Answer:
Crossing-over between homologous chromosomes (prophase 1), the random lining of homologous chromosomes (metaphase 1), and random fertilization are the mechanisms involved in genetic variation.
Explanation:
Crossing-over between homologous chromosomes (prophase 1), the random lining of homologous chromosomes (metaphase 1), and random fertilization are the mechanisms involved in genetic variation.
The Crossing-over events occur between two homologous chromosomes in the equatorial plane and make the daughter cells genetically different from the original one. The Chiasma is the position where two homologous chromatids interchange genetic information, giving a place for new genetic material or information to be provided to descendants. After crossing over, homologous chromosomes get separated again.
On the equatorial plane, homologous paired together, randomly aline with their kinetochores facing opposite poles. The random arrangement of tetrads is different in every cell going through the meiosis process. There is no equal alinement between two cells. When tetrads aline in the equatorial plane, there is no predetermined order for each of the homologous chromosomes of each tetrad to face one of the poles and then migrate to it while separating. Chromosomes of the homologous pair arrange to face any of the poles to migrate forward to it. Each of the chromosomes has two possibilities for orientation at the plane. When the new haploid cells are formed, the number of variations in each cell is also different and depends on the chromosomes that form that cell. The order in the equatorial plane is what introduces variation into the gametes, being almost impossible for two gametes to have the same genetic charge.
Independent assortment occurs when the alleles from two or more different genes distribute in gametes independently from each other. In other words, a gamete receives an allele from a gene that does not depend on nor influence the allele of another gene in the same gamete. This can only be applied to independent genes. An organism gets only one of the members of the chromatids pair of each parent.
The natural blind spot is due to lack of receptors where the optic nerve and blood vessels leave the eye. There can also be artificial blind spots when something blocks light from reaching the photoreceptors, or when there is local adaptation of the retina as just after seeing a bright light
Answer:
In the extracellular space
Explanation:
Disulfide bonds are interconnections between chains (or between parts of a chain) formed by the oxidation of cysteine radicals, this reaction is catalyzed by specific enzymes.
Intracellular proteins have no disulfide bonds, which are more common in proteins secreted into the extracellular environment.
Disulfide bonds do not form in the cytoplasm because there are a lot of reducers in the cytoplasm (intracellular environment) , making the disulfide bonds unstable. The reducing environment of cytoplasm causes disulfide bonds (S-S) to return to the form of cysteine groups (-SH).
Answer:
homologous, high levels of, natural selection
