Khan - 2C - Cellular division questions

Oogenesis, the process that creates female gametes, is halted at __ until puberty.

prophase I

Oogenesis, the process that creates female gametes, is halted at prophase I until puberty. Which of the following describes the DNA content of a female's gametes during her childhood?

46 chromosomes, 92 chromatids -Prophase I is the first step of the first division of meiosis. -A chromatid is a single copy of the genetic information, while chromosomes are counted by the number of centromeres. -In prophase I the cell has undergone DNA replication, but has yet to divide, leaving it with 46 chromosomes and 92 chromatids.

Which statement best describes chromosomal movement during mitosis? Centrioles send out asters, which bind to kinetochores to pull chromatids apart. Centrioles on chromatids bind kinetochores to rays sent by the asters. Microtubules bind tubulin polymers on centromeres to initiate homologous chromosome separation. Each centrosome binds an individual chromatid to ensure equal division.

Centrioles send out asters, which bind to kinetochores to pull chromatids apart. -The kinetochore is a protein structure centered around a chromosome's centromere. -Centromeres are found on chromosomes, centrosomes are found towards the poles of cells during cell division. -Asters are microtubules sent out by centrioles to bind kinetochores, and microtubule contraction helps pull chromatids apart.

A karyotype can be used to check for certain chromosomal mutations. In what cell cycle phase can cells be karyotyped?

Metaphase A karyotype is used to visualize separate chromosomes. Chromosomes do not begin to condense until prophase. A karyotype shows DNA as pairs of Xs - chromosomes composed of sister chromatids.

Oogenesis and spermatogenesis describe the process of meiosis in females and males respectively. What statement about the two processes is true?

Oogenesis produces a larger gamete than spermatogenesis -Cytoplasmic division is unequal in oogenesis. -Oogenesis produces one large oocyte and 2 polar bodies, while spermatogenesis produces four sperm cells with equal cytoplasmic volumes.

During which phase does the nuclear envelope begin to disappear?

Prometaphase -The nuclear envelope is responsible for protecting the genetic material from the rest of the cellular contents. -In anaphase, chromosomes move to opposite sides of the cell. -In order to allow for proper metaphase alignment and chromosomal division, the nuclear envelope dissolves in prometaphase.

Colchicine is a drug used to treat gout. It also happens to arrest cells in anaphase. Which cytoskeletal protein does colchicine effect?

Tubulin Anaphase is the stage where sister chromatids are pulled apart. Microtubules from centrosomes bind chromosomal kinetochores to separate the genetic material. Microtubules are made from tubulin, a protein that can be bound by colchicine. By binding the tubulin, colchicine inhibits tubulin polymerization, and so prevents microtubules from being formed.

Centrioles can be found in:

eukaryotes only