Meiosis
What is the primary purpose of meiosis in sexually reproducing organisms?
To produce gametes (sperm and eggs) with half the number of chromosomes
What is the main purpose of mitosis?
To enable growth, repair, and asexual reproduction by producing two identical daughter cells.
What are the main phases of the cell cycle?
Interphase (G1, S, G2) and M phase (mitosis and cytokinesis).
What is genetic variation, and why is it important?
Genetic variation refers to differences in DNA among individuals, which is important for evolution and adaptation.
How do the outcomes of meiosis and mitosis differ?
Meiosis results in four genetically distinct gametes, while mitosis results in two identical daughter cells.
Describe the main difference between meiosis I and meiosis II
Meiosis I separates homologous chromosomes, while meiosis II separates sister chromatids
List the phases of mitosis in order.
Prophase, Metaphase, Anaphase, Telophase.
What happens during the S phase of the cell cycle?
DNA replication occurs, resulting in two identical sets of chromosomes.
Name one mechanism by which genetic variation is introduced during meiosis.
Crossing over.
What type of cells are produced by meiosis, and what type by mitosis?
Meiosis produces gametes, while mitosis produces somatic cells.
What is crossing over, and during which phase of meiosis does it occur?
Crossing over is the exchange of genetic material between homologous chromosomes during prophase I.
What role does the spindle apparatus play during mitosis?
The spindle apparatus helps separate the sister chromatids and pull them to opposite poles of the cell.
What is the function of the G1 Phase?
The G1 Phase checks for cell size, nutrients, and DNA integrity before moving to the S phase
How does fertilization contribute to genetic variation?
Fertilization combines genetic material from two parents, resulting in unique offspring.
Describe how the processes of meiosis and mitosis are similar.
Both involve cell division and include similar phases (prophase, metaphase, anaphase, telophase).
How many chromosomes does a human gamete contain after meiosis?
23 chromosomes.
What is the end result of mitosis in terms of chromosome number?
The end result is two daughter cells, each with the same number of chromosomes as the parent cell (46 in humans).
Define cytokinesis and when it occurs.
Cytokinesis is the division of the cytoplasm and occurs after mitosis.
Explain how mutations can contribute to genetic variation.
Mutations are changes in DNA sequences that can create new traits and increase diversity within a population.
How does the role of DNA replication differ between meiosis and mitosis?
DNA replication occurs once before both processes, but only meiosis involves two rounds of division.
Explain the significance of independent assortment during meiosis.
Independent assortment leads to genetic variation by allowing different combinations of maternal and paternal chromosomes to be distributed to gametes.
Describe the checkpoints in the cell cycle and their importance.
Checkpoints ensure that the cell is ready to proceed to the next phase, checking for DNA damage, proper chromosome alignment, and sufficient resources.
What is the effect of uncontrolled Mitosis
Creation of tumors which can lead to cancer.
What role does sexual reproduction play in increasing genetic diversity?
Sexual reproduction combines genetic material from two parents, leading to genetically diverse offspring through independent assortment and crossing over.
Discuss how the regulation of meiosis and mitosis is crucial for organismal health.
Proper regulation prevents issues such as cancer (from uncontrolled mitosis) and genetic disorders (from errors in meiosis).