We do not need a lot

French Fries – Hatem

Fried Chicken – Priscilla

Bacon Fat – Sameer

Cheese – Stephan

Olive Oil – Hanna

Crisco – Stephan

Smoked Salmon – Hanna

Nuts (almonds) – Pierluigi

Cooked meat – Hanna

Egg whites (boiled and raw) – Ana C.

Tofu plain – Elizabeth

Beans Cooked -  Michi

Edamame – Himangi and Ms. Sini

11/11/2011

Lab report must be submitted by next Thursday, 17.11.2011!

Today:

If you do not come to the M lab to test for Proteins and fats after 16 to 17 hours of incubation with the enzyme, you cannot report the results in your lab report!!!!

Be responsible…..let me see how many of you come in to do the Biuret test, add2ml to test for proteins and Sudan III test for Lipids……add 5 drops…..

Ms S

6.1.5 to 6.1.7 More about the functions and also Absorption of digested food

http://leavingbio.net/Human%20Nutrition/Human%20Nutrition.htm

Ms S

Make sure you include the variables;

Address errors if any;

Suggestions and a valid conclusion based on your data analysis.

Ms S

[11/03/11]

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter26/animation__organs_of_digestion.html

More detailed:

http://kidshealth.org/kid/htbw/digestive_system.html#

Practical work:

http://eve.kean.edu/~breid/enzyme/enzyme.html

Ms S

4.4.1: The PCR reaction

http://highered.mcgraw-hill.com/olc/dl/120078/micro15.swf

13/10/2011: Restriction Enzymes

http://highered.mcgraw-hill.com/olc/dl/120078/bio37.swf

4.4.2 Gel electrophoresis

http://www.sumanasinc.com/webcontent/animations/content/gelelectrophoresis.html

http://www.accessexcellence.org/RC/AB/WYW/lander/lander_4.php

4.4.8  Gene transfer

http://highered.mcgraw-hill.com/sites/dl/free/0072835125/126997/animation46.html

18/10/11

4.4.9: Genetically modified crops

http://www.gmo-compass.org/eng/grocery_shopping/crops/

and 4.4.10: Benefits and risks of genetic modification:

http://cls.casa.colostate.edu/transgeniccrops/animation.html

4.4.11: Creating a clone

http://learn.genetics.utah.edu/content/tech/cloning/clickandclone/

4.4.12 The ethical issues of cloning

http://www.ornl.gov/sci/techresources/Human_Genome/elsi/cloning.shtml

Ms S

http://highered.mcgraw-hill.com/sites/0072556781/student_view0/chapter11/animation_quiz_4.html

http://www.tokyo-med.ac.jp/genet/dmu-e.htm

Ms S

Topic 3.5: Transcription

http://bcs.whfreeman.com/thelifewire/content/chp12/1202001.html

http://learn.genetics.utah.edu/content/begin/dna/transcribe/

August 31, 2011

Topic 3.5 continued:

Translation:

http://highered.mcgraw-hill.com/olc/dl/120077/micro06.swf

http://www.courses.fas.harvard.edu/~biotext/animations/TRANSLATE20b.swf

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

Have a good weekend!

Ms S

Use this as a resource to come up with your own

http://www.biologyjunction.com/dichotomous_keying.htm

http://cbe.wisc.edu/assets/docs/pdf/biolearn/Classification/WhatIsLife/dichotomous_key.pdf

We will discuss this further in class…..

Good night!

Ms S

Use this link to analyze CO2 data.

Ms S

How do you compare detritivores and saprotrophs as to their mode of eating?

Saprotrophs are organisms that break down dead organic material to inorganic products, important in recycling of nutrients in ecosystems.
Detritivores such as woodlice and earthworms are saprotrophic organisms that ingest dead organic material and break it down during digestion by enzymes to smaller particle size. Some of the digested particles are not absorbed but eliminated onto the soil where they form humus. Fungi and bacteria are saprotrophic organisms called decomposers. They further breakdown organic material in the humus by secreting enzymes externally then absorbing the digested material. Mineral nutrients such as ammonia are released to the soil at this stage.
The detritivores increase the surface area of the dead organic material making it easier for the decomposers to break it down completely to inorganic molecules.

Topic 5.1.10

http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway/greenworld/energyflowrev2.shtml

5.1.4 till 5.1.14

http://www.wadsworthmedia.com/biology/0495119814_starr/big_picture/ch41_bp.html

5.1.13 recycling of nutrients

http://higheredbcs.wiley.com/legacy/college/strahler/0471238007/animations/ch22_animations/animation3.html

The Nitrogen cycle:

http://bcs.whfreeman.com/thelifewire/content/chp58/5802004.html

5.2 The Greenhouse gases

identify these gases and describe the “greenhouse effect”.

http://news.bbc.co.uk/2/shared/spl/hi/sci_nat/04/climate_change/html/greenhouse.stm

5.1 and 5.2

http://ourecology.org/ozone_layer.html

5.2.4 The Precautionary Principle

http://www.sehn.org/precaution.html

5.2.6

http://www.greenfacts.org/en/arctic-climate-change/foldout-arctic-climate-change.pdf

Ms S

• Ambar:
• 5th paragraph: How will animals be affected by Arctic warming?

Colocasia leaf: Ana / Hanna / Sameer

Celery leaf: Ambar / Hatem / Priscilla

Mustard green: Michelle / Stephan / Eydel

Kale: Elizabeth / Pierluigi

Cilantro: Himangi / Michael

Frozen spinach: IF  Hatem REMEMBERS TO BRING IT TO CLASS!!!!!

http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120072/bio13.swf::Photosynthetic%20Electron%20Transport%20and%20ATP%20Synthesis

http://www.compulink.co.uk/~argus/Dreambio/photosynthesis/photosynthsis%20animation.htm

http://highered.mcgraw-hill.com/sites/0070960526/student_view0/chapter5/animation_quiz_1.html

http://www.slideshare.net/schneiderl/photosynthesis-2663889

Ms S

Due date: 17/2/2011

Prepare to lose points for every day that you delay submission of your design.

2. Try to study which factor affects the germination of beans. Use a minimum of 5 beans or more. Use styrofoam trays to bring them to school once they start sprouting.

Do not sow the beans on the ground yet!

Due date: 17/2/2011

To be done:

CO2 sensor lab procedure:

http://www.chinetek.com.hk/products/datalogger/B3-13%20Germinating%20Seed.pdf

Ms S

Please include a heart healthy item or activity in your daily routine until the 17th of February, 2011.

Losing or getting rid of “habits or foods” that do not support a healthy heart are also permitted.

I must see an entry in your log or book for each day so that I can assign “hearty” points!

Heartfully,

Ms S

http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_glycolysis_works.html

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

and more….

http://www.wadsworthmedia.com/biology/0495119814_starr/big_picture/ch07_bp.html

Extra info……

http://herbarium.usu.edu/fungi/funfacts/Fermentation.htm

24/1/2011

C.3.4

http://www.sumanasinc.com/webcontent/animations/content/cellularrespiration.html

http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_the_krebs_cycle_works__quiz_1_.html

http://click4biology.info/c4b/8/resp8.2.htm#five

One last link….

http://www.wiley.com/college/pratt/0471393878/student/animations/citric_acid_cycle/index.html

http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__electron_transport_system_and_formation_of_atp__quiz_1_.html

Ms S

C.2.4 Competitive and Non Competitive inhibitors

http://www.elmhurst.edu/~chm/vchembook/573inhibit.html

C.2.5 Final end product inhibition

http://www.ngfl-cymru.org.uk/vtc/Phase1/wales/aslevel/biology/molecules/enzymes/Inhibitors/Allostericeffectorsandendproductinhibition/

Ms S

3.1.2 and 3.1.3

http://www.csua.berkeley.edu/~wuhsi/elements.html

3.1.4, 3.1.3 and 3.1.4

http://www.chem1.com/acad/sci/aboutwater.html

Even if there is a lot of information in the last link, the details will be discussed in class!

5/11/10

Topic 3.2:

http://www.chemistry24.com/biology/the-macromolecules.html

Happy Deepavali!!

8/11/10

continued……

http://bcs.whfreeman.com/thelifewire/content/chp03/0302002.html

Peptide bonds

http://student.ccbcmd.edu/~gkaiser/biotutorials/proteins/protein.html#peptide

3.2.3

http://www.suite101.com/content/what-is-a-carbohydrates-a33362

15/11/10

3.2.5

http://www.biotopics.co.uk/as/lipidcondensation.html

http://www.biology.iupui.edu/biocourses/n100/2k4ch3carbolipidnotes.html

AHL / Option C1

C.1.1 Levels of protein structure

http://www.sumanasinc.com/webcontent/animations/content/proteinstructure.html

17/11/2010

http://www.biotopics.co.uk/JmolApplet/proteinjstructure.html

C.1.1 and C.1.2

http://www.ausetute.com.au/proteins.html

29/11/2010

3.6.1 / 3.6.2 Opt C2.1, C2.2 and C2.3
http://www.sumanasinc.com/webcontent/animations/content/enzymes/enzymes.html

For all of 3.6 and Option C

http://leavingbio.net/ENZYMES.htm

Opt C2.4

http://bcs.whfreeman.com/thelifewire/content/chp06/0602001.html

Ms S

2.5.1 and 2.5.3 The Cell cycle

http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP13604

2.5.2 Abnormal cell division and tumors

http://www.learnerstv.com/animation/animation.php?ani=206&cat=biology

2.5.4

http://www.sumanasinc.com/webcontent/animations/content/mitosis.htm

21/10/10

http://www.angelfire.com/de/nestsite/mitosis.html

http://iknow.net/cell_div_education.html

Ms S

http://telstar.ote.cmu.edu/biology/downloads/membranes/index.html

2.4.4 Osmosis

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

2.4.5 Diffusion and facilitated diffusion

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_facilitated_diffusion_works.html

2.4.6: Active transport

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_the_sodium_potassium_pump_works.html

2.4.7

http://www.college-cram.com/study/biology/cell-membranes/endocytosis/

http://click4biology.info/c4b/2/cell2.4.htm#endo

Ms S

http://videos.howstuffworks.com/hsw/10309-the-cell-prokaryotic-cells-video.htm

2.2. 1 upto and 2.3.3

 includes Electron micrograph pictures:

http://umanitoba.ca/Biology/lab3/biolab3_2.html

2.2.4: Binary fission

http://www.cellsalive.com/ecoli.htm

Ms S

What stem cell research strives to achieve is the cultivation and nurturement of stem cells, the basic cell of the body, enabling it to be reproduced to other specific parts of the body. The implications are obvious. Limbs and organs could be grown from scratch in a lab then used in transplants or to cure illnesses.

By providing the raw material for virtually every kind of human tissue, new treatments for a wide range of human diseases including diabetes, heart disease, some forms of cancer, and Parkinson’s disease can now be developed.

This research also benefits the study of development events that cannot be studied directly in a human embryo, which would cause major clinical consequences such as birth defects, infertility and pregnancy loss.

A more complete understanding of normal development will ultimately allow the prevention or treatment of abnormal human development.

Another advantage is the ability to test millions of potential drugs and medicine, without the use of animals or human testers. This requires a process of simulating the effect the drug has on a specific population of cells. This would tell if the drug is useful or problematic.

How Stem Cell Research Benefits Medical Treatments

1. Current Treatments
2. Potential Treatments – Brain, Spinal Cord
3. Potential Treatments – Muscle, Heart, Low Blood Supply
4. Potential Treatments – Baldness, Missing Teeth and Blindness
5. ALS Potential Treatment and Stem Cells in Animals

• It provides medical benefits in the fields of therapeutic cloning and regenerative medicine.
• It provides great potential for discovering treatments and cures to a plethora of diseases including Parkinson’s disease, schizophrenia, Alzheimer’s disease, Cancer, spinal cord injuries, diabetes and many more.
• Limbs and organs could be grown in a lab from stem cells and then used in transplants or to help treat illnesses.
• It will help scientists to learn about human growth and cell development.
• Scientists and doctors will be able to test millions of potential drugs and medicine, without the use of animals or human testers. This necessitates a process of simulating the effect the drug has on a specific population of cells. This would tell if the drug is useful or has any problems.
• Stem cell research also benefits the study of development stages that cannot be studied directly in a human embryo, which sometimes are linked with major clinical consequences such as birth defects, pregnancy loss and infertility. A more comprehensive understanding of normal development will ultimately allow the prevention or treatment of abnormal human development.
• Another advantage of stem cell research is that it holds the key to reversing the effects of aging and prolonging our lives. Stem cell research has already found many treatments that help slow the aging process, and a bonus of further stem cell research is a possible ‘cure’ for aging altogether.
• An advantage of the usage of adult stem cells to treat disease is that a patient’s own cells could be used to treat a patient. Risks would be quite reduced because patients’ bodies would not reject their own cells.
• An advantage of using embryonic stem cells is that they can develop into any cell types of the body, and may then be more versatile than adult stem cells.

Pillai, PH. (n.d.). Advantages and disadvantages of stem cell research. Retrieved from http://www.buzzle.com/articles/advantages-and-disadvantages-of-stem-cell-research.html

Pros and cons of stem cell research. (n.d.). Retrieved from http://www.bootstrike.com/Genetics/StemCells/proandcon.html

Hatem

So hey guys,

I’ve opened up a post that you can edit or leave a comment to if you are in the group of Cons against stem cells. you have to do research on the cons of stem cells so that we can debate in class.   remember the debate is Thursday. post any research on this post or in a comment to this post.  if you don’t remember how to access this blog or how to leave a comment just ask one of your class mates we really need all the info we can so we can win the debate tomorrow, so come prepared!

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Stem cells are: cells that can grow into almost anything, therefore generating new and healthy stem cells could possibly have many positive effects but not everything is so good about stem cell research.

• Stem cell research is when they take a cell and artificially grow them in a laboratory and then run tests on the fundamental properties of the cell.
  • Problems with that:
    • They take the cells from an aborted embryo just days after conceiving or when it is five to nine weeks. (This is a big controversy in ethics and morals).
    • Another concern is how this knowledge will be used.

    • This is all from an article on a debate before 2007.

      Some people also find that we “should not mess with human life” and that we humans “should not play god”

• Some say that stem cell research can lead to human cloning (not proven true) and that can have, even thought it might have good intentions, devastating effects. Take for example nuclear research.
• (Based on a debate before 2007 these were some cons from there) a human life cannot just be taken, we should look at an fertilized egg as a human life and there is no justification for killing a baby. And also science has flaws for example we do not know if we can use stem cells to make transplantable organs.
• This is all from an article on a debate before 2007.

• Experiment Resources (2008). Stem Cell Research – Pros and Cons. Retrieved [31.08.2010] from Experiment Resources: http://www.experiment-resources.com/stem-cell-pros-and-cons.html

Another website says that there is no problem with the research but with retrieving the stem cells, since they come from either fetuses or pluripotent cells in human embryos. And then it argues that this is causing a big up roar in the illegal organ market and that doctors or other people are illegally selling their fetuses or embryos.  And this has brought up many religious and social issues (morals ECT.).

• Ganesh, G. (2002-2010). Pros and cons of stem cell research. Retrieved from http://www.bootstrike.com/Genetics/StemCells/proandcon.html

Then there was another website which also stated another interesting fact.  It says stem cell research has been declared illegal in some countries. It is unethical and  some people feel that it is like cloning and they are against that. And depending on your ethics most people believe that life starts at embryo’s so aborting them would be killing.

• Godbole, M. (2002-2010). Stem cell research pros and cons. Retrieved from http://www.buzzle.com/articles/stem-cell-research-pros-and-cons.html

And then there are the medical oppositions , for example mice that have been treated for Parkinson disease with stem cells have died of brain tumors. Embryonic stem cells that have been kept for a long time have shown to create the type of chromosomal anomalies that create cancer cells. And funds for embryonic stem  cell research is taken away from the less controversial research.

• popular issues, . (2002-2010). Pros and cons of stem cell research. Retrieved from http://www.allaboutpopularissues.org/pros-and-cons-of-stem-cell-research.htm

 HK.

=======================================================================================================

• “We should not mess with human life.”
• “Humans should not be trying to play God”
• Some argue that stem cell research in the far future can lead to knowledge on how to clone humans. It is hard to say whether this is true, but we have seen devastating consequences of other research-programs, even with good intentions, such as nuclear research.

Some people think of embyos as having the potential for life and that potential should be preserved.

Some people think the embyos have dignity which should be preserved.

Some people think embryos have a soul.

Some people think that stem cell research constitues murder.

The crux of the matter for objectors is weither the right to life and dignity of the unborn child is being considered. Many would also object to the destruction of embryos in in vitro fertilisation. The use of adult cloned cells is considered very objectionable as it equates to creating a life(clone) with the express intention of destroying it.(See link to SPUC)

MICHELLE

*********************************

• Critics against stem cell research argued that the ethical issues of scientific work on aborted fetuses did not justify the possible benefits.
• “A life is a life and that should never be compromised. A fertilized egg should be valued as a human life even if it is in its very first weeks. Destroying human life in the hopes of saving human life is not ethical.”
• We should (and will) develop more ethical methods (such as using adult stem cells) which will enable us to research ethically. We should wait to those methods are available.
• The scientific value has been overstated or has flaws. E.g. we do not know for sure that we can use stem cells to clone transplantable organs.Citations

http://www.experiment-resources.com/stem-cell-pros-and-cons.html

On the darker side, which is supported by the naysayers, stem cell research is unethical. They say that the benefits should not shroud the issue of ethics in stem cell research. Cloning is vehemently objected to by those who are against stem cell research. It has also been said to be declared illegal in some countries. Human life shouldn’t be compromised for any purposes, even if it is in the form of an embryo that is needed for stem cell research. Some believe that life does not begin until birth, but those who argue against stem cell research say that embryos are where life begins and hence using them for research is like killing.

http://www.buzzle.com/articles/stem-cell-research-pros-and-cons.html

JV.

What are stem cells?

Stem cells are cells that have the capacity to self renew by cell division and differentiate. Differentiation is how multicellular organisms are efficient in their daily lives. The different functions carried out by cells is caused by differentiation. Cells need different genes to develop indifferent ways. Every cell has all of these genes, so in theory, in could develop in any way, but it choses to use the ones that it needs to follow its pathway of development. Once a cell has chosen its path, it  cannot change to follow another path. Stem cells can be found in adults, however to extract the stem cells it involves a painful bone marrow extraction. Stem cells can also be found in the liver and skin of the adults.

The human embryo consists of nearly entirely stem cells, that will eventually begin to differentiate. If the embryo is extracted, at an early period it will be a ball of stem cells, completely undifferentiated, and can be harvested and preserved for later use. Scientists today have also tried cloning embryos specifically for creating stem cells. However they are also obtained from terminated pregnancies or from embryos formed in in-vitro fertilization clinics. Placentas and the umbilical  are also drained after birth and hematopoietic cells are collected (these are cells that can differentiate into any type of blood cell)

Researchers agree that the use of stem cells may be very effective medical treatments. These cells offer the possibility of renewable sources to replace cells. Parkinson’s, Alzheimer’s, spinal cord injury, stroke, burns, diabetes, osteoarthritis, heart disease, birth defects diabetes, multiple sclerosis,  and rheumatoid arthritis. Limbs and organs could be grown in a lab from stem cells and then used in a transplant or to help treat the illness. We would be able to test the effects of drugs on these cells instead of an adult or an animal. It will also give us an amazing insight to development and human existence. Hopefully if someone ever ends up in the hospital, their own cells would be used to treat them, and avoid the rejection. These findings are only with the limited knowledge and research over the stem cells, so there might be a vast number of possibilities.

There have been breakthroughs in this science that are more appealing to the more conservative values of some who oppose stem cell resarch. A new method has been tried, where instead of removing the entire embryo, only one cell is taken, which will eventually grow into the ball of undifferentiated cells.

Allott, A. (2007). Biology. Oxford : Oxford University Press.

Experiment Resources (2008). Stem Cell Research – Pros and Cons. Retrieved August 30, 2010, from Experiment Resources: http://www.experiment-resources.com/stem-cell-pros-and-cons.html

MSNBC. (n.d.). Stem cells cells that won’t destroy embryo? – Health – msnbc.com. Breaking News, Weather, Business, Health, Entertainment, Sports, Politics, Travel, Science, Technology, Local, US & World News- msnbc.com. Retrieved August 30, 2010, from http://www.msnbc.msn.com/id/14481692/

Newsbatch. (n.d.). Stem Cell Research . News Batch Summaries. Retrieved August 30, 2010, from http://www.newsbatch.com/stemcell.htm

Pillai, P. (n.d.). Advantages and Disadvantages of Stem Cell Research. Buzzle Web Portal: Intelligent Life on the Web. Retrieved August 30, 2010, from http://www.buzzle.com/articles/advantages-and-disadvantages-of-stem-cell-research.html

SC

Stem Cells are crucial to develop organisms. They are nonspecialized cells which have the potential to create other types of specific cells, such as blood-, brain-, tissue- or muscle-cells.

Stem cells are in our body all our lives, but are far more potent in a fetus than in an adult body.

Some types of stem cells may be able to create all other cells in the body. Others have the potential to repair or replace damaged tissue or cells.

Embryonic Stem Cells are developed from a female egg after it is fertilized by sperm. The process takes 4-5 days.

There were two main issues concerning stem cell research with both pros and cons:

1. How the knowledge will be used
2. Concerns about the methods

The first issue is really not just about stem cell research, as it may be applied to most research about human health.

Pros of the study

Stem cell research can potentially help treating a range of medical problems. It could lead humanity closer to better treat and possibly cure a number of diseases:

• Parkinson’s Disease
• Alzheimer’s Disease
• Heart Diseases, Stroke and Diabetes (Type 1)
• Birth Defects
• Spinal Cord Injuries
• Replace or Repair Damaged Organs
• Reduced Risk of Transplantation (You could possibly get a copy of your own heart in a heart-transplantation in the future
• Stem cells may play a major role in cancer

Better treatment of these diseases could also give significant social benefits for individuals and economic gains for society

Pros of methods

• “The benefits of stem cell research have such a great outcome that they outweigh the ethical issues.” (Cost-benefit-analysis)
• “If someone is going to have an abortion, isn’t it better that we use it for something useful?”
• Adult stem cells would not be that interesting because they do not have the same properties as stem cells from a fetus.
• The research would give great insights about the basics of the body.

What is Stem Cell Research?
A relatively new field of research, stem cell research, entails employing primitive human cells and developing them into any of the numerous types of cells in the human body, including the blood and the brain cells. This research is being touted as proving to be extremely useful for fathoming the most serious of diseases and their cures. Be it neuro degenerative diseases orheart diseases and Parkinson’s , all have benefited from stem cell research. However, apart from being talked about as the next big thing in the field of medicine, stem cell research has also been a bone of contention, because of the possibility of genetic engineering and human cloning.

Now lets take a brief look at pros and cons of embryonic as well as adult stem cell research. Adult stem cells are obtained from embryos and in their nascent stage, they are called blastocysts.

Pros and Cons of Stem Cell Research
To talk about the brighter side, stem cell research has lead the scientists and the medical experts closer to the cures for birth defects, spinal cord injuries, heart diseases, diabetes and so on. Another major benefit of stem cell research, is that there is a possibility, that a way to replace or repair damaged organs can be forged from it. The research can lead to methods which can reduce the risks of organ transplants. Apart from this, the scientists can get a closer look at how the stem cells develop and grow. Therapeutic cloning and regenerative medicines are other exciting prospects of stem cell research. There is also an argument that embryos can be used to extract cells for stem cell research. Stem cell research will pave the way for engineering stem cells to replicate specialized cells in the brain, liver and skin.

It is hard to clearly demarcate the pros and cons of stem cell research. But the fact remains and no one can deny it, that stem cell research has ushered in, a significant development in the field of medical science. Stem cell research is certainly going to benefit the human race, even if there would be some who would try and exploit the darker side, or misuse its benefits. After all, you won’t see the silver lining if there wasn’t a dark cloud.

Reference:

Biotech/ biomedical poll. (2010). Retrieved from http://biotech.about.com/gi/pages/poll.htm?linkback=http://biotech.about.com/od/bioethics/i/issuestemcells_2.htm&poll_id=6903682813&poll=1&submit1=Submit%20Vote

Experiment Resources (2008). Stem Cell Research – Pros and Cons. Retrieved [September 1, 2010] from Experiment Resources: http://www.experiment-resources.com/stem-cell-pros-and-cons.html
Stem cell research pros and cons. (2010). Retrieved from http://www.buzzle.com/articles/stem-cell-research-pros-and-cons.html

HB

Topic 2.1.4

2.1.4 Compare the relative sizes of molecules, cell membrane thickness, viruses, bacteria, organelles and cells, using the appropriate SI unit

nm = nanometer um = micrometer

• Molecules – 1 nm
• Thickness of membrane – 10 nm
• Viruses – 100 nm
• Bacteria – 1 um
• Organelles – up to 10 um
• Most cells – up to 100 um (three dimensional nature/shape)

2.1.5:

A useful link

http://www.biologymad.com/cells/microscopy.htm

A scale bar: |——| = 1 µm

Magnification: ×250

To calculate magnification:

• Magnification = Measured Size of Diagram ÷ Actual Size of Object

but before this, both magnifications must be in the same measuremente, either in mm, cm etc..

Please refer to the examples we did in class.

2.1.6:

Explain the importance of the surface area to volume ratio as a factor limiting cell size.

• A cell needs a large surface area in order to carry out metabolic functions (as chemical reactions require a surface). As a cell grows, it needs to carry out more and more reactions. Therefore, since a cell has to maintain a certain surface area to volume ratio, its size is limited.
• The rate of exchange of materials (nutrients/waste) and energy (heat) is a function of its surface area.

Thus: As a cell grows in size (volume), the distance increases between the cytoplasm at the center of the cell and the cell membrane. The rate of chemical exchange with the surrounding environment may hence become too low to maintain the cell. It is not able to excrete waste quickly enough or take in important minerals.

Volume of a cell determines requirements while surface area determines supply.

We will be doing a mini lab followed by a regular lab to prove this fact!!!!!

Ms S

References:

http://en.wikibooks.org/wiki/IB_Biology/Cells

Dear students,

I hope this blog will keep us all connected beyond the classroom setting. Please use the blog to discuss, check, share and post details / items needed for you to be well informed. Let us work together and have fun along the way!

I need your support in keeping you motivated at all times!

Your teacher

Ms S