AP Bio Unit 1 Study Guide

Water

  • non living thing that all living things depend on

  • polar substance

    • one side (hydrogen atom) is positively charged, the other side (oxygen) is negatively charged

    • allows for water to form hydrogen bonds

      • hydrogen bond: a weak bond between the negative and positive regions of 2 separate molecules

water molecules hydrogen bonding

Properties of Water

  • cohesive/adhesive behavior

    • cohesion: when 2 of the same molecules form hydrogen bonds

    • adhesion: when 2 different molecules form hydrogen bonds

  • moderate temperature

    • has a high specific heat capacity

      • due to waters cohesive properties

      • absorbs thermal energy & resists changes in temp.

    • heat is absorbed when hydrogen bonds break

    • heat is released when hydrogen bonds form

    • allows life to thrive by keeping areas near water cool in the summer and warm in the winter

      • areas remote from water are not able to regulate temp.

  • universal solvent

    • due to it’s hydrogen bonds/polarity it is a good solvent in the liquid state

    • when dissolving an ionic compound each ion is surrounded by a sphere of water molecules

      • hydration shell

    • large molecules can be dissolved in water if they have ionic and polar regions

  • surface tension

    • measure of how difficult it is to break the surface of a liquid

    • has a high surface tension

      • due to hydrogen bond forces between water molecules

      • caused by cohesion

  • ice floats

    • ice is a solid = hydrogen bonds are more packed/ordered

      • ice is less dense than water

      • causes it to float

Dehydration vs. Hydrolysis Synthesis

  • dehydration synthesis: water is produced from OH & H —> creates a bond between monomers (creates covalent bonds)

    • the covalent bond caused by dehydration synthesis in carbs is called glycosidic linkage

    • the covalent bond caused by dehydration synthesis in lipids is called ester linkage

    • the covalent bond caused by dehydration synthesis in polypeptides is called peptide bonds

  • hydrolysis synthesis: adds water which separates polymers into monomers (breaks bonds)

Macromolecules

  • comprised of 6 main elements: hydrogen, oxygen, carbon, nitrogen, sulfur, and phosphorus

  • sulfur

    • primarily found in proteins

  • phosphorus

    • found in nucleic acids and phospholipids

  • 4 main types: proteins, polypeptides, nucleic acids, lipids, and carbohydrates

Carbohydrates

  • base building blocks for sugar

  • simplest carbohydrates are monosaccharides (simple sugars)

  • macromolecules of carbs are polysaccharides

  • examples are glucose, starch, cellulose, glycogen

  •   serve as fuel and building material

    Starch

  • form of storage

    • storage of polysaccharide in plants

    • contains glucose monomers

  • simplest form is amylose

  • plants store surplus starch as granules within chloroplasts

    Glycogen

  • storage polysaccharide found in animals

  • mainly stored in liver and muscle cells

    Cellulose

  • a polysaccharide

  • major component of plant walls

  • a polymer of glucose

    • different glycosidic linkages than starch

Lipids

  • diverse group of hydrophobic molecules

  • do not include true polymers

  • commonly fats, phospholipids, and steroids

  • store energy, make up cell membranes

    Saturated Fats

  • max. number of hydrogen bonds and no double bonds

  • typically animal fats

  • solid at room temperature

    Unsaturated Fats

  • have one or more double bonds

  • liquid at room temperature

  • typically plant and fish fats

Polypeptides

  • unbranched polymers built from amino acids

    • 20 different types of amino acids build up proteins

    • bonds between amino acids are called peptide bonds (covalent bonds)

  • proteins are functional molecules comprised of polypeptides

  • unique linear sequence of amino acids

    • with carboxyl (c-terminus) end and amino terminus (n-terminus)

    Amino Acids

  • organic molecules with amino (NH2) and carboxyl (COOH) groups

  • differ in properties depending on their side chains

    • R groups

    • amino acids differ depending on their R groups

Proteins

    Changes to Functions

  • physical and chemical conditions can affect the structure

    • changes in pH, temp., salt concentration

      • protein can unravel

  • loss of protein’s natural structure = denaturation

    • protein is biologically inactive

    • cannot perform function

    Primary Structure

  • dependent on genetic information;

   Secondary Structure

  • found in most proteins; consists of coils & folds in polypeptide chain

    • does not include R groups

    • all within the polypeptide backbone

   Tertiary Structure

  • overall shape of the protein is formed

    • determined by interactions of the different R groups

    Quaternary Structure

  • when 2+ polypeptide chains form a single macromolecule

Nucleic Acids

  • store, transit, and transport hereditary information

  • 2 different types: deoxyribunucleic acid & ribonucleic acid

    DNA (Deoxyribunucleic acid)

  • DNA has 4 nucleotides: Adenine, Guanine, Thymine, Cytosine

    • bonds between matching pairs form hydrogen bonds

    • nitrogenous bases

      • complementary base pairing (A—> T, G—> C)

  • two polynucleotides that form a double helix (always)

    • phosphate backbones that run from 5’ —> 3’

      • anti-parallel

  • one molecule holds many genes

    RNA (Ribonucleic acid)

  • single stranded

  • complementary base pairing can occur from two different RNA molecules or the same RNA molecule

  • no thymine —> replaced by uracil

    • A and U pair

      • nitrogenous bases

  • RNA molecules are more variable in form