The molecular mechanism of SCE is similar to homologousrecombination between homologs except that the two segmentsof DNA are sister chromatids instead of homologous chromatids.If branch migration occurs during SCE, will a heteroduplex beformed? Explain why or why not. Can gene conversion occurduring sister chromatid exchange?

A researcher examining a root tip observes a plant cell with condensed daughter chromo- somes at each pole and a cell plate at the central plane of the cell. Which of the following best describes what will occur next in the cell? A The nuclear envelopes will break down, and the spindle fibers will begin to form. B с D Sister chromatids will align at the central plane via spindle fibers. The nuclear envelope will break down, and the spindle will begin to form. The chromosomes will decondense, and the daughter cells will enter the interphase.

Crossing over occurs frequently during prophase 1 Play 0:12 / 1:43 1x CC 目: A tetrad is made up of Multiple Choice two homologous chromosomes, each consisting of two chromatids ) four nonhomologous chromatids four nonhomologous chromosomes four homologous pairs of chromosomes MacBook Air 20 F3 000 F2 F4 F5 F6 F7

Recall that the nuclear membrane disintegrates late in prophase of mitosis in most eukarvotic cells. Once the membrane is reformed in telophase in a daughter cell, several components of gene expression mignt therefore be "caught" out in the cytoplasm when they would otherwise onlv ever be found inside the nucleus. Consider where the following components of gene expression are made and where they runction. Which component is normally never found in the cytoplasm outside the nucleus? O A. Spliced intron • B. RNA polymerase O C. Histones • D. DNA polymerase

Describe the similarities and differences between homologousrecombination involving sister chromatid exchange (SCE) and thatinvolving homologs. Would you expect the same types of proteinsto be involved in both processes? Explain.

Why is a chromosome with two centromeres (adicentric chromosome) unstable? Would a backup cen-tromere not be a good thing for a chromosome, giving ittwo chances to form a kinetochore and attach to microtu-bules during mitosis? Would that not help to ensure thatthe chromosome did not get left behind at mitosis?