Cell Division and Chromosome Number

The diagram shows the chromosome number during mitosis. Use it to finish the following sentence.

Mitosis ensures the chromosome number of the daughter cells is __________________ the parent cells, allowing unicellular organisms to reproduce identical offspring _________________.

• identical to; sexually

• half that of; sexually

• identical to; asexually

• half that of; asexually

Tags

NGSS.HS-LS1-4

The diagram shows the phases of mitosis in an animal cell. When does cytokinesis occur?

• After prophase is complete

• After telophase is complete

• During anaphase when the chromosomes are being separated

• During interphase when the DNA is being replicated

Tags

NGSS.HS-LS1-4

Students viewed the cells in onion root tips using a light microscope. They collected data as shown in the table.

What does the data indicate about the cell cycle?

• There are only 36 cells in the tip of an onion root.

• At any given time, most cells will be undergoing mitosis.

• Cells spend most of their time preparing for mitosis.

• Metaphase, anaphase, and telophase are slower processes.

Tags

NGSS.HS-LS1-4

Examine the diagram showing a cell undergoing one of life's processes.

What process is illustrated?

• binary fission

• conjugation

• crossing over

• meiosis

Tags

NGSS.HS-LS1-4

An earthworm has 36 chromosomes in each of its diploid cells. How many chromosomes would be in each of its gametes?

• 12

• 18

• 24

• 36

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

The diagram shows the formation of daughter cells during meiosis and mitosis.

Which statement is correct about the two cell division processes?

• Meiosis and mitosis both occur in all types of cells.

• Meiosis and mitosis produce cells with the same numbers of chromosomes.

• The number of chromosomes in a cell is reduced to half during meiosis but remains the same during mitosis.

• Cellular material is divided equally into daughter cells during meiosis but is divided unequally during mitosis.

Tags

NGSS.HS-LS1-4

Examine the cell process shown in the diagram.

Why is this process significant?

• Mitosis is important in the production of alleles.

• Mitosis is important for the production of diploid cells.

• Meiosis is important in the production of haploid gametes.

• Meiosis is important in the production of clones.

Tags

NGSS.HS-LS1-4

NGSS.HS-LS3-2

Which description distinguishes the process of meiosis from mitosis?

• Unlike mitotic cells, meiotic cells undergo a single division to halve their chromosome number, after which they undergo crossing over to restore their diploid state.

• Unlike mitotic cells, meiotic cells undergo multiple divisions to produce an effectively unlimited array of daughter cells which are genetically identical to the parent cells.

• Unlike mitotic cells, meiotic cells undergo pairing of homologous chromosomes, allowing centromeres to remain intact throughout both cellular divisions.

• Unlike mitotic cells, meiotic cells undergo two divisions to produce haploid cells, allowing for genetic diversity in sexually reproducing organisms.

Meiosis is an important cellular process for organisms that reproduce sexually. Two lab partners (A and B) are shown this diagram of a meiotic cell and asked to identify its phase.

Partner A believes that this cell is in prophase of the first meiotic division. Partner B believes that this cell has moved past prophase of meiosis I and is in a later phase of meiosis.

Which partner is correct, and what evidence accurately would defend their belief?

• Partner A is correct. The chromosomes have clearly replicated during interphase and are beginning to decondense into chromatin.

• Partner A is correct. The nuclear membrane is beginning to re-form and centrioles are beginning to migrate to opposite poles of the cell.

• Partner B is correct. Homologous chromosomes are no longer paired together, so the cell must be in first phase of meiosis II, not meiosis I.

• Partner B is correct. The cell plate is beginning to form between the two centrioles, indicating the cell is actually in later phase of meiosis I.

DNA replication occurs before meiosis I but not before meiosis II. Why is that important?

• It results in uneven division of the cytoplasm.

• It results in increased genetic diversity for the species.

• It results in offspring that are genetically identical to the parents.

• It results in daughter cells with the haploid number of chromosomes.

Tags

NGSS.HS-LS3-2