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Discussion: Esterification and Infrared Spectroscopy

Submitted by crmckenzie on Thu, 04/12/2018 - 14:36

    In this experiment, 0.928 g of 3-methylbutyl propanoate were synthesized via a reaction between 0.973 mL of propanoic acid and 1.194 mL of 3-methyl-1-butanol. Sulfuric acid was used as a catalyst. The percent yield of the product is 58.51%. The 3-methylbutyl propanoate was purified and the identity confirmed by infrared spectroscopy (IR). The measured IR had a peak of 1751.361cmwhich confirms the ester although the value is slightly high. The IR also had peaks of 2980.02 1cm and 2873.94 1cmwhich indicate an alkyl CH stretch. 3-methylbutyl propanoate is an ester with a carbon chain and so these results are consistent with the product. The reactants, propanoic acid, 3-methyl-1-butanol, and sulfuric acid are all refluxed and the product of this distilled to ensure that the product is as pure as possible. There was also a peak of 3552.88 1cm which was an abnormal OH stretch and signifies that too much 3-methyl-1-butanol was added to the original mixture that did not evaporate during the reflux period, making the product impure. An electric pipet may have helped to eliminate measurement mistakes and prevent this abnormality.

 

Cyclohexane synthesis discussion

Submitted by benjaminburk on Thu, 04/12/2018 - 13:21

Cyclohexanol was dehydrated in an effort to synthesize cyclohexene, in this experiment cyclohexene was obtained with a 23.1 % yield. The distillation process and washing procedures as described in the procedure were followed successfully. The gas chromatography and IR results suggest that the product was cyclohexene and extremely pure. This is supported by the fact that the gas chromatography result has only one peak that takes up the entire area on the graph, this means that the substance that the test was performed on was homogenous and pure. The IR graph also proves that the substance is cyclohexene because it contains the respective peaks for the substances that make up cyclohexene and in the correct ratio as well. The potassium permanganate and bromine dichloromethane tests also produced the expected results for both cyclohexane and cyclohexene further supporting the conclusion that the end product was pure cyclohexene.

Bio 383H intro p 1

Submitted by liamharvey on Thu, 04/12/2018 - 12:59

Introduction

A mutant in its basic definition is a genetic variant that causes a phenotype that differs from what is usual for that species. Often, an approach that is used for identifying mutants is called forward genetics. In forward genetics, a gene function is identified by working from a mutant phenotype. However, in pot-genomic era studies, we often employ what is called “reverse genetics”. In reverse genetics, we start from a plant which is homozygous for a mutant allele of an unknown gene and then analyze that gene. We used our B. distachyon plants which were homozygous for a mutation in our unknown gene, analyzing the phenotype of our plant, to help hypothesize a function for the unknown gene.

Nyctinasty

Submitted by rmirley on Thu, 04/12/2018 - 12:54

Plants have several different types of circadian rhythm. The first is that plants orient themselves towards the sun during the day to maximize photosynthesis. Plants also undergo another circadian rhythmic nastic movement called nyctinasty. Nyctinasty is a response in higher plants to the onset of darkness. An example of nyctinasty in plants is when the leaves and petals of plants close at night. The action is brought about by darkness and is an evolutionary reaction that preserves water and sugar levels in the plant when conditions are not optimal for photosynthesis. 

Circadian Rhythm

Submitted by rmirley on Thu, 04/12/2018 - 12:53

Circadian rhythm is a biological process that displays a pattern of biological actions over the course of roughly 24 hours. All types of organisms display a circadian rhythm, including plants and animals. In animals, circadian rhythm is the animals sleep schedule. When it gets dark out the animal will get sleepy, and when the sun comes up the animal will feel energized. In plants, circadian rhythm is the plant’s orientation. Plants will reposition themselves at different times of the day in order to maximize photosynthetic output. 

LOV Domain

Submitted by rmirley on Thu, 04/12/2018 - 12:53

A LOV domain stands for a light-oxygen-voltage-sensing domain. This LOV domain is a protein sensor used by a large variety of higher plants to control phototropism, chloroplast relocation, and stomatal opening. The LOV domain has been found to do this by controlling gene expression through DNA binding. The LOV domain is also involved in redox-dependent regulations.

Etiolation

Submitted by rmirley on Thu, 04/12/2018 - 12:50

Plants are photosynthetic and require light to survive. When plants are left in the shade they don’t die immediately though. When left in the shade, plants become etiolated. Etiolation results in stem elongation, paleness, and a lack of photosynthetic maturation. Etiolation occurs usually in plants below a canopy. Far red light is what triggers etiolation, which penetrates through the shade of the canopy. In order to reverse etiolation, all that would be necessary would be for the plant to be exposed to red light again, because red light is what activates de-etiolation.

Photomorphogenesis

Submitted by rmirley on Thu, 04/12/2018 - 12:49

Plants use a technique called photomorphogenesis. Photomorphogenesis is the development of form and structure in a plant that is affected by light. This is a response to light that is independent of other light-based responses in the plant, such as photosynthesis. Some examples of photomorphogenesis in plants are their day/night cycles or hourly orientation towards the sun. Changing the day length will change how the flower or leaf orients itself at certain times in the day.

Photoreceptors

Submitted by rmirley on Thu, 04/12/2018 - 12:49

There are several types of photoreceptors in plants. Some of these photoreceptors are phytochromes, cytochromes, and phototropins. Phytochromes are a class of photoreceptor that plants use to detect light and mediate a photosynthetic response. Cytochromes are photoreceptors that function as electron transfer agents in metabolic pathways. Cytochromes are compounds consisting of a heme bonded to a protein. Finally, phototropins are photoreceptors that mediate phototropic responses in higher plants. They allow plants to alter their response and growth to light.

Microscopy

Submitted by mkomtangi on Thu, 04/12/2018 - 12:04

Temperature is the intensity of thermal energy within a substance or object and can vary
between being hot or cold. When it is too cold cell proteins may be destroyed as ice forms, or as
water is lost, heat coagulates proteins and changes the cell structure and function. Metabolic
activities of microbes, plants and animals are regulated by enzymes and those enzymes are
influenced by temperature, especially increased temperature, up to a certain limit. Increased
temperature brings about increased enzymatic activity, resulting in an increased rate of
metabolism. Temperature can have many effects on an organism, it can affect their cell structure,
metabolism, growth and even their behavior.

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