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
Examine the different kinds of prejudice and injustice which you have found in 'To Kill a Mockingbird'. How does Harper Lee convey these to the reader?
Examine the different kinds of prejudice and injustice which you have found in 'To Kill a Mockingbird'. How does Harper Lee convey these to the reader? 'To Kill a Mockingbird' was written by Harper Lee in 1960. Nelle Harper Lee was born on April 28, 1926 in Monroeville, Alabama, a city of about 7,000 people. She studied law at the University of Alabama and one year at Oxford University. After giving up working as a clerk for an airline she moved into a cold-water apartment in New York to concentrate on writing. She first handed this book to a publisher in 1957 but it was rejected so she took two further years to rework it before it was published as 'To Kill a Mockingbird' in 1960. The book tells a story very similar to Lee's own childhood. The town in which it is set is a small southern town just like her own with the characters matching friends and associates from her youth. It is set in the thirties and is a highly significant statement and important to that era. It was written at the time of the civil rights movement, which guaranteed basic civil rights for all Americans, regardless of race. 'To Kill a Mockingbird' was set thirty years before Lee wrote it, meaning she could use hindsight to give the story authenticity. Lee helped move the civil rights movement forward by reminding the population of the prejudice they had and showing them that something had to be done.
Fighter Pilot A Statistical Analysis of Reaction time and its Correlation with Dominant & Non-Dominant Hands
Fighter Pilot A Statistical Analysis of Reaction time and its Correlation with Dominant & Non-Dominant Hands Introduction This experiment seeks to determine reaction times in two groups of matched subjects; dominant and non-dominant hands, using the ruler drop test. Reaction time experiments are performed to measure the alertness of the mind and will give an indication of the speed of the reflexes that different groups of varied individuals have. The experiment tests how long it takes the brain to translate visual information into the voluntary motor commands, actions which lead to a ruler being grabbed. The shorter the length at which the ruler is grabbed, the shorter time and therefore the faster the person's reaction. The controls of these processes within the human body are the responsibility of the nervous system which is the seat of voluntary and involuntary movements along with language, emotion and memory. (1) The experiment begins with an environmental stimulus via light reflected from a moving ruler being dropped from a height above the subject's hand. (1) This transmits into a sensory nervous impulse within the optic nerve. Beginning in the retina of the eye, information is detected by photoreceptors (rods and cones) they relay the visual signals on to bipolar cells which transmit on to ganglion cells. (2) The axons of all ganglion cells in the retina of each
An investigation into the inhibiting effect of tomato juice on the germination of cress seeds.
An investigation into the inhibiting effect of tomato juice on the germination of cress seeds Introduction I intend to analyse the inhibiting effect of tomato juice on the germination of tomato juice. In this introduction I will answer important questions such as; what are inhibitors? How might inhibitors affect germination? , etc. When answering the questions, I will be considering different areas of the syllabus (e.g. genetics, inter-specific competition, enzymes and inhibitors, practical skills, etc.) This will help me appreciate the theory behind the investigation and hence help me formulate an effective plan and method. Inhibitors are chemicals, which inhibit the action of an enzyme. There are two main types of inhibitors: reversible and non-reversible. Non-reversible inhibitors permanently damage enzymes. They attach themselves to the enzyme molecule and cause important bonds to break, causing irreparable damage. This denatures the enzyme and does not allow it to function. Diagram showing non-reversible inhibition: Normal arrangement Change caused by non-reversible inhibitor Reversible inhibitors inhibit the action of enzymes but do not do permanent damage. Once the reversible inhibitor is removed; the enzyme will return to normal. Reversible inhibitors can be divided into two types:
An experiment to investigate how the effect of varying concentrations of salt solutions play on the movement of water in a potato.
PRELIMINARY EXPERIMENT AN EXPERIMENT TO INVESTIGATE HOW THE EFFECT OF VARYING CONCENTRATIONS OF SALT SOLUTIONS PLAY ON THE MOVEMENT OF WATER IN A POTATO. AIM The aim of this experiment is to try and find out how different concentrations of salt solutions affect the osmotic activity in a potato tissue. Thus we will be able to find out if the mass of the potato has increased or decreased in the different concentrations of salt solution. APPARATUS > A Single Fresh Potato > McCarthy Bottles = x 5 > Corks = x 5 > Water = 20cm3 x 5 > 2 Molar Salt Solution = 150cm3 > Test Tube Rack to hold 5 test tubes > Pipette > Scalpel - To cut the potato tubes into cylinders > Weight Measuring Scales > Ruler - To measure the potato cylinders accurately to 2cm long. > Cork Borer > Cutting Board - Where the potato can be placed and cut safely > Marker Pen will be used to write on the test tubes so that I will be able to distinguish between the potato cylinders and determine which salt solution is in which test tube. DETAILED INFO ON HOW TO PREPARE THE SOLUTIONS REQUIRED Just like my final experiment, in this preliminary experiment I increased the concentration in my five bottles by 0.5 moles, until it reaches 2 molar. mole in 1 litre requires 58.5g of salt to be dissolved in it. Therefore as 1 litre is 1000 cm3, I was thus able to take these into account and do my
The Effect Of Temperature on the Respiration Of Yeast.
The Effect Of Temperature on the Respiration Of Yeast Introduction: - I am going to find out how temperature effects the respitory action of yeast. I am going to do this by using six different temperatures, 25oC, 30oC, 35oC, 40oC, 45oC and 50oC and a solution called TTC which is absorbed by the yeast cells turning them pink when hydrogen is removed from the metabolic pathway by the dehydrogenase enzyme. Background Information: - Yeast: - Yeast is unicellular fungus that buds profusely under favourable conditions. They are classified as sac-fungi (Ascomyctes) even though they are unicellular. Yeast is common in areas where there is sugar because of this they are given the name saccharomyces (Sugar fungi). They grow on the surface of fruits, in the nectar of flowers, in sap excluded from trees, in the soil and in fresh water. Yeasts are used in all sorts of arrears such as alcoholic fermentation (fermentation is the name given only to the anaerobic respiration of yeast) to baking bread. Yeasts are of a great economic importance and are yeast for biochemical research for example in respiration and enzymes. Yeast exists as Diploid or Haploid cells and divides by mitosis and meiosis. Yeasts are not plant or animal because they do not photosynthesise and they do not have any chloroplast. Yeast is a saprophyte. This is an organism, which obtains its nutrients from dead or
'An investigation into the ability of two strains of the yeast Saccharomyces cerevisiae to utilise different carbon sources as substrates for cellular respiration'.
'An investigation into the ability of two strains of the yeast Saccharomyces cerevisiae to utilise different carbon sources as substrates for cellular respiration' Introduction The purpose of this investigation is to compare the ability of two different strains of yeast to respire, when using different sugars as respiration substrates. Considering the lengths that have been reached to develop varieties of yeast with greater suitability and effectiveness for very particular fermentation purposes, it seems reasonable to suppose that two different strains of the same species of yeast, selected for their different fermentation properties, have developed requirements that are not uniform. As a result of the selection and development process, yeast best suited to ferment in a given application, possess a range of different characteristics. One such characteristic may be the ability to metabolise different carbon sources at different rates. This quality is important because in each application where different respiration substrates are available, a specific strain of yeast may be required. Yeast unable to utilise the available carbon sources will have undesirable fermentation rates, and therefore may not be selected for use in that application. The two yeast here compared, have two such different applications. The first yeast from the Saccharomyces cerevisiae variety is of the
Enzymes - investigate how the substrate concentration (H2O2) affects the activity of catalase on hydrogen peroxide.
Enzymes Aim To investigate how the substrate concentration (H2O2) affects the activity of catalase on hydrogen peroxide. Introduction Enzymes are protein molecules, which can be defined as biological catalysts. A catalyst is a molecule that speeds up a chemical reaction, but remains unchanged at the end of the reaction. An enzyme catalyses virtually every metabolic reaction, which takes place within a living organism. Enzymes have a globular protein structure. The enzyme molecules are coiled into a precise three-dimensional shape, with hydrophillic R groups (side chains) on the outside of the molecule ensuring that they are soluble. Enzyme molecules also have an active site, which is usually a cleft of depression, to which another molecule or molecules can bind. This molecule is the substrate of the enzyme. The shape of the active site allows the substrate to fit perfectly, and to be held in place by temporary bonds, which form between the substrate and some of the R groups of the enzyme's amino acids. The combined structure is termed the enzyme-substrate complex. Each type of enzyme will usually act on only one type of substrate molecule. This is because the shape of the active site will only allow one shape of molecule to fit. The enzyme is said to be specific for this substrate. The enzyme may catalyse one of two types of reactions. One in which the substrate
Exploring the concept of genre - The Others.
Jenna Wright DJA3 Exploring the concept of genre - The Others. 'Stated simply, genre movies are those commercial feature films that, through repetition and variation, tell familiar stories with familiar characters in familiar situations. They also encourage expectations and experiences similar to those of familiar films we have already seen' (Barry Keith Grant, 1995) That is the fundamental theorem of the majority of genre studies. The audience's expectations are met within genre films due to familiar elements being fused together, enhanced and manipulated to create something new and different. Despite 'genre' being the correct term for classifying a certain film it is primarily used by film critics, historians and theorists, generally audiences don't tend to refer to this word, instead they are just aware that they are drawn to specific types of films. It is useful to group films into categories of genre, which is defined as a style of art or literature, as there are so many released into the UK every year. This then allows there to be contrasts and comparisons extracted from films that are within the same group. Or, on the other hand, it is made possible to analyse a film when compared to different groups, this has a fair few benefits, one being that attempting to decide the criteria for grouping films encourages us to study them closely. When referring to 'The
Osmosis. Aim: To find the molarity of potato tubers cell sap. BIOLOGICAL KNOWLEDGE
TABLE OF CONTENTS Biological Knowledge ... 3 Explanation ... 3 Types of solutions and its effects on plant cell ... 4 Factors affecting rates of osmosis ... 6 Outline Method ... 9 Apparatus ... 9 Materials ... 9 Risk Assessments ... 9 Precautions ... 9 Apparatus Diagrams ... 10 Factors to be controlled ... 11 Method ... 11 Calculations to be used ... 12 Predicted Results ... 12 Prior Test ... 13 Obtaining Evidence ... 16 Apparatus ... 16 Materials ... 16 Risk Assessments ... 16 Precautions ... 16 Method ... 17 Results obtained for Mass ... 18 Results obtained for Length ... 19 Analysis ... 21 Trends in the Bar charts ... 25 Scientific Explanation ... 25 Determination of molarity ... 28 How far I have reached my predicted results ... 30 Evaluation ... 32 Errors ... 32 Accuracy and reliability of my results ... 32 Extension work ... 33 Bibliography ... 33 INTRODUCTION Biology Coursework Aim: To find the molarity of potato tuber's cell sap. BIOLOGICAL KNOWLEDGE Osmosis is the diffusion of fluid through a semi-permeable membrane from a solution with a low solute concentration to a solution with a higher solute
