DEFINITIONS Flashcards
Homeostasis
Regulation of the internal environment to maintain a constant state.
Alternative splicing
A process in which primary transcripts from the same gene can be spliced in different ways to yield different mRNAs and therefore different protein products.
Amino acid
Building blocks of proteins.
Anticodon
The sequence of three nucleotides in a tRNA molecule that base pairs with the corresponding codon in an mRNA molecule.
ATP synthase
An enzyme that couples the movement of protons through the enzyme with the synthesis of ATP.
Autotroph
An organism that is able to synthesize its own food using energy from sunlight or inorganic chemicals.
Base
A nitrogen-containing compound that makes up part of a nucleotide.
Beta sheet
One of the two principal types of secondary structure found in proteins.
Calvin cycle
The process in which carbon dioxide is reduced to synthesize carbohydrates with ATP and NADPH as the energy sources.
Carbohydrate
An organic molecule containing C, H, and O atoms that provides a source of energy for metabolism and that forms the starting point for the synthesis of all other organic molecules.
Carboxyl end
The end of a polypeptide chain that has a free carboxyl group.
Carboxyl group
A carbon atom with a double bond to oxygen and a single bond to a hydroxyl group.
Cell
The simplest self-reproducing entity that can exist as an independent unit of life.
Central dogma
DNA -> RNA -> protein
The idea that information flows from nucleic acids to proteins.
Chemoreceptor
A receptor that responds to molecules that bind to specific protein receptors on the cell membrane of the sensory receptor.
Chemotroph
An organism that derives its energy directly from organic molecules such as glucose.
- type of metabolism (fungi, bacteria…)
Citric acid cycle
The third stage of cellular respiration in which acetyl-CoA is broken down and carbon dioxide is released.
Cohesion
Attraction between molecules, surface tension.
Complementary
Describes the relationship of purine and pyridine bases where base A only binds with T (or U) and G only pairs with C.
Complementary DNA
A DNA molecule produced by reverse transcriptase from an RNA template.
Covalent bond
A chemical bond formed by a shared pair of electrons holding two different atoms together.
Cytoplasm
The contents of the cell other than the nucleus.
Cytoskeleton
Helps eukaryotic cells maintain their shape.
Daughter strand
The strand synthesized from a parental template in DNA replication.
Deoxyribonucleic acid
DNA - the information archive in all organisms.
Deoxyribose
The sugar in DNA
Depolarization
An increase in membrane potential from a negative resting potential.
DNA polymerase
An enzyme that is a critical component of a large protein complex that carries out DNA replication.
DNA replication
The process of duplicating a DNA molecule during which the parental stands separate and new partner strands are made.
Double bond
A covalent bond in which covalently joined atoms share two pairs of electrons.
Double helix
The structure formed by two strands of complementary nucleotides that coil around each other.
Duplication
A region of chromosome that is present twice instead of once.
Electrochemical gradient
A gradient that combines the charge gradient and the chemical gradient of protons and other ions.
Electron
A negatively charged particle that move around the atomic nucleus.
Endoplasmic reticulum
ER - An organelle composed of a network of membranes that is involved in the synthesis of proteins and lipids.
Eukaryote
An organism whose cells have a true nucleus.
Exon
A sequence that is left intact in mRNA after RNA splicing.
Golgi apparatus
The organelle that modifies proteins and lipids produced by the endoplasmic reticulum and acts as sorting station as they move to their final destination.
Heterotroph
An organism that obtains its carbon from organic molecules synthesized by other organisms.
Hydophillic
Water loving - class of molecules with which water can undergo hydrogen bonding.
Hydrophobic
Water fearing - class of molecules poorly able to undergo hydrogen bonding with water.
Hyrophobic effect
The exclusion of non polar molecules by polar molecules which drives biological processes such as the formation of cell membranes and the folding of proteins.
Initiation factor
A protein that binds to mRNA to initiate translation.
Inhibitor
A synthesized compound that decreases the activity of an enzyme.
Ion
An electrically charged atom or molecule.
Intron
A nucleotide sequence that is excised from the primary transcript and degraded during RNA splicing.
Isomers
Molecules that have the same chemical formula but different structures.
Isotopes
Atoms of the same element that have different numbers of neutrons.
Kinetic energy
The energy of motion.