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The structure and formation of the ER outlines how the ER assists in protein and lipid synthesis among other biological processes. There are two types of ER, as seen in Figure 2, the rough ER and the smooth ER. The name of the rough ER originates from the fact that ribosomes spot the outer membrane. In contrast, the outer membrane of the smooth ER contains no ribosomes. Depending on the type of cell, the ratio of smooth to rough ER will vary drastically (“The Endoplasmic Reticulum”). Both types of ER, however, have a similar structure of a large, continuous membrane that folds to create intramembrane spaces of different sizes. This intramembrane space is known as the cisternal space and connections exist between the cisternal spaces themselves in addition to the nucleus. The whole organelle is supported by the cytoskeleton of the cell which allows the ER to maintain its structure (English).

The other day in my genetics class, we were talking about cloning and the idea of cloning your own pets such as dogs and cats came up. Although I don't have neither a cat or dog, I still would be againt cloning one of my pets. Aside from the ridiculous idea of cloning your pet, the price to do so was even more outrageous. It costs $50,000 to clone your dog and $25,000 to clone your cat. We took a class poll to see what the majority of people would answer to whether they would their pet, and the majority of the class voted no. This did not surprise me at all since this was never topic of discussion that has been brought up with anyone that I've ever talked to. I guess a valid reason to clone your pet is if it dies suddenly to a traggic accident; but even then, is that what's best to do?

Animals have been experimentally shown to navigate their environments using landmarks, beacons, and cognitive maps. A landmark an object or structure distinguishable from the background environment that gives information about the position of and direction to a goal, while a beacon directly locates the goal. A cognitive map is an image of the environment stored in the animal’s memory. The use of landmarks has been demonstrated in animals as different as wasps and birds. In wasps, a test was done where a circle of pinecones was placed around a wasp’s nest, and then moved once the wasp had left. When the wasp returned, it looked for its nest in the pinecone circle, evidencing it use of landmarks. In hummingbirds who were trained to locate a flower based on two differently coloured poles, it was found that moving the poles caused them to look for the flower at its absolute location from the poles. Additionally, Clark’s nutcrackers have been shown to use cognitive maps. In a test where seeds were buried halfway between two landmarks, the nutcrackers managed to consistently locate the seeds even as the landmarks’ absolute distance from each other changed. It was concluded that the nutcrackers had learnt the relationship between the landmarks and the seeds rather than judging distance and position of the seeds based on the landmarks. This has generally been accepted as evidence of a cognitive map in Clark’s nutcracker.

Hox genes are a family of genes that are vital to an animal’s embryonic development. The HOX genes belong to the homeobox gene family, which is the second-largest gene family. The Homeobox genes codes for the homeobox domain which are 61 amino acid that forms a helix turn helix structure. Homeobox domain is present in transcription factors that are important in development. Mutations in either the homeobox domain or in the HOX gene can cause serious developmental diseases. The expression pattern of HOX genes dictates the body plans of animals. In vertebrates, HOX genes are organized into clusters that are on different chromosomes named abcd which each contain 9 to 11 hox genes. In this proposal, we are focusing on HOXC genes. There are 9 HOXC genes. They are named HOXC4, HOXC5, HOXC6, HOXC8, HOXC9, HOXC10, HOXC11, HOXC12, and HOXC13. All of the HOXC genes reside on chromosome 12.

While studying for my Biology 287 class, which is introduction to Ecology, I have realized a lot of predators have broad diets. Most predators eat prey in relation to their availability without showing a preference for any particular prey species. While the preferences of many species are fixed, others frequently switch prey item. Switching usually results in the consumption of prey at a rate disproportionate to the prey's occurrence. A predator, like a lynx will be specific if it eats tat species more often than would be expected based on that prey's availibility. That is why it will choose the snow hare bunny. They are considered specialists. Same goes with the coyote. This constitutes 60-80% of the coyotes diet. Some predators concentrate teir foraging on what ever prey is most plentiful, which to me makes the most sense. The more they fill you up the better! In a research conducted, guppies were given fruit flies that float on the water surface or worms that sink, and they chose the one that is more abundant. They will switch to either, whichever is most abundant. 

The overall objective of our proposal is to identify a subject that contains a highly conserved gene that can be characterized by the amount of expression. One specific aim the proposal has is to identify highly conserved genes that are present in the Animalia kingdom. In preliminary work, we found that one example of a highly conserved gene is the BOP1 gene present in ribosomal DNA. Further research done on HOX genes has noted that “[the duplication of HOX clusters] are shared by all vertebrae.”1 The statement motivated our group to propose that the HOX genes express little variation in vertebrae, and test the statement by knowing how consistent this data would be if we were to expand our subject of interest to a whole kingdom, rather than specific subjects used for their evidence (chicken, zebrafish, Xenopus, and newt). We will now look into HOX genes to see how similar or different expression of the HOX gene is throughout the Animalia kingdom.

Over the past decade or two, scientists have been trying to study the effects of PTU on fish. Studies on amphibians and mammalians have been much more popular during the course of this time period. Mentioned in one of the excerpts, researchers have been able to figure out that low thyroid hormone levels prior to the development of the hypothalamus-pituitary-thyroid (HPT) axis leads to brain damage and impairments in humans and rodents. Due to the fact that the HPT axis does not form right away in zebrafish offspring, the levels of thyroid hormone comes directly from the maternal egg yolk. After about 60-72 hours post fertilization, the HPT axis is formed and the zebrafish can now produce their own thyroid hormones.  Altering thyroid hormone levels is one of the major factors involved in neuronal and oligodendrocyte balance in the development of the zebrafish brain.

When a patient complains of a headache, there are many different ways to respond. In many cases, the headache can be non-life threatening as millions of Americans experience headaches. There are three main types of headaches: tension, migraines and sinus headaches. An interesting fact, the brain itself does not have any pain receptors. This means that the pain coming from a headache is actually pain that is being picked up by facial or neck receptors not the actual brain. A tension headache can be due to stress and are caused by muscle contractions of the head or the neck. A migraine is said to be caused by changes in blood vessel size and can be described as being a pounding or throbbing pain. A sinus headache is caused by pressure in the sinus cavities, due to a buildup of fluid. Now, these are not concerning headaches and do not require emergency care. A headache that comes suddenly and causes changes in levels of consciousness are worrying signs. The main concerns for serious headaches include meningitis, hemorrhage, stroke or brain tumor. If you are in a location where more than one person is experiencing a headache, this could be due to carbon monoxide poisoning. All of these cases need immediate emergency transport and care. 

Why studying the similarities and differences between hox genes is important. And why their expression is important. In the development of animals, there is a special period of embryonic similarity, during which not only the appearance of the embryos but also the expression of their genes is very conservative. The existence of this period is associated with the appearance in the evolution of stable building plans. In hox genes, the genes themselves are located on the chromosomes in order, therefore, strict, consistent activation of them is necessary in order for the body to form correctly. However, the mechanism and regulation of the Hox genes themselves remain unclear. It is clear that this process is very complex and multi-staged; non-coding RNAs are involved in it. To a complete understanding of all these processes in different animals, science is still very far away. When the basic mechanisms of gene regulation during early ontogenesis are deciphered, biologists will be able to closely address the following fundamental question, namely: why is all this necessary? Why do multicellular animals suddenly switch from maternal transcripts to their own? Incidentally, this problem has not only theoretical but also practical significance.