Honors Biology - Unit 3: Biochemistry

carbohydrates

composed of carbon, hydrogen, and oxygen

used as a source of energy in cellular respiration

helps control blood glucose

ex: corn, potatoes, bread

monosaccharide

simplest carbohydrates, monomers

single-ringed sugars, names end in -ose

ex: glucose & fructose

isomers

2 molecules sharing the same molecular formula but different structural formula

disaccharide

double-ringed sugar formed through dehydration synthesis

ex: sucrose, maltase, lactose

dehydration synthesis

formation of a bond between monomers caused by the removal of water

starch

molecule in which plants store excess sugar in roots, stems, and leaves; easily digested

cellulose

tough, structural polysaccharide found in plant cells walls; cannot be digested

glycogen

molecules used by animals to store excess sugar in the liver (“animal starch”)

chitin

tough structural polysaccharide found in the exoskeleton of insects, spiders, and crustaceans

carbohydrate polymer

polysaccharide

ex: starch, cellulose, glycogen, chitin

organic compound

all contain carbon & hydrogen

produced by/occur naturally in organisms

C H O N P S

ex: ear wax, collagen, hemoglobin, glucose, breast milk

hydrocarbon

basic organic molecules made of carbon & hydrogen chains

substituted hydrocarbon

one or more hydrogen replaced by a functional group in a hydrocarbon

includes biological macromolecules

biological macromolecules

large, complex substituted organic molecules with specific roles in organisms

carbohydrates, proteins, lipids, nucleic acids

hydrolysis

breaking of a bond between monomers by adding water

proteins

contains C H O N S

found in hair, skin, nails, muscles, & feathers (structure for animals)

performs functions as hormones, antibodies, & enzymes in all life

one or more polypeptides folded into a specific shape

amino acids

monomers of proteins

20 different types each characterized by unique replacement group

ex: glycine & alanine

polypeptides

polymers of proteins, long chains of amino acids

range in size from 50-100,000 amino acids

dipeptide

2 linked amino acids

peptide bond

special bond that holds together a chain of amino acids

fibrous protein

structural, long straight chains

found in nails, skin, muscles, bones, hair, feathers, shells, fins

ex: collagen

globular protein

chemical reactions, chains folded into 3D shape

hormones, antibodies, enzymes

ex: hemoglobin

enzymes

organic catalysts

react only with a substrate that matches its unique 3D shape

names end in -ase

ex: lipase, catalase, amylase

catalyst

a substance that speeds up chemical reactions without being changed/destroyed itself

DOESN’T ADD ENERGY

substrate

the specific substance(s) undergoing a chemical reaction

enzyme temporarily bonds here

lock & key theory

describes how enzymes promote chemical reactions

1. enzyme & substrate are joined by weak covalent bonds

2. new products are formed

3. enzyme completes reaction & releases products

denaturation

destruction of the normal shape of the protein so that it no longer matches the shape of the substrate

caused by changes in pH & temperature increase

activation energy

energy needed to start a chemical reaction

law of conservation of matter/mass

states that matter cannot be created or destroyed during a reaction; balanced reaction represents this law

law of conservation of energy

states that energy cannot be created or destroyed during a reaction; total energy is equal before and after reaction

endergonic reaction

the total amount of PCBE in the reactants is less than is contained in the products; reaction appears cold and dark as energy is absorbed from the environment into the products

ex: photosynthesis

exergonic reaction

the total amount of PCBE in the reactants is more than can be contained in the products; reaction appears light/hot as energy is released to the environment from the reactants

ex: cellular respiration

lipids

contain carbon, hydrogen, & oxygen

insoluble in water (hydrophobic/non-polar)

reserve energy in animals

triglycerides

large lipid polymers found in fats/oils

made of fatty acids and glycerol

fatty acids & glycerol

lipid monomers

fats

solid

no double bonds

saturated with hydrogen

less healthy (difficult to digest → coagulating in blood)

found in animals; ex: bacon, butter

oils

liquid

one or more double bonds

unsaturated; not as much hydrogen

more health (less likely to coagulate)

found in plants; ex: peanut oil, soybean oil, olive oil

waxes

structural lipid, not a triglyceride

waterproofing on leaf surface

beeswax, ear wax (cerumin)

steroids

4 fused rings of carbon to which many different groups of elements are attached

cholesterol (builds cell membranes), testosterone, or estrogen

phospholipid

special type of triglyceride found within cell membranes

polar phosphate head & no polar fatty acid tails

nucleic acids

contain the code which stores hereditary information

nucleotide

monomer of nucleic acids

composed of 5 carbon sugar, phosphate group, & nitrogen base

DNA (Deoxyribonucleic acid)

polymer of nucleic acids

contains deoxyribose sugar

thymine, guanine, cytosine, & adenine

copied during cell division; found only in the nucleus; stores the genetic code & determines protein structure

RNA (Ribonucleic acid)

polymer of nucleic acids

contains ribose sugar

uracil (replaces thymine), guanine, cytosine, adenine

temporary copy of genetic code; found in nucleus, ribosome, & cytoplasm; directly used in protein synthesis

polar molecule

a molecule with 2 oppositely charged regions

hydrogen bonding is the attraction between oppositely charged regions of 2 neighboring polar molecules

temperature stabilization

water resists dramatic temperature changes, allows cells (contains lots of water) to more easily maintain homeostasis

adhesion

form of capillarity

attaches to other molecules

force of attraction between water molecules & molecules of the narrow tube

cohesion

form of capillarity

cooperates & sticks to each other

attraction between water molecules themselves

density

water is less dense as a solid; ice floats on top & water freezes from top down

solubility

water dissolves other polar or ionic substances easily, does not easily combine with nonpolar substances

hydrophobic substances

“water-fearing”; non-polar substances

do not easily dissolve in water

ex: lipids like oil

hydrophilic substances

“water-loving”; polar substances

easily dissolves in water

ex: alcohol

solution

homogeneous mixture of 2 or more substances; one substance (solute) is dissolved in another (solvent)

ex: air, soda, vinegar

Aqueous solution (Aq)

solution in which a substance (solute) is dissolved in water (solvent)

acids

form when hydrogen (H+) ions mix with water

have a low pH (low pH = stronger acid)

tend to taste sour

ex: HCl

bases

form when hydroxide (OH-) ions mix with water

have a high pH (higher pH = stronger base)

tend to taste bitter

ex: NaOH (sodium hydroxide)

indicator

types of substances that turn different colors in different pH solutions to indicate pH

ex: Litmus paper, pHydrion paper, phenolphthalein

neutralization reaction

acid + base → salt + water

HCl + NaOH → NaCl + H₂O

pH scale

percent of hydrogen

used to measure acidity or alkalinity of aqueous solutions

buffer

chemical that purposely neutralizes an acid or a base

NaHCO₃ + HCl → NaCl + CO₂ + H₂O