The answers are: A and B
A. A tubeworm retreating from a predator
B. A large fish chasing is a prey in the sea
<h2>Further Explanation
</h2>
The ability of cells to communicate, that is, receiving and sending signals from and to other cells, determines the interaction between unicellular organisms and regulates the function and development of the body of multicellular organisms. For example, bacteria communicate with each other in the quorum sensing process to determine whether they are sufficient before forming biofilms, while cells in animal embryos communicate to coordinate the process of differentiation into various cell types.
Learn more
Cell communication brainly.com/question/13383183, brainly.com/question/11239574
Details
Class: Middle School
Subject: Biology
Keywords: cell communication
Seafood, white mean, eggs, milk/dairy, Beef
<span>Discovery</span>
The operon model (Lac operon) of the regulation
of gene expression in bacteria was proposed by Jacob and Monod and hey got
noble prize in 1965 in Physiology and Medicine for this discovery.
Definition
<span> “</span><span>Operons are cluster of coregulated bacterial
genes which regulate other genes responsible for protein synthesis” </span>
Explanation
<span>Operons were first studied
in the bacterium E.coli, and they
involve the enzyme of lactose metabolism and tryptophan biosynthesis. </span>
Structure of Operon
<span> </span>Operon is generally
composed of three basic DNA components:
1. Promotor:
<span> It is a nucleotide sequence which is
recognized by RNA polymerase and initiate transcription.</span>
2. Operator:
It is a segment of DNA
that is present between the promotor and other genes to be transcribed. In presence
of repressor, RNA polymerase is physically obstructed and cannot transcribe the
genes. In the absence of repressor, operator is active and start transcription
of other proteins.
3. Structural genes:
<span>These genes are
responsible for synthesis of targeted proteins under the influence of operator<span>. </span></span>
Example of operon model:
<span> In bacteria two operon model have been
extensively studied, these are:</span>
<span> a. Lac Operon, and</span>
<span> b. Tryptophan operon</span>