Answer:
The answer to this question is given below in this explanation section.
Explanation:
"Alternation of generation"
Alternation of generations is the type of life cycle that occurs in those plant and algae in the archaeologist and the heterokontophyta that have distinct haploid sexual and diploid asexual stages.In these groups a multicellular haploid gametophyte with n chromosomes alternates with a multicellular diploid sporophyte with 2n chromosomes made up of n pairs.A mature sporophyte produces haploid spores by meiosis a process which reduces the number of chromosomes to half from 2n to n.
Two haploid spores germinate and grow into a haploid gametophyte.At maturity ,the gametophyte produces gametes by mitosis which does not alter the number of chromosomes.Two gametes from different organism of the same species fuse to diploid zygote,which develop into a diploid sporophyte . This cycle from gametophyte to sporophyte in the way in which all land plant and many algae undergo sexual reproduction.
Answer:
Its cells have thick, hard walls.
Explanation:
Equal amounts of radioactivity in the two daughter cells
Answer:
The major secretions of the adrenal cortex (Box 4.2) are cortisol (the main ... for steroid synthesis is captured by receptors which bind low-density lipoproteins (LDL) ... It is essential to do this slowly and progressively to avoid precipitating acute
Explanation:
Answer: A
Explanation:The Trp operon is responsible for synthesis of the amino acid trytophan when it is not available in the cellular environment.
When the tryptophan is plentiful, a repressor protein binds to two molecules of tryptophan.
Thiss repressor-tryptophan complex binds to the trp operator. This binding prevents the binding of RNA polymerase, so the operon is not transcribed, and no new trptophan is produce.
On the other hand, when tryptophan levels are reduced, the inactive repressor will not bind the tryptophan operator so the operon is transcribed.
Regulation of the trp operon is determined by the concentration of tryptophan; when adequate tryptophan is present in the growth medium, there is no need for tryptophan biosynthesis.
Transcription is turned off when a high concentration of tryptophan is present, and is turned on when tryptophan is absent. The regulatory signal is the concentration of tryptophan itself.
Therefore in the absence of tryptophan, the inactive repressor cannot bind trpO, so operon gene transcription occurs.
