kheredia's blog

It is difficult to plan around assignments and work when two factors come into play: unforeseen events and lack of motivation. The lack of motivation makes it hard to commit to completing an assignment. Unforeseen events such as illness, stress, oversleeping, etc. could make you lose minutes to hours of a day where you had planned to do homework instead. Being sick last week made me fall behind in a few classes because I had to skip classes and rest in order for my cold to pass. Stress from things happening at home and around me at school fog my mind and leave me feeling stuck. With all of these events happening every day, keeping track of the things I have to do or need to do becomes like a maze with no outlet. The work piles up and I end up cramming everything in one day while still being behind at the end of it. 

The axon is a nerve fiber that transmits electrical signals also known as action potentials from one cell to another. The signals travel from one direction, and that is from the cell body out to the synapse of a postsynaptic cell. The axon itself is comprised of many things. This includes the cell body, its nucleus where genetic material is held, dendrites, terminal buttons, nodes of ranvier, and the myelin sheath. The axon is a long fiber which generates action potentials. When the cell reaches threshold, an action potential fires. This is an all or nothing response. Anything below the threshold will not fire an action potential. In the same token, action potentials cannot be stronger or larger, they simple fire at a higher frequency if threshold is reached continuously. 

Modern day plants come from many lineages which trace back to a very important event: endosymbiosis. Endosymbiosis is the engulfing of an organism by something else and thus lives inside the other. In modern day plants, this began with cyanobacteria. Cyanobacteria is a blue-green algae that is photosynthetic. In the earliest forms of cyanobacteria, they did not release O2 into the atmosphere. But later down the line they began oxidizing. For plants to evolve, the primary event of endosymbiosis occurred. A eukaryotic cell engulfed the cyanobacteria and degenerated into a chloroplast. After this event, a second endosymbiosis event occurred that diverged into red and green algae and thus their divergents. Without these events of endosymbiosis, the ancestors of plants wouldn’t have been able to evolve into what they are today. 

When learning about wheat and rice dwarfism in class, i found some things to be similar in organization with type 1 and 2 diabetes. wheat dwarfism mimics type 2 diabetes while rice dwarfism mimics type 1 in the factors that are lost or changed. 

in wheat dwarfism, gibberellin, the protein that sends an inhibitor Rht to the proteosome, is no longer working. Rht becomes resistant, and does not get inhibited and plants stay short. There is no loss in the proteins involved in this pathway, but the gibberellin is no longer useful. Even if we were to stimulate gibberelin production in excess, it would do nothing to stop dwarfism. This reminded me of type 2 diabetes, where we still have sensors and effectors (pancreatic b cells), but we become insulin resistant. Simply injecting insulin into our blood will not solve anything because the insulin will not signal glucose transporters to bring glucose back into the cell. Insulin and gibberelin have the same issues in this case. 

In rice dwarfism, gibberelin is no longer existant but if we add gibberelin, it will stop the inhibitor. This is similar to type 1 diabetes. Although in type 1 diabetes, pancreatic b cells do not work, if we inject insulin in our blood, it will be able to bind and lower our blood glucose. Insulin and gibberelin are the same in this case as well.

The Rht gene is an inhibitor which stops a plant from growing. In a normal pathway, a gibberelin protein binds to the Rht gene and throws it away for degredation. Therefore, the plant is able to grow because gibberelin stops the inhibitor gene from inhibiting growth. When it comes to dwarfism, there is a defect or mutation in wheat that actually causes gibberelin to be ineffective. In dwarfs, because gibberelin is now inneffective, the Rht gene does not become inhibited and will thus be able to stop the wheat from growing. This is how dwarfism results in wheat

In rice however, there is a gene that is similar to Rht with the same function: it inhibits growing. With rice dwarfism, however, it is not that the gibberelin is ineffective, but that there is simply no gibberelin at all. This can be fixed however, by simply adding gibberelin which will then bind to the inhibitor and allow the rice to grow again. In wheat, this is not possible because the issue with the mutant is that gibberelin is rendered useless.

This is an outline to organize how differences between these two pictures for #5 be written in paragraph.

Overarching differences throughout

- weather

- camera quality

- labels are different

-arrows are different lengths and widths

Differences in panel a

- locations are different. Different buildings / objects / background

-there are additional plants in view in the first figure

-the first figure is a little bit more zoomed in

Differences in panel b

-less surrounding leaves in the first figure than the second

-the leaves in the first figure are yellow while in the second they are green

Differences in panel c

-background is different; bush and concrete behind figure 1. Grass and bush is absent in figure 2

-figure 1 arrow is pointing to a white spot on the bark

-figure 2 arrow is not pointing to a white spot on the bark

Comparison to Picture 5

Cortisol is a steroid hormone produced in the adrenal cortex of the adrenal medulla. It has various functions in the body. This includes increasing levels of blood glucose, and regulating metabolism. Sometimes, cortisol levels become high and can lead to stress and anxiety. Individual’s affected by Cushing’s disease have been exposed to high levels of cortisol for a long time. On the opposite spectrum, Addison’s disease is a condition where cortisol levels are too low, and because of this, individual’s rarely feel stress and are prone to being unmotivated. Cortisol is also part of a feedback loop. This begins with CRH, produced in the hypothalamus, ACTH, produced in the anterior pituitary, and ends with cortisol. Based on the levels of cortisol in the body, it will have a direct effect and change levels of CRH and ACTH. 

Skeletal muscle cells are different than the pacemaker cells we have in our cardiac muscle. When a skeletal muscle contracts, it is due to the voltage gated sodium channels opening and triggering the voltage gated calcium channels to open, bind to troponin, expose the tropomyosin binding site, and have myosin bind to actin to complete one cross bridge cycle. On a graph, before depolarization in a skeletal muscle cell, it is a flat line until there is a stimulus, then it rises, and repolarizes back to normal. Without stimulation, the skeletal muscle will not contract. 

In cardiac pacemaker cells, the heart begins to repolarizes even when it is generating maximum force. This is because the calcium channels that are triggered via the release of sodium are slow calcium channels. Due to this, the absolute refractory period is longer than a skeletal muscle’s absolute refractory period, and is the reason why the graph of a pacemaker potential does not have a straight line because the heart is overlappingly beating and resting. In cardiac cells, even without stimulation, the heart will beat. 

My natural hair is thick, curly, and brown and has many notable characteristics that make it equally intolerable but has a few benefits. It does not hold on to moisture well and dries up very fast, especially the back parts of my hair. When brushing it, the strands get tangled almost instantly and even when it is detangled it quickly goes back to being difficult to brush again. Also, when brushing dry curly hair, it becomes poofy and expands. This is different from when I brush my wet hair, which is easier to detangle and does not ruin it. Even with having so much hair, it is light and airy and makes for a good pillow. Curly hair also frizzes easily any time there is hot or humid weather. But most of the time I wear my hair straight to avoid the complications of curls.