They have similar structures to the substrate and competes with it for the active site, the effect can be reversed with an increase in the substrate concentration

Non-competitive Inhibitors

  • –  Does not have a structure like the substrate but it binds to the enzyme, not necessarily the active site.
  • –  It changes the shape of the enzyme and active site, therefore no reaction occurs
  • –  The effect is irreversible and therefore the substrate cannot fit the altered active site

    which than leaves it inactive.

    DNA/Nucleic Acid
    The amino acid sequence of a polypeptide is programmed by a unit of inheritance called a gene Genes are made of DNA, nucleic acid
    1 gene: 1 protein
    DNA is like a recipe to create proteins and etc.

There are two types of nucleic acids Deoxyribonucleic acid – DNA
Ribonucleic acid – RNA
Nucleic acids are polymers called polynucleotides Which are made of monomers called nucleotides Generic nucleotide (pic)

Each nucleotide consists of a nitrogenous group, pentose sugar and a phosphate group. The portion without a phosphate group is called a nucleoside.
The backbone of DNA is made up by phosphates
Nitrogenous bases

Prymidines – one cycle, Cytosine, thymine and uracil Purines -Double cycles, adenine and guanine
A prymidine always bonds to a purine and vice and versa Hydrogen bonds which keep helix together