What is the advantage of stopping mitosis at metaphase when making a chromosome spread?

1 answer:

3 0

The chromosomes are in their condensed, highly coiled form, where they can easily fall without overlapping and staining will show a banding pattern.

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From a chemical view, how is an amino acid is being recognized by its specific aminoacyl tRNA synthetase?

hammer [34]

During translation, rRNA and tRNA read mRNA in 5´ to 3´ direction. According to the codons being readen, tRNA transfers the correct amino acids to build the polypeptide chain. A codon is a short sequence of three nucleotides that store the genetic information for the aminoacids´ assembly.

Each tRNA has two important sites. One of them that couples with the codon of the mRNA molecule, named anticodon. The other site couples with an amino acid through the action of the aminoacyl-tRNA synthase enzyme. The whole complex, amino acid + enzyme + tRNA is named aminoacyl-tRNA.

Each tRNA is recognized by a specific aminoacyl-tRNA synthase enzyme. The enzyme is also capable of recognizing a specific amino acid. Let us say, for instance, that tRNA is specific for phenylalanine. The molecule is attached to the enzyme that is specific for that tRNA(Phe). Then, when the enzyme and tRNA(Phe) are together, they get to find phenylalanine. The enzyme links the aminoacid to the RNA. Once the whole complex is formed, the tRNA gets to pair its anticodon with the mRNA codon. This is,

Recognition of enzyme and the specific tRNA(aa) ⇒ aa being aminoacid
Recognition of enzyme and the specific aminoacid
Linkage of the aminoacid to RNA by the enzyme action
Pairing of tRNA anticodon to mRNA codon.

Considering that there are twenty amino acids available, there are also twenty complexes of aminoacyl-tRNA, one for each amino acid. Each of the mRNA codons represents one of the 20 amino acids used to build the protein. Each amino acid can be codified by more than one codon. Of the total 64 codons, 61 codify amino acids, and one is a start codon. The left three codons are stopping translation points.

tRNA decodes genetic information from the nucleotidic sequence in the mRNA molecule and allows amino acids to align composing the new protein.

Once the new peptidic link joins, placing together the new amino acid to the growing peptidic chain, the binding between the amino acid and the tRNA molecule breaks. The tRNA is now free to join another amino acid and repeat the cycle.

In conclusion, a specific aminoacyl-tRNA synthase enzyme recognizes a tRNA, which is also specific for a certain amino acid. When together, the enzyme recognizes the amino acid and links it to the RNA. The whole complex is known as aminoacyl-tRNA. Once the tRNA is joined to its amino acid, it gets to pair a codon of mRNA to add that amino acid to the new synthesizing protein.

6 0

3 years ago

Where does the first stage of cellular respiration occur?

Anestetic [448]

The first stage of cellular respiration is glycolysis. It takes place in the cytosol of the cytoplasm. The word glycolysis means “glucose splitting,” which is exactly what happens in this stage. Enzymes split a molecule of glucose into two molecules of pyruvate (also known as pyruvic acid). This occurs in several steps, as shown in Figure below.

8 0

3 years ago

Blood born pathogens refer to in body fluids

OLEGan [10]

Blood born pathogens refer to contaminants in body fluids

4 0

3 years ago

A single strand of DNA helix consists of 100 nitrogenous base pairs. On one strand, 36 of the bases are adenine and 24 are cytos

yawa3891 [41]

36 thymine (matches with 36 adenine)
24 guanine (matches with 24 cytosine)

6 0

3 years ago

Read 2 more answers

For a neuron to function, an input of free energy from ATP is required to set up the sodium and potassium ion concentration grad

Vlad [161]

Answer:

The lack of ATP would slow nerve responses to generate an action potential

Explanation:

Adenosine triphosphate (ATP) is the main source of energy in the cells. Moreover, ATPases are pumps that use ATP in order to transport sodium and potassium ions across the cell membrane and thus create an action potential. In stressful situations (e.g., escape from a predator) the lack of ATP would not allow to develop fast nerve responses, thereby ATP is required during rest periods and the flow of ions is used when is required a fast response.

4 0

3 years ago