If a bacterial cell undergoing binary fission failed to replicate its dna before the division process occurred, what might result?
*each daughter cell would continue on with one-half of the parent cell’s genes.
*one daughter cell would receive no dna but would continue to survive because it acquired all other cell components.
*at least one cell would die because it would not have a complete copy of every gene.
*the cell would switch to a sexual mode of reproduction.
4. an advantage of sexual reproduction over asexual reproduction is that sexual
takes less time.
requires more time.
provides genetic diversity.
produces identical offspring.

3. The right answer is At least one cell would die because it would not have a complete copy of every gene.

Although this is possible, it is very unlikely that replication stops occurring, thanks to the highly efficient replication and repair system.

The fidelity of replication is very large and it is largely due to the DNA polymerase, which incorporates the nucleic bases according to the complementarity of Watson-Crick pairings (A-T, C-G). Indeed, this very low error rate of DNA polymerase during replication is due to the fact that the replicative DNA polymerases have a replay activity that allows them to verify that the last nucleotide incorporated is the correct one.

In case of error, the DNA polymerases (I and III) correct them by means of their 3 '→ 5' exonuclease activity. This allows the polymerase to back up a notch by removing the incorrect nucleotide that is hydrolyzed, and then resume synthesis of the DNA strand.

Before this reading of the DNA the error rate is about 10-5 (one error per hundred thousand replicate bases) which is very little considering the number of bases replicated per second which is about 500 bases per second in bacteria. The replay step drops the replication error rate to about 10-7. Finally, the errors that may have escaped this control mechanism are then repaired in the double-stranded DNA by a specific mismatch repair mechanism (MR). The entire device is therefore an extremely efficient system since the error rate drops to about one mutation for 10 billion replicate bases.

4. The right answer is provides genetic diversity.

The advantages of sexual reproduction are:

• Produces a new organism that is a combination of traits from parents

• Creates increased genetic variability of organisms of the same species and even among the offspring of a single pair

• In the long term, allows the best adaptations to be spread within a species, especially in a changing environment

• The variability of organisms within a single sexed species ensures that a greater proportion will survive in perilous circumstances

• There may be two parents who look after the offspring

you are certainly talking about this picture:

a: is the label of the white square, it is showing the  replication fork, formed by helicase (d) ==> so it is the site of dna separation and replication 

b: is a new dna brand that is following directly the replication fork, so it is continuous ==> built continuously from 5' to 3

c: dna polymerase cannot replicate dna on its own, it needs the of their proteins, and one of them plays the role of a clamp which fixes  the dna with the dna template and increases  the processivity of the enzyme. ==>   stops polymerase from falling off the  template.

d: is the enzyme responsible for forming the replication fork (helicase) ==> unwinds and separates dna into two strands

e: is the delayed strand, it is built  in the opposite sense of the helicase, so dna will be built in fragments ==> built  fragments from 5' to 3 joins

and finally f: is the enzyme that builds  the new dna strand (dna polymerase) ==>   adds nucleotides to make a new dna helix.

credit: gradman555p98x9p

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