BISC 130 - Chapter 10: Cell Reproduction

How many chromosomes do humans have?

23 pairs of chromosomes (22 are autosomes, and the 23rd is a sex chromosome)

What type of genome do prokaryotic organisms have?

Prokaryotic genomes are typically haploid, consisting of a single circular DNA molecule.

What does diploid mean in the context of cells?

Diploid refers to a cell, nucleus, or organism containing 2 sets of chromosomes.

Give an example of a haploid organism.

Protists and mosses are examples of haploid organisms.

What is the structure formed by DNA wrapped around histone proteins?

Nucleosomes, which collectively make up chromatin.

What is the process of prokaryotic cell division called?

Binary fission.

What occurs during the S phase of the Eukaryotic cell cycle?

DNA replication takes place during the S phase. Centrosomes get replicated in animal cells here.

G1 Phase

Cells grow and accumulate resources for cell division. They also check if everything is in working conditions and if the environment is favorable.

G2 Phase

Replication of some organelles, and some further growth of the cell.

Name the phases of mitosis in order.

Prophase, Prometaphase, Metaphase, Anaphase, and Telophase (PPMAT).

What is the exact process of Eukaryotic Cell Division in the cycle?

Mitotic Phase

What happens in Prophase?

1. Nucleus, Golgi, and ER break down, allowing the chromosomes to move toward opposing sides for division.

2. Spindle apparatus forms

At what stage do microtubules attach to sister chromatids at kinetochores?

Prometaphase

Anaphase

Sister chromatids split from each other, each of them being pulled to opposite sides by microtubules

Telophase

Chromosomes de-condense

Nucleus, Golgi, and ER reform on the two opposing ends of the cell.

What are two identical copies of a chromosome that are attached together called?

Sister chromatids

Is Mitosis cell division?

NO, although it eventually results in a cell divided in two (cytokinesis).

In what part of the Eukaryotic Cell cycle does the cell divide into two genetically identical daughter cells?

Cytokinesis

What does the M (Mitotic) Phase consist of?

Mitosis and Cytokinesis

What phase is not a part of the cell cycle?

G0 (Resting) Phase; cells fulfill their normal functions (skin cells secrete oil) without growing or dividing actively.

What is the function of p53 in the context of cancer?

p53 locates damaged DNA and initiates repair; it can also trigger apoptosis if damage is too severe.

What is the significance of checkpoints in the cell cycle?

Checkpoints ensure that conditions are favorable for cell division and prevent the progression of damaged cells.

What happens in the G0 phase of the cell cycle?

Cells are in a resting phase and are not actively dividing, performing their normal functions instead.

What does a gene encode for or produce?

A protein

What is a Tumor Suppressor Protein

A protein that repairs damaged DNA, preventing mutations from happening. Also prevents mutated DNA from being replicated, leading to tumors. Ex: p53

What causes cancer?

Uncontrollable cell growth caused by faulty cell cycle proteins, whose DNA are mutated.

What causes proteins’ DNA to be mutated?

Unrepaired or damaged DNA

What is the worst thing that can happen that confirms the production of cancer cells?

The p53 protein’s gene is mutated.

The mutated gene then produces a faulty p53 which is unable to fix or destroy damaged DNA in a cell, causing the cell to eventually replicate out of control.

Oncogenes

Mutated version of a normal gene that can lead to cancer

Proto-oncogene

A normal gene involved in the cell cycle (when mutated, can turn into oncongene).