What happens to a cell's volume and surface area as it becomes larger?
The volume increases more rapidly than the surface area.
If you are given the number of times that the length of a cell is increased, how do you find how much the volume increases?
You cube the number of times that the length is increased.
Example: The length of a cell increases by 3 times its original length. The volume of the cell increases by about 27 times its original volume.
Why are large cells not as efficient as small cells?
Large cells have difficulty reaching all parts of the cell. Large cells also cannot take in or release materials as well as small cells due to the large surface area (in comparison to the volume).
What is the process by which a cell divides into two daughter cells?
Cell division
When during the cell cycle are chromosomes visible?
Mitosis, specifically prophase
When during the cell cycle is a cell's DNA replicated?
During the "S" phase of interphase
What are the three parts of interphase?
G1, S, G2
What occurs during the G1 phase?
The cell grows and synthesizes its structural proteins and enzymes needed for its functions.
What occurs during the S phase?
The DNA within the nucleus replicates.
What occurs during the G2 phase?
The cell prepares for mitosis. Proteins organize themselves to form a series of fibers called the spindle, which is involved in chromosome movement during mitosis.
What is the cell cycle?
The series of events in which a cell grows, prepares to divide, and divides to form two daughter cells.
Be able to label the centromere and the chromatids of the chromosome.
What events occur during prophase?
- Chromosomes condense to become visible.
- Spindle fibers form
- Nucleolus disappears
- Nuclear envelope dissolves
- Centrioles begin to migrate to opposite sides of the cell
- Chromatids attach to spindle fibers at the kinetochore
What events occur during metaphase?
- Pairs of chromatids line up in the middle of the cell
- DNA at the kinetochore duplicates
- Two chromatids separate from one another
What events occur during anaphase?
- Chromatids move apart from one another
- After separation, the chromatids are called chromosomes
- Each chromosome is attached to a spindle fiber
- Members of each chromosome pair are drawn to opposite poles of the cell by the spindle fibers
What events occur during telophase?
- Chromosomes finally arrive at the opposite poles of the cell
- Distinct chromosomes begin to fade
- Spindle is dismantled
- Nucleoli reappear
- Nuclear envelope is reformed
What events occur during cytokinesis?
ANIMAL CELLS: A cleavage furrow forms, and the cell membrane begins to pinch into the cytoplasm. The formation of two cells begins.
PLANT CELLS: Instead of a cleavage furrow forming, a new cell wall is assembled at the center of the cell, beginning with v
What is the sequence of the phases of mitosis?
Prophase, metaphase, anaphase, telophase
What are the two main stages of cell division?
Mitosis and cytokinesis
A parent cell containing 32 chromosomes will produce two daughter cells, each with how many chromosomes?
16
What happens when cells come into contact with one another?
Cell division stops.
What are cyclins?
A family of closely related proteins that regulate the cell cycle.
What is cancer?
A disorder in which some cells have lost their ability to control the growth and ability to respond to cell cycle regulators.
What is a benign tumor?
A tumor that is noncancerous; it does not spread to surrounding healthy tissue.
What is a malignant tumor?
A tumor that is cancerous; it invades and destroys surrounding healthy issues and can spread to other parts of the body.
What is the spread of cancer cells?
Metastasis
What is the effect of a defected p53 gene?
A defected p53 gene causes cells to lose the information needed to respond to growth signals.
Be able to draw the phases of mitosis.
What are some examples of asexual reproduction?
- Bacteria reproduce by binary fission
- Kalanchoe plants form plantlets
- Hydras reproduce by budding
What is the function of internal regulators?
They tell the cell when to enter mitosis.
What is the function of external regulators?
They direct cells to speed up or slow down the cell cycle.
What are growth factors?
External regulators that stimulate the growth and division of cells. They are important during embryonic development and wound healing.
What is apoptosis?
A process of programmed cell death.
How do tumors form?
Cells grow and do not respond to cell cycle regulators.
What are stem cells?
The unspecialized cells from which specialized cells develop.
What is differentiation?
The process by which cells become specialized.
What is the difference between chromatin and chromatid?
Chromatin: DNA molecules that are tightly coiled around proteins called histones
Chromatid: Each DNA strand in the duplicated chromosome