N-O Flashcards
NAD
Nicotinamide Adenine Dinucleotide
coenzyme participating in many enzymatic reactions; functions as an electron acceptor in many of the oxidation reactions of respiration
Negative feedback
The diminution or counteraction of an effect by its own influence on the process giving rise to it, as when a high level of Insulin in the blood may inhibit further secretion of insulin
Neuron
An electrically excitable cell that processed and transmits information through electrical and chemical signals
Neurotransmitter
Endogenous chemicals that transmit signals across a synapse from one neuron to another neuron
Noncompetitive inhibition
Inhibitor and substrate that bind simultaneously to an enzyme, forming an ESI-complex; a noncompetitive inhibitor acts by decreasing the turnover number; this can be overcome by increased concentration of substrate and Vmax is decreased
Nonsense mutation
A point mutation in DNA that results in premature stop codon in the transcribed mRNA, and thus creates a shortened, incomplete, and usually nonfunctional protein product
Nuclear envelope
A double membrane that surround the nucleus and that contains multiple pores. The pores regulate the passage of macromolecules with proteins and RNA, but permit free passage of water, ions, ATP and other small molecules
Nucleolus
A non-membrane bound structure composed of proteins and nucleic acids found within the nucleus. Ribosomal RNA (rRNA) is transcribed and assembled within this structure
Nucleoside
A purine or pyrimidine based bounded to a sugar
Nucleotide
Purine or pyrimidine base bounded to a sugar and a phosphate ester
Nucleus
The dense, round organelle present in eukaryotic cells, surrounded by a double membrane, containing the genetic material
Okazaki fragments
Short DNA fragments that are formed on the lagging template strand during DNA replication. They are complementary to the lagging template strand, together forming short double-stranded DNA sections
Osteoblasts
The cells that make bone. They do so by using calcium and other ions to produce a matrix that then becomes mineralized
Osteoclasts
The large, multinucleated cell responsible for the dissolution and absorption of bone
Ovulation
The process by which a mature egg is released from the ovary, pushed down the fallopian tube, and is available to be fertilized. Approximately every month, an egg will mature within an ovary
Ovum
An egg cell. Female reproductive cell (gamete) in oogamous organisms
Oxytocin
A hormone produced by the hypothalamus and stored and secreted by the posterior pituitary gland. Oxytocin acts primarily as a neuromodulator in the brain and during childbirth (As a regulator of uterine contractions)
