Monday February 22nd, 2010

Today´s class topic was: VIRUSES.

A virus has no cell which means that the virus is not alive. Viruses can have DNA or RNA, based in this, scientists classify them. When it has RNA are called retroviruses and are very harmful. Other components of a virus are:

-Proteins: Is a coat that protects the nucleic acid.

-Envelope: Made of carbs and is kind of mucous or sticky.

-Spikes: Located between the protein coat and the envelope. Spikes and the envelope of carbs work together in order to stick into other cell.

-Projections: To get stock to other cell. Have an appearance of little legs.

A virus floats inside the body of the organism in which it is (chicken, cow, human, etc.) until something stops it, so it attaches to that thing, in this case a cell for getting able to duplicate.

Something important to know is that a virus of other organism can affect a human, for example, a chicken virus can´t affect a human it just affects chickens.

There are 2 ways or forms of viruses to duplicate: LYTHIC CYCLE and LYSOGENIC CYCLE.

LYTHIC CYCLE: Lythic means destruction. It destroys the cell.

Steps:

1.- Virus attaches to the cell.

2.- It inserts DNA.

3.- The DNA gets to the nucleus. (Ehen the virus DNA gets to the nucleus, the cell DNA stops working, it is like if it deactivated the cell DNA).

4.- The cell is HIJACKED.

5.- It gets out (Inside the cell the viruses duplicates, and duplicates, and duplicates… until the cell its full of viruses and explodes, there is when each of the viruses gets to infect the nearest cell).

LYSOGENIC CYCLE: it can be familiarized as SPY CYCLE*.

Steps:

1.- The virus gets attached to the cell.

2.- It inserts its DNA.

3.- The DNA gets to the nucleus.

Up to here the first 3 steps are the same to the lythic cycle but the next 2 change.

4.- The DNA of the virus hides in the nucleus.

5.- When mitosis of the cell happens the result is 2 cells with DNA and virus, INFECTED CELLS.

*Spy cycle is not an official name for this cycle is just an example or an easier way to understand this cycle. With SPY it means that the virus gets silently into the cell and it starts getting the cell weaker and weaker until it duplicates by the mitosis of the cell.

Some words definition we saw really fast are VIROIDS and PRIONS.

-Viroids: Are biological agents with little RNA.

-Prions: Are proteins that cause disease.

Stephanie Sotelo

Friday, february 19th 2010

Today´s class topic was SYSTEMATICS.

First, we start with Linnaeus (about the 1700s) who divided nature in three kingdoms: Mineralia, Vegetabilia, and Animalia.

-Mineralia for rocks and minerals.

-Vegetabilia for plants.

-Animalia for animals.

Linnaeus developed the binomial system and named every living organism he knew. The names for the genus species have certain characteristics for being a genus:

- They are written in latin, because is a language that hasn´t change over the years such as Spanish or any other language.

- They must be in written on italics.

- The first letter of the two words must be in CAPITAL letters.

- Description: The genus must include the principal characteristic of the organism.

- Example: Homo Sapiens: man that thinks.

Haeckel (about the 1860s) modified the classification by eliminating Mineralia, since they aren´t living organisms, add another kingdom and renamed the other two. So the 3 kingdoms he put in his theory are:

- Protista: unicellular living organisms.

- Plantae: plants.

- Animalis: animals.

Whittaker (in 1959) proposed 5 kingdoms:

- Plantae: Multi-cell and autotroph*.

- Animalia: Multi-cell and heterotroph**.

- Protista (protozoans): Single cell organisms with a mixed feeding.

- Monera (bacterial): Single cell, heterotroph and prokaryotic, making it the only kingdom that has prokaryotic cells.

- Fungi (mushrooms): Multi and unicell and heterotroph. They have cell wall such as plants which make it eukaryotic but it doesn´t undergo photosynthesis.

*Organisms that produce their own energy.

** Organisms that take their energy from others.

Woese (in 1994) and a group of scientists, before named naturalists, raise the Monera kingdom to a higher level. This proposes 3 domains:

- Archaeobacteria and Eubacteria – instead of the Monera kingdom he created two domains (which is a higher level than a kingdom) and they are prokaryotic .

- The third domain is Eukarya in which are included the Animalia, Plantae, Protista and Fungi kingdoms.

They are many branches arising from one domain. The set of all branches is called Hierarchy of Classification:

Domain-Kingdom- Phylum- Class- Order-Family- Genus- Species

Example:

Stephanie Sotelo

Monday, November 9th, 2009

This class we saw pictures but this time were of the male reproductive system
And this are the parts of the reproductive system:
-scrotum; the sac of skin that holds the testicles
-testes: the reproductive glands that reproduc sperm
-seminiferous tubules: it creates gametes, namely sperms
-epididymis: tightly coiled tube connecting the efferent ducts from the rear of each testicle to its vas deferences
-vas deferences: is the sperm carryngtube until it reaches the urethra
-seminal vesicle: narrows at the botton and joins the vas deferences, forming the ejaculatory duct
-prepuce: is a piece of skin wich cover paart of the genitals
-prostate: it produces a fluid that carries the sperm out of the body during the ejaculation
-cowpper's gland: produced a secretion that helps lubricate the head of the penis during erection and ejaculation
-corpora cavernosa: two flexible cylinders of erectile tissue
-corpus spogiosum: is a spongy tissue surrounding the urethra within the penis
-penis glans: is the sensitive tip of penis and is communly referred to as the head of the penis
-urethra: travels trough the penis, and carries semen as well as urine
-the testes consist in numerous lobules

Marla Lopez Arechiga

The following links Were provided by Juanita Montoya, you should watch them.

http://kidshealth.org/misc/movie/bodybasics/male_repro.html

http://www.juganding.com/juegos/jugar-gratis-la-gran-carrera-del-esperma-3470.html

Friday, november 6th, 2009

On this class we talked about female body sexual organs, so heres one of the pictures the teacher explain: http://www.soc.ucsb.edu/sexinfo/images/05-08-femaleinternalside.jpg

We start talking about the outer organs which were:

• Labia majora, and labia minora
• Clitoris: is like a heat sensor, it is important on sexual pleasure, it’s also call the “female pennies”.
• Vagina: is the passage way to the inside organs (connects inner organs with outer organs), it’s made of muscle, and it’s length it’s from 5 to 10 cm.

The outer organs an the vagina works as a filter, and regulates levels of PH, so some bacterias cannot live there, and some bacterias can that’s why there are infections right there, and sperms can live there.

These are some inner organs we spoke about: http://kvhs.nbed.nb.ca/gallant/biology/female_anatomy_frontal.jpg

• Uterus: this part take care of the product of a pregnant, on this part also happens the process of menstruation.
• Cervix: connects the vagina with the uterus. This part isn’t flexible as the vagina, so it doesn’t let anything go trough.
• Fundus: is the upper part of the uterus
• Ovary: is connected with the uterus, is where female reproductive cells are produce
• Oviducts: this connect the uterus with the ovary, the ovule travel trough here. Also here starts the process of fecundation
• Infundibulum: (no it’s not a harry potter spell) the oviducts connect with this part to the ovary. The ovary retains in it’s place also with the suspensory ligament.

We also talked about some structure of the ovary:

http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f28-4a-d_ovary_c.jpg

• Primary folicus: is the first period of the ovule.
• The secondary oocyte: is the ovule almost complete
• Corpus luteum: after the ovary is release it left like an scar, which can be used as a count of how many ovules the ovary has release.

We talked about the menstrual cycle:

http://www.womentowomen.com/menstruation/images/060811_menstrualcycle_w-moon.gif

It’s a process of that occurs each 28 days. If an ovule is release and it’s not fecundated it need to bee throw it out. So when it’s first release from the ovary and then reach the uterus, it attach to the endometrium , this part feed the ovule with proteins and blood, to prepare it to be ready in case of a pregnance, and the endometrium wall start growing of blood, so if the the ovule isn’ fecundated it need to release all that blood and inside of that blood goes the ovule, here’s when the menstrual process occurs, and it hurts because the wall of blood it’s really attached , so it hurts when it’s release.

This are some hormones release during the menstrual cycle:

• FSH: (follicle stimulant hormone) it cause the ovule.
• LH: (luthinizant hormone) make the corpus lutheum for ovule.
• Progesteron: determines how thick is the endometrium.

Eduardo Lopez Ramade

Monday October 26th, 2009

reproduction

sexual vs asexual
good bad good bad
recombinatio slow no need 2 cells no variability
survival expensive quick no mutation
need 2 cells easy
rostore apolation

Sexual reproduction need haploid cells and a crossing over.
Crossing over is needed for variability of gens


We saw some videos were they explain the types of sexual and asexual reproduction

Types of sexual reprodduction
internal
external

Types of asexual reproduction
Binary fission
iw a division in two parts wich each have the potential to grow to the size of the original cell


Budding
the two resulting cells are not equal size


Fragmentation or Clonal Fragmentation
(reproduction or cloning) a organism is split into fragments. Each fragment develop into mature ,
fully grown individuals that are a clone of the original organism.
the mothers cells are very important in this reproduction.


Spores genesis
the type of reproduction that the fungi family use. Is by spores; the spores go out of the mashroom (in this case).
It can be male or female spores and mashrooms; and then this mashrooms trough female or male spores. This
female or male spores need the opposite spore to build a diploid mashroom.


Regeneration
is said to regenerate a lost or damaged part if the part regrows so the original function is restored.


Partenogenesis
this is ffound in female where growth and development of embryos occurs with out fertilization by a male.


Hermaphrodistism
is only in animals and plants; they have both male and female reproductive organs, only one works correctly.

Intersex
is only in humans; they have both male and female reproductive organs, only one works correctly.

Marla Lopez

Monday October 19th, 2009

So this Monday 19th of October =)... We keep watching a little of mitosis, but also we started with meiosis. so this is :

Here is a video of the 4 Steps of mitosis: http://www.youtube.com/watch?v=2WwIKdyBN_s

1. Prophase: the DNA condense to cromosomes
2. Metaphase: the Cromosomes get in the spindles
3. Anaphase: while the cromosomes are on the spindle... they separate to both poles
4. Telophase: the cell divides into 2

Here is other video in which there are many cells doing mitosis in real time =O: http://www.youtube.com/watch?v=m73i1Zk8EA0

So here are some specification about mitosis:

-It happens in EVERY cell EXCEPT on sperm and ovum/ova
-The mitosis happens for reproduction
-It happens all the time... but mostly at GROWTH


These are the similarities between the mitosis and meiosis:


MITOSIS V.S. MEIOSIS
- Division -Division
- mother/daughter - mother/daughter
-all cells except Sexual cells - ONLY sexual cells
- 2 daughters (46 cromosomes) - 4 daughters (23 cromosomes)
- Diploid (genetic info.) -Haploid (genetic info)

Heres a video

http://www.johnkyrk.com/meiosis.html

Juan Pablo Campos

(Liga del ultimo video enviada por Fernando Lopez)

Friday, october 16th, 2009