__________ (example: baby  adult) ___________________ (asexual reproduction in single celled organisms) ____________________________ of dead/damaged/infected (example: skin/red blood cells/bone cells) ______________________ formation in multi- cellular organisms (meiosis)

In eukaryotes: made up of ____________and _____________ At different times, proteins cause the DNA to: – be ________________________like spaghetti in a bowl – be tightly _______________into the X-shaped (these we can see in the microscope) Central constricted region called _________________ that serves as an attachment point for the spindle fibers during mitosis.

Chromosomes exist in 2 different states: -before DNA replication, chromosomes have one _____________________. -after DNA replication, chromosomes have 2 sister _________________, held together at the ___________________. Each chromatid is one piece of DNA with its supporting ____________________. Why is DNA replication necessary?

Cell Cycle __________________________: Longest part of the cell cycle Includes G 1, S and G 2 G 1 : cell ________________ S: cell growth; _________________________ G 2 : cell growth; organelles _________________ DNA begins to ___________________ into chromosomes

_________is the division of the eukaryote nucleus, which goes on throughout life in all parts of the body. Organelles can be randomly separated into the daughter cells but chromosomes must be precisely divided so that each daughter cell gets exactly the _______________DNA. Every human cell has the same __________ chromosomes Mitosis is usually divided into 4 phases: Prophase (P) ___________________(M) Anaphase (A) ___________________(T)

Phases of Mitosis: 1. __________________________ Chromatin finishes ___________________ into chromosomes (visible under light microscope) Nucleolus/nuclear envelope ___________________ down Spindle fibers form from centrosomes/_________________ with microtubules extending out Chromosomes appear as 2 identical sister chromatids joined together at centromeres

2. Metaphase _________________ stage of mitosis Chromosomes move to ______________of cell (metaphase plate) Chromosome’s centromeres are on metaphase plate with sister chromatids each facing opposite sides of cell ______________________ at opposite sides of cell

3. Anaphase: _______________ stage of mitosis Sister chromatids ________________ and begin moving towards __________________ends of cell (spindle fibers pull sister chromatids in via the centromere) and each one is now a “___________________” Cell elongates At end of phase, each end of the cell contains complete and _____________________ chromosomes

4. _________________________: -Chromosomes are at each side of cell and __________________ begins to re-form around -Chromosomes _________________to form _____________________ -Spindle fibers disintegrate -Cell is elongated and ready for ______________________

Animal Cell Cytokinesis inward ______________ of plasma membrane to form __________________ _________________ Plant Cell Cytokinesis cell __________ forms and moves outward towards the sides of the cell from central region

_________________= result of uncontrolled cell division The genetic checks that stop cells from reproducing fail to work and they grow out of control _______________ = gene that turns a normal cell into a cancer cell Tumors can occur in any organ or tissue, though are most common after exposure to carcinogens (e.g. tobacco smoke) or in particularly active tissues (e.g. breast, skin) Angiogenesis: tumor recruits blood vessels and grows larger Metastasis: part of the tumor invades the blood vessel, travels through the blood and starts to forma a tumor in another part of the body

 Normal cells are controlled by several factors:  Normal cells stay in the G1 stage of the cell cycle until they are given a specific signal. Cancer cells enter the S phase without waiting for a signal.  Normal cells are mortal. This means that they can divide about 50 times and then they lose the ability to die. This “clock” gets re-set during the formation of the gametes. Cancer cells escape this process of mortality: they are immortal and can divide endlessly.  Normal cells that suffer significant chromosome damage destroy themselves due to the action of a gene called “p53”. Cancer cells either lose the p53 gene or ignore its message and fail to kill themselves (process known as apoptosis)