Answer: the answer is mutualism. please give me brainliest
Explanation: Mutualism is a relationship between two different species in which both species have benefits. In this example, ants benefit because they feed on aphids' wastes while aphids benefit because ants provide them protection.Jul 8, 2016
Pie chart, I'm pretty sure
Answer:
a. The directionality of the complementary strand is antiparallel. The double-stranded DNA is antiparallel comprising two strands, which run alongside each other, however, point in reverse directions. In a double-stranded molecule of DNA, the 5 prime ends of one strand align with the 3 prime ends of the other strand, and vice versa.
b. The mediation of base pairing is done by non-covalent hydrogen bonds. It is reversible, that is, the strands can separate and can come combined again without any chemical modification.
The specificity of base pairing is illustrated by hydrogen bonds that is, the first strand produces hydrogen bonds only with a particular base in the second strand, and these two bases produce a base-pair.
c. The interaction or association of non-covalent type, that is, hydrophobic interaction and hydrogen bonding. Collectively, they both are strong. In the process, one base associate with the other base on the complementary strand.
d. The phosphate backbone possesses the tendency to associate with water on the outside of the molecule, and this is favorable chemically as both the strands are held together by hydrogen bond and hydrophobic interaction.
The polar molecules of sugar can produce hydrogen bonds with the surrounding molecules of water. The negatively charged phosphate group associate with the positively charged ions. The nonpolar nitrogen bases are found within the molecule and associate favorably through stacking interactions.
Answer:
a. tryptophan levels are low.
Explanation:
Attenuation occurs when the tryptophan level in the cell is high so there is no need to synthesize tryptophan any more. In this situation, tryptophan mRNA synthesis comes to an end.
Attenuation is based on two following attributes:
(1) Translation dependent transcription
(2) Ability of RNA to assume alternative secondary structures.
Leader peptide is 16o nucleotide long region which contains 4 regions named as R1, R2, R3 and R4. In R1 region there are 2 tryptophan codons while after R4 region there is a polyU sequence. It it only after leader peptide, tryptophan biosynthesis genes are present in tryptophan operon.
When tryptophan levels in the cell are high, ribosome at R1 region immediately clears the region without any halt as a result of which R1 is able to pair up with R2 and R3 is able to pair up with R4 making a secondary structure i.e. hair pin structure. Soon after that there is a polyU sequence. This is a perfect condition for rho independent transcription termination.
This phenomenon helps in conserving the energy by inhibiting transcription in cell when tryptophan is not required because it is already present in abundance.
In contrast to this, when tryptophan levels are low, transcript is supposed to be transcribed so as to enhance the level of tryptophan in the cell. In such situation, the tRNA charged with tryptophan amino acid is in scarcity so the ribosome keeps waiting for this charged tRNA in R1. Since ribosome has occupied this region, R1 will be unable to pair up with R2. So R2 will pair up with R3. Since R3 has paired up with R2, it will not be able to pair up with R4. So a <u>secondary hair pin structure</u><u> </u><u>immediately followed up by polyU sequence will not form and hence transcription by RNA polymerase will go on. </u>
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The hawk would get the least energy because it is at the top of the food chain, and 90% of energy is released into the environment on each level