SL Biology - Topic 2: Molecular Biology (copy)

a compilation of key terms and concepts from topic 2

metabolism

metabolism

all chemical reactions that take place within cells and organisms

anabolism

the building of large molecules from smaller molecules

catabolism

the breaking down of large molecules into smaller ones

water dipolarity

a weak negatively charged region on the oxygen atom and a weak positively charged region on the hydrogen atom

role of water as a solvent

allows chemical reactions to occur and a transport medium

role of water with a high specific heat capacity

allows water to be a suitable habitat and maintain optimal temperatures within cells and bodies

role of water with a high latent heat of vaporization

an effective coolant as large amounts of energy must be absorbed to break hydrogen bonds.

disaccharides

monosaccharides joined together via a condensation reaction, releasing a molecule of water.

starch

the storage polysaccharide of plants

glycogen

the storage polysaccharide of animals and fungi

cellulose

a polymer of beta-glucose monomers

triglycerides

a form of lipid made up of one molecule of glycerol and three fatty acids

saturated fatty acids

the bonds between the carbon atoms in the hydrocarbon tails are all single bonds

unsaturated fatty acids

the bonds between the carbon atoms in the hydrocarbon tail are not all single bonds

cis-isomers

at a double carbon bond, the attached hydrogen atoms are on the same side of the hydrocarbon chain.

trans-isomers

at a double carbon bond, the attached hydrogen atoms are on opposite sides of the hydrocarbon chain

proteins

polymers and macromolecules made of amino acids

amino acids

the monomers of polypeptides

fibrous proteins

proteins composed of long and narrow strands with a structural role

globular proteins

proteins with a more compact and rounded shape with a functional role

insulin

a short, globular protein produced and secreted in the pancreas binding to insulin receptors causing the absorption of glucose from the blood.

collagen

the most abundant fibrous protein in the human body made of 3 polypeptide chains

proteome

the full range of proteins that a cell organism is able to produce

enzymes

biological catalysts that are able to speed up the rate of chemical creations without being used up.

immobilized enzymes

an enzyme that is attached to an insoluble material to prevent mixing with a product

nucleic acids

polymers of nucleotides

nucleotides

formed from a pentose sugar, a nitrogen containing organic base and a phosphate group

helicase

an enzyme used in DNA replication which unwinds the double helix and separates the two strands by breaking hydrogen bonds

DNA polymerase

links nucleotides together to form a new strand using the pre-existing one as a template

thymine

bonds to adenine with 2 hydrogen bonds

cytosine

bonds to guanine with 3 hydrogen bonds

transcription

when DNA is transcribed and an mRNA molecule is produced

translation

when mRNA is translated and an amino acid sequence is produced

sense strand

the strand of the DNA molecule that carries the genetic code during transcription

anti-sense strand

the DNA strand that is transcribed to form the mRNA molecule

codons

three bases on mRNA that correspond to one amino acid in a polypeptide

ATP

a source of energy from cellular processes

aerobic respiration

requires oxygen and gives a large yield of ATP (36) from glucose

anaerobic respiration

glucose is only partially oxidized meaning only a small part of it’s chemical energy is released and transfers ATP (2)

Photosynthesis

Photosynthesis is a process by which phototrophs convert light energy and inorganic molecules into chemical energy

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

chlorophylls

primary pigments which absorb wavelengths in the blue-violet and red regions of the light spectrum

carotenoids

accessory pigments which absorb wavelengths of mainly the blue-violet region of the spectrum