Question

the strand of dna in the figure above that will be copied first as a series of fragments later joined together by dna ligase is labeled how?
○ the leading strand is labeled with 5.
○ the lagging strand is labeled with 3.
○ the lagging strand is labeled with 5.

question 8
2 pts
which of the following is not a main category of sexual life cycle in multicellular organisms?
○ chiasma-dominant
○ diploid-dominant
○ alternation of generations

Explanation:

First Question (DNA Replication)

1. Recall DNA replication: The lagging strand is synthesized as Okazaki fragments (fragments later joined by ligase), and it is synthesized in the 5' to 3' direction but faces the replication fork in a way that it's copied discontinuously. The lagging strand's template has a 3' to 5' orientation, but the newly synthesized lagging strand is built from 5' to 3', and the template for the lagging strand (the one being copied into fragments) has a 3' end? Wait, no—wait, the DNA strand labeled with 3' or 5' here: the lagging strand is synthesized from 5' to 3', and its template is the one with 5'? Wait, no. Let's clarify: DNA polymerase adds nucleotides only to the 3' end. So the leading strand is synthesized continuously (template is 3' to 5'), and the lagging strand's template is 5' to 3' (so the new strand is made in fragments, 5' to 3', each fragment starting with a primer). So the strand that is copied as fragments (lagging strand's template) – wait, the question is about the strand being copied (the template) that leads to the lagging strand. Wait, the options: "The lagging strand is labeled with 3'." No, wait: the lagging strand (newly synthesized) is made in fragments, but the template for the lagging strand is the one with 5'? Wait, no. Let's re-express: The two DNA strands are antiparallel. The replication fork has a leading strand (synthesized continuously, template is 3' to 5') and a lagging strand (synthesized discontinuously as Okazaki fragments, template is 5' to 3'). So the strand being copied (template) for the lagging strand is the one with 5' (since the template runs 5' to 3', so the new strand is made 5' to 3' in fragments). Wait, the options: "The lagging strand is labeled with 5'." Wait, no—the template for the lagging strand is labeled with 5'? Wait, the figure shows a 3' and 5' labeled strand. The lagging strand (the new strand) is synthesized in fragments, but the template for it is the one with 5' (because the template is 5' to 3', so DNA polymerase can't follow the fork, so it makes fragments). Wait, the correct option: "The lagging strand is labeled with 5'." Wait, no—wait, the leading strand's template is 3' to 5', so the leading strand is synthesized continuously. The lagging strand's template is 5' to 3', so the lagging strand (new strand) is made in fragments. So the strand being copied (template) that results in the lagging strand (new) is the one with 5' (the template). Wait, the question is: "The strand of DNA in the figure above that will be copied first as a series of fragments later joined together by DNA ligase is labeled how?" So the strand being copied (template) for the lagging strand (new, made in fragments) is the one with 3'? No, wait, no. Let's think again: DNA polymerase can only add to the 3' end. So the leading strand: template is 3' to 5', so new strand is 5' to 3', continuous. Lagging strand: template is 5' to 3', so new strand is 5' to 3', but since the template is 5' to 3', the polymerase has to go back (discontinuously), making Okazaki fragments. So the template for the lagging strand (the one being copied into fragments) is the 5' labeled strand? Wait, the options: "The lagging strand is labeled with 5'." Wait, no—the lagging strand (new) is labeled with 5'? Or the template? Wait, the question says "the strand of DNA in the figure... that will be copied first as a series of fragments" – so the template strand. So the template for the lagging strand (new, made in fragments) is the one with 5' (because the template is 5' to 3', so the new strand is made in fragments). Wait, the correct a…

1. Recall sexual life cycles in multicellular organisms: The main categories are diploid-dominant (e.g., humans), haploid-dominant (e.g., some fungi), and alternation of generations (e.g., plants). "Chiasma-dominant" is not a main category of sexual life cycles. Chiasmata are structures formed during meiosis for crossing over, not a life cycle category.

Answer:

The lagging strand is labeled with 5'.

Second Question (Sexual Life Cycles)