Double-stranded DNA loops around 8 histones twice, forming the nucleosome, which is the building block of chromatin packaging. DNA can be further packaged by forming coils of nucleosomes, called chromatin fibers. These fibers are condensed into chromosomes during mitosis, or the process of cell division.
Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.
During DNA packaging, long pieces of double-stranded DNA are tightly looped, coiled, super coiled, and folded so that they fit easily within the cell. This highly compacted DNA is then arranged into structures called chromosomes.
<span>Similarities and differences between intramembranous and endochondral ossification<span>
Ossification is the process of bone formation. Intramembranous and endochondral ossification are the two main processes of bone formation that occur during fetal development.
</span>Similarities between intramembranous and endochondral ossification<span>; they turn cartilage into bones during bone formation and they both involve bone cells such as calcium, vascular supply and osteoblasts.
</span>Differences between intramembranous and endochondral ossification<span>; In intramembranous ossification, an intermediate cartilage is not involved, rather the bone tissue is directly laid on a primitive connective tissue called mesenchyma while in endochondral ossification, cartilage is used as a precursor for bone formation. Also, in cases of fractures, the healing process by plaster of Paris occurs through endochondral ossification while fractures which are treated by open reduction and internal fixation are healed by intramembranous ossification.
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Answer:
1) Founder effect and genetic drift: Small colonizing population did not represent the original gene pool of the source population and was more likely to undergo genetic drift.
2) Natural selection
Explanation:
Evolution of the population of the finches with larger beaks might have occurred due to one of the following mechanisms:
a) Founder effect and genetic drift: Since the size of the colonizing population was small, it did not carry all the genes and their alleles present in the gene pool of the original population. The small population size made it more likely to evolve by any chance event.
b) Natural selection: The availability of different food types in the new habitat led to the natural selection of the larger beaks as the finches with larger beaks might have been able to better exploit the available food resources.
Answer: Audiovisual mirror neurons and action recognition
Explanation:
These are groups of neurons in the ventral premotor complex, that discharge responses both when the an individual performs a specific action and when he hears or see the same action executed by another person.
