Chapter 10: Cell Cycle and Cell Division Flashcards
What processes does cell division define?
- REPRODUCTION
- DEVELOPMENT
- MAINTENANCE OF ORGANS
What is reproduction?
SEXUAL REPRODUCTION IS WHEN A FEMALE SEX CELL IS FUSING WITH A MALE SEX CELL
• FERTILIZATION
THEN THE CELL DIVIDES
Why is there an unlimited amount of sperm?
UNLIMITED AMOUNT OF SPERM IS DUE TO MITOSIS
DIVIDE INTO A CELL DIVISION, MEIOSIS, TO BECOME SPERM
Why are tissues able to repair and maintain themselves?
Cell Division allows tissues to repair and maintain their own cells
example: the lining of the small intestine is replaced every 5 days.
What parts of the tissue are responsible for repair and maintenance?
The Erythrocyte, leukocyte, and platelets
Why don’t we run out of blood?
Cell division
What causes cancer?
Overwhelming, uncontrolled mitosis
What does cell division consist of?
DNA replication, separation of DNA, and regulation/control
What are Histones?
Histones are basic proteins, and their positive charges allow them to associate with DNA, which is negatively charged. Some histones function as spools for the thread-like DNA to wrap around.
What are chromosomes associated with? (2)
DNA and proteins
Haploid vs Diploid cells
Diploid cells, such as body cells, have two copies of chromosomes (2n), a total of 46 chromosomes. Haploid cells, such as sex cells, have 23 chromosomes each (n)
Chromosomes vs. chromatid
Each molecule is called a chromatid (initially attached all along their lengths by adhesive protein complexes called cohesins) and the two of the molecules are called a duplicated chromosome
Chromosome structure
Consists of 2 sister chromatids and a centromere in the middle
What does interphase consist of?
G1 (cell growth), G2 (cell preparation), S (DNA replication)
What is Mitosis and what does consist of?
Division of the nucleus
Prophase, Prometaphase, Metaphase, Anaphase, Telophase
What is Cytokinesis?
Actual cell division
What is the mitotic spindle?
Guide to make sure that the chromosomes are going in the correct path. Consists of Kinetochore microtubules, non-kinetochore microtubules, centrosomes ,spindle, microtubules, asters
What happens in Prophase?
- Chromosomes condense
- Nucleolous disappears
- Mitotic spindle begins to form
What are centrioles?
Structure: nine triplets of microtubules form one centriole
- two centrioles form one centrosome
Function - forms spindle fibers to separate chromosomes during cell
division
What happens in Prometaphase?
- Nuclear envelope breaks down
- Kinetochore formation occurs
- Microtubules are actually attaching to the centrometer
- Some microtubules are physically attaching Kinetochore microtubules
- NOT ATTACHED: nonkinetical. Makes sure the cell is stable
Kinetochore structure
Protein structure on chromatids where the spindle fibers attach during cell division to pull sister chromatids apart.
What happens during metaphase?
- Chromosomes perfectly align
- Distinct form of condensation
What happens during Anaphase?
-Spindles separate from the straight line (from metaphase) as chromosomes
What are non-Kinetochore microtubules?
- Sliding of the nonkinetochore microtubules pushes poles apart increasing the total length of the spindle
- The motor proteins from the microtubules are moving and attaching themselves. This shortens the microtubule.