Cell Respiration Lab

Linfei Liu

A Block Hon. Bio
05/24/14 

How fast could yeast be? --- Cell Respiration Lab 

ABSTRACT
The main purpose for this lab is to test whether the concentration of sugar allowed to the yeast will affect the rates of the cellular respiration in yeast or not. Five different amounts of sugar were given to different test tubes filled with yeast to test the amount of carbon dioxide produced by the yeast through cellular respiration. The control of this lab is constant temperature. The five different test tubes of yeast were able to respire at their own rates. The amount of carbon dioxide was recorded every minute for a total of twenty-one minutes. As expected, at the beginning of the experiment, the yeast with higher concentrations of sugar produced carbon dioxide faster than the yeast with lower concentrations of sugar. Unfortunately, lab errors occurred and altered the results of the experiment. Nevertheless, the beginning result of the rate of cellular repisration could prove that the concentration of sugar does have an effect on the rate of cellular respiration in yeast.

INTRODUCTION
QUESTION
Will the concentration of sugar affect the rate of cellular respiration of the yeast?

BACKGROUND
Yeast is a type of facultative anaerobe and will first respire aerobically (with oxygen) until there is no longer any O2 (oxygen) left in the test tube for the yeast to use. In order to compensate for this, the yeast will begin to respire anaerobically (without oxygen). The yeast begins to consume the sugar, crating ATP by undergoing alcoholic fermentation, producing C02 (carbon dioxide) its by-product. Sugar is a monosaccharide (simple sugar) which the yeast chemically breaks down into products the yeast can use. Cellular respiration, the process in which cells use to transfer energy from organic molecules to ATP, is used by the yeast to break down sugar into energy.

HYPOTHESIS
If the concentration level of sugar in each test tube (with equal amounts of yeast, salt and water) increases, then the rate of cellular respiration will increase as well. In other words, if the amount of sugar in each test tube increases, the rate of cellular respiration also increases since there is more supply for the yeast to consume.

METHODOLOGY
MATERIALS
• 42 grams of sugar
• 175 mL of water
• 5 grams of yeast
• 0.8 grams of salt
• Five test tubes
• Five syringes
• Five connecting tubes
• Five stoppers (with hole for tube)
• Scale
• Coffe filters
• Foam test tube holder
• Graduated cylinder
• Sharpie

PROCEDURE
1. Label the five test tubes with the numbers: 1, 2, 3, 4, and 5. The numbers will display the amount of sugar added to each test tube in grams.
2. Carefully weigh 1 gram of yeast on five separate coffee filters, and then add each into each test tube.
3. Carefully weigh 0.2 grams of salt on five separate coffee filters, and then add each into each tube
4. Carefully measure and add 35 grams of water into each test tube.
5. Carefully weigh 1g, 2g, 3g, 4g, and 5g of sugar on separate coffee filters. Then add the sugar into each of its respective test tubes simultaneously.
6. Attach one end of a connecting tube to a syringe and another end to the hole in the rubber stopper. Repeat for the remaining four sets.
7. Pull the syringes to 1mL.
8. Place the stoppers on each test tube.
9. Record the amount of air in the syringes every minute.
10. Periodically push the syringes down.

RESULTS

Credit to my partner Cathy

As shown on the graph show that in the beginning, the test tubes of yeast with a higher concentration of sugar would produce carbon dioxide faster than the test tubes of yeast with lower concentrations of sugar. However, towards the end, source of errors occurred that the data became inconsistent with what the original results ought to be (which is our hypothesis).

CONCLUSION
In conclusion, the result of this lab is unsuccessful due to the lab error that occurred. Nevertheless, at the beginning part of the lab, the result clearly supported our hypothesis to be correct as the test tube with the lowest concentration of sugar produced the least amount of carbon dioxide, and the test tube with the highest concentration of sugar produced the most amount of carbon dioxide. This phenomenon shows that the more sugar there was for the yeast to break down, the faster the rate of respiration was going to be. Furthermore, sugar is a monosaccharide that is the easiest and simplest form of an element for yeast to break down the fastest. As time passed by, my partner and I were confused by the inconsistency of the production of carbon dioxide in each test tube because we made sure all of our measurements (yeast, salt, water) and amount of sugars (1g, 2g, 3g,4g, 5g) were constant and accurate. Yet, we later discovered that our test tubes all had leaks in them, which caused the inconsistency, Other potential sources of error could be 1)  the temperature was not constant and 2) not placing the stoppers on the test tubes at the start of the experiment simultaneously.

Work cited

• http://www.phschool.com/science/biology_place/labbench/lab5/intro.html
• http://www.paec.org/biologypartnership/assets/february%2022/Cellular%20Respiration%20Protocol%20-%20Balloon%20Lab.pdf 
• http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20101/bio%20101%20laboratory/cellular%20respiration/cellular%20respiration1.htm

Diffusion and Osmosis lab

One re-drew graph:

Online Plant Transpiration Lab

Lab Data Table

Journal Question:
1. Describe the process of transpiration in vascular plants.
In general terms, transpiration is the release of water from plant leaves. More specifically, transpiration is the evaporation of water into the atmosphere from the leaves and stems of plants.

(Evaporation involves the process of any water changing from a liquid to a vapor).

Transpiration is the evaporation process occurring to the water held in the leaves and stems of plants.

In transpiration, water travels from the soil into the roots of plants, and up to the underside of plant leaves, where it is released into the air. This process occurs thanks to small pores in the leaves called stomates. Stomates are small openings on the underside of leaves that are connected to vascular plant tissues. Also, stomates are dotted on leaf and stem surfaces. Interestingly, some dry environment plants have the ability to close their stomata.

Transpiration is considered a passive process from the plants perspective because it is regulated by humidity in the atmosphere and moisture in the soil and is not the result of a conscious choice made by the plant itself. On the other hand, only 1% of the transpired water that passes through a plant is used in the actual growth process. Some of the water that eventually becomes part of the transpiration process is used as a vehicle to deliver nutrients from the soil into the plant. The purpose of transpiration is also to cool the plant. 

*Vascular: relating to, involving, typical of, or having fluid-carrying vessels. 

2. Describe any experimental controls used in the Investigation.
For this lab, experimental control is the timing for the transpiration --- one hour for all experiments. Also, the transpiration rate of plants in an hour under normal condition with standard room temperature, pressure, and without fan, heater or lamp.

3. What environmental factors that you tested increased the rate of transpiration? Was the rate of transpiration increased for all plants tested?
The environmental factors that are being tested in this lab are: the amount of wind, heat (temperature), and light. During the lab, all the factors increased the rate of transpiration at different levels. The amount of wind increased the transpiration rate of all plants the most. However, the amount of light did not increase the rate of transpiration for all plants tested. Also, the amount of light is the factor that affected the overall transpiration rate the least. The amount of light did not affect the rate of transpiration of dieffenbachia, rubber plant, weeping wig and zebra plant.

4.Did any of the environmental factors (heat, light, or wind) increase the transpiration rate more than the others? Why?
Overall, the increasing amount of wind led to the greatest increase in the rate of transpiration for all plants tested. Wind accelerates the movement of water from the leaf surface while reducing the boundary layer of water vapor. Also, wind would accelerate the speed of evaporating. Besides the wind, heat is another factor that increases the rate of transpiration. Higher temperature would cause water molecules to move faster; thus, the rate of transpiration would increase.

5. Which species of plants that you tested had the highest transpiration rates? Why do you think different species of plants transpire at different rates?
The species of plants with the highest transpiration rates are rubber plant, zebra plant, and dieffenbachia (from highest to lowest). Since different species of plants live in different environment; thus, they have different rates of transpiration. Also, different rates of transpiration are caused by different species of plants' abilities to adapt to different environments through evolution.

6. Suppose you coated the leaves of a plant with petroleum jelly. How would the plant's rate of transpiration be affected?
Since the leaves of a plant are covered with petroleum jelly, the rate pf transpiration would decrease. The jelly would close up the stomata on the leaves and prevent water from evaporationg. Also, light could not penetrate through stomata.

7. Of what value to a plant is the ability to lose water through transpiration?
It is essential for plants to lose water because of the ability of cohesion (the water). Evaporating water does not only help carry nutrients up from the roots through xylem (allowing the plants to absorb nutrients), but also helps moderate the surrounding temperature of the plant and the air humidity. Furthermore, losing water through transpiration helps the plant operate metabolism and keep balance of homeostasis.

Here is the link to the lab :) 

Wow! What's wrong with the plant?!

Three important hormones for plant growth and their functions: 

I. Auxin 

Auxin

Auxin has several important roles, such as development of the embryo leaf formation, phototropism, gravitropism, apical dominance, fruit development, abscission root initiation and development of the shade-avoidance effect. Auxin is produced in the plant tip, which controls vertical growth in shoots and lateral growth in roots. When the plant needs more water and minerals, Auxin would build up and cause lateral growth in the root system, which allows the plant to receive more nutrients. Furthermore, as we known, plants need light to be able to do photosynthesis. Thus, plants would release Auxin to control their growth. Auxin in the shoot tip is transported to the shady or dark side of the plant, causing that side to grow and therefore bend the plant towards the light or other stimulus (such as gravity). On the other hand, Information regarding auxin metabolism will most likely lead to genetic and chemical manipulation of endogenous hormone levels resulting in desirable growth and differentiation of important crop species. Ultimately, the possibility exists to regulate plant growth without the use of hazardous herbicides and fertilizers (Davies, 1995; Salisbury and Ross, 1992).

Functions of Auxin

• Stimulates cell elongation
• Stimulates cell division inthe cambium and, in combination with cytokinins in tissue culture
• Stimulates differentiation of phloem and xylem
• Stimulates root initiation on stem cuttings and lateral root development in tissue culture
• Mediates the tropistic response of bending in response to gravity and light 
• The auxin supply from the apical bud suppresses growth of lateral buds 
• Delays leaf senescence 
• Can inhibit or promote (via ethylene stimulation) leaf and fruit abscission 
• Can induce fruit setting and growth in some plants 
• Involved in assimilate movement toward auxin possibly by an effect on phloem transport 
• Delays fruit ripening 
• Promotes flowering in Bromeliads 
• Stimulates growth of flower parts 
• Promotes (via ethylene production) femaleness in dioecious flowers 
• Stimulates the production of ethylene at high concentrations

(Davies, 1995; Mauseth, 1991; Raven, 1992; Salisbury and Ross, 1992).

Auxin controlling the growth of plant, towards the light

The effect of auxin on strawberry development.
The achenes produce auxin.
When removed the strawberry does not develop (Raven, 1992).

Additional links: 

http://www.plant-hormones.info/auxins.htm
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/Auxin.html

II. Abscisic acid (ABA)

Abscisic acid (ABA) 

Abscisic acid (ABA) is an interesting hormone. It is a single, naturally occuring compound in plants unlike the auxins, gibberellins, and cytokinins. It was called "abscisin II" originally because it was thought to play a major role in abscission of fruits. However, at about the same time another group was calling it "dormin" because they thought it had a major role in bud dormancy. The name abscisic acid (ABA) was coined by a compromise between the two groups. Though ABA generally is thought to play mostly inhibitory roles, it has many promoting functions as well(Arteca, 1996; Mauseth, 1991; Raven, 1992; Salisbury and Ross, 1992). Furthermore, Abscisic acid in maple and birch buds causes the change from long-day to short-day conditions a marked increase in the activity of dormin (=ABA) and consequently stops the  growth of buds.

ABA is a sesquiterpenoid (15-carbon) which is partially produced via the mevalonic pathway in chloroplasts and other plastids. Because it is sythesized partially in the chloroplasts, it makes sense that biosynthesis primarily occurs in the leaves. The production of ABA is accentuated by stresses such as water loss and freezing temperatures. It is believed that biosynthesis occurs indirectly through the production of carotenoids. Carotenoids are pigments produced by the chloroplast which have 40 carbons. On the other hand, the transport of ABA can occur in both xylem and phloem tissues. It can also be translocated through paranchyma cells. The movement of abscisic acid in plants does not exhibit polarity like auxins. ABA is capable of moving both up and down the stem (Walton and Li, 1995; Salisbury and Ross).

Functions of Abscisic acid

• Stimulates the closure of stomata (water stress brings about an increase in ABA synthesis). 
• Inhibits shoot growth but will not have as much affect on roots or may even promote growth of roots. 
• Induces seeds to synthesize storage proteins. 
• Inhibits the affect of gibberellins on stimulating de novo synthesis of a-amylase. 
• Has some effect on induction and maintanance of dormancy. 
• Induces gene transcription especially for proteinase inhibitors in response to wounding which may explain an apparent role in pathogen defense.

(Davies, 1995; Mauseth, 1991; Raven, 1992; Salisbury and Ross, 1992).
Additional links:
http://www.biologie.uni-hamburg.de/b-online/e31/31e.htm
http://www.plant-hormones.info/abscisicacid.htm

ABA!

III. Ethylene

Ethylene is a gaseous hormone. Like abscisic acid, it is the only member of its class. Of all the known plant growth substance, ethylene has the simplest structure. It is produced in all higher plants and is usually associated with fruit ripening and the tripple response (Arteca, 1996; Mauseth, 1991; Raven, 1992; Salisbury and Ross, 1992). Ethylene is a small hydrocarbon gas. It is naturally occurring, but it can also occur as a result of combustion and other processes. You can't see or smell it. Some fruit will produce ethylene as ripening begins. Ethylene is responsible for the changes in texture, softening, color, and other processes involved in ripening. Fruits such as cherries and blueberries do not produce much ethylene and it doesn't influence their ripening. Ethylene is thought of as the aging hormone in plants. In addition of causing fruit to ripen, it can cause plants to die. It can be produced when plants are injured, either mechanically or by disease. Ethylene will cause a wide range of effects in plants, depending on the age of the plant and how sensitive the plant is to ethylene. Ethylene effects include fruit ripening, loss of chlorophyll, abortion of plant parts, stem shortening, abscission of plant parts, and epinasty (bending of stems). 

Ethylene can be either good or bad, depending on what commodity you work with. It is used in a positive manner in fruit ripening. However, it can also cause damage in crops. These damages might include yellowing of vegetables, bud damage in dormant nursery stock, and abscission in ornamentals (leaves, flowers drop off). Often two of the important items to know are 1) if a crop naturally produces a lot of ethylene and 2) if it is responsive to ethylene. The Responsiveness to ethylene will depend on 1) the crop, 2) the stage of plant development, 3) the temperature, 4) the concentration of ethylene, and 5) the duration of exposure.

Ethylene is produced in all higher plants and is produced from methionine in essentially all tissues. Production of ethylene varies with the type of tissue, the plant species, and also the stage of development. The mechanism by which ethylene is produced from methionine is a 3 step process (McKeon et al., 1995; Salisbury and Ross, 1992).
ATP is an essential component in the synthesis of ethylene from methionine. ATP and water are added to methionine resulting in loss of the three phosphates and S-adenosyl methionine.
1-amino-cyclopropane-1-carboxylic acid synthase (ACC-synthase) facilitates the production of ACC from SAM. Oxygen is then needed in order ro oxidize ACC and produce ethylene. This reaction is catalyzed by an oxidative enzyme called ethylene forming enzyme (Klee and Lanahan, 1995).

Additional links:

http://postharvest.tfrec.wsu.edu/pages/PC2000F
http://www.plant-hormones.info/ethylene.htm

LOS FLORES :)

For today's class, we had some time to truly relax and enjoy the world around us. :) By doing so, we went out to explore on campus and marvel at how complex yet simple life is --- finding three different types of flowers and one has to be from a tree. Here are the flowers I found:

I. I found this pretty flower outside of museum. This type of dreamy flower grows from a tree. The color of this flower is a soft white-greyish purple. It grows at the tip of branches and forms a bell looking shape. Also, it grows out with leaves. The pedals of this flower are narrow and long that the pedals form a bell shape and closes up (almost) at the top. The pistil part (stigma, style, ovary and ovule) of this flower locates deeply inside, and the stamen part (anther and filament) of this flower grows shorter than the pistil part (surrounds the pistil). In that way, the longer pistil would attract insects and entices the insects to go further down to the stamen part and pollinate. As mentioned before, this type of flower does not have a bright color. Thus, it attracts small insects, such as ants. Also, it is because of the special structure of this type of flower that small insects get into the flower more easily than bees do. The scent of the flower is very light, and the texture of the flower is soft and fuzzy. Inside of the flower is white. Also, the flower blossoms at the very tip of the branch with tiny leaves around it, and the leaves open up outwards (pointing to the ground).

The tree!

Leaves and flowers 

Bell-shaped flowers

Leaves!

Detailed flower (pistil and stamen)

II. This beauty was found outside of South Hutch. This is a type of roses with bright yellow(with a little bit of white) --- very eye-catching :) Although the position of this flower is on the ground, the flower is on the top of the bushes where makes it completely exposed to sunlight. This yellow rose is very open to pollen transport, and I found bees constantly surrounding the flower as well as some small flies. I could barely see the pistil part of this flower as the stamen part, especially the anthers are all packed together. The texture of the flower is soft and smooth; yet, it has horns on the stem and sharp edges on the leaves. These intense structures are primarily for defense against predators, which they developed throughout evolution. 

The beauty! 

Thorns

Sharp leaves

III. This flower was found outside of science building. Unlike the previous two flowers, the last one is relatively small.  Even though it is tiny on sizes, its color is really nice that it is purplish blue and near the center of the flower is white, which is eye-catching (attracting small insects, such as ants and flies). Also, the shape of its pedals is butterfly looking. Furthermore, the receptacle and sepal of the flower are a little bit red, and the texture of the flower is smooth. Last but not least, it is open to pollen transport.

  The diagram below is a very simple explanation for the structure of a plant. As shown in the diagram, the roots keep the plant anchored in place and also allow the absorption of water. The stem transports the water and nutrients throughout the plant and holds the leaves in the perfect position to capture the prime amount of sunlight. The leaves undergo photosynthesis to give the plant energy and produce oxygen.

   As for the coevolution of pollination of the flower, some plants are wind-pollinated, which means they rely on the wind to carry their seeds around to regrow as plants are fixed. However, some plants are insect-pollinated. This type of pollination is a mutualistic relationship since plant's pollen is sweet to smell that attracts the insects. Then, the flower is food source for the insects, and the insects would carry the pollen around which spreads the seeds around. Food for the bugs, reproduction for the plants. In addition, pollen is located differently on each flowers; furthermore, the flowers have different colors and smells. These characteristics are products of coevolution, since different flowers attract different insects or birds to help pollinate the flower and maintain species of the flower. At the same time, these birds and insects that feed on these flowers coevolved in a way to be able to feed on these flowers so these birds and insects could maintain their species as well.