HUMDEV 270; planning math activity for 2nd graders

Submitted by cberg on Tue, 11/14/2017 - 11:05

If we were to propose a math activity for a small group of 2nd grade children, we would teach them to add and subtract from 20 by using bags of skittles. Each child would start with 20 skittles of different colors. We would first have the children count and remove all of their purple skittles from their desk. After removing the purple skittles we would have the children count how many skittles remained in their pile. This concept would teach them that subtracting, say, 7 purple skittles from a pile of 20 skittles would leave them with 13 skittles. Afterwards, we would have the children put the purple skittles back into their pile. We would then have half of the children remove all of the orange skittles from their neighbor and put them into their own pile. This would teach the children that adding, say, 5 orange skittles into a pile that started with 20 skittles would give them 25 skittles. At the same time, the children that had 5 orange skittles removed from their pile would see that removing 5 orange skittles from their pile of 20 skittles would leave them with 15 skittles. We would then have the children switch so that the children who hadn’t practiced with addition yet would get to add skittles into their pile. We would continue this activity with different skittle colors until the children were able to predict the change to the number of skittles in their pile before actually adding or removing any skittles from it. Each time the children were able to accurately predict a change without physically seeing any added or removed skittles, they would get to eat a skittle from their pile. 

simple and fractional distillation conclusion

Submitted by daniellam on Tue, 11/14/2017 - 00:56

A mixture of cyclohexane and toluene were separated using both simple and fractional distillation.  The fractional distillation showed a much better separation than simple distillation, both proven in the temperature profiles and in the GC/MS taken.  The packing of copper in the columns influenced the separation the most and is the main distinction that makes fractional more successful than simple distillation.  To have better separation in the future, a longer column could be used as well as compounds with a larger boiling point difference.  Specifically for fractional distillation, a column that is packed with more copper can increase chances of complete separation.

post lab answers

Submitted by dalon on Mon, 11/13/2017 - 21:55

A saturated fat has no carbon-carbon double bond. A monosaturated fat has a single carbon-carbon double bond in one or more of the carboxylic acids and a polysaturated fat has 2 or more carbon-carbon double bonds in the carboxylic acid moieties. Trimyristin does not possess any carbon-carbon double bonds and can therefore be classified as a saturated fat. Using the older procedure of sudden cooling, as in cooling directly in the ice bath, the crystals observed would be smaller and temporary. This is because if you cool it too quickly, there is a chance that more precipitate would form in place of crystals and the precipitate would not catch in the filter paper. Thus, the yield would be very small. 

BLAST analysis

Submitted by briangriffin on Mon, 11/13/2017 - 14:43
                There are 2 amino acid differences between Homo sapiens and Pan troglodytes, not including the gaps. There are 8 nucleotides different between the orthologs when not counting the gaps. There are more differences in the nucleotide alignment because a change in the nucleotide sequence does not necesssarily lead to a change in amino acid sequence. But when there is a change in amino acid sequence there is a change in structure and function of that gene, therefore conservation of the amino acid sequence is important. The gaps are in multiples of three and this is because these gaps are deletions or insertions of amino acids which are coded for by a string of three nucleotides. 

Data from a “living” oxygen minimum lab could help predict the oceans future

Submitted by tterrasi on Mon, 11/13/2017 - 12:25

Researchers have collected 50 years of data showing the deoxygenating cycles of a fjord on the coast of Vancouver Island, cataloging the response of the microbial communities inhabiting this environment. Marine oxygen minimum zones (OMZs) are widespread and contribute up to 7 percent of global oceans. Expansion of these OMZs has potential to bring oxygen-depleted water into new regions, affecting fish populations and nutrient cycles. Environments of low-oxygen are not well suited for most metazoans, but microbial life can flourish. As oxygen becomes limiting, microbial communities can change their metabolism to use alternative electron sources like nitrogen, carbon, and sulfur. These microbial communities can drive nutrient cycling essential for ecosystem function and diversity. The research team collected data using time-series monitoring and multi-omic sequencing (DNA, RNA, and protein) to study microbial responses to deoxygenated ocean areas. By using this data, reconstruction of microbial communities metabolism can predict future responses to ocean deoxygenating.

Extraction of Trimyristin

Submitted by vthong on Mon, 11/13/2017 - 12:12

Nutmeg, tert-butyl methyl ether (TBME), and boiling chips were added to a 10 mL round-bottom flask. After allowing the solution to gently boil over a sand bath for 10 minutes, it was raised from the apparatus to let settle and cool. The solution was then filtered using a micro-scale filtration apparatus into an Erlenmeyer flask. TBME was added to the remaining round-bottom flask to rinse the remaining solid to obtain leftover trimyristin. After cooling, the liquid in the round-bottom flask was also pipetted into the micro-scale filtration apparatus into the Erlenmeyer flask. A gentle stream was air was passed into the flask to evaporate the trimyristin into a gummy yellowish solid.

Trimyristin procedure

Submitted by msgordon on Sun, 11/12/2017 - 23:03

Ground nutmeg (1.002 g) and tert-butyl methyl ether (3 mL, x mmol) was added to a round bottom flask along with several boiling chips. The mixture was condensed for 10 minutes using a distillation column and then the solids were allowed to settle. The resulting liquid was separated from the solid via a micro scale filtration assembly. The solvent was evaporated in the fume hood until a gummy yellow solid remained. The crude trimyristin was recrystallized in the presence of acetone and collected via suction filtration. A small portion of the once recrystallized trimyristin (95.8%) was set aside. The melting point of the recrystallized trimyristin was found to be 40℃-43℃ (56℃-57℃). The remaining product (0.058 g, x mmol) was transferred to a round bottom flask with 6M NaOH (2 mL), and 95% ethanol solution (2 mL). The mixture was refluxed for 45 minutes. At the same time, the once recrystallized trimyristin (0.102 g, x mmol) was recrystallized and subsequently collected via suction filtration. The melting point of the twice recrystallized trimyristin (60.7%) was determined to be 40℃-42℃ (56℃-57℃). Once the hydrolysis of the mixture was finished, the product was transferred into a beaker along with water (8 mL) before hydrochloric acid (2 mL) was added. Myristic acid (x g, x mmol) precipitated as a grainy yellow-brown substance and subsequently collected via suction filtration. The melting point of myristic acid was found to be ___.

 

HMG CoA Reductase - Perfect Paragraph

Submitted by jmazzola on Sun, 11/12/2017 - 22:09

HMG CoA reductase is a rate controlling enzyme in the pathway that synthesizes cholesterol within the cell. Usually this enzyme is suppressed when the process of LDL (low-denity lipoprotein) internalization is taking place, this is because LDL is a cholesterol transport molecule, and it is presumed that if the cell is internalizing cholesterol from outside, it does not need to synthesize it's own through the pathway with HMG CoA reductase. So it's been proposed that there is definetly some kind of coordination between these two pathways and even though the full expanse of it is not yet known, we've still be able to utilize it. Competative inhibition of this reductase enzyme leads to expression of LDL receptors, and thus lower concentration of cholesterol outside the cell because it is being properly internalized and metabolized. Furthermore, in regards to patients with high cholesterol, they can be given "cholesterol-lowering" drugs like statins to help, which target the HMG reductase enzyme in this way. 

HMG Reductase

Submitted by jmazzola on Sun, 11/12/2017 - 21:23

HMG CoA reductase is a rate controlling enzyme in a pathway that synthesizes cholesterol within the cell.
This enzyme is normally suppressed by internalization of cholesterol via LDL and LDL receptor. Competitive inhibitors of this enzyme cause expression of LDL receptors, and increased LDL concentration inside the cell following. This is the reason this enzyme is a target for cholesterol lowering drugs like statins.

Data from a “living” oxygen minimum lab could help predict the oceans future

Submitted by tterrasi on Sun, 11/12/2017 - 21:02

            Researchers have collected data over a 50-year span, showing the deoxygenating cycles of a fjord on the coast of Vancouver Island, and cataloging the response of the microbial communities inhabiting this environment. Marine oxygen minimum zones (OMZs) are widespread and contribute up to 7 percent of global oceans. Expanding of these OMZs has potential to bring oxygen-depleted water into new regions, affecting fish populations and nutrient cycles. Environments of low-oxygen are not well suited for most metazoans, but microbial life can flourish. As oxygen becomes limiting, microbial communities can change their metabolism to use alternative electron sources like nitrogen, carbon, and sulfur. These microbial communities can drive nutrient cycling, essential for ecosystem function and diversity. The research team collected data using time-series monitoring and multi-omic sequencing (DNA, RNA, and protein) to study microbial responses to oxygen-depleted ocean areas. By using this data, reconstruction of microbial communities metabolism can predict future responses to ocean deoxygenating.

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