Bio unit 7

• apoptosis


  programmed cell death
• Stages of the Cell Cycle

  interphase and mitotic phase
• The 3 Parts of Interphase

  G1, S, G2
• Interphase


  involves cellular growth and DNA replication. Cells spend about 90% of their time here
• mitoic phase


  the division of the cell into 2 daughter cells
• G1 (1st gap)


  small cell is absorbing nutrients, growing, and performing normal metabolic activities (such as making proteins).
• S (synthesis)


  cell is continuing to grow, condense its DNA and duplicate its DNA (the chromosomes) in preparation for making duplicate cells during mitosis.
• G2 (2nd gap)


  the DNA becomes un-condensed (chromatin), the cell keeps growing and performing normal metabolic activities; eventually it grows too large and must divide in two.
• Cytokinesis


  happens after mitosis, and is the movement of cells, where cytoplasm is distributed equally between the two new cells
• cleavage furrow


  in animal cells, its a wall that forms from the outside in. This pinches in until the cells split in two.
• cell plate


  In plant cells, its a wall that forms from the inside out because the cell wall is too rigid to pinch in. A cell plate eventually forms into a rigid cell wall.
• The product of mitosis

  2 cells, these daughter cells are identical to each other and identical to the parent cell
• Mitosis is a form of ____________ reproduction.

  asexual
• asexual reproduction


  new individuals are produced by one parent and are, therefore, identical to their parent.
• cancer


  a disease caused by an uncontrolled division of abnormal cells in a part of the body.
• Oncology


  the branch of medicine that specializes in the prevention, diagnosis, and treatment of cancer.
• tumor


  a mass of abnormal cells in the body
• A benign tumor


  is noncancerous and does not spread to other parts of the body.
• A malignant tumor


  is cancerous. They may be resistant to treatment and may spread (or metastasize) to other parts of the body. They can also sometimes recur after being removed.
• G0(Gap 0)


  resting stage, when a cell leaves the cell cycle temporarily or permanently. often they will never re-enter the cycle but instead carry out their function in the organism until they die
• Checkpoints in G1 and G2 look for:

  damage in DNA and try to repair it
• Checkpoint in Mitosis


  cell checks to make sure that the chromosomes are aligned correctly before they can split to go into the two new daughter cells.
• somatic cells (body cells)


  Contain the ''typical'' number of chromosomes, also known as the diploid (2n) number of chromosomes
• gametes (sex cells)


  Contain half the normal number of chromosomes, which is called the haploid (n) number of chromosomes.
• Meiosis


  the process by which gametes (sex cells) are produced, with half the number of chromosomes.
• Meiosis in males is called

  spermatogenesis
• Meiosis in females is called

  oogenesis
• Independent assortment


  the random orientation of homologous pairs relative to the poles occurs. This can give rise to different chromosome combinations in the daughter cells.
• Crossing Over


  the exchange of genetic material between chromosomes, may occur. As a result, new genetic combinations are formed and all 4 daughter cells will be genetically unique.
• The result of meiosis II (and of meiosis, in general) is that

  four non-identical haploid (n) daughter cells are produced.
• Why Would a Cell Divide?

  The surface area of a large cell is not great enough to support the cell's metabolic needs. It can no longer absorb nutrients and get rid of wastes fast enough to support the demands of its volume.
• When Would a Cell Divide?

  - growth occurs

  - repair and replacement of damaged tissues

  - an organism has cancer
• Binary Fission


  When the parent cell splits in half creating new identical cells
• Budding


  Is when an organism grows a bulge which makes a new organism grow
• Vegetative Propagation


  Is when a plant grows a plant
• Regeneration


  Is when an organism that lost a body part re-grows that body part
• What is created during the process of mitosis?

  During the process of mitosis, two new identical daughter cells copied from the parent cell are produced
• Do cells ever stop dividing?

  Yes, all cells are only allowed to divide a certain amount of times before going through apoptosis.
• When does a cell replicate its DNA?

  In the cell cycle, cells make a copy of their DNA during, the S phase(synthesis), which happens in the interphase