Seeing In The Dark Lab Report

This experiment was designed to assist with the practice of observation without a solid conclusion in a laboratory setting. In the scientific field, there is rarely an obvious answer to an hypothesis, and most of the time we can not be completely certain of any given answer, we can merely test the subject to see how the results compare to the hypothesis. This was the point of the Black Box Experiment, to prove how methods of deduction and observation can lead to a supported conclusion of a proposed hypothesis. Each group was given a sealed box that we could not see inside, and instructed to use the senses and comparisons to known objects to deduce the contents. Our group hypothesized that our black box contained three or more round, plastic, lightweight objects; more specifically, three plastic lids.

The mole is a convenient unit for analyzing chemical reactions. Avogadro’s number is equal to the mole. The mass of a mole of any compound or element is the mass in grams that corresponds to the molecular formula, also known as the atomic mass. In this experiment, you will observe the reaction of iron nails with a solution of copper (II) chloride and determine the number of moles involved in the reaction. You will determine the number of moles of copper produced in the reaction of iron and copper (II) chloride, determine the number of moles of iron used up in the reaction of iron and copper (II) chloride, determine the ratio of moles of iron to moles of copper, and determine the number of atoms and formula units involved in

Explain the visual process, including the stimulus input, the structure of the eye, and the transduction of light energy.

After being shown a picture of an elephant they eye will take the light that is reflected from the object and it will enter the eye through the pupil. Then the light will be focused by the cornea and the lens to form a sharp image of the elephant in the retina. The retina is the network of neurons that cover the back of the eye and contains the visual receptors for a person vision. The visual receptors are made up of cones and rods that contain light sensitive chemicals called visual pigments. Visual pigments reacht to light and cause a triggered electrical signals to occur. These electrical signals will then flow through a network of neurons and this network of neurons is what makes up a persons retina. After the flow through the network of neurons occurs the electrical signals will emerge from the back of the eye in the area

The purpose of this lab was to identify unknown bacteria cultures using various differential tests, and my unknown bacteria is #17. The identification of these unknown cultures was accomplished by separating and differentiating possible bacteria based on specific biochemical characteristics. Whether the tests performed identified specific enzymatic reactions or metabolic pathways, each was used in a way to help recognize those specifics and identify the unknown cultures. The differential tests used to identify the unknown cultures were Gram stain, Catalase, Mannitol Salt Agar (MSA), Blood Agar, Novobiocin, Coagulase, and DNAse (Alachi, 2007).

When it comes to vision, we see things based on the light reflected from surfaces. The reflected light waves enter the eye through the cornea at the front of the eye, it's resized at the pupil, focused by the lens, and hits the retina at the back. The light is then detected by rods and cones, photoreceptors, which alters the light into electrical signals. The optic nerve transmits those vision signals to the lateral geniculate nucleus, where visual information is transmitted to the visual cortex of the brain then converts into the objects that we see.

To understand the diverse causes of RP, a basic understanding of visual perception is required. Phototransduction (conversion of light to electrical signals) occurs first, which is initiated by two types of photoreceptors: rods and cones. These two types vary in their function as rods are primarily responsible for night vision and lack sensitivity to color while cones function in color vision. Light contacts these photoreceptors, and isomerizes a retinaldehydechromophore (retinal) which is bound to varying types of opsin proteins corresponding in their reactivity to different wavelengths of light. Upon absorption of a photon of light, the chromophore 11-cis-retinal is isomerized to the all-trans confirmation, which subsequently causes a series of molecular interactions which ultimately result in the electrical response of the photoreceptors (Vugler 2010). As 11-cis-retinal is required to absorb photons of light, this compound must be regenerated, a function that is performed with the aid of nearby cells of the retinal pigment epithelium

The experiment used the same red and green stimuli in each trial instead of other opponent colors such as black and white or blue and yellow. The small sample size studied could have also lead to random variation in the results.

If an Infrared Light with a wavelength of 750 nm were to be observed by humans, they would not be able to because none of their cone cells are sensitive to this wavelength of light, in a similar manner that the blue cone cells weren’t sensitive to the 600 nm wavelength of light. It is only possible for the human brain to view lights that are absorbed by their photoreceptor cells.

In the first article, Knight, Mazzi and Savazzi (2015) made 3 hypotheses. The first hypothesis was that the Transcranial Magnetic Stimulation (TMS) threshold would change when the background changed from uniform to pattern (Knight et al., 2015). The second hypothesis was that the likelihood of the participant sensing light versus dark percepts would change when global luminance of the background changed (Knight et al., 2015). The third hypothesis was that the likelihood of light versus dark percepts would stay the same at different TMS intensities (Knight et al., 2015). The study had 16 participants who all wore corrective lens (Knight et al., 2015). To test the threshold of phosophenes, a Method of Constant Stimuli (MOCS) was used (Knight et al., 2015). The participants received 120 randomly administered trials with pulses from TMS under two different background conditions (Knight et al., 2015). A paired t-test was used to analyze the difference in stimulator intensity threshold for inducing percepts between background conditions (Knight et al., 2015). A repeated-measures analysis of variance

According to O’Brien, Isayama, Richardson, & Berson (2002), the ganglion cells also consist of over a dozen different subtypes of cells and the functionality of these subtypes rely greatly on the individual responses that are stimulated by light entering into the retinal synaptic network. Early studies on ganglion cells in a cat’s retina showed that there were three physiological responses reported in the cat’s ganglion cells and that these cells had both a central and peripheral district within the retina. It was noted that both of these areas produce opposite effects upon activity of the ganglion cells (Enroth-Cugell, Goldstick, & Linsenmeier.

Two experiments were conducted to examined the movement of the planarians toward different light intensities. There are four light intensities, including ambient, high (19 cm), medium (29 cm), and low (43 cm). The hypothesis of the two experiment is that as the light intensity increases, the planarians’ speed increases as well. Generally, planarian brain perceives information from multiple external signals that receive from sensory neurons. The brain will then integrate the information and produce appropriate behaviors in response, such as thermotaxis, phototaxis, or chemotaxis (Inoue, 2015). When planarians were exposed to the ambient light, the brain sent out phototaxis. When the motor neurons received the signal, the planarians would gradually move to different place with dimmer lighting. However, when the intensity of light suddenly changed from ambient lighting to high intensity (19 cm), the planarians immediately changed the behavior and moved much faster which moving from 44.96 sec to 28.04 sec (Table 3) to go from one end to another end. This data indicates that planarian brain send out the same behavior but stronger signals which caused the planarian to move faster. In this case, the neural nervous system received the strong signals from the sensory neuron which generated the strong intensity in graded potential and high frequency in action potential (Campbell, 2010, 1097). The

They contain different pigmented photoreceptor proteins. Rod cells contain the protein rhodopsin and cone cells contain different proteins for each color-range. The process through which these proteins go is quite similar but electromagnetic radiation of a particular wavelength and intensity. The protein breaks down into two constituent products. Rhodopsin, of rods, breaks down into opsin and retinal; iodopsin of cones breaks down into photopsin and retinal. The breakdown results in the activation of Transducin. This activates cyclic GMP Phosphodiesterase, which lowers the number of open cyclic nucleotide-gated ion channels on the cell membrane, which leads to hyper polarization. This hyper polarization of the cell leads to decreased release of transmitter molecules at the

Vertebrate melanopsin phototransduction shares similarities with invertebrate-type opsin, which responds to light via activating a Gq protein (Gq)/ phospholipase C (PLC) signaling cascade5. Previous studies demonstrated a solar ultraviolet radiation (UVR)-sensitive phototransduction pathway in human epidermal melanocytes6,7,8,9. Specifically, UVR triggered a Gαq/11/PLCβ signaling pathway, which led to phosphatidylinositol (4,5)-bisphosphate (PIP2) hydrolysis to create diacylglycerol (DAG) and inositol 1, 4, 5-trisphosphate (IP3), and thus activated the transient receptor potential ankyrin 1 (TRPA1). The influx of Ca2+ and Na2+ depolarized the cell9. The recent discovered light-sensitive DRG neurons also innervate the skin and exhibit non-image-forming light responses. It’s likely that opsin X has a downstream signal cascade similar to the pathway characterized in opsin of human epidermal melanocytes and in non-image-forming melanopsin in retinal ganglion cells. Therefore, the current study is to characterize the G-protein pathway that is responsible for light transduction as well as to determine whether the light-sensitive DRG shares a similar pathway as human epidermal melanocytes. This project will test the central hypothesis that light stimulation activates the Gα /PLC signaling pathway, and then opens the TRP channel as well as depolarizes the cell.