It has the highest rate of chemical weathering because chemical weathering occurs much faster in hot, humid climates. This makes rain forests a target for <span>chemical weathering, and in hot seasons, the weathering skyrockets.</span>
Answer:
- Duplex RNA (dsRNA) can suppress the expression of a gene.
- miRNAs are short, single strands approximately 21 nucleotides long.
- miRNAs suppress gene expression by interfering with transcription.
- RNA interference can temporarily suppress the expression of a target gene.
Explanation:
The RNA interference (RNAi) mechanism is a naturally occurring biological process by which an organism suppresses gene expression by using sequence-specific small non-coding RNAs that are complementary to RNA (posttranscriptional silencing) or DNA (transcriptional silencing) sequences. Since its discovery, this mechanism has been exploited in molecular biology to control the expression of target genes. There are different classes of non-coding RNAs which are able to trigger RNAi gene silencing: microRNAs (miRNAs), small interfering RNAs (siRNAs), piwi-interacting RNAs (piRNAs, only present in animals), etc. During their functioning, these non-coding RNAs are loaded into the RNA-induced silencing complex (RISC) to direct them to target sequences and trigger RNAi (for example, by cleaving target mRNAs). miRNAs are short, evolutionary conserved RNAs, that associate to the RISC complex in order to trigger both transcriptional and posttranscriptional gene silencing. During their biogenesis, small non-coding RNAs are double-stranded RNA (dsRNA), but they lose a strand (the passenger strand) when associate with the RISC complex, conserving only one strand (the guide strand) that bind by complementary base pairing to target sequences (either DNA in the nucleus or RNA in the cytoplasm).
Answer: Acetyl-CoA
Explanation:
Acetyl-CoA can be obtained from the pyruvate, the end product of aerobic glycolysis. Also, Acetyl-CoA is the one of the starting materials of citric acid cycle.
For lipid synthesis, biotin carries activated CO2 that is incorporated into acetyl-CoA to form Malonyl-CoA, which is then elongated to yield various lipids of different length.
Thus, Acetyl-CoA is the building block of lipid synthesis
The
correct answer is RNA.
<span>
The
central dogma explains the flow of genetic information within a biological
system. It is a simplified explanation for a gene expression. DNA is copied
into mRNA during the process of transcription and the proteins are synthesized
using the information in mRNA during the translation.</span>
Answer: hybridisation between related species is unlikely to contribute to adaptive speciation.
Explanation: any population has natural genetic variation. The available resources are insufficient for all plants (and conversely, not all offspring survive). Natural selection favours variations better suited to the conditions.
Although hybridisation is more common in plants than animals, and can lead to speciation, adaptive radiation from an ancestral species is the general response to environmental change, such as from rainforest to savanna. There is low probability of selective advantage from hybridisation of two ancestral species adapted to niches within the original habitat when the conditions in those niches changes significantly.
