• Pre-AP Biology - The Cell Cycle •

True/False: A cell only divides once during its lifetime.

False, cells divide more than once throughout their lifetime

True/False: Cells spend most of their time in mitosis (dividing)

False, cells spend most of their time in interphase

True/False: All cells divide (go through the cell cycle) at the same rate

False, liver cells divide less frequently, while hair and skin cells divide frequently

True/False: Cancer cells are regular cells (such as skin or liver cells) that are dividing uncontrollably

True, cancer cells are not regulated and are uncontrolled, they ignore checkpoints

True/False: A cell must replicate its DNA prior to cell division, during the G1 phase

False, happens during G2 phase (synthesis phase)

True/False: All cells come from pre-existing cells

True, part of the modern cell theory

True/False: Mitosis results in gametes (sperm or egg cells)

False

True/False: Cells divide, but the cells themselves never increase in size or gain mass

False, cells grow as they divide (make more cells)

Mitosis happens in…

Body cells (somatic cells)

G1 phase:

The cell individually itself grows by making more cytoplasm and organelles.

Checkpoint checks if the cell is growing enough, if DNA is damaged, and if the cell has the resources needed to keep moving

G2 phase:

The cell grows more in preparation for mitosis. Cell makes all the structures necessary for division

Checkpoint checks if DNA was replicated properly, if its growing well enough, and has the resources to continue.

S phase:

Cell replicates its DNA (synthesis stage)

PMAT meaning:

Prophase, Metaphase, Anaphase, and Telophase

Is PMAT before or after Interphase?

After

What comes after PMAT?

Cytokinesis

Prophase (The preparation stage)

• Chromosomes appear

• Nuclear envelope breaks down

• Spindle fibers form

Metaphase (The middle stage)

• Chromosomes line up in the middle

• Each chromosome is connected to a spindle fiber at its centromere

Anaphase (The apart phase)

• Sister chromatids separate into individual chromosomes and are moved apart

Telophase (Two cell stage)

• The formation of two daughter cells

• Chromosomes gather at opposite ends of the cell and lose their distinct shape (become invisible)

• 2 new nuclear envelopes will form

Cytokinesis (Division of the cytoplasm)

• Cytoplasm pinches in half

• Each daughter cell has an identical set of duplicate chromosomes

The indentation at the center of a dividing cell (Animal cells)

Cleavage furrow

The indentation at the center of a dividing cell (Plant cells)

Cell plate

Mitosis

Mother cell divides into 2 daughter cells that are genetically identical to itself

• Happens in body cells (somatic cells)

Interphase (The in between dividing stage)

• DNA is not yet visible (called chromatin)

  Called chromosome when DNA is visible

• DNA replicates here

• Longest part of the cell cycle

Describe why the cell doesn’t spend most of its time in mitosis.

If the cell splits too much, it could become harmful (could disrupt the cell’s function)

Why was interphase included in your cards when it is not a part of mitosis?

Interphase prepares for mitosis by replicating its DNA, growing the cell, and producing more organelles

Homologous Chromosomes

Two corresponding chromosomes that have the same corresponding gene at the same loci (location)

Diploid (2N)

A cell that has 2 of each kind of chromosome

Spindle Fibers

Attached to pair of sister chromatids and then push and pull them during Mitosis

Microtubules

Spindle fibers are composed of these

Centrioles

Organelle that organizes spindle fibers in animal cells

Diploid # in humans (body cells)

46 chromosomes

Haploid # in humans (egg and sperm)

23 chromosomes