I believe the answer is During<span> prophase
</span>The nucleus during mitosis. Micrographs illustrating the progressive stages ofmitosis<span> in a plant cell. </span>During<span> prophase, the chromosomes condense, the </span>nucleolus<span>disappears, and the </span>nuclear envelope<span> breaks down. At metaphase, the condensed chromosomes </span>
Answer:
The correct answer is D)RNA polymerase
Explanation:
In DNA replication many enzymes and proteins are required to replicate a DNA template. For initiation of DNA synthesis the two DNA strands must be separated which is done by helicase.
Then primase adds short nucleotide sequence and initiate DNA replication. After that DNA polymerase acts and adds nucleotide at the 3' end of growing DNA strand. Ligase is the enzyme that joins the two Okazaki fragments that are created in the lagging strand.
RNA polymerase is not required in DNA replication and it works in transcription therefore the correct answer is RNA polymerase.
Mammalian fertilization comprises sperm migration through the female reproductive tract, biochemical and morphological changes to sperm, and sperm-egg interaction in the oviduct. Recent gene knockout approaches in mice have revealed that many factors previously considered important for fertilization are largely dispensable, or if they are essential, they have an unexpected function. These results indicate that what has been observed in in vitro fertilization (IVF) differs significantly from what occurs during “physiological” fertilization. This Review focuses on the advantages of studying fertilization using gene-manipulated animals and highlights an emerging molecular mechanism of mammalian fertilization.
