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Oliga [24]
3 years ago
5

Select the phrases that accurately describe properties of the most common form of the DNA double helix. There is more than one c

orrect answer. Select all that apply. DNA contains equal amounts of adenine and thymine, and equal amounts of cytosine and guanine. A helical turn consists of about 10 nucleotides. Base pairs have a spacing of 20 A. The phosphodiester bonds between nucleotide residues run in opposite directions in the two strands. The nitrogenous bases are exposed to the solvent, whereas the sugar-phosphate backbone of each nucleotide strand is on the interior of the double helix.
Biology
1 answer:
zhuklara [117]3 years ago
3 0

Answer:

A strand of DNA comprises pyrimidines, that is, cytosine and thymine and purines, that is, adenine and guanine. Of these pairing takes place between thymine and adenine and guanine and cytosine. Thus, it can be said that in DNA, the amount of adenine is corresponding to thymine, and the concentration of guanine is corresponding to cytosine. Hence, the given first statement is correct.  

DNA gives an appearance of a helical structure, in which each of the helices comprises approximately 10 nucleotides within them. Hence, the given second statement is also correct.  

The strands of DNA found in a helical structure are complementary to each other, or it can also be stated that the nucleotides present in one strand of the DNA are found in opposite direction and orientation with respect to the second strand of the DNA. The phosphodiester bonds play an essential function in combining a molecule of sugar of one nucleotide with the molecule of phosphate of the adjacent nucleotide. Hence, the given fourth statement is also correct.  

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Sperm cells are about to be made from a cell with 66 chromosomes. How many chromosomes will the sperm cells have?
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Answer:

33

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Gametes (sperm or egg) have half the chromosome of a diploid cell. That's why they are haploid cells.

If chromosomes come from a cell with 66 chromosomes, sperm will have 66/2 = 33.

That's why us humans have 46 chromosomes, but our egg or sperm has only 46/2 = 23 chromosomes.

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2 years ago
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vladimir1956 [14]
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I<span>t basically helps them define an animal or plant using specific defining characteristics. </span>
5 0
3 years ago
Each of the following will enhance and promote phagocytosis, except Multiple Choice tumor necrosis factor (TNF) and other cytoki
ozzi

Answer:

The correct answer is: deposition of interferon on bacterial cells.

Explanation:

Phagocytosis is the mechanism by which a cell uses its plasma membrane to ingest a big particle, forming a phagosome within the cell. It's a form of endocytosis used by the <u>immune system to eliminate pathogens such as </u><u>bacteria </u><u>and cell debris</u>.

Phagocytosis can be enhanced through various ways when an infection is taking place in the body. For example, cytokines and TNF are secreted by different kinds of cells to stimulate this process - for these cytokines to be released, certain parts of the bacteria called PAMPs need to be recognized by specific receptors located in phagocytes and epithelial cells called TLRs. Another way to stimulate this mechanism is by depositing complement fragments on bacterial cells, which is done thanks to the Complement cascade, a system of great importance in the innate immune response against extracellular bacteria - these fragments will opsonize ("mark") the pathogens for the phagocytes to recognize them and engulf them.

Interferon, on the other hand, while hugely important on the immune response against viruses and other pathogens that infect our cells by entering them and using their organelles to replicate and translate proteins, is not an enhancer of phagocytosis, as it is mostly involved in the translation of genes that will lead to the infected cell's death.

5 0
3 years ago
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tensa zangetsu [6.8K]

Answer:

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