Answer:
endocytosis
Explanation:
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Answer:
<em><u>Eukaryotic cells</u></em> contain membrane-bound organelles, such as the nucleus, while <em><u>prokaryotic cells</u></em> do not. Differences in cellular structure of prokaryotes and eukaryotes include the presence of mitochondria and chloroplasts, the cell wall, and the structure of chromosomal DNA.
Answer:
Genes coding for proteins involved in chiasma formation.
Explanation:
Chiasma is the connecting link between two non sister chromatids from homologous chromosomes. At chiasma chromosomal crossover takes place in which the genetic material is exchanged between the chromatids. During meiosis aneuploidy occurs if chiasma is absent or impaired due to a mutation in genes encoding for proteins involved in chiasma formation.
Aneuploidy is characterised by presence of abnormal number of chromosomes in cells. They can be 45 or 47 in number apart from the usual 46. Due to impaired chiasma, chromosome pair fails to separate and is passed on to the egg or sperm as it is hence there is one gamete with an extra chromosome and one gamete with a less chromosome. Aneuploidy can result in many genetic disorders like three copies of chromosome 21 can result in Down syndrome.
Genetic drift= Evolution that occurs as a result of chance events.
During inhalation, you breathe in and this contracts the diaphragm and moves downwards. This increments the chest cavity space which means the lungs are expanding. The intercostal muscles or the muscles in between the ribs also aids in the enlargement of the chest cavity. Both muscles contract to pull your rib cage upward and outward when you inhale. As your lungs expand, air is sucked through your nose and mouth. It then travels down to the windpipe and into the lungs to the bronchus, bronchioles and eventually in the alveoli where air exchange between carbon dioxide and oxygen happens.
The additional accessory muscles of respiration are typically used only under conditions that are of high metabolic demand or respiratory dysfunction. However, in instances where these muscles become stiff and hard, expansion of the rib cage can be quite restricted. The accessory muscles of respiration include sternocleidomastoid and the scalene muscles namely anterior, middle and posterior scalene. Both aid in elevating the rib cage. However, their involvement seems to depend on the degree of respiratory effort. During quiet breathing, the scalenes are consistently active at certain phases while the sternocleidomastoid is quite.