Biology Flashcards
enzymes
protein catalysts that accelerate reactions by reducing the activation energy without being consumed or altered by the reaction. Note that enzymes affect only the rate of reaction; they do not effect the underlying thermochemistry of the reaction or the number of products that can eventually be formed
Calcitonin
hormone synthesized and released by the thyroid gland that decreases plasma Ca2+ concentration
Tidal Volume
the volume of air that is normally inhaled or exhaled with each breath
Binary Fission
Method of asexual reproduction by which prokaryotes divide. the circular DNA molecule replicates and then moves to opposite sides of the cell. The cell then divides into two daughter cells of equal size
Stabilizing Selection
type of natural selection where the normal phenotype is favored while those outside the norm are eliminated
synapse
the space between the axon terminal of one neuron and the dendrite of another neuron. Synapses are where neurotransmitters are released
Parthenogenesis
The development of an unfertilized egg into an adult organism
Citric Acid Cycle
The cycle begins when the two-carbon acetyl group from acetyl CoA combines with oxaloacetate to form citric acid. This product then proceeds through a series of reactions that result in the regeneration of oxaloacetate and the production of three NADH, one FADH2, and one GTP
peptide hormones
hydrophilic hormones incapable of permeating the cell membrane that bind to surface receptors and act through secondary messengers
Directional Selection
Type of natural selection where one extreme phenotype is favored over the normal phenotype and other extreme phenotypes
Monohybrid Cross
A cross between two organisms where only one trait is being studied.
Gluconeogenesis
A process in the liver by which glucose is produced using by-products of glycolysis, lipids, or fats
Lysosome
membrane-bound vesicle that contains hydrolytic enzymes used for intracellular
Leading Strand
During DNA replication, the strand of DNA that is continuously synthesized in the 5’ to 3’ direction. The template strand is read in the 3’ to 5’ direction
Glycolysis
Through a series of enzymatic reactions in the cytoplasm, glucose is converted into two molecules of pyruvate. The energy released in this process is used to produce a net yield of two ATP and two NADH molecules
Action Potential
A sharp change in the membrane potential of neurons or muscle cells caused by a change in the selective permeability to K+ and Na+ using ion-gated channels. Action potentials are all-or-none events
Genotype
The genetic makeup of an individual
Endometrium
the mucosal lining of the uterus where the embryo implants. Progesterone is necessary for the maintenance of the endometrium during pregnancy
Sister Chromatids
After replication, each chromosome consists of two identical chromatids held together at a central region called the centromere. After the mitotic spindle pulls the sister chromatids apart, each chromatid is referred to as a chromosome
Residual Volume
the amount of air that must remain in the lung at all times in order to prevent lung collapse
Lagging Strand
During DNA replication, the strand of DNA that is synthesized in small fragments called Okazaki fragments and then ligated together. The Okazaki fragments are synthesized in the 5’ to 3’ direction, but the overall synthesis is in the 3’ to 5’ direction. The template strand has a 5’ to 3’ polarity
Negative Pressure Breathing
The contraction of the diaphragm and the intercostal muscles increases the volume of the thoracic cavity, reducing the pressure in the intrapleural space. This decrease in pressure creates a vacuum that causes the lungs to suck in air
Point Mutation
mutation in which one nucleotide base is substituted for another. The protein products are often functional
Active Transport
Membrane transport that utilizes energy. Unlike other methods of transport, active transport can move particles from a region of lower concentration to a region
