INTRODUCTION TO BIOCHEMISTRY NOTES

CH. 2 - CHEMISTRY OF LIFE

SECTION 2 – WATER AND SOLUTIONS

Water in Living Things
  • 70% of your body is made of water
  • 2/3 of the molecules in your body are water molecules
  • cells are filled with water and surrounded by water
  • water is known as the “universal solvent”
  • Solvent—the substance that dissolves the solute when making a solution
  • Solute—the substance that is being dissolved when making a solution

10 Properties of Water

1.Water is Inorganic—because it does NOT contain Carbon

  1. Water has a set molecular structure—Water, H2O (see diagram from Holt Biology)
  2. A Water molecule is held together by Covalent Bonds
  3. Water molecules are held to each other by Hydrogen Bonds

5.Water is Polar—because of its uneven distribution of charge

oPolar molecules (like water) dissolve polar and ionic molecules (“like dissolves like”)

oNonpolar molecules do not dissolve well in water

oImportant in membrane structure and function

6.Water has a high Specific Heat

Water heats slowly and retains heat longer than many other substances

Important in helping organisms maintain body temperature through evaporation of water, which carries the heat away

7.Cohesion and Adhesion

Water’s polar nature makes it exhibit both cohesion and adhesion

Cohesion – attraction between water molecules (hydrogen bonds)

-causes surface tension

-causes drops of water to form

Adhesion – attraction between a water molecule and another substance

-causes substances to get wet

-causes capillary action

  1. Water’s attraction to itself causes Surface Tension—a condition in which the surface of water will not break or stretch easily because of the attraction
  2. Water exhibits Capillary Action—process where water molecules can move up a tube, such as the xylem inside a plant stem
  3. Water has a Density around 1 g/ml—In general, Solid Water is less dense than Liquid Water

HOT Question—Why does ice float?

Acids and Bases

Acid – compound that forms hydrogen ions in water

Base – compound that forms hydroxide ions in water, or removes hydrogen ions from water

pH—(pondus hydrogenii meaning “potential hydrogen”) a value used to express the acidity or alkalinity of a solution

pH scale – measures the concentration of hydrogen ions in solutions; scale of 0 to 14

-0 to 6.9 is acidic

-7.0 is neutral

-7.1 to 14 is basic or alkaline

-a solution of pH of 3 has 10 times more hydrogen ions than one with a pH of 4

-therefore, an acid with a pH closer to 0 is consider to be “stronger/more acidic” than one of a pH closer to 6.9 because it has a greater concentration of hydrogen ions; likewise a base with a pH closer to 14 is “stronger/more basic” than one closer to 7.1 since it has fewer hydrogen ions and more hydroxide ions when in water

- rain water is slightly acidic

From Holt Biology

Organic Notes (Organic Compounds, aka biochemical molecules)

Objectives:

•Compare organic versus inorganic compounds.

•Describe the unique properties of carbon including formation of 4 covalent bonds, polymerization, carbon chains, and introduce carbon cycle. (IPC TEKS 7D)

•Describe the basic structure and function of proteins, fats, carbohydrates, and nucleic acids.

• Identify and describe the 4 types of biochemical molecules (carbohydrates, proteins, lipids, and nucleic acids) and their functions in biological systems—CHO focus on glucose polymers including chitin, starch, cellulose, glycogen; Proteins intro enzymes and give common examples including hemoglobin, antibodies, collagen, muscle fibers, hair, nails, and cell fibers actin and myosin; Nucleic acids focus on DNA structure and intro replication; Lipids intro membranes as transition to next unit on Cell structure and transport. (TEK 9A)

Biochemistry (Organic)

  • ALL LIVING THINGS ARE COMPOSED OF THE FOLLOWING BASIC ELEMENTS: aka “CHNOPS“

______

  • A MOLECULE CONTAINING CARBON ISCALLED AN ______MOLECULE (except CO, CO2)

Unique Properties of Carbon

  • Forms 4 covalent bonds (because it has 4 valence electrons it shares with another bonding atom)
  • Polymerization--the process by which a polymer is formed by linking monomers together through dehydration synthesis.
  • Carbon chains are formed
  • Carbon Cycle

Carbon Cycle

  • Plants create glucose (a carbon compound) during photosynthesis and give off oxygen.
  • O2 is used to oxidize organic molecules in respiration, C02 is a byproduct that is returned to the atmosphere
  • Marine organisms use CO2 to make CaCO3 shells, then die and turn into limestone that erodes and enters back into the cycle or then fossil fuels are formed, produced, then burned and returned to the atmosphere through combustion.

THERE ARE 4 BASIC CARBON COMPOUNDS IN ALL LIVING THINGS:

(aka Biochemical molecules or Organic Molecules/Compounds)

1. ______2. ______3. ______4. ______

1. Carbohydrates

Include: sugars, starches, & cellulose

  • PROVIDES ENERGY FOR ORGANISMS
  • 4 Calories/gram
  • CHO in 1:2:1 ratio
  • 3 Types: 1. Monosaccharides2. Disaccharides3. Polysaccharides
  • Monomer/subunit = monosaccharide
  • Most end in –ose

Examples of Carbohydrate Types

  • Monosaccharides (single sugars)
  • glucose, fructose, galactose
  • Disaccharides (double sugars)
  • sucrose (table sugar) = 1 glucose + 1 fructose
  • maltose (malt sugar) = 1 glucose + 1 glucose
  • lactose (milk sugar) = 1 glucose + 1 galactose
  • Polysaccharides (many sugars) Ex. Starch, Glycogen, Cellulose

Glucose is a Monosaccharide

  • Glucose: ______
  • Main product of photosynthesis
  • Starting material for cellular respiration—must be converted into the form our cells use (“ATP”)
  • Basic form of “fuel” in living things
  • Soluble and transported by body fluids to all cells, where is it METABOLIZED to release energy.

Polysaccharides: complex carbs

  • Formed by linking many monosaccharides
  • Starches: hundreds of glucose units linked together, found in cells of PLANTS
  • Storage for carbohydrates in PLANTS
  • Glycogen: stored in liver/muscles in ANIMALS (including humans!)
  • Thousands of glucose units linked differently than starches in ANIMALS
  • Cellulose: structural carbohydrate, found in cell walls of PLANTS
  • Glucose units, but cannot be released from one another except in a few species of organisms ***Humans CANNOT digest cellulose!***
  • Wood ; Cell walls of plants

2. Lipids

Include: fats, oils, waxes, phospholipids, steroids, chlororphyll; made of CHO

  • CARBOHYDRATES MAY BE CONVERTED INTO LIPIDSFOR LONG-TERM ENERGY STORAGE.
  • Monomer/subunit: 1 glycerol + 3 fatty acids “Fat E”
  • 9 Calories/gram
  • FATS–act as insulators
  • WAXES-help plants conserve water
  • OILS–make some birds’ feathers waterproof
  • PHOSPHOLIPIDS – main component of cell membrane
  • nonpolar molecules so they are not soluble in water
  • Saturated fats—NOdouble bonds between Carbons, Ex. animal fats; solids at room temp
  • Unsaturated fats—somedouble bonded Carbons, Ex. Plant fats & oils; liquids at room temp

3. Proteins

  • Include: meat, fish, nuts; provide 4 Cal/gram
  • Most complex organic molecule, made of CHON (some also contain S, P, Fe, or Cu)
  • Composed of smaller subunits called amino acids (AAs)
  • There are 20 AAs. Each has amine group NH2, carboxyl group --COOH, & radical group --R
  • Make up more than half the dry weight of organisms
  • Formed by dehydration synthesis--amino acids form a protein by removal of water; links called peptide bonds (between the AAs) and small proteins are peptides, large are polypeptides
  • Protein Functions
  • enzymes that promote chemical reactions
  • structural functions like collagen in skin, muscle (actin & myosin), ligaments, tendons & bones
  • proteins found in muscles and hair
  • antibodies (immune system) are also proteins
  • hemoglobin is a protein that carries oxygen in blood

4. Nucleic Acids

  • large complex molecules containing genetic material
  • Made of nucleotides (sugar, phosphate group, and nitrogen base)
  • 1. DEOXYRIBONUCLEIC ACID -DNA2. RIBONUCLEIC ACID - RNA

(deoxyribose sugar)(ribose sugar)

  • D N A carries instructions that regulate cells activities
  • R N A –uses information from DNA to tell the ribosomes what proteins to make.

ATP = adenosine triphosphate is another important biomolecule.

  • ATP is the energy source used by cells for them to function.
  • Food molecules are broken down and the energy is stored temporarily in ATP until it is needed by the cell.