The exercise tells you to complete the table showing different cases of mutation in different parts of the operon.
First, what is an operon?An operon is a genetic unit of coordinated expression. It comprises a group of adjacent structural genes encoding the enzymes of the same metabolic pathway, as well as the regulatory sequences affecting the transcription of these structural genes (like operon lactose or tryptophan). It is composed by:
Structural genes/cistrons: code for the enzymes participating in the same metabolic pathway, they are co-transcribed into a single polycistronic mRNA.
• Promoter common to all structural genes: this is the binding site of RNA polymerase.
• The operator: it is a regulatory sequence, it is the site of binding of the protein of the regulation, it controls the transcription of the gene downstream.
• The regulatory gene: located upstream of the operon promoter, it encodes regulatory proteins capable of binding on the operator. He owns his own promoter.
*If a mutation touch one of the genes that the operon code for, this gene will be not functional
*If a mutation touches the operator none of the enzymes will be synthesized
*If a mutation touches a repressor (a molecule which inhibits the expression of the operon genes by binding specifically to the DNA at the operator level).
Based on this, the right answers are:
Mutant 1 ==> gene A
Mutant 2 ==> repressor
Mutant 3 ==> gene B
Mutant 4 ==> promoter
Symbiotic Relationship.
Hope this helps.
The answer should be D, because it’s always good to provide statistics
To complete the statement above:
Ions are transported across membranes using channel-mediated facilitated diffusion; which requires <span>kinetic energy.
The channels can be opened by the requirements of the cell. Transmembrane proteins, called transporters, utilize the vitality of ATP to drive particles or little atoms through the layer against their focus angle.
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Answer and Explanation:
When mRNA leaves the nucleus and meets a free ribosome in the cytosol, it starts the protein building. Ribosomes read the mRNA code and begin protein synthesis by adding the correct amino acid using transference RNA.
Ribosomes attached to the RER membrane are responsible for synthesizing membrane proteins, exportation proteins, or enzymes.
The synthesis of proteins destined to become enzymes, membrane proteins, or exportation proteins starts in the cytoplasm with the production of a molecule portion known as a signal aminoacidic sequence. This signal sequence in the amino extreme of the synthesizing protein, and when it reaches a certain length, it meets the signal recognizing particle that leads the synthesizing protein and associated ribosome to the Rough endoplasmic reticulum, where it continues the protein building until finishing the elongation process. When the new protein synthesis is complete, the polypeptide is released into the reticulum lumen, suffering a few posterior steps related to conformation and structure, such as folding to become functional and the initial glycosylation stages.
The new proteins get packaged into vesicles that carry them to the Golgi complex where occurs the final association of carbohydrates and lipids with proteins, to originate glycoproteins and glycolipids.
Enzymes destined for exportation are packaged and sent from the Golgi complex to the cell membrane into vesicles. When the secretory vesicle reaches the target, its membrane fuses with the cell membrane, releasing its content to the extracellular space. This secreting process is known as exocytosis.