"An investigation into the Respiration of Carbohydrate Substrates by Yeast."
AS Biology Coursework 2004. Lucy Nuttney "An investigation into the Respiration of Carbohydrate Substrates by Yeast." Abstract. The investigation considered the reactivity of respiration of three different carbohydrate substrates; glucose, sucrose and starch, by two different sub-species of saccharomyces cerevisiae yeast. The rate of reaction was measured by collecting volumes of gas in a displacement reaction at standardised conditions e.g. time, temperature, pressure, volume of yeast/ sugar. Results showed that glucose produced the most carbon dioxide, followed by sucrose then starch, the biggest difference being between sucrose and starch. Baker's yeast had a slightly higher average than brewer's yeast but it was not considered to be a significant difference and therefore could have been due to chance. It was concluded that both yeasts respire glucose and sucrose at insignificantly different rates but the difference between starch is much larger and therefore much more significant. Pilot Experiment. Before we could test which carbohydrate and type of yeast produced more carbon dioxide, we had to standardise the other variables of this experiment; temperature and concentration. Therefore, in order to find the optimum conditions we carried out a pilot experiment. In this experiment we used a range of temperatures from 10° to 60°C and
An investigation into the abundance of fresh water black fly larvae, Simuliidae, between pools and riffles in Woodford meanders on the 19th September 2003.
An investigation into the abundance of fresh water black fly larvae, Simuliidae, between pools and riffles in Woodford meanders on the 19th September 2003. Abstract:- My investigation was to see where the black fly larvae, Simuliidae, preferred to inhabit, slower moving pools or fast moving riffles. I accomplished my results on the 19/09/03 at Woodford meanders using a "stone shake" sampling method. The results were conducted on the same day and within 3 hours from the first to the last. Readings of temperature, width, depth and impellor travel time were taken at each sample point. I plotted a graph of, pools or riffles against number of black fly larvae, Simuliidae. To analyse my results I used a Mann Whitney U significance test which showed with a 5% significance that the black fly larvae, Simuliidae, preferred the faster moving riffles or the slow moving pools. Introduction:- I accomplished my investigation at Woodford meanders (Grid reference - Sr06370638) on the 19th of September 2003. I chose to investigate the abundance of the black fly larvae, Simuliidae, whether they are in higher concentration in the slow moving pools or the fast moving riffles. I chose a freshwater dwelling species because there was a stream, Woodford meanders near to the base camp, Nettlecombe court, where we were staying, therefore it was more accessible, there was no time limit and in case of
Human Reproductive System
The Human Reproductive System Structures of the male reproductive system Bulb of penis The bulb of penis is the expanded posterior part of the corpus spongiosum of the penis. It lies in the interval between the crura of the penis. It contains slightly dilated and angulated portion of the urethra. Bulbourethral (Cowper's) gland The bulbourethral gland is pea-sized structures located on the sides of the urethra below the prostate gland. It produces a clear, slippery fluid that empties directly into the urethra. These fluids lubricate the urethra and neutralises any acidity that may be present due to residual drops of urine in the urethra. Corona The corona is a rounded projecting border that forms the circumference of the base of the glans. It is located behind the penis and overhangs a deep retroglancular sulcus Corpora cavernosum penis The corpus cavernosum penis is one of the pair of sponge-like regions of erectile tissue in the penis. It contains irregular spaces which are filled with blood during erection. These spaces are lined by endothelium and separated by connective tissue septa. Corpus spongiosum penis The corpus spongiosum penis is the median column of erectile tissue located between and ventral to the two corpora cavernosa penis. Posteriorly It expands into the bulb of penis and terminates as enlarged glans penis anteriorly. Ductus (vas) deferens The
Enthalpy of Neutralisation.
TITLE: Enthalpy of Neutralisation. AIM AND HYPOTHESIS: My aim in this experiment is to compare the enthalpy change of neutralisation by titration, for each reaction between the following 3 acids: Sodium hydroxide (NaOH) and hydrochloric acid (HCl) - pH 1 Sulphuric acid (H2SO4) and NaOH - pH 1 NaOH and Ethanoic acid (CH3COOH) - pH 2.88 - 3 I predict the reaction between the above-mentioned acids would be exothermic because heat will be given off during the reactions and the temperatures will be rising due to the heat evolved. I also predict the reaction between the chemicals is exothermic because the energy content of the products is less than that of the reactants, resulting to heat being given out from the system. These predictions show that the stronger the acid used in neutralization, the more energy is released per mole of water. I will be able to compare these predicted energy changes with my actual results after my experiment. When I have my results- the temperature change from beginning to end of the experiment - I can use the equation Energy change = mass of solution x temperature change x specific heat capacity of water to work out the actual energy change. In neutralization, we assume that the density of the acid/alkali is the same as that of water, so volume of acid = mass of acid. We know that the specific heat capacity of water is always 4.2 Jk - 1 g
AN INVESTIGATION OF THE DIFFERENT SPECIES OF MAYFLY WITHIN THE POOL & RIFFLE
AN INVESTIGATION OF THE DIFFERENT SPECIES OF MAYFLY WITHIN THE POOL & RIFFLE AIM: I am going to investigate the different species of Mayfly within the pool and riffle. I am going to create tables to show results from my investigation. I am also going to draw graphs to show the distribution of Mayfly Nymphs within the pools & riffles. NULL HYPOTHESIS: There is no significant difference in numbers of Mayfly Nymphs found within the riffles and pools. ALTERNATE HYPOTHESIS: There is a significant difference in numbers of Mayfly Nymphs found in the riffles and pools. STREAM: Data was collected from Nant Iago (James Stream) which is situated in St Mary's Vale. It is surrounded by Beech woodland. The source of the stream is the Sugar Loaf Mountain. It also contains peaty soils that are slightly acidic. Many erosive streams receive most of their energy from organic matter washed into the stream, largely as leaf litter. The litter is processed to carbon dioxide by a succession of microrganisms and animals, which deal with successively smaller particles of it in a continuous sequence, as it is moved downstream. This is common where the stream is bordered by gallery forest A flowing freshwater stream is all business. It rushes forward. If it slows at all, it is just to create small whirlpools or eddies and then it's back on down the mountain. It makes its bed on gravel or hard
Contract Law - Offer And Acceptance
Contract Law Offer And Acceptance Contract Unilateral - Bilateral Contract Subjective-Objective Approach To An Agreement Offer Invitation To Treat Counter-offer Revocation Of Offer, Recall of Acceptance Acceptance Postal Rule-Limitation Contract Definition * Is an agreement between two or more parties that is intended to be legally binding (enforceable agreement) * Legally binding agreement needs of offer, acceptance, intention to create legal relations and consideration(difference between social agreement and legal agreement) * Is any promise or set of promises made by one party to another for the breach of which the law provides remedies * The remedies for the breach of contract is an award of monetary compensation, injunction, & specific performance(quantum meruit) Essential Element * The promise or promises may be express (either writing or oral) or may be implied from circumstances * Needs of writing is not essential for contract the Courts of US approved that as long as there is meeting of minds as though there is written, formal, signed contract then contract exists * However, for certain type of contract signed writing contract is needed (Statute of Fraud) * Mass production and nationalisation have led to the standard form contract * Freedom of contract is modified by some acts such as Consumer Credit Act 1974 & Unfair Contract Act
The Gradient Function
The Gradient Function Aim: To find the gradient function of curves of the form y=axn. To begin with, I should investigate how the gradient changes, in relation to the value of x. Following this, I plan to expand my investigation to see how the gradient changes, and as a result how a changes in relation to this. Method: At the very start of the investigation, I shall investigate the gradient at the values of y=xn. To start with, I shall put the results in a table, but later on, as I attempt to find the gradient through advanced methods, a table may be unnecessary. As I plot the values of y=x2, this should allow me to plot a line of best fit and analyze, and otherwise evaluate, the relationship between the gradient and x in this equation. I have begun with n=2. After analyzing this, I shall carry on using a constant value of "a" until further on in the investigation, and keep on increasing n by 1 each time. I shall plot on the graphs the relative x values and determine a gradient between n and the gradients. Perhaps further on in the investigation, I shall modify the value of a, and perhaps make n a fractional or negative power. Method to find the gradient: These methods would perhaps be better if I demonstrated them using an example, so I will illustrate this using y=x2. This is the graph of y=x2. I will find out the gradient of this curve, by using the three methods -
'How is Love Presented in Romeo and Juliet in Acts - 1 Sc 5; 2 Sc 2 and 3 Sc 5.
"Romeo and Juliet" By -William Shakespeare In this essay I will concentrate on the love aspect in one of William Shakespeare's most popular tragedies, written during the 16th century - Romeo and Juliet. This essay will mainly concentrate on three key scenes and these are as follows - Act 1 Sc 5; Act 2 Sc 2 and Act 3 Sc 5. In these scenes I will show how Shakespeare portrays the love aspect in Romeo and Juliet - and in these scenes it is shown in a clear, clever and coherent way. Shakespeare shows this cleverly by the use of stage-craft and dramatic irony to show clear organisation of characters on stage when the play is being acted to a large number of audience. Even the structure in which the scenes are organised can be interpreted,noticed and referred to by the audience as the play graduates. Not only this; the ingenious linguistic features that Shakespeare uses can be used to show tension,timidness, love and even happiness. This essay will give a thorough analysis of the three ways in which Shakespeare portrays the love aspect. Structure, stage-craft, language and some cultural issues that might can show this. During Act 1 Sc 5, in terms of structure, Shakespeare has the audience waiting until this scene to introduce Juliet and the two lovers together. Shakespeare does this in order to inform us, the audience, about the history of both the Montagues and Capulets
effect of temperature on the rate of respiration in yeast
Effect of temperature on the rate of respiration in yeast Aim: My aim is to investigate the effect of temperature on the rate of respiration in yeast by using a universal indicator. Background theory: Enzyme: Enzymes are organic catalysts that speed up the rate of a chemical reaction without being permanently altered in the process. Enzyme Characteristics * Lower the energy of activation * Form reversible complex with substrate. * Not consumed in the reaction therefore they are effect in small amounts * Very specific - (Induced fit hypothesis) react with only a single substrate. * Many need cofactors, such as certain vitamins, to be activated. * 2000+ enzymes per cell, different cells have different enzymes. * Enzymes are produced by genes. * Genetic disorders are the result of faulty enzymes. * Operate best in optimum conditions of pH, temperature, etc. * Are controlled by feedback mechanisms. Enzyme mechanism: Key and theory: The substrates (reactants) are attracted to the enzyme molecule. They join forming an enzyme-substrate complex. The reaction occurs on an area of the enzyme molecule known as the active site producing new substrates(s) or products. Induced fit hypothesis: The attraction of the substrate and enzyme form an enzyme-substrate complex. It was originally referred to as the Lock and Key Enzyme Theory. The current theory
An Investigation into the Effects that Different Light Intensities have on the Speed of Woodlice:
An Investigation into the Effects that Different Light Intensities have on the Speed of Woodlice: Introduction: Woodlice are one of the easiest terrestrial arthropods to obtain in large numbers throughout the year. Porcellio scaber, the most common species is not difficult to identify with the naked eye, and is large enough to be handled without employing special techniques. Their behaviour is relatively simple yet providing perfect examples of kinesis and taxis. i A species, which shows taxis, can orient the direction of their movement with respect to the source of an external stimulus whilst kinesis is a steady-state dependence of the movement velocity on the stimulus intensity.iii Thus it is clear that kinesis will be the important response in my investigation as I am not concerned with the stimulus direction. Woodlice lack a waxy cuticle on their exoskeleton and have a high surface area to volume ratio. This means that they are prone to desiccation. As a result, much of their behaviour is concerned with reducing water loss. Woodlice will therefore tend to congregate in more humid, cooler and darker regions where their water loss will be lower.ii Although light does not affect the physiological state of woodlice in the same way as humidity and temperature, it plays a very important part in woodlice behaviour. Woodlice have a negative photokinesis- they move faster as
