1. Research question: How does glucose concentration affect the rate of yeast respiration?

2. Hypothesis:

- Respiration of yeast is a step that yeast breaks down the glucose to make energy using oxygen [1].

- I predict the rate of yeast respiration (amount of CO2 produced) will increase as the glucose concentration (amount of sugar) increases.

- I predict this because the more sugar added to the yeast mixture (yeast and water), the more glucose will be broken down by yeast [1] and that produces carbon dioxide which stands for the sign of yeast respiration.

3. Introduction:

Yeast respiration is a very important step in food production because it can be used in producing alcoholic beverages such as beer, wine and liquor. It can be used in the bread making business in which yeast respiration can help to increase the volume of the bread, bring about higher taste quality for the products [2].

In this experiment we will examine about the relationship between glucose concentration and yeast respiration rate. To achieve this objective, all variables are kept constant whereas the glucose concentration is increased gradually. The rate of respiration is measured accordingly. In this manner, the relationship between glucose concentration and yeast respiration rate can be determined.

4. Method and Materials:

4.1. Variables:

4.1.1. Independent variable:

The amount of sugar in the yeast and water solution

- 2g

- 4g

- 6g

4.1.2. Dependent variable:

The amount of carbon dioxide gas will be produced

4.1.3. Control variables:

- The amount of time

- The temperature

- The volume of yeast

- The amount of water

- Same type of measuring cylinder

- Same type of sugar

4.2. Materials & Equipments:

Yeast (3g  x 3 tests = 9g)

Sugar (12 g x 3 tests = 36 g)

Water (90ml x 3 trials = 270ml )

Funnel (x3)

Measuring cylinder (100ml type)

Spoon

Paper

Pencil

5. Results:

Table 1: Relationship between glucose content and rate of respiration

Graph 1: Relationship between glucose content and rate of respiration

6. Discussion and conclusion:

After the experiment, it can be seen that when the glucose concentration increases, the rate of respiration decreases. It could be because of the osmotic pressure. When the level of glucose increases, there is higher level of osmotic pressure and slows down the metabolism of the yeast therefore decreases the rate of respiration [2]. This is opposite from the hypothesis that I have at the beginning because I thought that the higher the glucose concentration, the higher the rate of the yeast respiration.

Regarding the trend in the graph, when the glucose concentration is 2gm per 35ml of water, the rate of yeast respiration is the highest. When the glucose concentration is 4gm per 35ml of water and 6gm per 35ml of water, the rate of respiration decreases.

Regarding the consistency of trial results, at 2g and 4g glucose content, there were some inconsistency in the trial results. However, at 6g glucose content, the results of rate of respiration were more consistent.

References:

1. http://www.123helpme.com/view.asp?id=121963

2. http://www.classofoods.com/page2_2.html

The post relationship between glucose concentration and the rate of yeast respiration appeared first on TechScreens.Com | The Class Of TECHNOLOGY.

The Venus Fly Trap (Dionaea muscipula) is a carnivorous plant. It has green leaves with small traps featuring on two sides of the trap. Its flowers have five white petals [2]. Venus Fly Trap is able to get nutrients from soil, insects and through photosynthesis process [3]. We will further examine about the harsh environment they live in, their special adaptive features and their photosynthesis process to help them survive in such poor-nutrient environment.

venus fly trap

Picture 1: Venus fly trap

Firstly, regarding the environment, the Venus Fly Trap is able to survive in a special environment where nitrogen and phosphor are not sufficient. Example of harsh environment are bogs and wet savannahs [1]. This kind of environment can be acidic in nature which is a potential hazardous for most of plants. Many minerals and nutrients do not present in such environment. To be able to survive, this plant has evolved to develop its special feature to capture insects for its nitrogen requirement. Venus Fly Trap is small in size and grows slowly. In wet sandy and peaty soil, this plant can still grow normally. It can be found in many places in the world but the native forms of plant could mainly be found in North and South Carolina (United States of America) (more detail in picture 2).  

venus fly trap with its prey

Picture 2: Venus fly trap with its prey

Secondly, one of their prominent features to help them survive in the acidic environment is that the plant is able to trap insects. Their ability to trap insects is still mysterious because no nervous system is found in the plant [2]. The theory has been given and accepted is the pressure on the trap creates an electrical potential, which triggers a change in fluid pressure to shut the trap. Venus Fly Trap only needed few insects either killed or alive per year [2]. This plant has an ability to live underwater for several months. It can live in the environment of bogs which the soil is acidic, minerals and other nutrients are scarce. In order to gain the nitrogen resource, the plant has evolved to capture living creatures like insects and bugs as a replacement of this source of nutrients missing from the soil, and carbohydrates as well [3]. Related to the digestion of insects, enzymes are excreted by glands in the lobe to catalyze the digestion . Digestion process takes about ten days, after the prey is reduced to a husk of chitin. After that, the trap open again, and it is ready to trap a new prey [1].

Dionaea muscipula

Picture 3: Venus fly trap in forest

Thirdly, apart from nutrients from the insects and the soil, this Dionaea muscipula plant can also gain nutrients through photosynthesis process. This is the process in which the plants convert carbohydrates and water into oxygen and sugar through the utilization of solar energy. After that, ATP (a form of energy) is produced from the sugar products [3].

In conclusion, the Venus Fly Trap is an extreme plant which live in a harsh environment and has developed many special features especially carnivorous ability to survive in such environment. It also has photosynthesis process like many other green plants to help them to utilize energy from sunlight.

Bibliography:

1. http://en.wikipedia.org/wiki/Venus_Flytrap

2. http://www.freeinfosociety.com/site.php?postnum=518

3. http://science.howstuffworks.com/environmental/life/botany/venus-flytrap2.htm

The post Venus fly trap appeared first on TechScreens.Com | The Class Of TECHNOLOGY.