Grade 12 Biology Exam

Biology 4U Exam Review

Intro to Biochemistry

Types of bonding:

Ionic
Results from the attraction between two oppositely charged atoms or molecules. They must lose or gain electrons to become charged. For example, a sodium molecule and a chlorine molecule form an ionic bond to create sodium chloride (NaCl)
Covalent
Results from the sharing of one or more pairs of valence electrons to create a stable molecule. For example, the covalent bonding of hydrogen ions creates hydrogen gas (H2) or the covalent bonding between carbon and hydrogen can create variations of a hydrocarbon like methane (CH4)
Hydrogen
The attractive force between a partially positively charged hydrogen atom and a partially negative charged atom (like oxygen or nitrogen) in another molecule. For example, in water molecules, there are many hydrogen bonds that exist which is why water has it's unique qualities like high surface tension (refer to pg. 15 in txtbook if confused)
Hydrophobic

Functional Groups:

Functional Group
Name of Compound
Formula
Hydroxyl
Alcohols
R – OH
Carbonyl
Aldehydes
Keytones
R – C=O (end)
R – C=O (middle)
Carboxyl
Carboxylic acids
R – C=O \ OH
Amino
Amines

Amides
R – N – H \ H

R – C=O \NH2
Sulfhydryl
Thiols
R – SH
Phosphate
Organic phosphates

(double bond between O and P) O
R – O – P – O O
Alkanes
(single carbon bonds)
R – C – C – H
Alkenes
(double carbon bonds)
R – C = C – H
Alkynes
(triple carbon bonds)
R – C = C - H
Ester linkage
(double bond between O and C) O
R – C – O – R
Ether linkage

R – O – R

Biochemical Molecules (Macromolecules)
Carbohydrates
composed mostly of carbon, hydrogen, and oxygen (1:2:1) organic molecule having two or more hydroxyl groups along with a carbonyl group sugars may be aldoses or keytoses (depending on the location of the carbonyl group) monomer: monosaccarides – simple sugars (glucose, fructose, galactose) 5 or 6 sided chain disaccarides – two monosaccarides bonded by a glycosidic linkage (sucrose, maltose, lactose) polysaccarides – a chain of monosaccharides with many subunites joined by glycosidic linkages (starches, cellulose, glycogen) three major functions: 1) important source of energy (quick, body's first source)
2) means by which chemical energy can be stored (short term)
3) serve as structural materials (chitin in insects)
Lipids
non-polar and so therefore insoluble in water five major functions: 1) major component of all cell membranes (phospholipids)
2) long term energy storage
3) insulation
4) cushioning for internal organs
5) making of steroid hormones types of lipids: 1) triglycerides – glycerol and fatty acid chains 2) phospholipids – glycerol, fatty acids, phosphate group 3) waxes – long chains of many carbon atoms and monohydroxy alcohol 4) steroids (cholesterol) – three fused cyclohexane rings, and one cyclopentane ring triglycerides are fat molecules composed of one glycerol and three fatty acid chains can be saturated (completely covered with single bonded hydrogen) eg., animal fats, lard or unsaturated (one or more double bonds of hydrogen to create “kinks”) eg., plant fats, oil
Proteins
contain N, C, H, and O with similar basic structures monomer: made up of long chains of amino acids (20 a.a.) peptide chains: two or more a.a combined at carboxyl end to amino end via dehydration synthesis one end called c-terminus other end called n-terminus

there are a variety of functions (ST. HER CD'S): 1) Structural 4) Enzymes 7) Defensive 2) Transport 5) Regulation 8) Storage 3) Hormones 6) Contractile
There are four levels of protein folding: 1 (primary), 2 (secondary), 3 (tertiary), 4 (quaternary) refer to your notes on page 30 for more detail denaturation: changes of 3D shape caused by disruption in pH environment, temperature, or ionic concentrator
Nucleic Acids
Two types: 1) DNA – deoxyribonucleic acid
2) RNA – ribonucleic acid
* responsible for passing on and storing genetic information and protein synthesis located in the nucleus of a cell (DNA) and in the cytoplasm outside of nucleus (RNA) monomer: nucleotides: 1) phosphate group
2) 5 carbon sugar
3) nitrogenous base
Structures and Functions of Eukaryote Cells

three cell structures and/or organelles that have folded membranes:
Golgi Apparatus
Rough Endoplasmic Reticulum
Smooth Endoplasmic Reticulum
Chloroplasts
Mitochondria the function of these membranes are used for greatly increasing the surface area to optimize the organelle's potential (eg., more space for receptors, and absorption to occur)
Peroxisomes
They are small vesicles found around the cell. They have a single membrane that contains digestive enzymes for breaking down toxic materials in the cell. major function is the breakdown of very long chain fatty acids through beta-oxidation
Endoplasmic Reticulums
Rough – have thousands of ribosomes attached to the outer surface of the ER. The ribosomes create polypeptide chains that are released into the ER to fold and take on their own structure (i.e., tertiary, quaternary)
Smooth – has no ribosomes, so it does not make proteins. Some of the polypeptides that are made in the rough ER end up in the smooth ER as enzymes that assemble lipids or inactivates toxins
Nucleus
contains, and protects almost all DNA in a eukaryotic cell
Also contains other organelles within it:
Nuclear envelope – two lipid bilayer membranes that encloses the nucleus contains different types of membrane proteins like receptors and transporters. Selectively permeable and porous. Connected to the ER
Nucleolus – enclosed by the nuclear envelope. Contains nucleoplasm (similar to cytoplasm) Dense, irregularly shaped region where subunits of ribosomes are assembled from proteins and RNA.
Chromatin – total collection of all DNA molecules and associated proteins in the nucleus
Nuclear pores and nucleoplasm
*