Cell Growth and Mitosis
Explain why a humpback whale and an anchovy have similar-sized cells even though one organism is much larger.
Cell size is generally similar across organisms; the whale is larger because it has more cells, not bigger cells.
Identify the two main stages of the cell cycle and describe what happens in each.
1. Interphase: cell grows and replicates DNA
2. Mitosis: cell divides into two identical cells
Describe what happens during prophase.
Chromosomes condense, nuclear membrane breaks down, and spindle fibers form.
What is complementary base pairing?
Specific pairing of DNA bases: A-T and C-G.
Define differentiation.
The process by which a cell becomes specialized to perform a specific function.
Describe two reasons why cells undergo mitosis in multicellular organisms.
1. Growth
2. Repair/replacement of damaged or old cells
Explain the role of the G1 checkpoint in the cell cycle.
Ensures the cell has enough size, nutrients, and space before DNA replication.
Explain how metaphase ensures equal distribution of chromosomes.
Chromosomes line up at the center, allowing spindle fibers to attach correctly for equal separation.
Explain how complementary base pairing ensures accurate DNA replication.
Each base pairs with its correct partner, ensuring the new strand is an exact copy.
Explain how cells with identical DNA can have different functions.
Different genes are turned on or off (gene expression), producing different proteins.
Explain why DNA must be duplicated before mitosis occurs.
DNA must be duplicated so that each daughter cell receives a complete and identical set of genetic information, ensuring proper function.
Why is the G2 checkpoint critical before a cell enters mitosis?
It verifies DNA has been completely and accurately replicated to prevent mutations.
Describe the role of spindle fibers during anaphase.
They pull sister chromatids apart to opposite ends of the cell.
Describe the structure of daughter DNA molecules after replication.
Each molecule contains one original strand and one new strand (semi-conservative).
Describe the role of stem cells in development.
Stem cells can self-renew or differentiate into specialized cell types.
Predict what would happen if a cell divided without duplicating its DNA first.
Daughter cells would have incomplete genetic material, leading to malfunction or cell death.
It verifies DNA has been completely and accurately replicated to prevent mutations.
Chromosomes may not separate properly, causing unequal distribution of chromosomes, leading to defective daughter cells.
Compare telophase and cytokinesis.
Telophase: nuclei reform
Cytokinesis: cytoplasm divides into two cells
Predict what might happen if errors occur during DNA replication and are not corrected.
Mutations may occur, potentially causing cell malfunction or disease.
Analyze how a cell’s location in an embryo affects its differentiation.
Cells receive different signals from nearby cells, which influence gene expression and specialization.
Compare the roles of mitosis in growth versus repair, including how the outcomes are similar.
Both processes produce genetically identical daughter cells, but growth increases organism size, while repair replaces damaged cells.
What is the cell cycle?
The process by which cells grow and divide to produce more cell.
Predict the consequence if sister chromatids fail to separate during anaphase.
Daughter cells may receive extra or missing chromosomes, causing dysfunction.
Justify why DNA replication is essential before mitosis rather than after.
Replication must occur before division so each daughter cell receives complete genetic information.
Compare gene expression in a lung cell vs. a skin cell, and explain how their DNA differs.
Gene expression is different (different proteins produced)
DNA is identical, but different genes are activated