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Reflection

Submitted by alexispena on Fri, 12/15/2017 - 11:00

            

            Over the course of the semester in Writing in Biology, we worked on four major projects: Methods, Proposal, Project, and Reflection. Each project connected to topics discussed in class, and prepared us for a career in the biological fields. The proposal project was very exciting and a little daunting in the beginning. When the project was explained, having the opportunity to design an experiment about anything surrounding planarians seemed like a big task. Doing the project in groups was extremely helpful, as well as the one on one meeting with Dr. Brewer to help work through the details of the proposal. Drafting the proposal went well and we had a lot of fun. Planarians were an interesting invertebrate to use, because I had never heard of them and they were really cute in their own interesting way. Learning about a new species and designing our own experiments was great, because it gave me an idea of what being in a science field could be like. 

Reflection

Submitted by alexispena on Fri, 12/15/2017 - 10:58

The proposal project was very exciting and a little daunting in the beginning. When the project was explained, having the opportunity to design an experiment about anything surrounding planarians seemed like a big task. Doing the project in groups was extremely helpful, as well as the one on one meeting with Dr. Brewer to help work through the details of the proposal. Drafting the proposal went well and we had a lot of fun. Planarians were an interesting invertebrate to use, because I had never heard of them and they were really cute in their own interesting way. Learning about a new species and designing our own experiments was great, because it gave me an idea of what being in a science field could be like. 

Methods Rewrite

Submitted by alexispena on Thu, 12/14/2017 - 21:51

The original and replicate figures are different. The differences in the figures are a result of a non concise methods section. Three out of four of the images for the replicate figure were different. To ensure that they are the same, a more accurate description of the control factors:  time and flower species. The description of the time of day was accurate, but the season was not taken into account. When the photos for the original figure was taken, it was still relatively warm. The eastern carpenter bee would not survive a frost, and therefore the pictures would need to be taken before then. The description of time to create a more accurate figure includes a time frame the photograph needs to be taken in as well as the time of day.  

Animal Movement Class Notes

Submitted by alexispena on Sun, 12/10/2017 - 20:28
  • Energy consumption in terms of locomotion
    • Unit of mass, distance, and time in terms of kinetic energy
      • Ek= 1/2mv2
  • Efficiency of biological movements is calculated by the ratio of mechanical work produced to chemical energy consumed
    • Efficiency= mechanical work produced/chemical energy consumed
  • Molecular motors convert chemical energy to mechanical energy
    • E.g  sperm uses a flagella for motion
    • Not very efficient
    • Vertebrate muscle efficiency is 25% the rest is lost as heat
  • In animals with muscles, muscles and tendon produce force for locomotion
    • Muscles use energy (ATP) to produce force, and tendons recover energy to produce force like a spring
  • Mass effects how tendons act as springs
    • Large animals like kangaroos can take advantage of these elastic savings because of gravity
  • Kinetics is the study of forces during locomotion
    • force plates & the rate of oxygen consumptions can be used to measure kinetics
      • flowmeters or flow tanks 

Plant Cell

Submitted by alexispena on Thu, 12/07/2017 - 16:16

Introduction

  • Senescence: The process of deterioration with age, the loss of a cells ability to divide and grow
    • Slower process than cell death
    • Systemic process
    • Example: Chlorophyll degradation that causes leaves to change color in deciduous trees during fall
  • Cell Death: cell death in any form controlled by an intracellular program
    • More rapid than senescence
    • Localized process
  • Both are normal and controlled processes

Programmed Cell Death

  • There are 3 types of programmed cell death:
    • Apoptosis: Type I cell death
    • Autophagy: Type II cell death
      • Self-eating process
    • Necrosis: not programmed, caused by outside forces
  • Programmed Cell Death (PCD): an active process to remove unneeded/ damaged cells
    • C Elegans model system: small soil nematode that has a short life cycle and feeds on bacteria. It is easily raised in labs in mass quantities. The nematode maintains a certain amount of cells (959)  C. elegans has been proven to be an excellent model organism for studies of programmed cell death. Its transparency and the knowledge of its cell lineage, including its invariant life vs. death fate of all cells, allow programmed cell death to be studied in vivo at single cell resolution

Apoptosis

  • Mammalian Cells: apoptosis initiates with chromatin condensation and DNA fragmentation, leads to formation of apoptotic bodies, and they are engulfed by neighboring cells or macrophages
  • Plant Cells: Chromatin condenses and DNA fragments but apoptotic bodies do not form, the cell remains whole. Neighboring cells do not consume the dead cell.
  • Mechanism: signal transduced from mitochondria through Cyt C to caspases
    • Cyt C – a small cellular protein associated with the mitochondria membrane and helps initiate apoptosis
      • Bax or Bek stimulates release of Cyt C protein
    • Caspases: executioners 

Marine Iguana Energy Production

Submitted by alexispena on Wed, 12/06/2017 - 21:41

The paper Lactic Acid Production during Field Activity in the Galapagos Marine Iguana, Amblyrhyncus Cristatus by Todd T. Gleeson is a study that analyzes the significance of anaerobic energy production in Galapagos marine iguanas. Prior studies have shown that marine iguanas are physiologically adapted to burning energy while foraging underwater, and that their energy production does not vary from other iguana species. The purpose of this experiment was to understand the significance of anaerobic energy production through measuring the concentration of lactic acid after the iguanas performed normal activities: basking, foraging, diving, and running. The scientists captured basking iguanas after they had been basking for at least 30 minutes. The foraging iguanas had been sampled as they returned from foraging and were one meter on shore. To sample the marine iguanas after diving, they were forced to dive for 6 minutes then allowed to cruise for 15 minutes and then sampled. Lastly, lactic acid build up after running was sampled by chasing the iguanas for two minutes, giving them 5 minutes to recover and then drawing their blood. The results of these experiments showed that marine iguanas are capable of having large amounts of lactic acid build-up. The marine iguanas’ accumulated lactic acid while running, and it continued to get higher after they rested. During the forced dives, they also accumulated a large build-up of lactic acid that did not go down while cruising. In contrast, when blood was sampled after basking, it did not have a high concentration of lactic acid. These results support that marine iguanas undergo anaerobic energy production during bursts of activity, because there was an increase in blood lactic acid after they performed rigorous exercise. 

Marine Iguana Energy Production

Submitted by alexispena on Wed, 12/06/2017 - 21:40

The results of these experiments showed that marine iguanas are capable of having large amounts of lactic acid build-up. The marine iguanas’ accumulated lactic acid while running, and it continued to get higher after they rested. During the forced dives, they also accumulated a large build-up of lactic acid that did not go down while cruising. In contrast, when blood was sampled after basking, it did not have a high concentration of lactic acid. These results support that marine iguanas undergo anaerobic energy production during bursts of activity, because there was an increase in blood lactic acid after they performed rigorous exercise. 

Anaerobic energy production in Marine Iguanas

Submitted by alexispena on Tue, 12/05/2017 - 23:36

 

Introduction:

  • Physiological adaptations of marine iguanas suggests that they can compensate for periods of anaerobiosis due to foraging under the water
  • More recent body studies have shown that energy production between marine iguanas and terrestrial lizards isn’t much different
  • Forced dives produced large amounts of lactic acid
  • Blood samples from free ranging and foraging marine iguanas to analyze lactic acid to determine the importance of anaerobic energy production

Materials and Methods:

  • 36 iguanas were captured
  • Basking lizards were allowed to rest for a minimum of a half an hour before capturing and sampling, body temperature was recorded
  • Lizards were captured upon return from foraging after moving one meter on shore and sampled
  • To test lactic acid after vigorous running, 10 adults were forced to run, sampled after 2 minutes, allowed to rest for 5 minutes, and then sampled again
  • Elevated levels of lactic acid in the blood were to signify anaerobic energy production

Chimpanzee vs Human Strength

Submitted by alexispena on Fri, 12/01/2017 - 13:08

The paper Chimpanzee Super Strength and Human Skeletal Muscle Evolution by Matthew O’Neill is a study analyzing the notion of chimpanzee “super strength”. Previous studies have suggested that chimpanzees have 1.5 times greater muscular performance than humans. They hypothesized that chimpanzees are stronger due to the ability to generate greater isometric forces, faster shortening velocities and the difference in myosin heavy chain (MHC) isoform content. (O’Neill 2017) To test this, they measured the single fiber contractile properties and the MHC isoform distributions of muscles in chimpanzees. Small samples of muscle fibers were removed from the right hind limbs of three adult male chimpanzees that were around the same age. The force and velocity was recorded and the distribution of MHC was found for each of the samples. The results of these tests were applied to a muscle model to compare the human and chimpanzee performance abilities. The results of the force and velocity comparisons of human and chimpanzee muscles were not significantly different. The MHC isoform distributions showed more MHCII isoforms in chimpanzees and a higher distribution of MHCI in humans. Chimpanzees were also found to have muscle fibers that were much longer than human muscle fibers. (O’Neill 2017) MHCII isoforms are related to fast-twitch muscles and MHC1 isoforms are related to slow-twitch muscle. This result means that chimpanzees have a higher and more even distribution of fast twitch muscles than humans. The higher composition of fast-twitch muscle and the longer muscle fibers in chimpanzees can cause a greater dynamic force and power output. The computer simulations computed that chimpanzees have a 1.35 times higher dynamic force and power than humans, which is very close to the previous suggested 1.5. This study supports that chimpanzees are stronger than humans, and suggests that MHC distribution and fiber length are the reasons why. 

Chimpanzee vs Human Strength

Submitted by alexispena on Fri, 12/01/2017 - 13:07

The paper Chimpanzee Super Strength and Human Skeletal Muscle Evolution by Matthew O’Neill is a study analyzing the notion of chimpanzee “super strength”. Previous studies have suggested that chimpanzees have 1.5 times greater muscular performance than humans. They hypothesized that chimpanzees are stronger due to the ability to generate greater isometric forces, faster shortening velocities and the difference in myosin heavy chain (MHC) isoform content. (O’Neill 2017) To test this, they measured the single fiber contractile properties and the MHC isoform distributions of muscles in chimpanzees. Small samples of muscle fibers were removed from the right hind limbs of three adult male chimpanzees that were around the same age. The force and velocity was recorded and the distribution of MHC was found for each of the samples. The results of these tests were applied to a muscle model to compare the human and chimpanzee performance abilities. 

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