The randomness in the alignment of recombined chromosomes at the metaphase plate, coupled with the crossing over events between nonsister chromatids, are responsible for much of the genetic variation in the offspring. To clarify this further, remember that the homologous chromosomes of a sexually reproducing organism are originally inherited as two separate sets, one from each parent. Using humans as an example, one set of 23 chromosomes is present in the egg donated by the mother. The father provides the other set of 23 chromosomes in the sperm that fertilizes the egg. Every cell of the multicellular offspring has copies of the original two sets of homologous chromosomes. In prophase I of meiosis, the homologous chromosomes form the tetrads. In metaphase I, these pairs line up at the midway point between the two poles of the cell to form the metaphase plate. Because there is an equal chance that a microtubule fiber will encounter a maternally or paternally inherited chromosome, the arrangement of the tetrads at the metaphase plate is random. Thus, any maternally inherited chromosome may face either pole. Likewise, any paternally inherited chromosome may also face either pole. The orientation of each tetrad is independent of the orientation of the other 22 tetrads.
Explanation:
Answer:
i think A
Explanation:
since its not in front of the moon and at the side it has to be a crescent moon and the sun is on the right side, so pick A
The answer are plants im sure
Answer:
<em> e) Ala</em>
Explanation:
Alpha helix is a secondary structure of proteins, it is made of 3.6 aminoacids residues per turn, this structure is possible thanks to local hydrogen bonding between C=O and N-h groups. The result is a cylindrical structure with a hydrogen-bonded backbone and the outside studded with side chains.
Glycin has an -H in its side chain, this makes it a too flexible molecule, therefore it's unusual to find them in alpha-helical structures because their presence could cause the helix to deform. Large R-groups can also affect this stability, phenylalanine has a bulky aromatic side group, this discards it as a stabilizer. Serine has a hydrogen bond donor or acceptor as a side chain, due to the proximity to the main chain it competes with the main chain to form NH and CO bonds. Alanine is the most common amino acid in alpha-helix structures because it has a short and no charged R group (unlike arginine that even when it's short it has a charged R-group), this makes it flexible enough to keep the structure stabilized.
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Marine mammals , with few exception are viviparous.
Explanation:
- Mammals are those animals which are characterized by the presence of mammary gland and body hair.
- They feed milk to their young ones.
- The vertebrates are classified as viviparous, oviparous and ovoviviparous depending on the way their young ones develop and are nourished during their embryonic and foetal development.
- Viviparous animals are those which directly give birth to their young ones and have a distinct gestation period during which their babues develop inside their womb. These are placental mammals.
- Oviparous animals are those which lay egg and the embryo develops outside mothers body.
- Ovoviviparous animals are those who do not lay their eggs but their eggs hatch inside their body .These are aplacental animals.
- Most mammals are viviparous.
