Exam 1 Review:  Chapter 2 - Nucleic Acids and ATP

nucleic acid - Any of a group of complex organic polymers/macromolecules found in all living cells and viruses, composed of nitrogenous bases ( the purines, adenine and guanine, and the pyrimidines, cytocine, thymine, and uracil), pentose sugars (ribose and deoxy-ribose), and phosphate ions; these macromolecules, DNA and RNA, control cellular function, especially protein synthesis, and heredity.

nucleotide - Any of various compounds consisting of a nitrogenous base covalently bound to a pentose sugar (a "nucleoside") and combined with one, two, or three phosphate groups/ions; they serve as the basic monomers for the synthesis of DNA and RNA; certain of them also play important roles as recyclable energy transfer compounds in a wide variety of metabolic reactions, e.g., ATP.

nitrogenous base - A basic compound that contains nitrogen, specifically the purines (adenine and guanine) and the pyrimidines (cytosine, thymine, and uracil) which are components of the nucleotide monomers of the nucleic acids, DNA and RNA.

deoxyribonucleic acid  (DNA) - A nucleic acid which carries the genetic information in the cell and is capable of self-replication and serves as the template for the synthesis of RNA; it is located in the nucleus and in the mitochondria of cells; it consists of two long chains of nucleotides linked by the repeated sugar-phosphate bonds, twisted into a double helix in which the two single strands are joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine (A=T and C≡G); the sequence of coding triplets of nucleotides determines individual hereditary characteristics, especially the primary structure of all proteins.  Also visit The DNA Workshop.

double helix - The coiled three dimensional configuration of double-stranded DNA molecule in which the two strands are linked by the series of hydrogen bonds between opposing complementary nitrogenous base pairs (A=T and C≡G); so linked the two sugar-phosphate backbones form a spiral configuration around a common axis, with the two strands oriented in opposite directions ("anti-parallel").


ribonucleic acid (RNA) - A group of three functional classes of nucleic acids (messenger RNA, transfer RNA, and ribosomal RNA) which participate in protein synthesis under the direction of the genetic information (DNA) in the cell; they are synthesized in the nucleus and migrate to the cytoplasm or to various cell organelles, especially the ribosomes, to carry out their functions; they consists of single long chains of nucleotides linked by the repeated sugar-phosphate bonds, twisted into various configurations, depending on their class and function; the nitrogenous bases found in RNA are adenine, guanine, cytosine and uracil.

ATP = adenosine tri-phosphate - A nucleotide [C10H16N5O13P3] which contains the purine adenine, a pentose sugar (ribose or deoxyribose) and three high-energy phosphate groups; the potential chemical energy in the bonds connecting the phosphate groups is used to transport energy within cells for biochemical processes (including muscle contraction and enzymatic metabolism) through its hydrolysis; the mitochondrion is the primary cell organelle synthesizing this compound using energy derived from the final oxidation of nutrient molecules; it also serves as an excitatory or inhibitory neurotransmitter in the central (CNS) and peripheral (PNS) nervous systems; its release from injured cells can stimulate pain receptors.

anaerobic - (1) a process not depending on free oxygen or air, e.g., anaerobic glycolysis; (2)  living or occurring only in the absence of oxygen, e.g., anaerobic bacteria. 

aerobic - (1) a process depending on free oxygen or air, e.g., aerobic glycolysis; (2) involving or improving oxygen consumption by the body, e.g., aerobic exercise; (3) living or occurring only in the presence of oxygen, e.g., aerobic bacteria.

 

List:

10. three examples of major functions for nucleic acid molecules.

          (1) structural components of ribosomes [RNA]
          (2) participants in protein synthesis (transcription and translation) [RNA]
          (3) the hereditary material, the location of genetic blueprints for the cell [DNA]

Describe:

3. the role and the mechanism of ATP in energy transfers in cells.

 
When ATP is split (hydrolyzed) to yield ADP + an inorganic phosphate ion (Pi) and some amount of useful chemical energy, the ATP hydrolysis is coupled to another endergonic reaction, and the useful chemical energy derived from the ATP hydrolysis is used to drive the coupled reaction.   See examples of this mechanism depicted in the figures below.

Sketch and Label:

3. the "double helix."

 


4. the action of the Na+/K+ ATPase "sodium-potassium" pump.

 
The central concept to note is that ATP hydrolysis is required for each action of the pump.  With each action of the pump, 3 sodium ions are moved from the cytoplasm to the extracellular fluid and in the same cycle, 2 potassium ions are moved from the extracellular fluid to the cytoplasm of the cell.