Both strands of the DNA double helix contain nitrogenous bases held together by hydrogen bonds. In DNA, the sequence of nitrogenous bases varies widely. What is the significance of the nitrogenous bases? (6A) Question 4 options: They determine the amino acids in the proteins synthesized. They prevent mutations from occurring in the process of DNA replication They help complete the sugar-phosphate backbone of DNA molecules. The amount of adenine and cytosine determines the length of the gene on a DNA molecule.

Which of the following elements does soil need in the largest quantities to sustain plant life? a. copper b. iron c. nitrogen d. zinc

You have been asked to lead a demonstration for the undergraduate microbiology lab course about the uses of negative staining when studying bacteria. a "negative" stain does not stain the bacterial cell itself but stains the space between cells. under magnification, the acidic (negativelycharged) nature of the stain will be repelled by the negatively charged bacterial cell wall and willleave the cell colorless in a stained background. negative stains are used primarily to reveal the presence of negatively charged bacterial capsules; therefore, they are also called capsule stains. encapsulated cells appear to have a halo surrounding them. the negative stain procedure does not require heat fixation, which limits any chances of alteration in bacterial cell shape and size. the bacterial suspension is added to a drop of stain, such as nigrosin or eosin, and drawn across the glass slide using a coverslip.nigrosin staining-not safranin staining-of klebsiella pneumoniae will allow for the visualization of the cell shape and the determination of the presence of a capsule.true/false

Aflame cell is at the end of each tubule of the nephridium malpighian tubules kidneys none of the above