Answer:
The ability of sequences within the leader mRNA to pair with one another and form stem-lopp structures
Explanation:
A form of feedback regulation controls the trp operon by regulating transcription termination, a mechanism referred to as Attenuation.
-In the presence of high concentrations of tryptophan, RNA polymerase ceases transcription shortly after initiation in a region called the leader sequence.
-If the concentration of tryptophan is low, transcription does not terminate until the entire operon is transcribed. The mechanism of attenuation links alternative RNA secondary structures to transcription termination.
-Immediately after transcription, RNA from the leader region folds into one of two alternative secondary structures.
-One of these structures is a transcription termination signal that stops RNA polymerase from continuing to the end of the operon.
-The alternative structure does not contain a transcription termination signal and allows transcription of a single mRNA that encodes all the structural genes.
-The decision as to which of the two alternative RNA structures formed is regulated by the concentration of tryptophan.
Due to natural selection in finding a mate, t<span>he </span>color<span> of the </span>dewlap would start to lighten slightly in order also to <span>adapt to their surroundings.</span>
Rhinoviruses and herpes simplex are just two common viruses out of the other thousands of them that the immune system has to protect the body against.
The process of fertilization involves the deposition of sperms into the vagina to the egg cell during sexual intercourse. Sperms make their way towards the cervix and uterus, and eventually goes to the fallopian tubes. <span>Only a few hundred will remain as they interact with the egg through the use of their heads and movement patterns.
</span><span>The process of implantation happens when the embryo, the fertimized eggs develops inside the fallopian tube after three days, and then travels to the uterus.</span>
Answer:
Option-D
Explanation:
In the given question the genotype of parental allele is- AbaB X AbaB. The alleles formed will be- AB, Ab,aB, ab in which the crossover allele will be AB and ab.
1. Unlinked genes
Now of these alleles are unlinked then the alleles will assort independently of each other therefore performing the punnett square we will get dihybrid ratio as 9:3:3:1 in which
1. A_B_ are 9
2. aaB_ are 3
3. A_bb are-3
4. aabb- 1
Since the crossover allele are AB and ab therefore A_B_ are 9 and aabb- 1 represent recombinant genotype.
2. Linked genes
When the genes will be linked then chances of crossing over will be reduced as a result of which only two type of allele will be formed which are- Ab and aB and the recombinant frequency will become less.
Crossing these allele will form Aabb
, AaBb
, AaBb and aaBB genotypes.
The recombinant ratio will decrease as A_B_ is 2 and aabb is not present.
Thus, option-4 which states that the unlinked ration is 9:3:3:1 and linked ratio is <9: >3: >3: <1 is correct.
