Transcript Chapter 6

 http://www.youtube.com/watch?v=kVMb4Js99tA&fea
ture=related&safety_mode=true&persist_safety_mode
=1
 Haploid= half the genetic content (n)
 Diploid = genetic equal to the parent.
Full genetic content (2n)
The process that produces
gametes (eggs and sperm) with
half the number of chromosomes
as body cells occurs in the sex cells.
 http://www.youtube.com/watch?v=D1_-
mQS_FZ0&safety_mode=true&persist_safety_mode=1
 DNA replication occurs only once in the
process.
 Meiosis I: the result is two daughter cells.
 Meiosis II: the result is four haploid cells,
each with half the number of chromosomes.
 Prophase I: homologous chromosomes
pair up.
 Metaphase I: homologous
chromosomes line up in the middle of
the cell.
 Anaphase I: homologous chromosomes
separate and are pulled to opposite
sides.
 Telophase I: one chromosome from
each pair is at each pole of the cell.
 Prophase II: one chromosome of the
homologous pair in each cell.
 Metaphase II: the x-shaped
chromosomes form a single line across
the middle.
 Anaphase II: sister chromatids move to
opposite poles of the cell.
 Telophase II: a nuclear membrane
forms around the chromosomes.
 http://www.youtube.com/watch?v=R_LUJSqeSrI&NR=
1&safety_mode=true&persist_safety_mode=1
Mitosis
Meiosis
 In body cells
 In sex organs to
produce sex cells
 Two daughter cells
 Same number of
chromosomes as
parent cell
 Four daughter cells
 Asexual reproduction
parent cell.
 Sexual reproduction
 Half the number of
chromosomes as the
 1. Mosses:
 External fertilization
 Water allows the egg and sperm
cells to meet
 Reproduces both sexually and
asexually
 2. Flowering plants
 Pollination
 Transfer of male gametes in structures
called pollen from the male structure to the
female structure of the plant.
Flowering
Plant
Pollen can be transported by:
 1.Pollinators such as bees and other
insects, fruit bats
 2.Wind
 3.Water
After fertilization, seeds are often
protected in fruit or cones.
Seeds contain the plant embryos.
 In many insects, the male deposits a
package of sperm inside the female.
 Insects often change a great deal
between hatching and adulthood
 This change in form is called
metamorphosis.
 Metamorphosis can be incomplete or
complete
Incomplete
 Three stages: Egg  Nymph  Adult
 The adult and the nymph resemble one
another
 Ex. grasshopper
Complete
 Four stages: Egg  Larvae  Pupa  Adult
 The adult and the larva look completely different
 Ex. Butterfly
Asexual
Sexual
 1 parent cells
 Two parent cells
 No gametes; cell
 2 sex cells unite to form
divides
 Little variation in
offspring
 Little energy required
 Less parental care
a zygote
 Greater variation in
offspring
 Greater energy
required
 Greater parental care
 Gregor Mendel
 Mid-1800s
 Experimented with inherited traits
in pea plants.
 Francis Crick & James Watson (1953)
 Described the structure of DNA and how it replicates.
The Human Genome Project
 1986-2003
 Genome: consists of the full set of genetic
material that makes up an organism.
 Made a map to identify genes
 This information may be used to check
for particular diseases.
 ◦Ex. Allderdice syndrome where part of
one chromosome is reversed. Identified
in Sandy Point NL.
A special “picture” of a person
showing all their chromosomes
arranged in a particular order
called a karyotype is studied.
 Can help to determine if there is any
abnormalities in the chromosomes.
 Can identify syndromes such as Down’s
Syndrome (extra 21st chromosome).
Cystic fibrosis
Can be used to save the genetic
information from endangered
plants and animals or to massproduce an organism with a
desired trait.
Reproductive cloning:
 Also called DNA cloning
 Purpose is to produce a genetic duplicate of an existing
organism with desirable qualities.
Therapeutic cloning
 Used to correct health problems.
 Stem cells and embryonic stem cells are able to
become many different types of cells.