th-scienceteen-s.bs.com
Thursday, August 26, 2010
Alright, yesterday and today. In class, we had to go around the class to view other group's poster. Well, i was confused . Yet i've learnt something. Ms wang ask us to blog on 3 things we're confused and 5 things we have learnt from this.
3 things that we're confused.
- What type of enzymes is used in dark stage?
- So how do we know if we're using aerobic respiration or anaeriobic respiration?
- What is ATP & NADPH ?
5 things we've learnt:
- Aerobic respiration is what we use all the time.
- Anaerobic respiration is used when we're lacked of oxygen. When we're excising.
- Photosynthesis doesn't occurs only when there is the pressence of light.
- Photosynthesis occurs in two stages. These stages are called the light reactions and the dark reactions.
- In plants, during photosynthesis, electrons are removed from glucose and transferred to oxygen during cellular respiration.
----
Photosynthesis occurs in two stages. These stages are called the light reactions and the dark reactions. The light reactions take place in the presence of light. The dark reactions do not require direct light, however dark reactions in most plants occur during the day.Light reactions occur mostly in the thylakoid stacks of the grana. Here, sunlight is converted to chemical energy in the form of ATP (free energy containing molecule) and NADPH (high energy electron carrying molecule). Chlorophyll absorbs light energy and starts a chain of steps that result in the production of ATP, NADPH, and oxygen (through the splitting of water). Oxygen is released through the stomata. Both ATP and NADPH are used in the dark reactions to produce sugar.Dark reactions occur in the stomata. Carbon dioxide is converted to sugar using ATP and NADPH. This process is known as carbon fixction or the Calvin cycle. Carbon dioxide is combined with a 5-carbon sugar creating a 6-carbon sugar. The 6-carbon sugar is eventually broken-down into two molecules, glucose and fructose. These two molecules make sucrose or sugar.
(back to the top.)
Sunday, August 22, 2010
A plant that receives the nutrition it needs will continue to live. But what if we took all its oxygen away? Do you think the plant still can grow ? Why?
Answer: No, we think it will not be able to grow as plants need carbon dioxide to photosynthesis. It depends on light dependent reactions. It has to under go photolysis. Which breaks up water into hydrogen and oxygen. More photolysis, means higher rate of photosynthesis. If oxygen is taken away, photolysis is not completed. So, photosynthesis rate would be affected.
(back to the top.)
our experiment to test for photosynthesis~
Thursday, August 19, 2010
last friday, we went to the science lab and do out experiment on photosynthesis. We came out with 2 experiments incase the first one did not went well. our first experiment was to test of presence of oxygen and the second one was to see if plants photosynthesis in different types of water-salty water and sugar water. We set up our apparatus as quickly as possible so as not to waste time as the experiment needs lots of time to see the results. As we notice tat the plant was not destarched according to out plan,we change our experiment and did the "types of water"experiment instead. our experiment went out wrong as we did not have enough time to let the plant photosynthesis. But looking from the results in the graph we printed out, our conclusion is that plant photosynthesis better in sugar water.
(back to the top.)
experiment on respiration
today miss wang show us an experiment on respiration.she use mealworm,beatles to test for respiration...
she used hydrogen carbonate indicator to test for the presence of carbon dioxide. and xia xue was given the chance to blow carbon dioxide into the test tube. we also added 20mealworms and 40mealworms separately on each test tube containing hydrogen carbonate. After 30mins,the results are : hydrogen carbonate turn from purple to red to yellow color.
we also learned tat the inhaled air we breath in contain 0.03% of carbon dioxide and the air we breathe out contain 0.04% of carbon dioxide. we also learned the difference between aerobic and anaerobic.aerobic is large amount of energy released while anaerobic is little amount of energy released,produce lactic acid and incomplete breakdown of glucose.
(back to the top.)
our experiment~ [:
Tuesday, August 3, 2010
Aim: To find out if the different types of water affect the rate of photosynthesis.
Hypothesis: Plants photosynthesis well in normal water then in other types of water.
Approach (summary of how do an experiment): Place 3 same water plants under the lamp each with half the test tube filled with tap water. Pour 5 tablespoon of salt in one of the test tube. Pour 5 tablespoon of sugar in the other test tube. Place the oxygen sensor inside each test tube after 10 minutes. Place it inside for 8 seconds. Observe the rate of photosynthesis.
Apparatus:
• 3 test tube
• 1 data logger
• 1 lamp
• 3 beakers
Materials:
• 3 identical hydrilla
• 5 table spoons of salt
• table spoons of sugar
• Tap water
Variables:
I. Constant:
a) Number of Hydrilla,
b) Amount of tap water
II. Changing:
a) Oxygen,
b) Concentration of tap water
Procedures:
1) Fill half the test tubes with tap water. Do it for all 3 test tubes.
2) Fill one test tube with 5table spoons of sugar and fill the other test tube with 5 table spoons of salt. And the last test tube with tap water only.
3) Label each test tubes with ‘Salt’, ‘Sugar’ and ‘tap water’ .
4) Submerge all the 3 identical hydrilla in each test tube
5) Put all the test tubes in each beaker to hold the test tubes
6) Place all the set-ups under the light for abou10 minutes.
7) After 10 minutes place an oxygen sensor in each test tube to find out if photosynthesis has occurred.
8) Place oxygen sensor inside each test tube for 8 seconds.
Results:
Salt:
Time(s) 2 4 6 8
Amount of oxygen(g/L) 8.1 8 8 8.1
Sugar:
Time(s) 2 4 6 8
Amount of oxygen(g/L) 7 6.75 6.75 6.5
Discussion:
Conclusion: Hydrilla plant can photosynthesis better in salt water.
(back to the top.)
Monday, August 2, 2010
Q: A plant needs its own food to function. It can't really make its own food at night. Beyond a few hours of darkness, can a plant stay alive without light how
A: Yes. The plant uses its stored starch and change it to glucose to use it for respiration in the plants.
(back to the top.)
A tree inhales carbon dioxide it needs to if it wants to survive. But can it release enough oxygen to keep just one person alive?
Some trees couldn't produce enough oxygen to keep one person alive. An average size tree could produce oxygen for more than one people.
(back to the top.)
