The image contains several biology-related questions. Let's focus on question V and VI, which involve numerical calculations. V: A single strand of a gene has a total of 750 nucleotides. The difference between the number of adenine nucleotides and other nucleotides is 300. a. Find the number of each type of nucleotide. b. If this gene is a template to transcribe 4 mRNA molecules, what is the total number of free ribonucleotides required? VI: During the synthesis of a protein molecule, an mRNA molecule enters the ribosome 489 times. a. Calculate the number of nucleotides in the gene. b. Find the percentage of each type of nucleotide, given that there are 441 adenine nucleotides.

1. Problem Description

The image contains several biology-related questions. Let's focus on question V and VI, which involve numerical calculations.

V: A single strand of a gene has a total of 750 nucleotides. The difference between the number of adenine nucleotides and other nucleotides is

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0. a. Find the number of each type of nucleotide.

b. If this gene is a template to transcribe 4 mRNA molecules, what is the total number of free ribonucleotides required?

VI: During the synthesis of a protein molecule, an mRNA molecule enters the ribosome 489 times.

a. Calculate the number of nucleotides in the gene.

b. Find the percentage of each type of nucleotide, given that there are 441 adenine nucleotides.

2. Solution Steps

V. a. Let $A$ be the number of adenine nucleotides, and $O$ be the number of other nucleotides. We have:

$A + O = 750$

$A - O = 300$

Adding the two equations, we get:

$2A = 1050$

$A = 525$

So, $O = 750 - 525 = 225$

The other nucleotides (G, C, T) total

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5. Since this is a single strand of DNA, the numbers of G, C, and T are not necessarily equal. The question only asks for the number of each *type* of nucleotide, so we only need $A$ and other nucleotides.

V. b. For transcribing to mRNA, we use the other strand which is complementary to the DNA strand. The number of nucleotides from the complementary strand becomes the number of ribonucleotides in mRNA. Since the gene has 750 nucleotides on one strand, 750 ribonucleotides are needed to form one mRNA molecule. Four mRNA molecules will require: $4 \times 750 = 3000$ ribonucleotides.

VI. a. An mRNA molecule enters the ribosome 489 times to synthesize a protein. Each time the mRNA enters the ribosome, the *same* mRNA is used for protein synthesis. The question is actually about how many nucleotides are *in the gene*. The gene has two strands. The template strand has the same number of nucleotides as there are bases in a molecule of mRNA created using it, so we can assume it would require 489 triplets, for a total of $489 \times 3= 1467$ nucleotides of mRNA. However, question VI. states that "ARN ដឹកនាំចូលក្នុងរីបូសូមចំនួន 489 ដង". So, there is no relation to the coding number of ARN. The mRNA gets created from the template (one of the two strands). Thus, The length of the template strand determines the mRNA length, which is the same as the coding strand. So the coding strand must have the same length. So the gene that produced the mRNA strand must have a *length*. So, the total number of nucleotides in the gene is $2 \times 1467=2934$.

Each codon has 3 bases, which correspond to one amino acid. Since there are 489 amino acids, the mRNA must have $489 \times 3 = 1467$ nucleotides. Since mRNA is transcribed from DNA, we only need to know length of the template strand (one side of the gene) which contains 1467 nucleotides. The double-stranded gene contains $2 \times 1467=2934$ nucleotides

VI. b. There are 1467 nucleotides in the mRNA, and 441 of these are adenine. So the percentage of adenine is $(441 / 1467) \times 100 \approx 30.06\%$. In DNA, $A=T$ and $G=C$. So the template strand has $A, T, G, C$. Let's assume $A$ is

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1. Now for the DNA, we have the coding strand, with a total of 1467 nucleotides. The other (template) strand will also have 1467 nucleotides. On the template strand, the numbers $A, T, G, C$ may be different, but that ratio is already in the mRNA molecules. The gene will have a double helix with complementary base pairing. So in the mRNA molecule of 1467 nucleotides, we have 441 adenines. So $A=441/1467$. Thus, the total number of A in the gene will be double that of mRNA $=2\times 441 =882$, and the percentage is then $882/(2 \times 1467) \times 100 = 882 / 2934 \times 100 \approx 30.06\%$.

3. Final Answer

V. a. Adenine: 525, Other nucleotides:

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5. V. b. 3000

VI. a. 2934

VI. b. Approximately 30.06%