Answer:
allows the recombination of genetic information
Explanation:
Crossing over is a process that occurs only in meiotic division in sexually reproducing organisms. It is the process whereby the segments of a gene are exchanged between the non-sister chromatids of homologous chromosomes.
Due to this crossing over process that occurs in prophase I of meiosis, the alleles of a chromosomes are recombined to ensure genetic diversity. Hence, according to this question, crossing over results in additional genetic variation during meiosis because it allows the recombination of genetic information.
Answer:
Electrons are many thousand times smaller than the nucleus and negatively charged.
Explanation:
Electrons possess negligible mass and carry a negative charge.
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DNA replication occurs in the 5 prime (5') to 3 prime (3') direction.
I'm sure you've heard this many times. I tutor in genetics, and all of my students can rattle that off. Less understand what it means.
First, understanding what 5' and 3' mean is important. DNA is composed of a ribose sugar, a phosphate group, and a base (A,T,G,C). The sugar has a phosphate group attached to its fifth carbon, and a hydroxyl group on its 3rd carbon. Nucleotides (separate components of DNA) are linked by the phosphate group and the hydroxyl group. So, every nucleotide is linked at the phosphate group and the hydroxyl group besides two - the two nucleotides at either end of the strand of DNA. The one that leaves a phosphate group exposed is called the 5' end of DNA, and the one that leaves a hydroxyl group exposed is called the 3' end of DNA.
<span>A problem with many students just memorizing that replication occurs in the 5' to 3' direction is that there are two strands of DNA involved in replication. DNA polymerase (the major enzyme responsible for replication) reads the already existing strand of DNA in the 3' to 5' direction, and creates the new strand of DNA in the 5' to 3' direction (meaning that it adds nucleotides to the 3' end of the new strand).</span>
What do the different organelles tend to have in common? What are their common differences?
