HESI Rediness Course (Biology): Cellular reproduction

What are the four phases of a Cell’s Life Cycle

G1, S, G2, and M (Mitosis)

What are two ways that cells can reproduce?

Meiosis and Mitosis.

What is Mitosis?

The duplicated X-shaped chromosomes will be separated and distributed to two new daughter cells. The “daughter cell” is the exact replica of the parent cell because they have the same number of chromosomes. (2n = 2 red and blue chromosomes.

What is Meiosis?

When cells divide through this process, the daughter cells have different genetic coding than the parent cell.

meiosis takes place in germ cells, or the cells that make sex cells (gametes).

What are the two phases of Meiosis

Parent cell: Diploid

Gamete: Haploid

List all the major events in order for Mitosis?

Interphase, Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis

What happens during Interpahse?

Cell prepares for division by replicating its genetic and cytoplasmic material. It can further be divided into G1, S, and G2

What happens during Prophase?

The nuclear membrane breaks down and the duplicated chromosomes condense (or become more compact) and are visible (at this point, you can actually see them under a microscope!). Are compacted to one side!

What happens during Metaphase?

The spindle moves to the center of the cell (known as metaphase plate) and chromosomes pairs align along the center

What happens during Anaphase?

Pair of chromosomes, called sisters, begin to pull apart, and may bend. When they are separated, they are pulled to opposite poles of the cell and are called daughter chromosomes.

What happens during Telophase?

New nuclear membranes reform around the two sets of chromosomes.

What happens during Cytokinesis?

The physical splitting of the cell. The cell membrane pinches inward during this step, cutting the cytoplasm in half and resulting in two daughter cells. 

How does the process of Meiosis work?

Meiosis has two phases of nuclear division.

• Meiosis I separates the homologous chromosomes (the paternal and maternal chromosomes) and creates 2 haploid cells. This is when then chromosome number changes from diploid to diploid.

• Meiosis II separates the duplicated X-shaped chromosomes into four daughter cells.

What happens to cell during Meiosis I?

Meiosis I separates the homologous chromosomes (the paternal and maternal chromosomes) and creates 2 haploid cells.

Once cell has split into two through Meiosis I, what happens during Meiosis II?

Each cell goes through second cell division, which consist of Interphase (II), Prophase (II), Metaphase (II), Anaphase (II), Telophase (II), and Cytokinesis (II).

Resulting in 4 daughter cells with different sets of chromosomes. This process has similar steps to mitosis

What happens during the G1 phase?

When cells enter G1 (G for growth or Gap) cells recover from the previous cell division by doubling cell components (DNA, organelles, cytoplasm, etc.)

What happens during the S phase?

During the S phase (S for synthesis) is when the DNA is replicated. The chromosomes are duplicated and look X-shaped (two copies of the same chromosome).

The section where the two chromosomes are joined together is called the centromere (think of centromere like the center or middle of the duplicated chromosomes).

What happens during the G2 phase?

During the G2 phase, the cell continues to grow and prepares for the next phase, which is mitosis.

What is a Parent cell: Diploid

two sets of chromosomes (2n).

The parent cell has two sets of chromosomes is because one set was received from the father (sperm) and the other set was received from the mother (eggs)

What is Gamete: Haploid

one set of chromosomes (n)

For example, human sperm cells have 23 chromosomes, and human egg cells have 23 chromosomes.

What is the difference between Mitosis and Meiosis?

The end result of Mitosis is two diploid daughter cells (the chromosome number in the daughter cells is the same as the parent cell).

However, the end result of Meiosis (after Meiosis II) is four haploid daughter cells that have half the number of chromosomes than the parent cell.