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Factors Affecting Urease Activity | Experiment

Aim: To investigate Urease activity and the effect of two other chemicals which are Lead Nitrate, and Thiourea (CS (NH2)2
Background Information
Urease is an enzyme that catalyzes the hydrolysis of urea as shown below:
CO (NH2)2 H20 CO2 2NH3
Ammonia releases and dissolves in water to form ammonium hydroxide, which is a strong base.
NH3 H20 NH4 OH-
The level of alkali can be then used as a measure of the speed of the reaction. Universal Indicator solution will be used to measure this.
Research question:
What is the effect of lead nitrate and thiourea activity?
Volume of urea, urease, lead nitrate, thiourea, distilled water, Temperature
Time Interval
I predict that at the conclusion of the experiment Thiourea will function as a modest inhibitor. Because it has a similar molecular formula to Urea, the substrate for the enzyme, so then there will not be sufficient substrate created or even there will not be any substrate formed at all for the Thiourea that would prevent the urea from reacting with the urease. Still, with the addition of Lead Nitrate, increasing the concentration will lead to excess substrate. The lead nitrate will then attach to the urea to destroy the active site to counteract any more ammonia from forming.
Materials and apparatus 6 Boiling tubes
Test tube rack
50cm3 beakers
5cm3 syringe
Stop watch
Lead nitrate
pH buffer
Distilled water
Universal indicator
Data logger
Label boiling tubes from 1-6
In the boiling tube labeled 1, add 2cm3 of buffer solution, 5cm3 of Urea and 5cm3 of distilled water.
In the boiling tube labeled 2, add 2cm3 of buffer solution, 5cm3 of Urea, 2.5cm3 Thiourea and 2.5cm3 of distilled water
In the boiling tube labeled 3, add 2cm3 buffer solution, 5cm3 of Urea and 5cm3 of distilled water.
In the boiling tube labeled 4, add 2cm3 buffer solution, 5cm3 of Urea, 2.5cm3 of lead nitrate and 2.5cm3 of distilled
In the boiling tube labeled 5, add 2cm3 of buffer solution, 5cm3 Urea and 5cm3 of lead nitrate.
In the boiling tube labeled 6, add 2cm3 of buffer solution, 5cm3 of Urea and 10cm3 of distilled water
Add 5 drops of the universal pH indicator to each boiling tube
Add 5cm3 to the boiling tubes labeled 1-5 and mix completely
Using the color scale, find the pH changes in the course of the experiment
Record pH changes in each container using the pH probe with the data logger at a 5 minute interval or20 minutes
Mix the content of each boiling tube from time to time
Record all the other relevant observations.
Observations: Before Urease was added pH was 5.3.When Urease was added to the first boiling tube it turned green after 5 minutes with a little fizzling at the top of the solution, also the pH in the first boiling tube increased as the time increased. When urease was added to the 2nd boiling tube it also turned green with after 5 minutes with no fizzling at the top of the top of the solution. As time increased so did the pH in the second boiling tube. When urease was added to the 3rd boiling tube it turned green within 5 minutes and also as the time increased with the urease inside the boiling tube its pH also increased with a little fizzling at the top of the solution. When urease was added to the 4th boiling tube it turned peachy orange and also as the urease was being check for its pH it decrease as the time was increased with a lot of fizzling in the boiling tube. When urease was added to the 5th boiling tube
Explanation: A strong base was formed when urease was added to solution 1 and 2, for the urease catalyzed the reaction of urea and water whiles the buffer offered an acidic channel in order to get the reaction to respond. In solution 1 the urea and the distilled water has provided ammonia with the aid of the urease enzyme. In solution 1 and 2 we see that the solution becomes stronger as the time increases but solution 1 became stronger as the time was increased to 20 minutes this shows that the addition of thiourea brought the pH of the base produced a little and not too much so then the activity of the urease was not in anyway affected by thiourea because the urease still catalyzed the reaction of urea and distilled water. Solution 3 started out as a strong acid, the pH of solution 3 rose above solution 1 and 2 due to the presence of distilled water, which made the urease react properly with urea and the ammonia, which dissolved in water to produce a strong base. Solution 4 started out as a weak acid but the addition of urease neutralized it, the pH of 3 did not rise as much as 1 and 2 due to the absence of the distilled water in order for the urease to properly react with the urea and the ammonia to dissolve in the water and produce a strong base. The product of the reaction was also not able to properly stabilize to become a strong base due to the absence of water. Unlike the thiourea, lead nitrate had a major effect on the activity of urease, although 4th and 5th test turned peachy, they have different pH. The 6th test, which was the control, the 5th test was lower than it.
EVALUATION I contemplate that, overall the experiment was fair. There might have been some measurement errors but it wasn’t that serious in order to make the experinment erroneous and unrealiable.

Processes of Spermatogenesis

The testes that is responsible for producing the male gametes and carries the sequence of processes in the seminiferous tubulus is known as Spermatogenesis. Such process commence during puberty, at and around of 14 years of age in males and stage a continuous process throughout a person’s life. The production of sperm in a healthy male is found in researches to be 400 million sperms. Spermatogenesis takes 64 days for development from a spermatogonium to a mature sperm. At any given time, different seminiferous tubules are in different stages, so that up to several hundred million sperm may reach maturity daily. Spermatogenesis encompasses three major stages; mitotic proliferation, meiosis and packaging.
Two gonadotropic hormones are controlled by the testes in a male which is secreted by the anterior pituitary, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), the same cell type is responsible for the production which is gonadotrope. The luteinizing hormone and follicle-stimulating hormone tend to act as separate elements of the testes. The luteinizing hormone displays on the Leydig cells to generate testosterone secretion. While on the other hand, follicle-stimulating hormone displays on the sertoli cells to improve the vitality of the spermatogenesis. Secretion of the luteinizing hormone and follicle-stimulating hormone from the anterior pituitary is stimulated in turn by a single hypothalamic hormone, gonadotropin-releasing hormone (GnRH). However, FSH and LH are segregated to a large extent into separate secretory vesicles in the gonadotrope and are not secreted equal amounts because other regulatory factors influence how much of each gonatropin is secreted. Testosterone, the creation and triggering of luteinizing hormone of the leydig cells, behave in a negative manner to interfere with the secretion of the luteinizing hormone in dual ways. The most important negative effect of testosterone is to reduce GnRH to be released by an act on the hypothalamus. This will result in an indirect reduction in both luteinizing hormone and follicle-stimulating hormone to be released by the anterior pituitary to selectively reduce LH secretion. The latter action explains why the exertion from the testosterone has greater impact on luteinizing hormone rather than the follicle-stimulating hormone.
The hypothalamus releases GnRH, which dominates the letting off of the anterior pituitary gonadotropins, the follicle-stimulating hormone and luteinizing hormone. The GnRH reaches the anterior pituitary cells via the blood of the hypophyseal portal system. Binding of GnRH to pituitary cells (gonadotrophs) prompts both to secrete follicle-stimulation hormone and luteinizing into the bloodstream. The follicle-stimulation hormone trigger spermatogenesis consequentially by triggering the sustentacular cells to let off androgen-binding protein (ABP). ABP stimulates the spermatogenic cells to hold together and focus on testosterone, which will then trigger spermatogenesis. The reaction of follicle-stimulating hormone then makes the cells responsive to testosterone’s trigger the effects. The luteinizing hormone hold together the interstitial cells and triggers them to release testosterone. LH is therefore sometimes is known as interstitial cell-stimulating hormone (ICSH) in males. Locally testosterone benefits as the end stimulant for spermatogenesis. Testosterone flows into the blood stream that exerts a number of effects at other body sites. Both hypothalamus and the anterior pituitary are subject to feedback inhibition to blood borne hormones. Testosterone slow down the process of hypothalamic release of GnRH thus acts instantly on the anterior pituitary to slow down gonadotropin release. A protein hormone called Inhibin, which is made by the sustentacular cells, carry out as a barometer of the normalcy of spermatogenesis. Inhibin release will increase tremendously when the sperm count is high, and it slow down anterior pituitary secretion of Follicle-stimulating hormone and GnRH secretion by the hypothalamus. When the sperm rate falls 20 million/ml and below, the inhibin releases declines steeply.
Mass production of testosterone and sperm by the testes shows a balance reaction of the three hormones which are GnRH, gonadotropins and inhibin. GnRH, triggers the testes through the follicle-stimulating hormone and the interstitial cell-stimulating hormone. Secondly, the gonadotropins, which instantly stimulates the testes while the testicular hormones which is (testosterone and inhibin), shows opposing command on the hypothalamus and anterior pituitary.
In the absence of GnRH and gonadotropins, the testes atrophy, and for all practical purposes, sperm and testosterone production ceases. As more GnRH is released, more testosterone is secreted by the testes, but the threshold for hypothalamic inhibition keeps rising until the adult pattern of hormone interaction is achieved. Maturation of the brain-testicular axis takes about three years, and once established, the balance between the interacting hormones remains relatively constant.
The testicular inhibitory signal specifically directed at controlling FSH secretion is the peptide hormone inhibin, which is secreted by the Sertoli cells. Inhibin behave instantly on the anterior pituitary do cautiously inhibit follicle-stimulating hormone release. Thus the understanding is inhibition of the follicle-stimulating hormone by a sertoli cell product is appropriate, because FSH stimulates spermatogenesis by acting on the sertoli cells.
Testosterone, secreted by Leydigcells under LH stimulation, acts as a paracrine regulator by stimulating spermatogenesis in the adult human testis. FSH is not absolutely required for spermatogenesis, as demonstrated by men who have mutated and nonfunctional FSH receptors. LH-stimulated testosterone secretion promotes spermatogenesis, whereas FSH only enhances this effect. The FSH receptors are located in the Sertoli cells, and the follicle-stimulating hormone triggers Sertoli cells which process androgen-binding protein and inhibin. Newborn male has only about 10% of his adult number of Sertoli cells, and this increases to the adult number as the boy enters puberty. It appears that FSH, acting together with testosterone, promotes this proliferation of Sertoli cells. Without FSH, spermatogenesis would still occur but would begin later in puberty. FSH is required for maximal sperm production, and so it may be required for optimal fertility.
Follicle-stimulating hormone and testosterone performed a very important task in managing spermatogenesis, both play its own effect by acting on the Sertoli cells. The germ cells of mitosis and meiosis are very important for Testosterone, while follicle-stimulating hormone is required for spermatid remaking. The Leydig cells which is produced locally is withheld in the intra tubular fluid complex added with androgen-binding protein which will be secreted by the Sertoli cells, created a much higher testosterone concentration in the testes than in the blood stream. The sperm production is sustainable through high concentration of testicular testosterone.