HL IB Biology Unit 3 Test Review

Covalent Bond

Electron pairs are SHARED between two atoms

Hydrogen Bond

Interaction between slightly positive Hydrogen and slightly negative other atom

Ionic Bond

Electrons are completely transferred from one atom to another

The 2 most common bonds in Biology

Hydrogen, Covalent

Organic Chemistry

The study of compounds that contain carbon

Valence

The number of covalent bonds an atom can form

4 most common elements of life

Carbon, Hydrogen, Oxygen, and nitrogen

Valence of Carbon

4 valence electrons, 4 valence

Valence of Hydrogen

1 valence electron, 1 valence

Valence of Oxygen

6 valence electrons, 2 valence

Valence of nitrogen

5 valence electrons, 3 valence

Biological Macromolecules

Nucleic acids, carbohydrates, lipids, proteins.

Metabolism

All chemical reactions in the cell.

Monomer

Small building block molecule

Polymer

Large molecules consisting of the same or similar building blocks

Monomer and polymer of Nucleic acid

Monomer: Nucleotide

Polymer: Polynucleotide

Monomer and polymer of Carbohydrate

Monomer: Monosaccharide

Polymer: Polysaccharide

Monomer and polymer of Protein

Monomer: Amino Acids

Polymer: Polypeptide

Monomer and polymer of Lipids

No true monomers or polymers

Carbohydrate

An organic molecule with Carbons, Hydrogens, and Oxygens in the following ratio (CH₂O)_n

Simple sugars

Monosaccharides and disaccharides

Complex carbs

Polysaccharides

Monosaccharides and disaccharides functions

Immediately broken down for energy, and used to build polysaccharides

Polysaccharides functions

Energy storage, and structural material

Number of carbons in Trioses

3 carbons

Number of Carbons in Pentoses

5 carbons

Number of carbons in hexoses

6 carbons

Glucose formula

C₆H₁₂O₆

Glucose functions

Broken down for ATP energy during cell respiration, and building blocks for polysaccharides

Electronegativity

A measure of an atom's ability to attract shared electrons to itself. The strength that the atom pulls the shared electrons.

Polar Covalent Bonds

A bond between two atoms with different electronegativities

Nonpolar Covalent Bonds

A bond between two atoms with similar electronegativities.

3 polysaccharides glucose can build

Starch, glycogen, and Cellulose

Hexose examples

Galactose, fructose

Pentose examples

Ribose, and Deoxyribose

Disaccharide

A molecule that is created when 2 monosaccharides join together during a condensation reaction

Glycosidic linkages

The bond that connects Monosaccharides together

Examples of disaccharides

Sucrose(Glucose + Fructose), Lactose(Glucose + Galactose), and Maltose(Glucose + Glucose)

Starch and Glycogen

The polysaccharides that are used for energy storage

Cellulose and Chitin

The polysaccharides that are used for structural material

Starch

Energy storage polysaccharide found in plants

Glycogen

Energy storage polysaccharide found in animals

Cellulose

Structural material polysaccharide found in cell walls of plants

Chitin

Structural material polysaccharide found in cell walls of fungi.

Glycoprotein

A sugar protein molecule with many functions, such as structural support and cell to cell communication.

Polarity and solubility rule

Polar molecules (like water) dissolve other polar molecules because of hydrogen bonding capabilities. And Nonpolar molecules dissolve other nonpolar molecules.

Lipids

A class of macromolecule that are united because of hydrophobic properties

4 classes of lipids

Triglycerides(fats and oils), phospholipids, steroids, waxes

Fats and oils building blocks

Glycerole molecule, and 1, 2, or 3 fatty acid chains

Tryglyceride

Fat with glycerole molecule and 3 fatty acid chains.

Ester linkage

The bond that fatty acids and glycerole

Fatty acid

Long hydrocarbon chains attached to a carboxyl group (carboxylic acid) - COOH

Saturated Fat

Only contains single bonds in the hydrocarbon chain.

Monounsaturated fat

Contains 1 double bond in the hydrocarbon chain.

Polyunsaturated fat

Contains 2+ double bonds in the hydrocarbon chain.

Cis-Unsaturated fat

The hydrogen atoms attached to the carbon double bond are on the same side - creates a bend in the hydrocarbon chain

Trans-Unsaturated fat

The hydrogen atoms attached to the carbon double bond are on different sides - no bend is created

Function of fats and oils

Long term energy storage, insulation, protection/cushioning of internal organs.

Adipose Tissue

Where fat is stored in animals for regulating body temperature and breaking down for energy.

Where plants store fat.

In seeds, being used to provide energy for photosynthesis.

Phospholipids

The major component of cell membranes in the form of a phospholipid bilayer

Components of a phospholipid

Glycerol, 2 fatty acid tails, and a phosphate head group.

Phospholipid diagram (Be able to draw this)

Phospholipid bilayer

The major structural component of the cell membrane. Where hydrophilic head on either side of the cell(In or out), and the hydrophobic tail is in the middle.

Steroids

A molecule that contains 4 fused hydrocarbon rings. EX: Cholesterol, estrogen, testosterone

Cholesterol functions

Reduces the permeability of the cell membrane by reducing fluidity at higher and lower temperatures. It is also modified into other steroids.

Steroid Hormones

A class of hydrophobic hormone molecules that control a wide range of physiological functions. EX: Testosterone, estrogen.

Waxes

Class of diverse lipids that are generally long hydrocarbon chains, used by plants and animals to make them “water proof”.

Protein

A diverse group of macromolecules with functions such as Enzymes, Hormones, Transport Structure, Movement, Storage, Defense, and Receptors.

4 components of amino acids

Alpha (central) carbon, amino group, carboxyl acid group, side chain/R group

Diagram of amino acids (Be able to draw this)

Amount of different side chains

There are 20 side chains that give amino acids their properties.

Essential amino acids

Amino acids humans cannot make on their own, and must get from food. The best sources being meat and eggs, making vegan/vegetarian diets difficult to maintain.

Non-essential amino acids

Amino acids are made by humans and therefore do not need to be received from another source.

Dipeptide

A molecule composed of 2 amino acids held together by a peptide bond.

Peptide bonds

Bonds that hold together 2 amino acids to make a dipeptide, created during condensation reactions.

Drawing of 2 amino acids coming together to make a dipeptide (Be able to draw this)

Polypeptide

A chain of 3+ amino acids connected together using peptide bonds. They are the polymers of proteins and a protein is consists of 1 or more of these.

Variety of Dipeptides and Polypeptides

There are 20 different amino acids that can be combined in any different way, meaning there are a possible 400 different dipeptides and 20ⁿ amount of polypeptides.

Polypeptide examples

Lysozyme, Glucagon, Myoglobin, and Alpha-nuerotoxins.

Primary Structure

Definition: The sequence of amino acids in the polypeptide chain

Bonds Involved: Peptide Bonds

Secondary Structure

Definition: Local folding of the polypeptide chain into alpha helices and beta pleated sheets

Bonds Involved: Hydrogen bonds between backbone

Tertiary Structure

Definition: Further folding of the polypeptide determined by interactions between the side chains

Bonds Involved: Hydrogen bonds, Ionic bonds, Disulfide bridges, Hydrophobic interactions

Quaternary Structure

Definition: Arrangement and interaction of two or more polypeptide chains to form a functional protein

Bonds Involved: Non covalent bonds and interactions

Conjugated Proteins

Proteins that contain a non-protein component (metal ion or carbohydrate). EX:  Haemoglobin and glycoproteins

Non-Conjugated Proteins

Proteins that consist of only polypeptides. EX: Insulin and Collagen

Globular Proteins

Complex proteins that are usually spherical in shape with irregular folds.

Fibrous Proteins

Long, narrow, simple shape usually composed of repeating structures.

Integral Proteins

Proteins that are embedded in the phospholipid bilayer of a cell membrane

Denaturation

A process where the protein’s structure is changed, therefore changing the function caused by changing the pH or the temperature.

Functions of Catalyst

Speeding up the rate of a chemical reaction without being used up in the process.

Enzyme macromolecule

Protein

Activation energy

The amount of energy it takes to make a reaction begin

Transition State

The point on the reaction coordinate diagram with the highest energy (aka at the top of the activation energy)

Why are enzymes essential?

Most of the reactions in living organisms would not occur without enzymes present.

How do enzymes impact the reaction coordinate diagram?

Enzymes LOWER the activation energy of a reaction

Anabolic pathways controlled by enzymes

Synthesizing polypeptides (catalyzed by ribosomes), Building glycogen (6+ enzymes including glycogen synthase), Photosynthesis in plants building glucose

Catabolic pathways controlled by enzymes

Digestion of starches (salivary amylase), Digestion of lactose (lactase), Cellular respiration - breaking down glucose to produce energy.

Active site

Where the substrate binds to the enzyme.

Induced fit

When the active site and substrate change shapes slightly to more tightly “fit” the substrate into the active site.