Notes on Genetics - HEREDITY by xiuliliaofz



Why do we look like we do?
Learning Targets
 Describe how evolution lead to the diversity of species on
    earth today.
   Explain the function of chromosomes, where they are
    located and what information they carry.
   Explain the process of mitosis and why the offspring of
    sexual reproduction have more diverse characteristics that
    asexual reproduction.
   Understand that genes are passed on independently of each
    other trait.
   Be able to predict the outcome of genetic crosses .
   Explain why genetic variation is important to survival of a
Read pgs. 110 – 117; Ch.6 Friday 4/23
Vocabulary Definitions of key terms pgs. 110
Questions pg. 115
Read pgs. 118-123
Questions pg. 123
Questions pg. 130
Read pg. 131-137 & 144 - 155

Class survey
Punnett Squares
Corn toss
Dragon activity
   Opening Tasks
How do the nitrogen bases pair up to code for protein.
What is your definition of genetics?
Which scientist led us to understanding genetics?
Where are your genes located?
What are dominant and recessive traits?

What are phenotype and genotypes?
   April 6, 2010
 ?? of the day
 How do the nitrogen bases pair up to code
  for protein?

 Go over DNA/Genes Worksheet
 Read Pages 110-117
 Vocabulary due Thursday, key terms page 110
 Pre – activity worksheet
 Begin Notes
April 7, 2010
 ?? Of the day:
 Which scientist led us to understanding
 Where are your genes located?
 Go over Video Worksheet
 Notes/Review on DNA
 Start that genetics!!
DNA Replication
 Ensures each daughter cell will have an exact copy of the
  genetic material it needs to carry out its activities.
 Reminder: DNA (and RNA) is made up of nucleic acids –
  long organic molecules made of – C, O, H, N, and
 Replication of DNA takes place during Interphase
  DNA Replication (cont.)
 DNA is made of a sugar molecule called deoxyribose, a
  phosphate, and nitrogen bases in the shape of a ladder or
  spiral staircase.
   – Deoxyribose and phosphate make up the outside supports (or the
     sides of the ladder)
   – Nitrogen bases make up the rungs of the ladder
       • The same bases always pair, A-T and C-G and in a specific order
         determining protein formation.
       • Adenine - Thymine
       • Guanine - Cytosine
The Structure of DNA
  DNA Replication Process
 Replication begins when the two sides unwind and
  separate (like unzipping a zipper)
 The DNA separate between the paired bases
 Nitrogen bases floating in the nucleus pair up with the
  bases on each half of the DNA molecule to make two
  new identical strands.
DNA Replication
DNA Replication (in action)


 Mendel’s research led
  to our understanding
  of genetics.

 • The genetic code
 DNA, determines all our
 traits inherited from our

 • These traits are passed on by genes which
 are located on the chromatids in the nucleus.
Mendel’s Experiment
 P generation = grandparents
 F1 generation are the offspring of the grandparents
  (your parents)
 F2 generation are the offspring of the F1
  generation (you)
 Trait is a characteristic passed on to the offspring
  like height.
 Traits are controlled by the alleles inherited from
  the parents
 Alleles are different forms of a gene, for example
  the gene for height has 2 alleles – tall and short.

              Dominant                                Recessive
      traits that are strongest                 traits that are weak
they show up & can hide other traits   they can be hidden by dominant traits
Inheritance Patterns Continued
 Genotypes show the           Phenotypes show your
  combination of genes          physical
  that are specific for all     characteristics like
  traits.                       height, eye, hair color
                                & skin color.
  Dominant traits are
 symbolized by capital
 letters, TT. One letter         In each pair of
 from each parent.              genes, one comes
                                from the mother and
  Recessive traits are         the other comes from
 symbolized by lower            the father.
 case letters, tt.
Punnett Squares
 These can be used to show the probability of
  specific traits showing up in the offspring. For
  Example, sex of the child
                  X      X
          X

          Y
 XX = mother; XY = father genotyoes, now bring
  the letter over the box into the boxes under it.
 Write mom XX; dad XY
 Now draw a square like the last slide and place
mom’s traits over the top 2 boxes and dad’s traits
next to the boxes on the side.
 Start with mom and the first X, bring it down &
write it into each box it’s over. Do the same for the
second X.
 repeat this for dad’s traits bringing each trait
across into the boxes it’s next to.
 Let’s do some others.
Cell division of the sex cells that
form gametes.

                      Parent cell has 23 pairs
                      of chromosomes

                       The chromosomes duplicate
                       in the first stage
                                                Chromosomes duplicate
                                                giving 46 pairs

                                                           Cell divides into 2
                                                           cells with half the
                                                           number of the
                                                           previous cell. Each
                                                           has the original
                                                           number. 23 pairs

After the final division 4 gamete cells are formed with ½ the number of
chromosomes as the parent. Gametes are the egg cells in females and the
sperm cells in males. Fertilization of the egg and sperm form a zygote.
The father determines
the sex of the child
because he passes on
the Y chromosome.

Remember mom is XX
and dad is XY, therefore
Mom can only pass on
the X.
These traits can be passed on by mom
only. The reason for this is only the X
chromosome carries traits.

Baldness, colorblindness & hemophilia are
examples of these traits.

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