The probability is 1/16 that a gamete will receive only paternal chromosomes. In life
cycles that alternate between haploid and diploid stages, fertilization doubles
the number of chromosomes per cell, The pairing of chromosomes along
their lengths , which is essential for crossing over is referred to as synapsis
Answer:
a. Trisomic
Explanation:
A trisomy is a genomic phenomenon whereby a particular chromosome is present in three copies. In this case, the trisomy involves the chromosome P, being this species a tetraploid with 5 pairs of homologous chromosomes (2n = 10). In humans, the trisomy for chromosome 21 is one of the most common types of aneuploidies that lead to the Down syndrome by producing alterations in gene expression patterns that are associated with changes in the phenotype
Answer:
a. DNA polymerase proofreading: consequence of its absence is the DNA mutation
b. Mismatch repair enzymes
: consequence of its absence impedes homologous recombination resulting in the final mutation
c. Nucleotide excision repair enzymes
: the absence of nucleotide cleavage repair enzymes would impede the functioning of damaged DNA repair mechanisms
Explanation:
a. DNA polymerases are the enzymes that form the DNA in cells. During DNA replication (copying), most DNA polymerases can "check their work" with each base they add. This process is called review. If the polymerase detects that you have added a wrong nucleotide (incorrectly paired), remove it and replace it immediately, before continuing with DNA synthesis
b. In homologous recombination, the information from the homologous chromosome that matches that of the damaged one (or from a sister chromatid if the DNA has been copied) is used to repair the fragmentation. In this process the two homologous chromosomes are approached and the undamaged region of the homologue or the chromatide is used as a template to replace the damaged region of the broken chromosome. Homologous recombination is "cleaner" than the union of non-homologous ends and does not usually cause 11 mutations
c. Excision repair: damage to one or a few DNA bases is usually fixed by removing (excising) and replacing the damaged region. In repair by base cleavage, only the damaged base is removed. In nucleotide excision repair, as in the mating repair we saw earlier, a nucleotide section is removed
First would be A Second would be c\
