Online Test. 10th grade

Link is here

Quiz. Online. 8th Grades

Here is it. Touch to GO Further

New Online Quiz at the lesson time. Enjoy 9th Graders

One two three GO!

Brand New Lab. 10th Grade. Photosynthetic pigments.

Thin layer chromatography is used to separate components of a plant extract, illustrating the experiment with plant pigments that gave chromatography its name

Hey there. This lab is the newest one and we've never done before. So, enjoy!

Title: Chromatography. Pigments separation method.

Background: By extracting pigments from leaves and placing these samples into a chromatography machine, scientists can identify which wavelengths of light an organism can absorb. Methods for the identification of plant pigments include various types of chromatography that separate the pigments by their relative affinities to solid and mobile phases.

Chlorophyll a, chlorophyll b, and β-carotene are hydrophobic organic pigments found in the thylakoid membrane. Chlorophyll a and b, which are identical except for the part indicated in the red box, are responsible for the green colour of leaves. β-carotene is responsible for the orange colour in carrots. Each pigment has a unique absorbance spectrum. Chlorophyll a absorbs wavelengths from either end of the visible spectrum (blue and red), but not green. Because green is reflected or transmitted, chlorophyll appears green. Carotenoids absorb in the short-wavelength blue region, and reflect the longer yellow, red, and orange wavelengths. The carotenoids found in fruit—such as the red of tomato (lycopene), the yellow of corn seeds (zeaxanthin), or the orange of an orange peel (β-carotene)—are used as advertisements to attract insects and birds. In photosynthesis, carotenoids function as photosynthetic pigments that are very efficient molecules for the getting rid of excess energy. When a leaf is exposed to full sun, the light-dependent reactions are required to process an enormous amount of energy; if that energy is not handled properly, it can do significant damage. Therefore, many carotenoids reside in the thylakoid membrane, absorb excess energy, and safely cause to disappear that energy as heat.

Purpose: To identify pigments of green leaves of the plant.

Equipment: 

Procedure: You write it using the file (Simple chromatography technique. Download this file before writing the procedure. It is in Russian) in English.

Result:

Conclusion:

Use the SAMPLE LAB WORK REPORT for the best grade!

8th Grade BRAIN DISSECTION lab

Here below is a BRAIN DISSECTION lab report. We do the lab with the 8^th graders. Enjoy!

Title: Brain dissection.

Purpose: to list and describe the principal structures of the sheep brain; to identify important parts of the sheep brain.

Equipment: dissection pan, brain scalpel, scissors.

Background: The sheep brain is quite similar to the human brain except for proportion.  The sheep has a smaller cerebrum.  Also the sheep brain is oriented anterior to posterior whereas the human brain is superior to inferior.

Procedure:

External Anatomy (Part A).

1. The tough outer covering of the sheep brain is the dura mater, one of three meninges (membranes) that cover the brain. You will need to remove the dura mater to see most of the structures of the brain.  Remove the dura mater while leaving other structures intact.

2. The most famous feature of the brain is the cerebrum - which is divided into nearly symmetrical left and right hemispheres by a deep longitudinal fissure.

3. The surface of the cerebrum is covered with large folds of tissue called gyri. The grooves between the gyri are sulci. The deeper sulci are often termed fissures. The fissures are used as landmarks to divide the surface of the cerebrum (the cerebral cortex) into regions: locate each of the lobes: frontal lobe, parietal lobe, occipital lobe, temporal lobe.

4. The smaller, rounded structure at the back of the brain is the cerebellum. The cerebellum has smaller gyri that are roughly parallel to one another. Compare the gyri of the cerebellum to that of the cerebrum. Removing the dura mater from the cerebellum can be not that simple. Look for areas on the side of the brain that you can snip to peel the dura mater off.

5. Turn the brain over so that the cerebrum is down. The most prominent structure on the ventral (down) side of the brain is the optic chiasma, where the two optic nerves cross over each other and form an “X” shape. Locate the optic chiasma.

6. The hypophysis is a large round structure under the chiasma.  If you removed this area with the dura mater, you may need to replace it to see the chiasma and pituitary gland.

7. Toward the front of the brain are two prominent round structures, the olfactory bulbs.

8. Toward the back of the brain are bulges that indicate the midbrain, the pons, and the medulla.

9. Occulomotor nerves may be visible to each side of the pituitary gland. Or in some cases you may find them stuck to the dura mater that you removed with the pituitary gland.

10. Carefully bend the cerebellum to get an inside glimpse of the brain. The bumps you see (kind of resemble a “butt”) are the superior colliculi.  The smaller ones underneath are inferior colliculi.

11. If you gently push those structures down, you can see the tiny nub of the pineal gland.

Internal Anatomy (Part B).

1. Use a knife or long-bladed scalpel to cut the specimen along the longitudinal fissure. This will allow you to separate the brain into the left and the right hemisphere. Lay one side of the brain on your tray to locate the structures visible on the inside. You should also cut through the cerebellum.

2. The corpus callosum had been connecting the two cerebral hemispheres and can now be clearly seen in the brain section.

3. The tiny space within the corpus callosum (which hold cerebrospinal fluid) is called the lateral ventricle. Underneath it, you can find the third ventricle. There are other ventricles within the brain, but those are the easiest to locate in a preserved specimen. The white area between those two ventricles is the fornix. The fourth ventricle is the space under the cerebellum.

3. Inferior to the corpus callosum is a round structure known as the thalamus. It seems it almost perfectly centred. Just behind the thalamus is the pineal body (gland). The hypothalamus is also round shaped but is lower and toward the front of the brain.

4. The pons, medulla, cerebellum and spinal cord are also visible in the side view of the brain. Gently separate the cerebellum at the transverse fissure, which separates it from the cerebrum.

5. Within the cerebellum, you can see the arbor vitae, named such because the white lines resemble a tree.

6. Use a scalpel to cut a cross section of the cerebrum in the occipital lobe area.  You should be able to see the color and texture differences of the white matter and the gray matter.

Result: We carried out all the stages of the lab work correctly.

While conducting part A …

In part B …

Conclusion: In part A … I think it was … It is also possible that the brain …

In part B … I think it was the result of … Point proven.

Enzyme activity Lab. 9th Grade

Catalase (source: wikipedia)

Title: Catalase enzyme activity.

Purpose: To identify factors affecting enzyme activity in the cell (by using catalase enzyme).

Equipment: 2 beakers labeled A, B; vinegar; cold and hot water; peroxide 100ml; potatoes.

Background: In green plants and our body, H2O2 forms when alcohol is broken down. H2O2 is a strong oxidant. It has harmful effects on living cells. To prevent this, catalase enzyme, found in cells, breaks down the H2O2 into oxygen and water. The reaction below shows the breakdown of H2O2 into H2O and O2.

2H2O2 ⎯⎯⎯⎯→2H2O +O2

Procedure:

We proceed by changing factors affecting catalase enzyme activity. There are four factors which we cover in our lab. In each step you have to draw graph (dependence of reaction rate from time) showing changes of rate of reaction.

1. Enzyme amount
2. Substrate acidity (using vinegar)
3. Reaction temperature
4. Substarte amount

Result:

Conclusion:

ДЗ для 11классников

Доброго времени суток, дорогие друзья. Эта лекция по экологии. Надеюсь будет крайне полезна

Наше будущее зависит от нас. Биоразнообразие имеет значение

Доброго времени суток, дорогие друзья. Делюсь с вами тем, что наболело и тем, что реально имеет значение для нас всех. Это наше будущее. Точнее - будущее нашей планеты, природы, растений, животных и нас, людей. Недавно был опубликован доклад WWF Living Planet Report 2018, в котором описывается что люди сделали за последние 50-60 лет и как это изменило нашу планету. Всё очень серьезно.

Биоразнообразие имеет значение

Наша еда, здоровье  безопасность зависит от биоразнообразия. Мы получаем еду, лекарства - все это разнообразие и количество видов организмов на планете.

Вся экономика планеты зависит от природы. Каждый год человечество использует природу на 125 триллионов $!

Люди по всему миру встревожены перспективами нашего будущего и развития в нынешних реалиях использования природных ресурсов.

Что давит

Гипериспользование и увеличение сельского хозяйства - главные причины уменьшения количества видов организмов.

Ухудшение качества земли влияет на всю жизнь наземной цивилизации, уменьшаются доходы населения.

Сильное давление на опылителей и плодородие почв.

Вылов большого количества рыб и загрязнение водных экосистем пластиком.

Новые технологии и большие данные помогают понять насколько все нехорошо.

Биоразнообразие в изменяющемся мире

Среднее уменьшение на 60% количества популяций видов организмов между 1970 и 2014 годами.

Сильно уменьшается количество популяций в тропиках Южной и Центральной Америки.

Уменьшение количества популяций видов водных организмов на 83% с 1970 года по наши дни.

Что мы хотим

Не смотря на международные договоренности, по всему миру уменьшается количество организмов.

Больше амбиций - лучше результат.

По-умному использовать организмы на планете для всеобщего блага, а то кирдык.

Улучшение качества индикаторов изменения среды как инструмент влияния на биоразнообразие Земли.

Как вам такое? Это важно. Каждый из нас может сделать зависящее от себя. Начинаем с себя, прямо сейчас!

Данные вот отсюда: WWF. 2018. Living Planet Report 2018. Aiming Higher. Grooten, M. and Almond, R.E.A.(Eds). WWF, Gland, Switzerland.