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: Option B. "Deep"
Explanation:
Thermohaline circulation helps to drive the global conveyor belt, which is a global-scale system of currents. Due to the movement of ocean currents through different polar regions, it allows depletion of nutrients and carbon dioxide at surface waters and get enrich again as move through deep waters in the conveyor belt.
Winds in the ocean helps to drive ocean currents in the upper ocean’s surface and these ocean currents moves below the ocean surface as well. the process that controls the movement of ocean current deep in the ocean is called Thermohaline circulation that is based on differences in the water’s density, and controlled by temperature (thermo) and salinity (haline).
Thermohaline circulation forms in the polar regions of Earth. Ocean water in the polar region gets colds that allows the formation of sea ice, which in turn make the surrounding seawater saltier and increases the ice density and sinks. This allows the deep-ocean currents to drive the Global conveyer belt.
The conveyor belt starts from the surface of North Atlantic pole, where seawater become saltier and ice starts sinking. This deep water heads south along the western Atlantic basin. The conveyor belt get recharged as it travels along the coast of Antarctica and carries more cold, salty, dense water. The current get divided into two different sections, one traveling to the Indian Ocean and the other moves into the Pacific Ocean. The two sections of the current get warm and rises, as they travel northward, then turn back around westward and southward.
The warmed surface waters continue to circulate around the globe and follows depletion of nutrients and carbon dioxide. But they get enrich again when they travel through deep waters all around the the Global conveyer belt.
Hence, the correct answer is option is B "Deep".
Homo means same. hetero means opposite
Answer:
A) The two genes are unlinked and are assorting independently, leading to a 1:1:1:1 ratio of phenotypes in the offspring.
Explanation:
The χ2 value means nothing on its own--it is used to find the probability that, assuming the hypothesis is true, the observed data set could have resulted from random fluctuations. A low probability suggests the observed data is not consistent with the hypothesis, and thus the hypothesis should be rejected. The hypothesis that you are testing are two genes are unlinked and are assorting independently, leading to a 1:1:1:1 ratio of phenotypes in the offspring.
