Sexual Reproduction

is a process that creates a new organism

by combining the genetic material of two

organisms; it occurs both in eukaryotes

and in prokaryotes. A key similarity

between bacterial sex and eukaryotic

sex is that DNA originating from two

different individuals (parents) join up so

that homologous sequences are aligned

with each other, and this is followed by

exchange of genetic information (a

process called genetic recombination).

After the new recombinant chromosome

is formed it is passed on to progeny.

Asexual Reproduction

It can be advantageous and/or

disadvantageous. One positive aspect is

that it can create individuals rapidly

and in large quantities. Secondly,

bypassing the sexual process can help a

plant in times of dryness since motile

sperm require water to fertilize the

egg. Another advantage lies in the fact

that plants with the desired

characteristics can be cloned for

economic reasons (agriculture).

However, if something goes wrong, such

as the occurrence of a fatal mutation,

the whole society of clones can be

terminated. For this reason, farmers are

careful in determining how to propagate

their vegetation. In conclusion, the

asexual process of reproduction is an

important one to plants.

Mitosis Is the process by which a cell separates

the chromosomes in its cell nucleus into

two identical sets, in two separate

nuclei. It is a form of karyokinesis, or

nuclear division. It is generally

followed immediately by cytokinesis,

which divides the nuclei, cytoplasm,

organelles, and cell membrane into two

cells containing roughly equal shares

of these cellular components.[1] Mitosis

and cytokinesis together define the

mitotic phase of the cell cycle—the

division of the mother cell into two

daughter cells, genetically identical to

each other and to their parent cell. This

accounts for approximately 10% of the

cell cycle.

Meiosis The meiosis has many parts like:

Diploid Cell: From a preceding mitotic

division, the ogonium (Spermatogonium)

enters meiosis with DIPLOID chromosomes

but TETRAPLOID DNA. Chromosomes then

duplicate to produce SISTER CHROMATIDS

(or HOMOLOGOUS DYADS).

Prophase I: Dyad pairs align to create

"TETRADS", non-sister chromatids connect

and trade sections at a "CHIASMA", a

process called "CROSSING OVER".

Metaphase I: SPINDLE FIBERS attach to

each dyad at the KINETOCHORE. Tension

from spindle fibers aligns the tetrads

at the cell equator.

Anaphase I: Chiasmata break apart and

sister chromatids begin migrating

toward opposite poles.

Telophase I: CLEAVAGE FURROW forms

beginning the process of CYTOKINESIS

(cell division). Resulting daughter cells

are HAPLOID.

Prophase II: Spindle formation begins and

centrosomes begin moving toward poles.

Metaphase II: Tension from spindle fibers

aligns chromosomes at the metaphase

plate.

Anaphase II: CHROMATIDS separate and

begin moving to the poles.

Telophase II: CLEAVAGE FURROW forms

beginning CYTOKINESIS.

Gamete: NUCLEAR ENVELOPES form and

chromosomes disperse as CHROMATIN.

Meiosis has produced 4 DAUGHTER CELLS,

each with 1N chromosomes and 1N DNA.

Later, in fertilization, male and female

1N gametes will fuse to form a 2N ZYGOTE.

Allogamy Is a term used in the field of biological

reproduction describing the

fertilization of an ovum from one

individual with the spermatozoa of

another. By contrast, autogamy is the

term used for self-fertilization. In

humans, the fertilization event is an

instance of allogamy. Self-fertilization

(also known as autogamy) occurs in

hermaphroditic organisms where the two

gametes fused in fertilization come from

the same individual.

Autogamy Of male and female gametes (sex cells)

produced by the same individual. Self-

fertilization occurs in bisexual

organisms, including most flowering

plants, numerous protozoans, and many

invertebrates. Autogamy, the production

of gametes by the division of a single

parent cell, is frequently found in

unicellular organisms such as the

protozoan Paramecium.

Image of Asexual Reproduction:

Image of Mitosis:

Image of Meiosis:

Image of Autogamy: