Topics in Plant Bio Notes - Cell Expansion and Walls

Submitted by samihaalam on Sat, 11/18/2017 - 16:16

Animals usually do not form multiple identical organs and usually can not grow back whole organs once they have been lost. Plants, however, usually can do this; they can produce thousands of leaves and roots and hundreds of stems in a lifetime. This process in plants is known as iterative development. It is important for plants to be able to do this becaue they have a transitory existence - their leaves and flowers fall off every year, their roots die and regrow, etc. This is a major difference between plants and animals. 

In plants, new organs form at the meristems. This region of the plant contains undifferentiated cells called meristematic cells.They are regions where cell division occurs in the plant. An apical meristem is a meristem that occurs at the tips of the plant, and cause primary growth by lengthening the plant. Lateral meristems cause secondary growth by widening the plant. 

A developing root or shoot tip normally contains four regions. The bottom-most layer is where the mature cells are - tisues in this region are usually fixed unless there is injury to the area. The next layer in the Zone of Cell Differentiation. In this region, mature cells start forming. The layer on top of that layer is the Zone of Cell Elongation. Here, cells elongate, with little division. The outer-most layer is the Zone of Cell Division - new organs begin to form in this layer. 

After a cataclysmic injury, formerly fixed tissue can begin to regenerate and produce new shoots. This is due to plant cells' totipotent nature - they can de-differentiate, begin to divide, and re-differentiate into any other cell type at any point. This means that an entire plant could potentially be regenerated from a single plant cell.

Wheat Varieties

Submitted by samihaalam on Sat, 11/18/2017 - 15:26

Wheat originated around 10,000 BP in Southwestern Asia. One species of wheat is Triticum monococcum, or Einkorn. Today, it is harvested mainly in the Middle East and Southern Europe. It contains glumes that fit tightly around its seeds. The domesticated version of this species differs from the wild version only in its shattering abilities; the seeds don't fall off in the domesticated species as easily as they do in the wild species, which makes it easier to harvest them. Another species of wheat is Triticum turgidum. Two common subspecies of this are Triticum turgidum ssp. dicocooides (emmer) and  Triticum turgidum ssp. durum (durum). Their seeds do not have glumes around them. A third species of wheat is Triticum aestivum, or bread wheat. There also appears to be no glume around its seeds. Interestinglty, although these are all species of wheat, each of these species has a diffferent number of chromosomes.  

Topics in Plant Bio Notes - Polyploidy Part II

Submitted by samihaalam on Sat, 11/18/2017 - 14:33

The number of somatic cells in an organism is referred to as the diploid number, or 2n. The number of gametes is the haploid number, or 1n. The ancestral haploid number is 1x, which is the base number. For example, and individual with three sets of homologous chromosomes would be 3x, or triploid. The diploidy number is when an individual has two sets of homologous chromosomes. The haploidy number is when an individual has half the normal set of homologous chromosomes. Aneuploidy occrus when one or more chromosomes of the normal set are absent or present in excess. Polyploidy occurs when an individual has more than two complete sets of homologous  chromosomes. 80% of flowering plants are polyploids, as well as some fish, amphibians, and lizards. A subset of polyploidy is called allopolyploidy, which is when there is a doubling of the haploids of two different ancestral species into one hybrid. This is opposed to autopolyploidy, which is when there is nondisjunction in meiosis or mitosis, causing all the chromosomes to not separate from each other, leading to diploid gametes. This is derived from a single species or closely related species. An example of a common autopolyploidy species is the potato. Bananas are triploid, which leads to them being larger and have a lot less seeds. In general, polyploidy leads to an increased nucles and cell size, which leads to larger plants, larger fruits, and more seeds. It also leads to a slower growth rate and later maturity, increased heterozygosity, releaxed natural selection due to redundant gene copies, and overall exra copies, leading to greater variation and greater adaptability.

Topics in Plant Bio Notes - Polyploidy

Submitted by samihaalam on Sat, 11/18/2017 - 01:06

Wheat originated around 10,000 BP in Southwestern Asia. One species is Triticum monococcum, or Einkorn. TOady, it is haarvested mainly in the Middle East and Southern Europe. The domesticated version of this species differes from its wild version by its shattering abilities - its seeds don't fall off as easily in the wild version, which makes it easier to harvest them. They're glumes that fit tightly around the seeds. THere is also only one seed per spikelet. Another species of wheat is Triticum turgidum. A subspecies of this is Triticum turgidum ssp. dicocooides, or emmer. a second subspeices of this is Triticum turgidum ssp. durum, or durum. It is harveter mainlty in Italy, Spain, and the US. Its seeds do not have glumes around them. A third what species is Triticum aestivum, or bread wheat. There are several different subspecies of this. There also appears to be no glume around its seeds. Interestinglty, although these are all species of wheat, each of teh three species has a diffferent number of overall chromosomes from one antoher.  

mutagenesis discussion

Submitted by daniellam on Sat, 11/18/2017 - 00:18

The number of yeast colonies for both UV exposure times were substantially low, even lower than expected values. Of the 1000 estimated yeast colonies placed on the YED plate prior to UV exposure, 200 (20%) were supposed to survive and recover from the DNA damage, and from that recovery there were supposed to be some mutants. Due to higher levels of radiation from the transilluminator, more yeast were killed than anticipated. For future experiments, this can be resolved by reducing exposure time and increasing the yeast population on the plate before exposing them. This method relied on the chance that a mutation would be introduced into the yeast through a problem occurring with DNA repair.

The FOA plate had 7 colonies, which means that the yeast mutated in order to stay alive in that plate. They gained the inability to produce 5-fluoro-uracil which is a self toxin. Only one other group in a different lab period also had colonies in their FOA plate. This indicates that inducing this specific mutation or any specific mutation is a rare occurrence and is not guaranteed to happen.

Lungfishes

Submitted by msgordon on Fri, 11/17/2017 - 21:12

Lungfish have been found in SA, Africa, and Australia,. There are 3 families/genera and 6 species. Lunfish respire through buccal pumping, using a modified swim bladder as a lung. They have labyrinthine dentition. Reproduce by spawning, males guard eggs in Leptosiren - grow external gills to exhale O2 on eggs. Natural history: live in slow waters, swamps etc. Can aestivate, make slime cocoons. Larval Lepidosiren have external gills. Protopterus and Lepidosiren are obligate air breathers while Neoceratodus are facultative air breathers (optional)

Planarian abstract 1

Submitted by chengqian on Fri, 11/17/2017 - 18:13

The Planarian is a peculiar organism and the research of the planarian is also worth exploring. Planarians are photophobic and is influenced by different wavelength. Its regeneration feature allows it regenerates even it is cut into two pieces. The memory from the initial individual is also inherited by the second individual which grew from the cut part of the body. In order to decrease the cost of the biochemical memory experiment about the planarian and widely distribute the research on planarians, this project try to use a cell phone in-built flash light instead of a light with an electric shock to do the experiment.

 

Planarian abstract 1

Submitted by chengqian on Fri, 11/17/2017 - 18:12

The Planarian is a peculiar organism and the research of the planarian is also worth exploring. Planarians are photophobic and is influenced by different wavelength. Its regeneration feature allows it regenerates even it is cut into two pieces. Memory from the initial individual is also inherited by the second individual which grew from the cut part of the body. In order to reducethe cost of the biochemical memory experiment about the planarian and widely distribute the research on planarians, this project try to provide a way to use a cell phone in-built flash light instead of a light with an electric shock to do the experiment.

Zebrafish lab abstract

Submitted by cberg on Fri, 11/17/2017 - 15:12

This experiment was conducted in order to observe the effects of sex-specific socialization on zebrafish metabolic rates. We wanted to observe whether zebrafish metabolisms would change in accordance with the gender of fish with which they shared an environment. We hypothesized that more energy is consumed during opposite-sex socialization because sexual arousal causes the fish to exert an excess amount of energy. We therefore predicted that if we put a male and female fish in an environment together we would find that the two would have a higher metabolic rate than a hypothetical sum of the metabolic rates of those two fish when in same-sex environments. However, our data did not end up being consistent with this prediction because of cofounding variables. Our trials were not accurate representations of sex-specific socialization because of overuse and exhaustion of the fish, and the time of day at which the trials were conducted. It would be important to repeat the experiment with greater recovery periods in between trials, and in the early day, during the period of morning at which zebrafish mate naturally. This would allow a more accurate representation of opposite-gender socialization, and therefore a conclusive analysis of the effect on the fish’s’ metabolic rates.  

Orgo Procedure

Submitted by hamacdonald on Fri, 11/17/2017 - 14:40

      In a 250 mL round bottom flask, nutmeg (1.010 g, 2.29 mmol) and tert-butyl methyl ether (3 mL) were added and boiled for ten minutes. Once the solution had boiled and cooled, the liquid layer was filtered into a 25- mL Erlenmeyer flask via microscale filtration techniques. Tert-butyl methyl ether (2 mL, 22.69) was added to the round bottom flask, heated, and filtered again (percent recovery, 24.578- 24.107). After the second filtration, the 25- mL Erlenmeyer flask was warmed and air was blown over the solution until all of the solvent evaporated and the solid yellow product remained. The product was dried for five minutes and the crude weight was obtained (0.471 g, 0.65 mmol) and acetone (9.4 mL) was added and warmed until the solid dissolved. The solution was cooled to room temperature for 5 minutes and then cooled in an ice bath for 15 minutes. The solid product was filtered via suction filtration and washed with cold acetone. After filtration and drying the crystals were collected, weighed (0.189 g, 0.261 mmol) and the melting point range (49-51 °C) of the product was obtained.

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