Biological Molecules Test AP Bio 12

Why is water vital for life?

Why is water vital for life?

• High heat absorption (allows for large bodies of water to maintain constant temperature)

• Freezes from the top-down (protects organisms living in ponds and lakes)

• Acts as a solvent —> dissolves other polar molecules

• Cohesion/Adhesion of water —> fills tubular vessels (relates to capillary action)

Cohesion

Property of water that refers to water molecules sticking to other water molecules (Hydrogen Bond)

Adhesion

Property of water that refers to water molecules sticking to different surfaces (water and plant cell walls)

Capillary Action

Ability of a liquid to flow in a narrow space against the force of gravity due to cohesion, adhesion, and surface tension

Surface Tension

Measure of how hard it is to break the surface of a liquid

Water’s resistance to temperature change

Water resists changing it’s temperature due to high specific heat

High Specific Heat

Amount of heat absorbed or lost for 1g of substance to change temperature by 1°C

Evaporative Cooling

As a liquid evaporates, it’s remaining surface cools (helps stabilize temperatures in organisms and bodies of water)

What allows ice to float on water?

Hydrogen bonds in ice are more “ordered”, making ice less dense

Solution

Liquid that is a homogenous mixture of substances

Solvent

Dissolving agent of a solution

Solute

Substance that is being dissolved

How does water dissolve ionic compounds?

In water, ions are surrounded by a sphere of water molecules called a hydration shell

Hydrophillic

Has an affinity for water

Hydrophobic

Does not have an affinity for water

Oxidation Reaction

Loses elections

Reduction Reaction

Gains electrons

When acids dissociate

Hydrogen ions are released (H+)

When bases dissociate

Hydroxide ions are released (OH-)

pH (potential hydrogen)

• Measures the acidity or basicity of a solution

• Increasing OH- ions will raise pH (more basic)

• Increasing H+ ions will lower pH (more acidic)

Buffers

Chemical combinations that take up excess H+ or OH- ions in order to keep the pH of a solution constant (helps maintain pH and homeostasis in living things)

Monosaccharides

Simple sugars (ex. glucose, fructose, galactose)

Disaccharides

Double sugars

Dehydration Synthesis

The synthesis of two molecules with the removal of water

Types of Disaccharides

• Sucrose = glucose + fructose

• Lactose = glucose + galactose

• Maltose = glucose + glucose

Hydrolysis

The process of adding water to break apart any molecule

Polysaccharides

Complex sugars

Types of Polysaccharides

• Starch —> Somewhat branched form

• Glycogen (animal starch) —> Branched form

• Cellulose (“fibre”) —> Straight form

Carboxyl Group

Saturated Fatty Acid

• Have a maximum number of hydrogens

• NO double bonds between carbons

Unsaturated Fatty Acids

• Do NOT have the maximum number of hydrogens

• DO have double bonds between carbons

Characteristics of Phospholipids

• 2 fatty acid chains + 1 phosphate group

• Polar end (from phosphate group)

• Non-polar end (from fatty acid chain)

• Can dissolve in water because they are polar

Characteristics of Cholesterol

• An example of a sterol molecule

• NOT soluble in water

• Contains C, H, and O arranged in rings

• Precursor to sex hormones (ex. estrogen and testosterone)

Protein Basics

• Contain C, H, O, and N

• Make up structural parts and functions (ex, ligaments, connective tissues, hair, muscle, bones, etc)

• Enzymes —> help catalyze reactions in your body

• Hormones —> along with lipids

Amino Acid

Contains…

• An amine group (NH2)

• An organic acid group (carboxyl)

• An “R” group (the rest of the amino acid)

Dehydration Synthesis between Amino Acids (Peptide Bond)

You need 50-100 amino acids joined together with peptide bonds to form a protein

• During Dehydration Synthesis, water is removed and peptide bonds form between amino acids

Primary Structure

Getting the right order of amino acids —> Peptide bond

Secondary Structure

Becomes a spiral —> Hydrogen bonds holds a spiral shape

Tertiary Structure

Becomes a “blob” shape (3D shape) —> Ionic bonds hold 3D shape

Quaternary Structure

Interactions (bonding) between 2 or more tertiary structures

Nucleic Acids

• DNA (Deoxyribonucleic Acid)

• RNA (Ribonucleic Acid)

• ATP and ADP (Adenosine Triphosphate)

Nucleotides

• Building block of all nucleic acids

• Phosphate + Sugar + Base

Types of Nitrogenous Bases

DNA:

• Adenine

• Thymine

• Guanine

• Cytosine

RNA:

• Adenine

• Uracil

• Guanine

• Cytosine

DNA

Structure: double-stranded, spiral shape

• general nucleic acid has the sugar-phosphate backbone + nitrogenous bases projecting to the side

RNA

Structure: single-stranded and shorter than DNA

3 kinds of RNA:

• mRNA (messenger)

• tRNA (transfer)

• rRNA (ribosomal)

ATP

• Excellent place to store energy

• ATP is energy currency of cells

• Produced from energy released by “burning: food

• Used for large number of energy demanding reactions

What are the protein structures?

• Primary (chain)

• Secondary (spiral)

• Tertiary (“blob'“)

• Quaternary (2 or more tertiary structures bonded)

Maltose

Glucose + Glucose

Sucrose

Glucose + Fructose

Lactose

Glucose + Galactose

Saponification

Soap is formed by reacting a fat + an inorganic base (usually NaOH, “lye”)

Lipids

Energy-rich organic compounds such as fats, oils, and waxes (made from carbon, hydrogen, and oxygen)

• Function in energy storage, cell membranes, insulation

3 Major Groups of Lipids

Fats, Steroids, Phospholipids

Glycerol

A three-carbon alcohol to which fatty acids are covalently bonded to make fats and oils

Triglyceride

A lipid made of three fatty acid molecules and one glycerol molecule

Emulsification

To mix together two things that don't like each other, like oil and water

Important uses of lipids in the body

• Insulation and protection

• Long term energy storage

• Structure of cell membrane

• Basis of hormones (ex. sex hormones)

What causes a protein to become denatured?

• Extreme high temperatures

• Non-optimum pH

• Addition of heavy metals (Pb, Hg)

ADP

• “Low energy” form of ATP

• Releases free energy —> useful in energetically favorable reactions

Hydration Shell

Water molecules that surround an ion during dissociation (dissolving ionic compounds)

Starch Structure

Somewhat branched structure

Cellulose Structure

Straight and rigid structure

Glycogen

Highly branched structure

What are the 4 macromolecules?

Carbohydrates, Lipids/Fats, Proteins, Nucleic Acids

Identify this molecule

Saturated fatty acid

Identity this molecule

Cholesterol

Identify this molecule

Lipid

Identify this molecule

Amino Acid

Identify this molecule

Nitrogenous Base

Identify this molecule

Nucleotide