Unit 1: Chemistry of Life

What is a hydrogen bond?

A weak bond between a hydrogen atom of one molecule and an electronegative atom (like oxygen) of another

Polar molecule

unequal sharing of electrons, dissolve in water and other polar substances (water)

Nonpolar molecule

equal sharing of electrons, cannot dissolve in water but can in other nonpolar substances (oils, fats)

Property of carbohydrates (elements, monomer, common types, primary function, bond)

Elements: Carbon, Hydrogen, Oxygen

Monomer: Monsaccharides

Common types: monosaccharides (glucose, fructosem, galactose), disaccharides (Lactose), polysaccharides (starch, glycogen, chitin)

Primary function: Short term energy storage and structural support

Bond: Glycosidic linkage

starch vs glycogen

starch: energy storage in plants

Glycogen: energy storage in animals

Both are carbohydrates polyssacharides

-ose

sugar

Properties of Lipids (elements, monomer, common types, primary functions, bond)

Elements: Carbon, hydrogen, oxygen

Monomer: no true monomer

Common types: Fats, Oils, phospholipids, steroids

Primary function: Long-term energy storage, insulation, making cell membranes (phopholipids), and signaling (steroid hormones)

Bond: ester linkage

Glycerol and fatty acids are the "building blocks" of many lipids

Unsaturated vs saturated lipids (fats)

saturated fats: no double bonds and solid at room temperature

Unsaturated fats: one or more double bonds and liquid at room temperature

Properties of Proteins (elements, monomer, primary functions, bond)

Elements: Carbon, Hydrogen, Oxygen, Nitrogen (sometimes sulfur)

Monomer: amino acids

Primary function: enzymes catalyze reactions, structure (muslce, skin), transport (hemoglobin), communication (hormones), defense (antibodies)

Bond: peptide bonds

What determines the function of a protein?

Its 3D structure (tertiary structure)

Properties of nucleic acids (elements, monomer, common types, primary functions, bond)

Elements: Carbon, hydrogen, oxygen, nitrogen, phosphorous

Monomer: nucleotides

Common types: DNA, RNA

Primary function: store and transmit genetic information

Bond: phosphodiester bonds (also hydrogen bonds between A-T G-C pairing)

4 structures of proteins

Primary structure: sequence of amino acids

Secondary structure: alpha helices and beta sheets (due to hydrogen bonding)

Tertiary Structure: 3D folding (interactions between r group side chains)

Quaternary Structure: multiple polypeptides combines to form a functional protein compelx

Note: many proteins are fully cuntional after reaching its tertiary structure. Quaternary structures are only needed for proteins made of more than one polypeptide

Function of Enzymes

Speed up chemical reactions by lowering activation energy required for a reaction to occur

Enzymes are very specific!

Structure of Enzymes

Enzymes are mainly proteins

Active site: Region where the substarte binds. Then site is specifically shaped to fit the substrate

• Tertiary structure is crucial for proper functioning of the active site

Enzymes sometimes need a little “helper” to help ctalyze reaction so the enzyme may function properly

• Cofactors: (usually inorganic - like metals)

• Coenzymes (organic - like vitamins)

Inorganic vs organic molecules

Ogranic: Carbon + Hydrogen bonded together

Inorganic: No carbon-hydrogen bond

Effects of environment on Enzymes (Temperature, pH, substrate concentration)

Environment:

• Low temp: enzymes move slower → slower reactions

• High temp: enzymes may denature → lose their shape and stgop functioning

pH

• Enzymes have an optimal pH at which they work best

• too low or too high → denature

Substrate concentration

• increasing substrate concentration → increase rate of reaction (only up to the saturation point where the rate plateaus)

Inhibition of Enzymes

Competitive Inhibition

• compete with the substrate to bind to the active site

• typically has a simiar shape to the substrate

Noncompetetive inhibition

• inhibitors bind to the allosteric site causing a change in the enzymes shape and making the active site less effective

• does not directly compete with the substrate

Allosteric regulation

• Allosteric activators: activator molecule binds to the allosteric site causing a change in the enzymes shape making the active site more accessible for substrate binding, increasing enzyme activity

• Allosteirc inhibitors: inhibitor molecule binds to allosteric site, changes the enzyme shape, and makes the active site less effective at binding the substrate decreasing enzyme activity

• Feedback inhibition: the final product of the pathway acts as an inhibitor to the first enzyme in the pathway, preventing it from producing more product.

  • Negative Feedback Loop: Feedback inhibition prevents the overproduction of a substance by slowing down or stopping its own synthesis when it is no longer needed. It’s an important regulatory mechanism for maintaining homeostasis within cells.

dehydration synthesis

joining two monomers by removing a water molecule

hydrolysis

adding a water molecule to break a bond between monomers

Structure of DNA (shape, sugar, nitrogenous bases, backbone, function)

Double helix

Sugar: Deoxyribose

Nitrogenous bases: Adenine - Thymine (2 hydrogen bonds), Cytosine - Guanine (3 hydrogen bonds)

Backbone: altering sugar and phosphate groups

Function: Stores genetic information (instructions for making proteins)

Structure of rna (shape, sugar, nitrogenous bases, backbone, function)

Single-stranded

Sugar: ribose (one more oxygen than deoxyribose)

Nitrogenous bases: Adenine - Uracil (2 hydrogen bonds), Cytosine - Guanine (3 hydrogen bonds)

Backbone: Sugar-phosphate like DNA

Function: Helps make proteins based on DNA instructions

Elements of life (CHNOPS)

C - central to all oragnic molecules, can form 4 stable bonds, macromolecules

H - hydrogen bonds, water

N - found amino and nucleic acids (DNA, RNA), important in enzymes

O - Crucial for respiration and energy production, found in water

P - phosphate groups in nucleotides (DNA, RNA, ATP), part of energy transfer and storage

S - found in certain amino acids, build disulfide bridges and stablize protein sturcture

These 6 elements are the basic building blocks of life

hemoglobin

protein found in red blood cells that is responsible for carrying oxygen from the lungs to the tissues and organs throughout the body and returning carbon dioxide from the tissues back to the lungs to be exhaled.