Cell Structure Module 4

Why are cells considered to be the basic unit of life?

The cell is the smallest unit of life, and all living things are made of cells.

How do various cell types differ from one another?

Cells differ by turning different genes on and off, which makes them have different structures and functions.

What features do all cells have in common?

Plasma membrane, cytosol, chromosomes, and ribosomes.

How do organelles improve the efficiency of chemical reactions in a cell?

Organelles divide the cell into compartments, making reactions more efficient.

How does evolution explain the diversity of cell types?

All cells come from earlier cells and have changed and specialized over time.

Describe the major differences between prokaryotic and eukaryotic cell types

Prokaryotes have no nucleus or membrane-bound organelles; eukaryotes have a nucleus, membrane-bound organelles, and are larger.

Compare and contrast plant and animal cell structure

Plants: box-shaped, chloroplasts, cell wall, large vacuole
Animals: round/irregular, no cell wall, smaller vacuoles, lysosomes

Describe the evidence that supports endosymbiont theory

Mitochondria and chloroplasts evolved from free-living prokaryotic cells that were taken in by a larger cell.

What data has been collected to support endosymbiont theory

Mitochondria and chloroplasts have their own DNA, are similar in size to bacteria, divide like bacteria, and have double membranes.

Explain why life is an emergent property of the cell

The cell is the simplest level of organization that can be alive.

Describe how DNA structure is well suited for its replication

DNA is double-stranded, and each strand serves as a template to copy the other strand, allowing accurate replication.

Explain the significance of DNA polymerase proofreading

DNA polymerase proofreading makes replication very accurate but not perfect.

Describe events that occur during the cell cycle

G1 (cell grows), S (DNA is replicated), G2 (cell grows), M phase (mitosis and cytokinesis occur).

Be able to recognize what is going on in S phase and mitosis

S phase is when DNA is replicated; mitosis is when chromosomes are separated.

Why would you NOT want to skip S phase?

DNA would not be copied.

What happens in G1 phase? (cell cycle, interphase)

The cell grows.

What happens in S phase?

DNA is replicated.

What happens in G2 phase?

The cell continues to grow.

What happens in M phase? (FINAL of cell cycle)

Mitosis and cytokinesis occur.

What happens during prophase? (1)

Chromosomes condense and the mitotic spindle begins to form.

What happens during metaphase? (2)

Chromosomes align along the center of the cell.

What happens during anaphase? (3)

Sister chromatids separate and move toward opposite poles

What happens during telophase? (4)

Nuclear membranes reform and chromosomes begin to decondense.

What happens during cytokinesis? (5)

The cell splits into two cells.

Describe the process of binary fission in bacteria

The bacterial chromosome replicates and the cell divides into two genetically identical cells.

Explain how eukaryotic mitosis may have evolved from binary fission

Mitosis likely evolved from binary fission but became more complex as cells developed nuclei and multiple chromosomes.

What is the difference between mitosis and meiosis?

Mitosis produces identical body cells (diploid), while meiosis produces sex cells (haploid) and creates genetic variation.