Plant Ecology

Submitted by jgcahoon on Wed, 11/15/2017 - 22:51

There are many competitive advantages of early emergence. The first is how plants that emerge early get first access to the resources in that area. M. A. Ross and John Harper (1972) showed this in their experiment, and came to the conclusion that plants that appeared above the ground first were 1000 times larger than those who appeared last, most likely due to the disproportionate amount of resources between the two. Plants that emerge early will also be able to mature faster than plants that emerge at a later time, and therefore can possibly pick the best locations for resources first. 

Topics in Plant Bio Notes - Genetically Modified Crops

Submitted by samihaalam on Wed, 11/15/2017 - 16:45

There are four levels of reproductive barriers that determine use for crop improvement. The primary level involves the actual biological species in question that you want to modify and/or cross. The secondary level involves all species that can be crossed with some fertility. The tertiary level involves hybrids that are lethal or sterile. This is obviously not ideal. It is possible to use advanced techniques to implement gene transfer. It is also possible to rescue the embryo by in vitro implementation of the plant embryo. The quaternary level involves scenarios in which genetic engineering is the only way to achieve viable crops. This would take the most time and energy.

Boltwood 6 Reflection

Submitted by hamacdonald on Wed, 11/15/2017 - 16:02

This week at Boltwood we started out again with some crafts. We had everyone make turkeys from tracing their hands. Everyone seemed to enjoy the activity. Barbara came a little later to the craft so everyone else finished before her. Nicky finished very quickly so I helped her make a crown she seemed really excited about this. Next the group made crescent roles and per usual ended with a game, this week we played bingo. This week the girls were kind of upset because one of their in house nurses was leaving. We talked about this and also talked a little bit about death of family members because Rosie brought up missing her mom. We talked about this briefly and were able to change the topic back to positive things. Overall it was a good week! 

Boltwood 6 Reflection

Submitted by hamacdonald on Wed, 11/15/2017 - 16:02

This week at Boltwood we started out again with some crafts. We had everyone make turkeys from tracing their hands. Everyone seemed to enjoy the activity. Barbara came a little later to the craft so everyone else finished before her. Nicky finished very quickly so I helped her make a crown she seemed really excited about this. Next the group made crescent roles and per usual ended with a game, this week we played bingo. This week the girls were kind of upset because one of their in house nurses was leaving. We talked about this and also talked a little bit about death of family members because Rosie brought up missing her mom. We talked about this briefly and were able to change the topic back to positive things. Overall it was a good week! 

procedure edit (#2)

Submitted by dalon on Wed, 11/15/2017 - 15:11

Boiling stones, 0.064 grams of sodium hydroxide, and 0.200 grams of 2-napththol were added to a 10 mL round bottom flask. 3 mL was added to the RB flask and an air condenser was attached to the flask. The sand bath was turned on upon arrival to 30% and the flask was lowered so it was hovering above the sand. The mixture was refluxed until all the solids were dissolved and then for another 25 minutes. Through the top of the air condenser, 0.200 mL of n-butyl iodide was added and the flask was lowered into a position just above the sand bath to reflux for another hour. 50 minutes into the reflux time, 25 mL of water was cooled in an ice bath until the completion of the reflux. The reaction mixture was poured over 10 grams of ice in a beaker and any mixture that remained in the RB flask was rinsed using the cooled water. The contents of the beaker were mixed until 95% of the ice melted. The product was then collected using suction filtration for 25 minutes. After 25 minutes, a small amount of the product and the starting material were analyzed via a 3 lane TLC analysis in a 95% hexane 5% EtOAc mixture, a 5% hexane and 95% EtOAc mixture, and a 20% hexane and 80% EtOAc mixture. The percent yield was then also calculated.

 

Trimyristin Discussion

Submitted by eodonovan on Wed, 11/15/2017 - 13:15

Trimyristin is an organic compound found in nutmeg, whose structure consists of a glycerol backbone and fatty acid groups. In this lab, pure trimyristin was extracted from nutmeg via filtration and recrystallization using acetone as the solvent; acetone also helped to purify the sample along the way. Trimyristin undergoes an acid- catalyzed hydrolysis reaction with HCl to form a carboxylic acid (myristic acid). The percent recovery of crude yellow trimyristin, or in other words, the amount of trimyristin (per gram) of nutmeg as a percentage was found to be 65%.  After the first recrystallization, the percent recovery decreased significantly to 22.5%. Some possible sources of error for this drastic decrease in percent recovery include cooling the solution to quickly instead of properly letting it cool to room temperature before placing it onto the ice bath. In addition, the compound may also have not completely dissolved which would result in a decreased number of crystals formed. Following the second recrystallization of the trimyristin, the remaining nutmeg used resulted in a percent recovery of 68.88%. The precipitate formed from the hydrolysis was myristic acid and its percent recovery was calculated to be 75%. The purity and identity of both products were assessed using their melting point ranges. 

Results for distillation

Submitted by daniellam on Tue, 11/14/2017 - 23:37

Plateaus in temperature are sought out for good distillation because it means that the liquid and vapor of the mixtures are at equilibrium. This is important for distillation because it creates a condition called total reflux which creates a good separation (Zubrick 179).  In the second temperature profile, there are many plateaus suggesting that the separation of the two compounds are at equilibrium and is much more effective.  There are drops in temperature at certain points which is a sign of a successful separation. At the first drop in temperature, it shows that there is no more vapor meaning that at this point, there would a low amount of cyclohexane left. The second drop in temperature, which occurs at a volume of 32 mL, shows the cyclohexane running to completion.  The final plateau of this temperature profile indicates that there is only toluene with a corresponding ratio of approximately 99:1 of cyclohexane.

lab

Submitted by dalon on Tue, 11/14/2017 - 16:24

The lab that most interested me was Mariana Pereira’s lab regarding mother/child interactions. There were three main facets to Professor Pereira’s lab. The first facet was just in general what the different brain structures were that are involved within mom/child interaction. Professor Pereira found that there were limbic-cortical-striatal interactions and also that the mesocorticolimbic dopamine system was involved. Another facet of Professor Pereira’s research was how postpartum depression in mice affected mouse interaction with the pup. Some observations made were that the mouse licked her pup less often and generally interacted with the pup less. In addition, the third and most interesting facet to me, was the impact drugs have on the mother/pup interactions. Although Professor Pereira briefly discussed this, through my own meeting with her she summarized it well. The mice that are addicted to cocaine are more likely to choose to use the cocaine rather than take care of the pups. This is especially interesting because of the VTA system and the dopamine release due to the fact cocaine is known to release dopamine into the VTA system and is the cause for the addictive effect. Therefore, this could potentially demonstrate that the cocaine use overrides the mother’s instinct to take care of her pup.

Neurobio Study Guide Exam 2

Submitted by samihaalam on Tue, 11/14/2017 - 12:23

 

How cortical area 6 differs from area 4 in generating movement:

  • area 6 = higher motor area 
    • planning
    • premotor cortex (PMA and supplementary motor area (SMA))
    • SMA and PMA similar functions, correspond to different groups of muscles 
    • mirror neurons!!
      • only imagine neurons, some neurons in area 6 fire!
      • maybe to understand actions of others
      • very specific movement processes
  • area 4 = lower motor cortex 
    • executing
    • lower intensity of current to elicit movement 
    • homunculus for area 4 
      • can make one! (like how did for somatosensory thing?)
      • finer motor control is overrepresented -  hands, face, tongue, swallowing huge 
      • if stimulate something in this brain region, person would twitch! 
  • study with monkey! as the monkey knows it's gonna press the button, just waiting for the light to go on - area 6 is activated; after light goes on, right before/as monkey is hitting the button - area 4 is activated!!

Basal Ganglia Motor Loop!

  • info goes from prefrontal cortex and sensory cortex → basal ganglia → VLo → areas 6 & 4 → {corticospinal tract or red nucles → lateral vs reticular nuclei or uperior and vestibular nuclei → ventromedial pathways }→ spinal cord
  • very important loop! 
  • basal ganglia structures:
    • basal ganglia = where input for VL (called VLo) arises
    • VL nucleus of thalamus 
    • striatum
      • cauadate nucleus 
      • putamen
      • target of the cortical input to basal ganglia - where info from cortex comes into basal ganglia 
    • globus pallidus
      • source of the output to the thalamus
    • subtalamic nucleus
    • substantia nigra
      • midbrain structure also in the basal ganglia of the forebrain
  • pathway = cortex (cerebral cortex, spec. frontal, prefrontal, and parietal) → basal ganglia and thalamus → cortex ( spec. supplementary motor area)
  • imprortant for selection and initiation of willed movements
  • basal ganglia focuses activate onto spec areas of motor cortex 

Part of analysis for gas chromatography

Submitted by daniellam on Tue, 11/14/2017 - 11:20

Based on the gas chromatography/mass spectroscopy data, it is seen that the experiment with the simple distillation of the first sample (2nd fraction) shows a higher percent area for toluene (36.74%) compared to the fractional distillation of toluene (25.62%), suggesting that the fractional distillation went much better. This means that during the distillation, not only cyclohexane was distilled, but also some toluene.  For fractional distillation, the packing allowed a higher ratio of cyclohexane to vaporize while both of them condensed onto the copper column.  This creates better separation between the two compounds.  Similarly, for the second sample (2nd to last fraction) that was taken for simple distillation, the GC/MS shows that there is very little cyclohexane (6.14%) while the majority is toluene (93.86%).  However, fractional distillation had a much better separation since the remainder of cyclohexane (1.49%) is miniscule to toluene (98.51%).  Though most of the cyclohexane was separated from the toluene, the two compounds could not be completely separated from both simple and fractional distillation.  Fractional distillation is better for separation than simple distillation because of this packing.

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