I'm stuck on a few questions. If you can just answer what you can-
25. Describe the role of an operon in a prokaryotic cell, and give an example of how an operon works.
31. The word transcribe means "to write out," and the word translate means "to express in another language." Review the meanings of transcription and translation in genetics. How do the technical meanings of these words relate to meanings of the words in ordinary language?
32. How does the possible impact of a chromosomal mutation that occurs during meiosis differ from that of a similar event that occurs during mitosis?
33. A researcher identifies the nucleotide sequence AAC in a long strand of RNA inside a nucleus. In the genetic code, AAC codes for the amino acid asparagine. When that RNA becomes involved in protein synthesis, will asparagine necessarily appear in the protein? Explain.
34. Recall what you know about mitosis and meiosis. Describe how a given amount of a cell's DNA might be alike or different after each process was complete.
Thank you soooo much!
So exactly what is your reasoning here?
25. An operon is a functional unit of DNA that consists of a promoter, operator, and a set of genes. It plays a role in gene regulation in prokaryotic cells. It controls the expression of genes by coordinating the transcription of the entire operon, rather than regulating each gene individually. This allows for the efficient control of multiple genes with related functions.
One example of how an operon works is the lac operon in E. coli. The lac operon is responsible for the metabolism of lactose. When lactose is present, it binds to the repressor protein, causing a conformational change that prevents it from binding to the operator region. This allows RNA polymerase to bind to the promoter and transcribe the genes involved in lactose metabolism. In the absence of lactose, the repressor binds to the operator, blocking RNA polymerase and preventing transcription.
31. In ordinary language, the word "transcribe" means to write out or copy something. In genetics, transcription refers to the process of copying the information encoded in DNA into RNA. It involves making an RNA molecule that is complementary to a specific region of DNA.
Similarly, the word "translate" in ordinary language means to express something in another language. In genetics, translation refers to the process of converting the information carried by an RNA molecule into a specific sequence of amino acids to form a protein. It involves reading the mRNA sequence and assembling the corresponding amino acids in a specific order.
In both cases, the technical meanings of transcription and translation in genetics relate to the ordinary language meanings, as they involve the copying and expression of genetic information in different forms.
32. The impact of a chromosomal mutation that occurs during meiosis differs from that of a similar event occurring during mitosis.
During meiosis, which is the process of cell division that produces gametes (sperm and eggs), a chromosomal mutation can be passed on to offspring. This can have a lasting impact on the genetic makeup of future generations. For example, if a chromosomal mutation results in the loss or duplication of genetic material, it may lead to genetic disorders or variations in the offspring.
On the other hand, during mitosis, which is the process of cell division to produce somatic cells (body cells), a chromosomal mutation affects only the individual organism. It may lead to abnormalities or disease within the affected individual's body, but it is not passed on to future generations unless it occurs in the gametes produced by the organism.
33. The nucleotide sequence AAC codes for the amino acid asparagine in the genetic code. However, the appearance of asparagine in the final protein synthesized from the RNA is not guaranteed.
This is because the genetic code is degenerate, meaning that multiple codons can code for the same amino acid. For asparagine, the codons AAC and AAU both code for the same amino acid. Therefore, if the RNA is involved in protein synthesis, the codon AAU can also be used, which would still result in the incorporation of asparagine into the protein.
The translation process involves reading the mRNA sequence in sets of three nucleotides, called codons, and matching them with the corresponding amino acids. While AAC specifically codes for asparagine, there are other codons that can also code for the same amino acid.
34. In mitosis, a given amount of a cell's DNA remains essentially the same after the process is complete. The cell starts with a diploid set of chromosomes (two sets of chromosomes), and after mitosis, it continues to have a diploid set of chromosomes. The purpose of mitosis is to generate two identical daughter cells with the same genetic information as the parent cell.
In meiosis, however, a given amount of a cell's DNA is reduced by half after the process is complete. The cell starts with a diploid set of chromosomes, but after meiosis, it produces four haploid daughter cells (gametes) with half the number of chromosomes as the parent cell. This reduction in DNA content is essential for sexual reproduction, as the gametes from two parents combine to restore the diploid number of chromosomes in the offspring.