Grade 10 – Mitosis and the Cell Cycle (2025)

30 question-and-answer flashcards covering chromosome structure, DNA replication, the cell cycle, mitosis phases, and cytokinesis differences.

What are chromosomes?

Thread-like structures in the nucleus composed of DNA and histone proteins.

What is the primary hereditary role of chromosomes?

They transfer genetic characteristics from one generation to the next.

What is the chromatin network?

The mass of long, thin DNA threads seen when a cell is not dividing.

How do chromosomes change as a cell enters division?

Chromatin condenses into shorter, thicker, visible single-stranded chromosomes.

Around which proteins is DNA helically wrapped?

Histones.

Define a gene.

A specific segment of DNA that controls a particular hereditary characteristic.

What must occur to nuclear DNA before a cell divides?

All genetic material must be duplicated by DNA replication.

What is DNA replication?

The process by which DNA makes an identical copy of itself.

After replication, what does one chromosome consist of?

Two identical sister chromatids.

What structure joins sister chromatids together?

The centromere.

What is the cell cycle?

The series of events leading to cell growth, DNA duplication, and division into two daughter cells.

Approximately how long does one complete cell cycle take in human cells?

About 25 hours.

What is binary fission and where does it occur?

A simple cell-division process in prokaryotes that produces two cells without a nucleus-stage mitosis.

Name the three main stages of the eukaryotic cell cycle.

Interphase, mitotic (M) phase, and cytokinesis.

Which stage of the cell cycle occupies the greatest amount of time and what are its general functions?

Interphase; cell growth, nutrient accumulation, and DNA replication.

List the three sub-phases of interphase and a key event in each.

G1 – growth and organelle production; S – DNA replication; G2 – final growth and preparation for mitosis.

Give two examples of cells that generally do not undergo mitosis.

Mature red blood cells and muscle cells (also mature nerve cells).

Define mitosis.

Division of a single nucleus into two genetically identical daughter nuclei.

What are the two major stages included in mitosis?

Karyokinesis and cytokinesis.

State the four distinct phases of karyokinesis in order.

Prophase, metaphase, anaphase, telophase.

List four key events of prophase.

Chromatin condenses; chromosomes become double-stranded; nuclear membrane and nucleolus disappear; spindle fibers form as centrioles move to poles.

What characteristic arrangement do chromosomes assume in metaphase?

They line up single-file along the equator of the cell.

How are chromosomes held to the spindle during metaphase?

Spindle fibers attach to each chromosome at its centromere.

What happens to sister chromatids in anaphase?

They separate and move to opposite poles, becoming individual daughter chromosomes.

Which protein complex breaks down to allow chromatid separation in anaphase?

Cohesin.

Give three key events of telophase.

Daughter chromosomes reach poles; nuclear membranes and nucleoli re-form; spindle fibers disappear (karyokinesis complete).

How does cytokinesis differ between animal and plant cells?

Animals form a cleavage furrow that pinches the cell; plants build a cell plate (new wall) at the equator.

What is a cleavage furrow?

The indentation of the cell membrane in animal cells that deepens to split the cell during cytokinesis.

What is a cell plate?

A new transverse wall forming at the equator of dividing plant cells during cytokinesis.

Why is cytokinesis essential?

It divides the cytoplasm and organelles, ensuring each daughter cell obtains a full complement of cellular components.