C6 Chromosomes and Cell Reproduction

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C6 Chromosomes and Cell Reproduction Powered By Docstoc
       How do we repair?
       How do we grow?

If “all” human cells have 46 chromosomes,
 what must happen to those chromosomes
 before the cell divides, in order for the
 next two cells to each have 46
Start notes here                Cell Cycle & Chromosomes

   - 2 trillion cells reproduced daily by our
   - 25 million cells reproduced per second
   - new cells are reproduced when older
     cells divide

Intro to Cell Cycle

  See Board   (compare human cycle to cell cycle)

                                      Text book page 204 & 206
                  In your notes copy the image on page 206 in your text. The image should
                  take up half of your paper. (Be sure to include the outside label)

                  Now, in each section (G1, S, G2, Mit, Cyto) list what happens in that phase


               Below the image, in your notes, write and answer the following questions:
                   Where are there checkpoints?
                   What are checkpoints?
                   What happens if check points don’t exist?
2 You tube videos                                  

Why Cells Reproduce                                                                         (end of cycle cycle)

                  Grow and develop
                  Heal a wound
                  To produce gametes (sperm or egg)

Two types of Cell Reproduction:

  1. Asexual Reproduction
     - mitosis
     - In bacteria this is called binary
         fission, which creates identical offspring
        Both mitosis and binary fission have two stages
             1. DNA is copied
             2. The cell divides

                                                       46        46
                     Chromosome # stays the SAME!!!!
Two types of Cell Reproduction cont.:
   2. Sexual Reproduction
       - Meiosis
            - to make sperm and egg (great
                 detail of this will come soon)
How many copies of
DNA do you want your
                                           Chromosome #
sperm or egg to have?                      is cut in half!!!
                          23         23
     This page all side notes, you decide what you NEED to write . . .

Now we know cells divide, in order to go into
  depth on the topic, we need to get some
  terminology for what is inside the cell.

What is the control center?
  Inside the control center are _________.

Terminology Check to Dive Deeper into Cell Cycle:

    Get text book, open to page 205
Chromosomes:                     Remember are DNA, made of nucleotides

            Chromosomes are made of segments called genes
                 Genes code for our characteristics

            Most of a cells life, chromosomes in the nucleus are
             spread out as chromatin while they are being read
                 Think of an extension cord, how is it when being used?

            Right before they’re ready to divide a chromosome
             makes a copy,
                 These copies coil up and are called chromatids

            Chromatids are attached at the centromere

At this point, I would copy figure 8.10 from text into my notes

Types of Cells and Chromosome Number
                                Somatic cell (any cell except sperm and egg)
                                                               Have two pair of chromosomes
                                                               Each pair are called homologous chromosomes
                                                               Are called diploid
                                                                                             2n (n = number of chroms in one set, 23 in humans so 2n =
                                                               Mitosis creates these cells
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Types of Cells and Chromosome Number
                                                     Sex cells (sperm and egg)
                                                                                   Have one copy of each chromosome
                                                                                   Are called haploid
                                                                                                                 n (n = 23 in human cells)
                                                                                   Meiosis creates these cells

Types of Cells and Chromosome # Cont.

    Fertilization – fusion (coming together) of
     two haploid (sperm and egg) cells, this a
     zygote or a fertilized egg cell.
        First cell of many new organism
Cell Division/Reproduction:
               Asexual Mitosis
    Used for growth, healing, cancer when out
     of control
    4 Stages
                   Things that happen in stage
        Prophase
        Metaphase
        Anaphase
        Telophase

HW Draw and label 3 times. Time 1, use
 your notes, time 2 peek at your notes
 when you need to, time 3 complete
 without notes (keep repeating until can
 draw and label accurately without looking
 at your notes and your book.
Cell Division/Reproduction:
               Sexual Meiosis
-   View Meiosis on PP
-   Meiosis on Elmo and on your own sheet
-   Meiosis with straws

     Go back and look at karyotype to see differences in sex chromosomes
                                                                                                               eiosis.html&h=338&w=273&sz=16&hl=en&start=2&usg=__hXd4nPD-                       jHATFBgo29E5g4prAsE=&tbnid=ZK6o4X2ZY4fTUM:&tbnh=119&tbnw=96&
7/meiosis.gif&imgrefurl=                               prev=/images%3Fq%3Dmeiosis%26gbv%3D2%26hl%3Den%26sa%3DG
Just Look
    Notice I did not have an actual
           picture of meiosis
   Following slides must be covered in
    another unit.

                                                                                                                                                                                                                                                                                                 Male onion
Notice I do not have a REAL picture
             of meiosis.
Causes of variation in gametes (good,
 - crossing over
 - random assortment of chromosomes
Types of Chromosomes and Sex determination

   Autosomes – chromosomes not involved in
    determining if an organism (you) are
    going to be a male or female
   Sex Chromosomes – one chromosome of
    our 23 ( or 2 of our 46)
       Female is XX (X from mom and X from dad)
       Male XY – (x from mom and Y from dad)
        Only chromosome not “identical” to its pair (see Figure 6.5 in
            Male gamete determines sex of fertilized egg
                    Types of Mutation
                These occur in metaphase I, why?
Name of Mutation        Description                      Sketch

Deletion                A piece of a chromosome
                            breaks off; a piece is
Duplication             A chromosome fragment
                            breaks off and attaches to
                            its homologous chrom-
                            osome; now it carries 2
                            copies of same gene
Inversion               The chromosome piece breaks
                            off reattaches to the
                            original chromosome in a
                            reverse manner
Translocation           The piece reattaches to a

                           Great Website
    A                A                              A                   A
    B                B                              B                   B
    C                C                              C                   C
                                                       
    D   deletion                                    D   Inversion
                     D                                                  F
    E                E                              E                   E
    F                F                              F                   D

A       A                        A   A
B       B                        B   B
C       C                           C
                   duplication   C

D       D                        D   D
E       E                        E   E   A                          A
F       F                        F   F   B                          B
                                         C   X 
                                                            C       X
                                         D   Z               D
                                         E                          Z
                 Abnormalities in Chromosome Number

   Karyotype – a photo of the chromosomes in a
    dividing cell (See p.329)
   Abnormalities in Chromosome Number, happen
    in anaphase I, as a result of non-disjunction
       Trisomy – an extra chromosome, 3 instead of two in
        a pair, 47 instead of 46 in a human karyotype
            Down syndrome – Trisomy 21, an extra 21st chromosome
            Klinefelter’s syndrome – Male with XXY
       Monosomy – missing a chromosome, havine 1 instead
        of 2 in a pair, 45 instead of 46 in a human karyotype
            Turner’s syndrome – Female with only 1 sex chromosome, or
             missing part of one (XO)
                                                                                                                                                                                 Awesome website
                                                                                                                                                                                 for images!!!!
  The end . . . for now!!
  Ready for the test?????

Nash – go over Go in cell cycle, as check points.
11/14                         Cell Cycle
  What are the stages to the cell cycle
  (remember the image you drew
  yesterday). What can you remember
  happens in each piece of the pie?
   Homework the night before this started
    was to take notes on 6.1 using the topics
    given to them
   Therefore in class, they would just be
    following along in there notes, adding and
    highlighting points
11/12                    Cell Division

   How do you think a cell divides. There
is tons of information inside the nucleus,
and when the cell divides, that same
information must be in the new cell and
the old cell. What methods do you think,
or do you remember, will a cell go
through to replicate? If you have no
idea, be creative.

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