Nov. 9

Today we finished the notes packet of Meiosis, did a demo of meiosis using
beads and magnets, and started the lab on UP 19-37.

Errors:

Nondisjunction: The chromosomes fail

to separate at Anaphase I or II. Occurs

with autosomes or sex chromosomes.

Nondisfunction causes some syndromes like

Klinefelter syndrome for males and Turner

syndrome for females.

Those syndromes cause almost like a steroid effect. For the people effected by these syndromes, they may become sterile.

Klinefelter syndrome: males, XXY: have 47 chromosomes instead of 46

Turner syndrome: females, XO: have 45 chromosomes and only one X chromosome.

Breakage of a Chromosome:

Deletion: part of chromosome is lost or removed

Duplication: a region of the chromosome is repeated

Inversion: a segment of the chromosome repositions and reverses the order of the genes

Translocation: one part of a chromosome goes on another chromosome and that piece cannot be found

next scribe: Kristin

11-8-10

Yunsu Y.

Today we took notes on MEIOSIS.

Meiosis goes through reduction division, 2 part division. Reduction=reduce , Division= Separate sister chromatids. Meiosis occurs in the ovaries or testes. It starts with a diploid parent cell then goes into prophase 1, metaphase I, anapahse I, telophase I, prophase II, metaphase II, anaphase II, then telophase II. The cell goes through each step twice but it does not really go through interphase II. It "goes" through interphase II, but it is just a resting period, it does not go through the same steps like in interphase I because it does not need to synthesize more chromosomes. (No G1, S, or G2 just stays the same.) These phases are very similar to mitosis, but are slightly different and have different end products.

1. Metaphase I: the homologous pairs of chromosomes called tetrads, line up in the middle.

2. Telophase II: instead of having 2 daughters cells, like in mitosis, you end up with 4. They also are not genetically identical.

Through meiosis, egg and sperm (gametes) cells are produced, not like mitosis where many different kinds of cells can be produced. Remember because this is sexual reproduction there are variations among offsprings. This variations amoung offspring occurs because of independent assortment and random fertilization.

1. Independent Assortment: when the chromosomes line up, there is no specific way it is all by chance.

2. Random Fertilization: a random pairing of 1 egg to 1 sperm, many different combinations.

Crossing over: where genetic material gets exchanged, segments of homologous chromatids.

-Crossing over happens because the genetic material gets tangled and they cross, so when they divide the daughter cells are not all the same. This would occur in prophase I.

There are somatic cells and sex cells---

1. Somatic cells: out body cells which are diploid -46 chromosomes for humans.

2. Sex cells: Sperm and egg which are haploid -23 chromosomes for humans.

-The end products of meiosis are sex cells that are haploid cells (n) and the parent cells in the beginning are diploid cells (2n). The diploid is the total number of chromosomes, 2 sets. Haploid is half the number of chromosomes.

★It is important to remember that end products of meiosis are haploid. They have to be haploid so that when an egg meets a sperm it can create a full human equaling 46 chromosomes. (23+23=46)

-Each human has sex chromosomes, usually 2. Females have XX and males have XY, so since 2 are sex chromosomes there are 44 leftover chromosomes. These are called autosomes. (not sex)

Karyotypes:

These are karyotypes of female and males humans.
-On the left is the female and on the bottom is the male. You can tell by the difference of the last 2 sex chromosomes.

-You can see that the first somatic chromosome is the largest and the last somatic chromosome is the smallest.

We also watched a video on meiosis:

1. There are 4 egg cells and 4 sperms cells produced. All 4 of the sperm cells are viable but only 1 of the 4 eggs will be used and mature, the other 3 eggs are useless.

2. Centrioles move before the second division, making a right angle to the first location of the centriole at the first division.

Homework: UP. pgs 15-16B, Study Meiosis, Read Up pgs 13-14, Cut out pg 21 for tomorrows lab

Next scribe: Carey E

Friday, Oct. 29th, 2010

How Allergies Develop


Develops in two stages:

1. The first exposure to the allergen causes sensitization (you get sensitive).

2. The following exposures of the same allergen cause allergy symptoms.

• Histamine – a chemical that reacts to an allergy

• We take anti-histamine when we get allergies to fight them off



The Details

1. Allergen enters the blood stream.

2. B cells make the antibodies

3. The antibodies attach themselves to the mast cell.

4. Allergen binds onto the antibodies on the mast cell.

5. Histamine is released and starts causing allergy symptoms.

Allergens usually tend to enter through the nose and the throat so symptoms are most abundant in these areas.

Anaphylactic shock – sudden releases of inflammatory chemicals into the body of people with extreme sensitivity to certain allergens such as:

• Bee stings

• Peanuts

• Shellfish

So what happens?

Blood vessels expand greatly causing a great drop in blood pressure, a condition also known as shock.

Anaphylactic shock can be fought off with injections of epinephrine (adrenaline).



Common Autoimmune Diseases

Rheumatoid Arthritis – causing damage and inflammation of bone joints due to T-cell attack

Juvenile Diabetes – a cell-mediated attack of insulin that produces cells in the pancreas

Multiple Sclerosis – T-cells attack the myelin sheath (fatty tissue) of neurons

Lupus – immune attack on skin and vital organs

Every disease or infection has a different reaction depending on how weak or strong your immune system is.



Immunological basis for organ/skin graft rejection?

Transplant Rejection – an immune system recognizes the donor’s cells or organs as foreign and starts attacking

Donors with self proteins that match the recipient’s as closely as possible are used in order to minimize rejection.

Drugs are used to hold back to suppress the immune system. The donors and recipients may not be related.



Immunodeficiency Diseases

Examples:

1. SCID (Severe Combined Immunodeficiency) – a case where someone does not have functional T and B cells; as a result, they do not have specific responses.

2. Hodgkin Disease – a type of cancer that affects the number of lymphocytes, affecting the T and B cells.

3. AIDS/HIV



AIDS (Acquired Immune Deficiency Syndrome)

HIV attacks the helper T cells that activate T bells and B cells.

Since 1981, AIDS has killed more than 20 million people, and 40 million people are living with the virus. Over 1/3 of the adult population in Africa has been infected as well.

Death is usually not a result of HIV, but because of other life threatening infections.



Next Scribe: Yunsu Yu

Immune System: T Cells, Allergies, Cancer, Immunity, Immune Response

10/28/10

Claire

Disease and the Immune System

After taking a quiz and finish the spice lab we went over these notes:

Supresser T Cells: get concentrations back to normal after the infection goes away

Cytotoxic T Cells: help protect body fro own cells if they become cancerous

-sometimes cancer is hard to fight because our bodies don't reconize our own cells as cancerous

Immune system has a "memory"

-our bodies remember the antigens we have encountered

-if we encounter the same antigen again, our immune system destroys them before symptoms occur

Immunity: resistance to specific invader

-can be done actively or passively

Active Immunity: body produces antibodies in its own defense

-if antibodies are produced, so are memory cells

2 ways:

-having disease

-vaccination: injection of weakened variant of disease-carrying microbe or one of it's components

Passive Immunity: receiving pre-made antibodies

-through mother's blood stream (baby's can't produce antibodies)

-through shot containing antibodies produced by another organism

Ex: Tetnus shot- gives you antibodies, not the pathogen because the pathogen is too dangerous and harmful, can get sick from it.

-have to get these shots more than once, no memory cells are produced

Primary Immune Response:

- first exposure of lymphocytes to an antigen

-takes days to produce antibodies-through colonal selection

-memory cells produced to remember antigen

-these are located in lymph nodes and live for decades

Secondary Immune Response:

-occurs when the same antigen is encountered again

-memory cells multiply leading to production of antibodies

-more effective than primary immune response

-person is symptom free

-could offer lifelong immunity

You can get infected by the same pathogen twice, but only get sick from it the first time because memory cells are produced

Immune Disorders: consequence of malfunctioning immune system

-allergies: sensitivity to antigens in environment

-how they are developed: 1st exposure to allergen cause sensitization, following exposures to same allergen produce symptoms

-Autoimmune Disorder: immune system fights its own molecules-vey bad

-Immunodeficiency Disease: body lacks part(s) of immune system

Next Scribe: Sally Y

Scribe Post: 10/26/10

Today was a big day in Biology!

We started to plan out our independant spice labs. Accompanied with that was the assignment to get your experiment approved by Mrs. Andrews. When approved, we were to turn in a lab report up until the procedure part.

Spice Lab:
An independant lab that we invent and carry out by oursleves. We are to measure the zone of inhibition in the bacteria, Bacilis subtilis. We are to perform the lab and to write a lab report.
The finished lab report is due on 11/8/10. Guidelines are:
-Materials have to be LIQUID
-Must have TESTABLE AND MEASURABLE hypothesis
-Have multiple trials
-Can only use 4-5 Petri dishes
-Can vary in concentration, product brand..ect
-Compare and contrast products.

In your lab report, remember to:
- Include background on ALL of your materials (should vary with group members)
- Match your procedure with your group's
- Use roman numerals, letters, and numbers for every section of your report
- Have an ORIGINAL title
- Must incude how/when to gather data (give times; 24 hours, 2 days..ect.)
- Include charts and graphs
- Lab report guidlines on UP pg. 43 and in Survival pk. pg. 13
- HAVE IT IN CLASS!

Homework:
- STUDY FOR TEST
- Read UP pgs 37-38
- Re-read chp 24
- Review notes

next scribe: Bridget S.

October 27, 2010, B-Cells and T-Cells

Today, we watched two short movie clips.

One was about the role of an antibody.

• neutralization
• aggulination
• precipitation
• complement proteins

The other was about:

• humoral immunity- provided by B-cells, defends primarily vs. bacteria and viruses present in body fluids
• clonal selection

Notes: Page 21, 23, 24
Clonal Selection

• When an antigen enters the body fluids, it binds with B-Cells that have complementary receptors
• The B-cells are then activated; they grow and divide, creating effector cells
• These cells then secrete antibodies specific to that antigen
• plasma cells- make the antibodies
• memory cells- "remember," this is why you don't get the same exact infection again because your body produced the antibodies needed to fight that infection

T-Cells

• Cell-mediated immunity
• Respond to antigens that have already entered the body
• More "hands on" than B-Cells
• 3 kinds- Helper T-Cells, Cytotoxic T-Cells, and Supressor T-Cells

Helper T-Cells

• Macrophages engulf a microbe, produce antigens, and displays the foreign antigens on the cell membrane
• it is essentially saying "I found something and I don't think it's good!"
• The Helper T-Cell binds to the macrophage at the site and determines if it is good or bad
• If bad, the Helper T-Cell divides, produces memory cells, and stimulates activity of cytotoxic T-Cells

Cytotoxic T-Cells (Killer T-Cells)

• Identifies infected body cells and binds to them
• Discharges perforin which is a protein that creates a hole in the infected cell's membrane, causing it to die.
• This needs to happen because the infected cell has become a factory of pathogens and the body needs to have it shut down.

Homework:

• UP pgs. 47 and 57
• UP pg. 5 What is Ecology Good For (E.C.)
• Work on Lab Report, Due: 11/8
• The Test may be on Tuesday, but please still plan on Friday!!!

Next Scribe:

• Claire T

October 25, Immune System

Using cell signaling, a healthy cell makes proteins which inhibit viral replication, meaning it kills off the exported viruses that the bad cell releases.

2. Prostaglandins. Inscreases blood flow to the wound area = RED and WARM.
i. Also sends pain signals to brain. AH! Brain, help me!3. Pyrons. travel to the hypothalamus (it's in the brain and it analyzes your blood.) They cause a low fever which is GOOD because the heat makes the enzymes work faster.

III. Lymphatic System
A. Two main functions
1. To return tissue fluid to circulatory syste
2. To fight infection.
It's a highway of vessels that touches upon every part of your body so they can react fast when tissue is damaged.

Scribe: Aliza R.