AP Biology ch 8 Review for short answer by WbCO40m7


									   Review for short answer/essays: Important Terms…Vocabulary

You will be given 5 short answer questions and YOU will choose 2 to write
about. Remember these three tips: 1) Use the vocab!; 2) Define the
vocab; and, 3) Give an example and relate the vocab. to the topic (i.e.,
put in context). The Good Vocab comparisons section below contain
bullets which are ideas that will help you earn a “advanced proficient” score
(10-12 on the rubric= A- to A+).

AP Essay Themes:

  A. Cancer and the Cell Cycle: What is the cell cycle and what is
     cancer? Why does it occur? What does the cell do in response?

  B. Diet and Nutrition: What are the 6 essentials in the diet? Why are
     they important? How is diet related to good health?

  C. Mitosis v. Meiosis: Compare and contrast

  D. Cell Signaling: What are the steps of cell signaling? Describe and
     explain an example such as G-protein linked receptor; Tyrosine
     Kinase; Ion-gated Ligand channels. Why is cell signaling important?

Good Vocab comparisons to Know:

  1. Sex chromosomes and autosomes

      Sex chromosomes are XX (human female); XY (human male)
      22 pairs of chromosomes are autosomal; and 1 pair is related to
       sex chromosomes (gender)
      Chromosomes are made of DNA and they have genes that code
       for specific traits

  2. The chromosomes of a homologous pair

      You inherit 1 chromosome of each type from each parent
       (maternal (mom) and paternal (dad))
   They find each other in meiosis 1 (prophase I and metaphase 1)
    to form a tetrad (2 Xs or 2 copied homologous chromosomes
    from mom and dad)
   The homologous chromosomes from each parent contain the
    same genes, but they may have different forms (“alleles”) of the
    trait; ex. Mom’s homologous chromosome #1 may have a gene for
    eye color that is green in shade and Dad’s homologous
    chromosome #1 may have a gene for eye color that is brown in

3. The two sister chromatids of a single chromosome

   Sister chromatids are created during the S phase of Interphase,
    which is when DNA is replicated
   The replicated chromosome copy attaches to the original
    chromosome and looks like an “X”
   These copies are attached with the help of proteins, and the
    attachment site is called the “centromere”
   These sister chromatids are identical and have the same genes
    (codes= sequence of A, T, C, and G bases)

4. A diploid and a haploid cell

   A diploid cell is a somatic cell (comes from tissue/cells of the
    body that are not sex cells) such as liver, skin, heart, muscle, etc…
   A diploid cell has a 2n number of chromosomes (twice as many
    as the haploid number); ex. Humans have a diploid number of 46
   A haploid cell is a sex cell (either sperm or egg) and it contains an
    “n” number of chromosomes which is half the diploid number; ex.
    Human sperm and egg cells have 23 chromosomes which is half
    of the diploid number of 46

5. A somatic cell and a gamete
    Somatic cells are cells of the body that are not part of the cells
     that make sex cells. Examples are: skin cells, heart cells, neurons
     (brain cells), muscle cells, liver cells, stomach cells, etc…
    A gamete is a sex cell such as the sperm or eggs
    Somatic cells divide through the process of mitosis and gametes
     are formed from the process of meiosis
    Somatic cells have a diploid number of chromosomes and
     gametes have a haploid number of chromosomes
    Two gametes come together in the process of fertilization (i.e., a
     sperm fertilizes as egg) to make a diploid cell

6. Mitosis and Meiosis
   See if you can use the textbook to label this diagram: (Mitosis is on
   the left and Meiosis is on the right)
 DNA Replication occurs in the S-phase of Interphase before
  either mitosis or meiosis occurs

 Mitosis has one complete division ( one PMAT) whereas meiosis
  has two complete divisions (2 PMATs)
   In metaphase of mitosis chromosomes line up single file (ex., 1-
    46 in humans) and in meiosis metaphase I chromosomes line up
    in pairs (2 x 2; or 23 tetrads)…homologous chromosomes find
    each other

   Crossing over occurs in prophase I and metaphase I of meiosis;
    no crossing over in mitosis

   Mitosis creates 2 somatic cells that are diploid (same
    chromosome number as the original cell); Meiosis creates 4
    haploid sex cells

   Mitosis produces cells for growth, repair or asexual
    reproduction (binary fission); Meiosis produces sex cells for
    sexual reproduction (genetic variability is a key feature; more
    diversity, better survival!)

7. X and Y chromosomes

   Sex chromosomes are XX (human female); XY (human male)

   X chromosome is much larger than the Y chromosome

   In some species the number of X chromosomes determines
    gender; not the possession of a Y chromosome

   X and Y are the sex chromosomes and sperm cells have either an
    X or a Y; egg cells have only X chromosomes

8. Gene and Locus

   A gene is a DNA code for a specific protein; a Locus is a specific
    location of a gene or allele on a chromosome

   In other words, a gene is the instructions, and a locus is the
    position or location of the instructions
9. An egg and a zygote

   An egg is a haploid sex cell or gamete produced by meiosis; a
    zygote is a fertilized diploid cell that will go through several
    mitotic divisions to produce a new diploid organism (ex., a human

10.    Fertilization and meiosis

   Fertilization is the process of two gametes (an egg and a sperm)
    uniting their nuclei to form a diploid cell

   The gametes were produced in the process of meiosis; gametes
    are haploid

   Example: human sperm has 23 chromosomes and a human egg
    (oocyte) has 23 chromosomes

   When a human sperm fertilizes a human egg, a zygote is
    produced with 46 chromosomes

11.    Cell Cycle and Cancer

   The Cell Cycle is comprised of Interphase (G1 (Growth), S (DNA
    Synthesis), G2 (Growth)) and M (which can be either mitosis or
    meiosis depending on the cell type)

   The Cell Cycle has checkpoints in which P53, cyclins, kinases,
    MPF and other proteins tightly regulate the timing and accuracy of
    the processes

   If a cell is mutated (usually DNA damage) and the cell cycle
    becomes damaged and unregulated, then the cell will undergo
    apoptosis or cell suicide
 P53 helps regulate cell suicide, but if P53 is damaged, then the
  cell may become cancerous

 The immune system can give outside signals to the cell to commit
  apoptosis, but sometimes the signals are ignored, especially if P53
  is damaged. This may result in a malignant cancer.

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