IB CH: 2 Molecular Biology

Water molecule

A polar molecule made of 1 oxygen and 2 hydrogen atoms.

Polarity

Having positively & negatively charged areas because of an uneven distribution of electrons.

Hydrogen bond

A weak bond formed between polar water molecules.

Cohesion of water molecules is high

because H-bonds make water molecules attract each other more strongly. It causes surface tension.

Water has high specific heat capacity

because some heat is used to break H-bonds so more is needed to raise the temperature.

Water is an excellent solvent

because polar water molecules dissolve so many substances.

Water has dipolarity

because water molecule contains both positve and negative charges.

Water is a good coolant in sweat

because it has a high specific heat.

Water is good for transport

because it can easily dissolve glucose, sodium chloride, oxygen, and many amino acids.

Organic chemistry

chemistry of carbon compounds

Biochemistry

branch of organic chemistry that attempts to explain the chemistry characteristics of living organisms

Metabolism

all of the reactions within all of the cells when molecules collide with enough energy to cause a reaction

Catabolism

enzyme reactions that convert large, complex molecules like food into smaller simpler molecular forms

Anabolism

enzyme reactions that convert small, simple molecules into a large, more complex molecule

Hydrolysis

reactions that requires a water molecule to split apart a larger molecule

Condensation reactions

water molecules are produced when monomers are linked together to form larger molecules

Adhesion

attraction between two unlike molecules

Specific heat

amount of heat per unit mass required to raise the temperature 1°C

Hydrophilic

water loving

Hydrophobic

water fearing

Monosaccharides

monomer of carbohydrates

Cellulose

component of plant cell walls for rigid support of stem, roots, and leaves

Starch

products of photosynthesis are stored in plants as starch in roots

Glycogen

animal stores excess glucose as glycogen in liver and muscle tissue

Saturated fatty acids

carbons are carrying as many hydrogen atoms as they can

Monounsaturated fatty acid

one double bond in the chain of hydrocarbons

Polyunsaturated fatty acid

have at least 2 double bonds in the carbon chain

Cis unsaturated fat

naturally curved fatty acids with H on the same side of the double bond

Trans unsaturated fat

man-made hydrogenated straightened fatty acid with H on opposite sides of the double bond

Hydrogenation

polyunsaturated fats are hydrogenated by removing or partly eliminating the double bonds by adding hydrogen atoms

Triglyceride lipids

made up of glycerol and three fatty acids

Peptide bond

covalent bond that links amino acids together

Primary structure of proteins

sequence of amino acids

which will determine the 3D shape

Secondary structure of proteins

repetitive shapes of

either helix (spiral staircase) or

pleated sheet

Tertiary structure of proteins

globular shape

Quaternary structure of proteins

two or more polypeptides combined together to make a single protein

Active site

section of the enzyme that matches the substrate

Enzymes

organic molecules (proteins) that act as catalysts

Substrate

substance on which the enzyme acts

Activation energy

energy needed to start the reaction

Competitive inhibition

a competitive inhibitor molecule competes directly with the usual substrate for the active site of an enzyme

Non-competitive inhibition:

involves an inhibitor that does not compete for the enzyme's active site, but the inhibitor interacts with another site on the enzyme

End-product inhibition

prevents the cell from wasting chemical resources and energy by making more of a substance than it needs