Answer:
Mechanisms enabling one cell to influence the behavior of another almost certainly existed in the world of unicellular organisms long before multicellular organisms appeared on Earth. Evidence comes from studies of present-day unicellular eucaryotes such as yeasts. Although these cells normally lead independent lives, they can communicate and influence one another's behavior in preparation for sexual mating. In the budding yeast Saccharomyces cerevisiae, for example, when a haploid individual is ready to mate, it secretes a peptide mating factor that signals cells of the opposite mating type to stop proliferating and prepare to mate (Figure 15-2). The subsequent fusion of two haploid cells of opposite mating types produces a diploid cell, which can then undergo meiosis and sporulate, generating haploid cells with new assortments of genes.
Explanation:
Brainliest please?
Answer:
The main function is protection, breathing and support.
Explanation:
An exoskeleton covers the entire surface of arthropod animals, such as arachnids, insects, crustaceans, etc. Its main function is the protection, breathing and support of the muscular system, favoring its fossilization.
Answer:
1-Wegener was a German meteorologist, geophysicist and polar researcher. In 1915 he published 'The Origin of Continents and Oceans', which outlined his theory of Continental Drift. Wegener was a member of four expeditions to Greenland.
2-The evidence for continental drift included the fit of the continents; the distribution of ancient fossils, rocks, and mountain ranges; and the locations of ancient climatic zones.
3-The movement of these tectonic plates is likely caused by convection currents in the molten rock in Earth's mantle below the crust. ... The long-term result of plate tectonics is the movement of entire continents over millions of years
Answer:
A) purine
Explanation:
There are two ways for the synthesis of purines and pyrimidines:
- de novo synthesis-from basic simple units
- "recycling" synthesis-reuse of metabolites
Purines are synthesized directly on ribose sugar, in segments.
Pyrimidines are attached to the ribose after the synthesis of the base.
5-Phosphoribosyl-1-pyrophosphate (PRPP). is used for the synthesis of purine (ribose 5-phosphate reacts with ATP to form ribonucleotide).
