Answer: RNAs are not processed before translation in prokaryotes, this process only takes place in eukaryotes.
Explanation:
Messenger RNA or mRNA is a single-straded ribonucleic acid that transfers the genetic information from the DNA (deoxyribonucleic acid) molecule of the cell nucleus to a ribosome (which are the machinery responsible for protein synthesis) in the cytoplasm. mRNA determines the order in which the amino acids of a protein will be joined and acts as a template or pattern for the synthesis of that protein. To accomplish this, the DNA molecule must be transcribed into an RNA molecule, which is used for protein synthesis.
The messenger RNA obtained after transcription is known as primary transcribed RNA or precursor RNA or pre-mRNA, which in most cases is not released from the transcription complex in a fully active form, but in eukaryotes it must undergo modifications before it can perform its function (RNA processing or maturation). These modifications include:
- Elimination of fragments (splicing): In most cases, the <u>mRNA undergoes the removal of internal, non-coding sequences called introns, and the connection of exons. This does not occur in prokaryotic cells</u>, as they do not have introns in their DNA.
- Protection by CAP: <u>Addition to the 5' end of the structure called "cap" or "capping"</u>, which is a modified guanine nucleotide, 7-methylguanosine triphosphate, via a 5'-5' triphosphate linkage, instead of the usual 3',5'-phosphodiester linkage. This cap is necessary for the normal RNA translation process and to maintain its stability.
- Polyadenylation signal: <u>Addition to the 3' end of a poly-A tail, a long polyadenylate sequence, whose bases are all adenine</u>. Its addition is mediated by a sequence or polyadenylation signal (AAAAAA), located 11-30 nucleotides upstream of the original 3' end. This tail protects the mRNA from degradation, and increases its half-life in the cytosol, so that more protein can be synthesized.
The mature mRNA (in eukaryotes) is transferred to the cytosol of the cell through pores in the nuclear envelope. Once in the cytoplasm, ribosomes are coupled to the mRNA. However, in prokaryotes, ribosome binding occurs while the mRNA strand is being synthesized. After a certain amount of time, the mRNA is degraded into its component nucleotides by ribonucleases. So, the transcription and translation processes are carried out in a similar way as in eukaryotic cells but they occur simultaneously. But, the fundamental difference is that, in prokaryotes, the messenger RNA does not undergo a maturation process and, therefore, no cap or tail is added and no introns are removed. Moreover, it does not have to leave the nucleus as in eukaryotes, because in prokaryotic cells there is no defined nucleus.
So, RNAs are not processed before translation in prokaryotes, this process only takes place in eukaryotes.
Answer:
The scientific name of an organisms is always given as a two part name with the genus and the species. :)
Temperature inversion or thermal inversion is a phenomenon during which the temperature increase when there is an increase in the altitude. It is an uncommon process that happens in the troposphere-the layer of atmosphere closest to the earth.
When there is an increase in temperature with altitude that warm air acts as a blockage for the cool air near the surface of the earth. So this is just opposite to the normal behavior of the air, where it becomes cooler with an increase in altitude.
So how air circulation behaves during inversion?
So as we said that the cool air nearer to the earth will be blocked by a layer of warm air. This blockage will hinder the circulation of air upwards from the lower layers. Let’s see how:
• As we know that, warm air is less dense and more buyout than cool air and normally less dense warm air is close to the earth and cool air is in above layers. But when the process is reversed, this warm air acts like a blanket for the proper circulation of air. Due to this, many environmental pollutants which normally leave the earth during air circulation get trapped in our air.
• The trapped environmental pollutants like nitrogen oxides and hydrocarbons get convert into harmful ozone that ultimately deteriorates the quality of air and causes problems like smog.
• The improper air circulation also causes suspension of the harmful gases near the earth instead of allowing them to leave the earth atmosphere. This ultimately causes air pollution.
• When smoke will not rise, carbon dioxide will be build up in the atmosphere; this will cause greenhouse effect and global warming.
Therefore, air circulation behaves very different during temperature inversion process and poses hazardous effects on global climate.
Hope it helps! :)
The answer is <span>B. contains enzymes that begin the breakdown of proteins.
Saliva is watery substance secreted by salivatory glands. <em>It cleanses the mouth</em> and maintenance oral hygiene. <em>It moistens the food</em>, so the created food bolus could easier pass into the esophagus. It also <em>carries food chemicals to taste receptors</em> so they can be tested. It contains enzymes involved in the food digestions. Some of them are amylase, which begins the breakdown of the starch, and lipase, which begins the breakdown of triglycerides. <u>There are no enzymes in the saliva that break down proteins</u>.</span>
What is ATP? why is it an important product of cellular respiration? ATP is stored energy. ATP is an important part because it is the energy that living things that cant go through photosynthesis have to ingest in order to recieve energy
