Drafts

Cheetahs are the world's  fastest land animal. They can reach speeds up to 68 miles per hour (110 km/h). Gazelles can also run fast about 50 mph (80 km/h). With that in mind they are able to escape from a cheetah's grasp. A cheetah is a smallish cat, they take longer strides at a faster pace. They can generate energy quickly but they also can lose it just as quickly. A cheetah can only run at its top speed for 400 yards. Gazelles are large African deer, they take shorter strides at a slower pace and have elastic recoil to store and use energy. They have great endurance, able to go 5468 yards (5 km) at top speed. That is a lot further than the cheetah. The gazelles can also change direction fast and easily due to their elastic recoil. So while they are not as fast as the cheetah, gazelles have ways to escape predation.

Most mammals use all four limbs to move and so are called quadrupedal. Animals that spend most of their time walking are called ambulatory, and are generally plantigrade, which means that they walk on the soles of their hands and feet. Animals that do a lot of running are called cursorial, and are either digitigrade or unguligrade. Digitigrade mammals are mostly carnivores, and are called digitigrade because they run on their toes. Hoofed animals have unguligrade foot posture, which means that they have extended limbs with reduced digits, and elongated and fused tarsal bones. Another form of locomotion is saltatory locomotion, which includes jumping and ricocheting. Jumping is saltatory locomotion that uses all four feet, whereas ricocheting primarily only uses the two hind limbs, and most animals that use it are bipedal. Other types of locomotion include swimming, flying and gliding, and digging and burrowing.

Today in comparitve physiology we learned about how different animals respire in various ways. Most animals in the water breathe via gills. Gills are not well designed for respiration in air, but there are a few terrestrial organisms which breath through gills. One of these organsims is the coconut crab. Gills are essentially lungs that are not invaginated into the body. Instead they project into the environmental medium. There are both external and internal gills. Internal gills have a protective coating over them. There are also different typed of lungs. One type of lungs are diffusion lungs which respire air via diffusion and ventilation liungs which respire via tidal flow of air.

One system within the endocrine system, known as the male HPG axis, is responsible for a variety of different physiological functions such as spermatogenesis and the development of sex organs. HPG axis stands for hypothalamus-pituitary-gonad axis and is characterized by neurons in the hypothalamus region of the brain releasing hormones that signal receptors in the anterior pituitary gland. The pituitary gland then releases its own hormones that signal receptors in the gonads and leydig cells, initiating its physiological functions. The hypothalamus releases a hormone called GnRH, or gonadotropin releasing hormone. Hormones released from the hypothalamus set for the pituitary travel through a specialized pathways called the portal system. Once the GnRH has bound itself to receptors in the pituitary, two more hormones are released from the gland: LH and FSH. LH, or luteinizing hormone, will leave the pituitary and enter the bloodstream, traveling to leydig cells. This will stimulate the leydig cells to release testosterone, initiating spermatogenesis and reducing the secretion of LH from the pituitary. FSH, or follicle stimulating hormone, however, takes on a different role. FSH goes straight to the testis to upregulate the production of sperm.

The first step in genotyping adult zebrafish generally is fin clipping. Like the name probably already indicates, it involves clipping the fin of the zebrafish specimen. However, some important protocols have to be observed to do so optimally, with as little distress and mortality as possible. First, a water bath is set up to contain 200ml of system water i.e. water used to fill up the fish tanks. To this bath, about 15ml of tricaine, an anaesthetic, should be added. This will temporarily render the fish immobile and unconscious, making the clipping process easier and causing the fish less distress. If the fish does not stop moving when placed in the bath, more tricaine can be added, no more than 10ml. Too much tricaine can kill the fish. When the fish is finally floating sideways in the bath, a razor blade should be used to carefully amputate roughly half the caudal fin. Again, endeavor not to cut living tissue, as this will cause the fish to bleed. Bleeding may lead to infection or, worse, death. The clipped fin should be placed in a tube, labelled properly, according to the tank the fish was obtained from. The fish can, then, be returned to fresh system water. The fish should regain consciousness and become mobile again in about 5 minutes. If this is not the case, then, the fish is probably dead, due to some error in fin clipping. The fin tissue obtained can then be taken to the lab and DNA extracted from it. Subsequent genotyping steps will follow once DNA is extracted.

The Noctuid Moth or Owlet Moth, living in arctic and antarctic regions, exhibits a seemingly complex but quite simple method of escape from predators. Noctuid Moths are hunted mostly by insectivorous bats. These bats hunt using echolocation, so in their evolution, the moths have had to develop a means of countering this. Their answer to echolocation is a simple neural reflex circuit. The moths use ears located on their thorax to listen for the screeches of bats. Their ears contain two receptors, A1 receptor and A2 receptor, sensing location and proximity respectively. These receptors are connected to a group of interneurons in the thorax of the moth called the thoracic ganglion. This thoracic ganglion is connected to wing muscles on the opposite side of the moth. Once the sensory receptors in the ear receive enough stimulation from the screeches of the bats, the moth will automatically react, dodging and diving. It seems as though the moth is processing complex thought in avoiding the bat, but is actually just undergoing a series of reflexes as the chase goes on.

This experiment tested both the range as well as frequency and amplitute of the sounds that male mosquitos would react to. It was conducted by starting from one metere away and at 50Hz, play sound for 300 ms and recordign if there was a response. This was reapeated 16 tiems for each frequency and was tested in 1-- Hz incramintes up to 2050 Hz. This was then repeated for 4 different amplitudes at the same distance and then the whole experiment was repeated twicewit hthe sound at distances 5M and 10M. The results of this showed that there were responses at certain frequncies  at all of the distances even 10M. This is a big deal due to the fact that the previous assumtion was that hair based auditory organs were only functional up to 10s of centimeters. This experiment shows us one of these auditory organs functioning at 10 meteres away. This discovery is exciting due to the fact thatt it opens up a whole new area for microphonedesign at a potentially much smaller size that current microphone tech allows.

Link to article: https://www.cell.com/current-biology/fulltext/S0960-9822(19)30028-4

Today in biochemistry we learned about the charges of amino acids and the effect that those charges have on structure. Acidic and basic amino acids have R-groups that can ionize. The individual R-groups have different pKa values at which they deprotonate. Each peptide chain also has an N-terminus at the front of the chain and C-terminus at the end which are cabale of ionizing. Certain amino acids cannot be next to each other on peptide chains due to opposing charges. When two positively or two negatively amino acids are next to each other, they will repel each other. This greatly effects the structure of the protien. This is a problem because protein structure determines its function. Therefore, if there are structural issues then this will effect the overall function of the protien. 

Multiple studies have come to the conclusion that post-learning sleep enhances the consolidation of memories. Specific memories post-learning sleep consolidates are declarative, procedural and emotional. Additionally, memory function can be divided into three categories including encoding, consolidation, and retrieval. Encoding refers to writing new learning material to the brain that has been experienced throughout the previous day. These newly acquired memories are then brought through the process of consolidation. These fresh memories are strengthened and adapted into a stable and more permanent form that is then able to be integrated into already developed knowledge networks. Consolidated memories then remain dormant and easily accessible for later retrieval when they needed to be recalled.

The starting materials were reacted using conditions specific to the reaction being performed and the target product was obtained in 35.7% yield. This number is low, so it is not likely that pure cyclohexene was obtained through this experiment. The experimental boiling point was determined to be 70°, which is not what it should be, as the actual boiling point if Cyclohexene was 83°. The GC run showed a reaction time of .207 which is too low to be Cyclohexene.Also, based on the IR abortion, there was a peak for an aromatic ring and for a C-H bond. Based on the bromide test and the potassium permanganate alkanes should be present. The color from the bromide test was brown and there was precipitate on the bottom. The potassium permanganate test showed up purple. So both of the tests ran by the TA expressed that pure cyclohexane was not formed, but the test that were done chemically showed that it was formed.