Chemistry of Life

Individual elements combine to form __________

compounds

What is an atom composed of (4)

electrons, neutrons, protons, nucleus

How do you read the elements

element name on top, atomic number under (is also equal to the number of protons. will always be the smaller number), element symbol in the middle, atomic mass on the bottom (atomic weight = number of protons + neutrons)

Isotopes

variations of an element (same number of protons, however different number of neutrons). less stable, decay over time, emit radiation

What is the max number of electrons in the first energy level

2

What is the max number of electrons in the second energy level and above

8 (octet rule)

The number of valence electrons determines what

the chemical properties of the element

Ions

atoms that gain or lose electrons and thus become charged

atoms that donate electrons

cation (positive)

atoms that accept electrons

anion (negative)

What are the four types of chemical bonds or interactions

ionic bonds, covalent bonds, hydrogen bonds, van der Waals interactions

Ionic bonds

Transfer of electrons from one atom to another

Ionic bonds are held together by what

an attraction of opposite charges

Covalent bonds

sharing of electrons between atoms. the strongest and most common chemical bonds

What are the two types of covalent bonds

polar (equal sharing of electrons), non polar (unequal sharing of electrons)

Hydrogen bonds

a weak attraction between hydrogen atoms and small, strongly electronegative atoms

van der Walls interactions

weak interactions caused by partial charges formed when electrons move around a nucleus

What are the 4 properties of water

polarity, strong resistance to changes in temperature, is an effective solvent, has cohesive and adhesive properties

Water is a

polar covalent molecule

The negatively charged oxygen in water faces what

a positively charged hydrogen

The partial charges in water result in what

hydrogen bonding between water molecules

Hydrophilic substances do what in water

interact with and dissolve

Hydrophobic substances do what in water

do not interact with and dissolve in water

Hydrophilic: polar or non polar

polar

Hydrophobic: polar or non polar

non polar

Evaporative cooling

since sweat is mostly water, the evaporating water absorbs excess body heat, which is released into the atmosphere

Solvent

a dissolving agent

Solute

substance being dissolved

Solution

mixture of the solvent and the dissolved solute

Water can ____________________________________

dissolve many polar and ionic substances

Cohesion

the tendency of molecules to stick together

Surface tension

capacity of a substance to withstand rupture when places under tension or stress

Adhesion

the attractions of water molecules to other substances like glass, cotton, plant tissue, soils, etc. allows water to travel against gravity

Aqueous solution

a solution that contains a substance dissolved in water

Some water molecules break apart into what two things in an aqueous solution

hydrogen ions and hydroxide ions

What determines the pH in an aqueous solution

the concentration of hydrogen ions (more = low pH, less = high pH)

pH

a measure of the acidity of a solution

Buffers

chemicals that minimize changes in pH by accepting hydrogen ions

Why is carbon a "foundation" element

it can form up to 4 bonds with other elements creating many shapes, chains, and carbon skeletons

What are macromolecules

large, complex molecules that we called polymers

Polymers are made of what

many small repeating molecules called monomers (a protein is a polymer of amino acid monomers

Monomers join by what and can be broken down by what

dehydration synthesis, and hydrolysis reactions

Hydrolysis Reactions

breaking down a polymer. hydrolysis adds a water molecule, breaking a bond

Dehydration Synthesis Reaction

synthesizing a polymer. dehydration removes a water molecule, forming a new bond

What do carbohydrates consist of

subunits (building blocks) called monosaccharides

Carbohydrates

common source of energy and cellular structure for living organisms

What are carbohydrates classified into (3 major groups)

monosaccharides, disaccharides, polysaccharides

Monosaccharides

simple sugars. building blocks for large, complex carbohydrates. quick source of energy

What are 3 examples of monosaccharides

glucose, deoxyribose, fructose

Disaccharides

two monosaccharides joined together by covalent bonding (glycosidic bond) via dehydration synthesis

What are two examples of disaccharides

sucrose, lactose

Polysaccharides

consists of tens or hundreds of monosaccharides joined through dehydration synthesis. provide long-term energy source and structural component for plant cell walls

What are 3 examples of polysaccharides

starch, cellulose, glycogen

All lipids are ___________________

non-polar molecules (hydrophobic)

Lipids

consists of monomers called triglycerides

5 main functions of lipids

energy storage, insulation, cushioning, membrane function, hormone regulation

3 classes of lipids

fats (simple lipids), phospholipids (complex lipids), steroids

Fats: Simple Lipids

aka triglycerides. composed of 1 glycerol and 3 fatty acid chains (that are composed of carbon and hydrogen)

Components of fats are linked together by a covalent bond called what via dehydration synthesis

ester bonds

What are the 2 basic varieties of dietary fats

saturated fats and unsaturated fats (trans fats and omega-3 fats)

Saturated Fatty Acids

no double bonds in the fatty acids (only have single bonds). single bonds allow for more hydrogens which results in a more compact and "straight" structure. tend to be solids at room temperature. higher amounts in animal products. less healthy

Unsaturated Fatty Acids

one or more double bonds in the fatty acids. the double bonds remove hydrogens and make "kinks" or bending in shape. tend to be liquids at room temperature (oils). higher amounts in plant products. more healthy. can be solid by hydrogenation processes

hydrogenation produces what

trans fats, a type of unsaturated fat that contains an unusual bond

Trans Fats

very unhealthy and is a major contributor to heart disease. increase bad cholesterol, reduce good cholesterol

Essential Fatty Acids

required but not synthesized by the human body. must be obtained by dietary sources (omega 3's and omega 6-F.A). fats containing omega-3 fatty acids are known to reduce the risk of heart disease

Phospholipids

make up cell membranes and are complex lipids. form the phospholipid bilayer of the cell and regulate transport (controls what enters and leaves the cell and leads to homeostasis)

What does the phospholipid structure of saturated fatty acids look like compared to unsaturated fatty acids

saturated = closely packed

unsaturated = loosely packed

Steroids

type of lipid composed of four fused hydrocarbon rings. used as a precursor to other molecules (hormones, testosterone, and estradiol). used as a structural component of the cell membranes of eukaryotic cells

Cholesterol

a sterol found in animal cell membranes

Phytosterol

a sterol found in plant cell membranes

Ergosterol

a sterol found in fungi cell membranes

Types of Cholesterol

LDL = low-density lipoprotein (bad cholesterol)

HDL = high-density lipoprotein (good cholesterol)

Proteins

the most diverse and abundant macromolecule. are essential in cell structure and many cell functions. are made of amino acid monomers

What are some of the many cell functions of protein (6)

structural proteins, transporter proteins, movement, enzymes, antibodies, bacterial toxins

How many total amino acids are there

20

Amino acids are linked together by a covalent bond called what via dehydration synthesis

peptide bond

Protein structure determines what

the protein function

If protein loses/changes its structure (denaturation and mutations), what happens

it loses/changes its function

Denaturation

high temps, pH

What are the 4 levels of protein structure

primary structure (a sequence of amino acids in a polypeptide chain), secondary structure (hydrogen bonding of the amino acid chain. primary structure folds and coils in a helix or pleated sheet), tertiary structure (the 3D folding of the alpha helix or beta pleated due to side chain interactions. folding formed by disulfidge bridges, hydrogen bonds, and ionic bonds between amino acids in the chain), quaternary structure (consists of two or more polypeptide chains bound to each other

Nucleic acids

DNA and RNA

DNA

genetic material found in all living organisms

RNA

used for protein synthesis

DNA and RNA both consists of what

nucleotide monomers linked together by a covalent bond called phosphodiester bonds via dehydration synthesis

Nucleotides consist of what 3 things

sugar (5-carbon pentose sugar), phosphate group, base (nitrogen-containing base from either the purine or pyrimidine family)

What are the two purine bases

Adenine and Guanine

What are the three pyrimidine bases

Cytosine, uracil, thymine

What are the differences between DNA and RNA

DNA is a double stranded molecule, has A-T and C-G base pairing through hydrogen bonds, and stores genetic information. RNA is single stranded, has no base pairings, there are 3 kinds (mRNA, tRNA, and rRNA), and is for protein synthesis. however, both have a sugar-phosphate backbone

What is the Biuret test for

detecting proteins in a substance

In the biuret test, you are shown two test tubes. Which indicates a positive ?

If the color changes from blue to purple

What is the Benedict's test used for ?

To learn if a solution has sugar

In the Benedict's test you are shown two test tubes. which indicates a positive for reduced sugar ?

A color change from blue to green, yellow, orange, or brick-red

What are the 4 major macromolecules

Carbohydrates, lipids, proteins, nucleic acids

What does the Sudan test test for ?

lipids

Monomers create a larger subunit which is ?

the polymer

The monomer for proteins is ?

amino acids