Unit 1: Chemistry of Life

AP BIO

What are the four elements + trace elements?

• Elements are substances that cannot be broken down into simpler ones by chemical means

• O, C, H, and N make up biological molecules like carbs, proteins, lipids, and nucleic acids + to form storage compounds and cells

• Trace elements are required by an organism in small quantities like Iron Fe, Iodine I, and Copper Cu

What are subatomic particles + atoms?

• Atoms are the unit of life and building blocks of physical world

• Protons +

• Electrons -

• Neutrons uncharged

Some atoms have the same number of protons but different neutrons called isotopes

What are compounds?

• Compounds are two or more elements that are held together by chemical bonds like ionic, covalent or hydrogen bonds

What are ionic and covalent bonds?

• Ionic bonds are formed between atoms that have one or more electrons transferred. They become charged and are called ions

• Covalent bonds are formed between shared electrons. When electrons are equally shared, the bond is nonpolar but when electrons are unequal, the bond is polar.

How is water a versatile molecule?

• Polar covalent bonds between O and H IN h20 molecule. Hydrogen bonds between O and H BETWEEN h20 molecules

• Universal solvent

  • partial negative O binds with other polar molecules that have partial positive and pos charge ions called cations

  • partial pos of h binds with other partial neg end molecules and neg charged ions called anions

• Less dense when solid meaning h bonds inhibit compaction so ice floats and is a temperature buffer for coastal regions and body temp

• High specific heat where water must absorb or release a large amt of energy to change 1 gram of water by 1*c

• Evaporative Cooling is when the surface water of organism absorbs heat energy from body and is released to keep cool

• Hydrogen bonds are weak chemical bonds that form when a H atom is bonded covalently and contribute to its properties

• Cohesive forces are the tendency of water to stick together. Adhesive is when water molecules stick to other substances

• Capillary action is when cohesion and adhesion together allow water to rise up roots, trunks, and branches

• Surface tension is when water molecules at the surface are stuck together bc of cohesion allowing light, debris, and bugs to sit on top without sinking

What are acids and bases?

• A acidic solution has more H+ ions than OH- (hydroxide). If acid dissolves in water, it will release H+

• Bases have more OH- than H+, releasing them more when in water

How do you read pH scales?

• Acidity or alkalinity of a solution is measured with a pH scale.

• the concentration of H+ indicate if its basic, acidic, or neutral

• More H+ = acidic, less H+ = basic

• The equation to calculate pH is -log[H+]

What are organic molecules (CARBON)?

• Molecules with CARBON are organic and molecules with NO CARBON are inorganic compounds

• Carbon is important for life because its versatile meaning it can bind with other carbons and other elements like HON

What are polymers and monomers?

• Polymers are chains of building blocks in macromolecules. They are formed through DH/condensation causing a loss in a water molecule

• Monomers are the building blocks of polymers

• Hydrolysis is when polymers are broken down into monomers causing a gain in a water molecule that breaks the bond between two monomers

What are carbohydrates?

• Contains C, H, O (cho chang) in a 1:2:1 ratio

• monosaccharides, disaccharides, polysaccharides meaning sugar

What are monosaccharides?

• An energy source for cells

• glucose and fructose (C6H12O6) most common. Can be straight or like rings with OHs and Hs attached

• Glucose in food we eat and a product of photosynthesis

What are disaccharides?

• when two monosaccharides are joined, the bond is called a glycosidic linkage forming a disaccharide

• Two glucose molecules = maltose

• To break it up, add water

What are polysaccharides?

• repeating units of monosaccharides that are branched or unbranched

• Glycogen and starch are sugar storage molecules where glucose is in animals and starch is in plants

• cellulose is made up of β-glucose and major part of plant cell wall allowing structural support

• Chitin is a polymer of β-glucose and is a structural molecule for the walls of fungi and exoskeletons of arthropods.

What are proteins?

• Amino acids make up proteins containing HONC (honk honk) that create 20 diff amino acids

• The four parts of an AA surrounds the central carbon. An amino group (-NH2), a carboxyl group (-COOH), a hydrogen, and R-group

• The r-group is the only one that differs also called a side chain.

  • If its non-polar and uncharged = hydrophobic AA.

  • If its polar and uncharged = hydrophilic AA.

  • If its polar and charged = ionic AA

How do you split an Amino Acid?

Look for amino group and then carboxyl group

remember nh2 then cooh (never hit two coochies (cats))

What are some Amino acids to remember?

• Glutamic and aspartic acid donate a proton making them - charged

• Lysine and arginine accept a proton making them + charged

• methionine and cysteine contain sulfur

What are polypeptides?

• when two AAs join, they form a dipeptide. The carboxyl group of one combines with the amino group of the other forming a peptide bond

• If a group of AAs are joined as a string, they create a polypeptide. It can twist and fold to form a 3D structure called a protein

What are the levels of protein structure?

1. primary is peptide bonds between AAs

2. Secondary is hydrogen bonds between backbone creating alpha helix/beta pleated sheet

3. tertiary is any bond like hydrogen, covalent, ionic between r groups of AA creating final 3D structure

4. quaternary is any Bondy between R groups of DIFFERENT polypeptides

What are lipids?

• Contains CHO (cho chang)

• triglycerides, phospholipids, and steroids

• nonpolar structure makes them imp. for cell membranes, insulation, signalling molecules, and energy storage

• Triglycerides are made up of glycerol molecules and three fatty acid chains that is covered in Hydrogen and the end has a carboxyl group (COOH)

• Saturated fatty acids means its carbon chain is surrounded with Hydrogens. Unsaturated means it has a double bond chain ( i mean like actual = instead of -)

• Lipid saturation is the extent to which saturation in a lipid can affect its structure + function. The more double bonds = the more unsaturated

What are phospholipids?

• they contain two fatty acid tails and a neg charged phosphate head

• the hydrophic tails make then nonpolar and dont mix well with water which is polar

• the hydrophilic phosphate head means it mix well with water bc it has neg charge and it draws it to the + end of h20

• amphipathic = bc both hydrophilic and hydrophobic

What is cholesterol?

• four ringed molecule in membranes

• increases membrane fluidity (not when its a high temp tho)

• makes certain hormones and vitamin D

What are nucleic acids?

• CHONP (chomp chomp)

• made up of nucleotides

• The bond between phosphate and hydroxyl is a phosphodiester linkage

• DNA contains hereditary info for life and RNA is imp. for protein synthesis

• The nitrogenous bases include double ring purines A and G and single ring pyrimidines CUT

Geneticists investigated the mode of inheritance of a rare disorder that alters glucose metabolism and first shows symptoms in adulthood. The geneticists studied a family in which some individuals of generations II and III are known to have the disorder. Based on the pedigree (Figure 1), the geneticists concluded that the disorder arose in individuals II-2 and was caused by a mutation in mitochondrial DNA. (a) The disorder alters glucose metabolism. Describe the atoms AND types of bonds in a glucose molecule.

the atoms are carbon, hydrogen and oxygen which are held together by covalent bonds

During meiosis, double-strand breaks occur in chromatids. The breaks are either repaired by the exchange of genetic material between homologous nonsister chromatids, which is the process known as crossing over (Figure 1A), or they are simply repaired without any crossing over (Figure 1B). Plant breeders developing new varieties of corn are interested in determining whether, in corn, a correlation exists between the number of meiotic double-strand chromatid breaks and the number of crossovers. (a) The double-strand breaks occur along the DNA backbone. Describe the process by which the breaks occur.

• hydrolysis occurs between sugars and phosphate/nucleotides

• Covalent bonds between sugars and phosphate/nucleotides are broken