Core Biology 1 Exam 3 Study Guide – Step-by-Step Guidance

Q1. Describe the difference between the mitotic phase and mitosis.

Background

Topic: Cell Cycle and Cell Division

This question tests your understanding of the stages of the cell cycle, specifically distinguishing between the overall mitotic phase and the process of mitosis itself.

Key Terms:

• Mitotic phase (M phase): The part of the cell cycle that includes both mitosis and cytokinesis.

• Mitosis: The process where the nucleus divides, resulting in two identical nuclei.

• Cytokinesis: The division of the cytoplasm, which usually follows mitosis.

Step-by-Step Guidance

1. Start by defining the mitotic phase (M phase) as a part of the cell cycle that includes both nuclear and cytoplasmic division.

2. Next, define mitosis as the process of nuclear division, which is only one component of the mitotic phase.

3. Identify that cytokinesis is the other component of the mitotic phase, responsible for dividing the cytoplasm.

4. Compare and contrast: The mitotic phase includes both mitosis and cytokinesis, while mitosis refers only to the division of the nucleus.

Try explaining the difference in your own words before checking the answer!

Q2. What are the subphases of mitosis?

Background

Topic: Mitosis

This question is about identifying and understanding the sequential stages of mitosis during cell division.

Key Terms:

• Prophase

• Prometaphase

• Metaphase

• Anaphase

• Telophase

Step-by-Step Guidance

1. Recall that mitosis is divided into several distinct subphases, each with specific events.

2. List the subphases in order, starting from the beginning of mitosis to the end.

3. Briefly describe the main event that occurs in each subphase (e.g., chromosome condensation, alignment, separation, etc.).

4. Remember that some textbooks may combine or further subdivide these phases (e.g., some include prometaphase as a separate phase).

Try listing and describing each subphase before revealing the answer!

Q3. What is the structure and function of the following: chromatin, condensed chromosomes, chromatid, sister chromatids, non-sister chromatids, centromere, centriole pairs, centrosome, aster, spindle fibers, kinetochore, metaphase plate?

Background

Topic: Mitosis – Chromosome Structure and Mitotic Apparatus

This question tests your ability to define and explain the roles of key structures involved in mitosis and chromosome organization.

Key Terms:

• Chromatin: DNA and protein complex in the nucleus.

• Condensed chromosomes: Highly coiled chromatin visible during mitosis.

• Chromatid: One of two identical halves of a duplicated chromosome.

• Sister chromatids: Two identical chromatids joined at the centromere.

• Non-sister chromatids: Chromatids from homologous chromosomes, not identical.

• Centromere: Region where sister chromatids are joined.

• Centriole pairs: Cylindrical structures involved in spindle formation (in animal cells).

• Centrosome: Microtubule-organizing center.

• Aster: Star-shaped array of microtubules around centrosomes.

• Spindle fibers: Microtubules that separate chromosomes.

• Kinetochore: Protein structure on centromere where spindle fibers attach.

• Metaphase plate: Imaginary plane where chromosomes align during metaphase.

Step-by-Step Guidance

1. For each term, write a brief definition describing its structure.

2. For each, explain its function or role during mitosis.

3. Consider how these structures interact during the process of chromosome segregation.

4. Organize your answers in a table or list for clarity.

Try defining and explaining each structure before checking the answer!