How caffeine affects daphnia heartrate
Aim: How caffeine affects the heart rate of Daphnia (water fleas) During this experiment we were examining the effects of different concentrations of caffeine on a type of water fleas called daphnia; the heart-rate is the dependant variable and the concentration of the caffeine is the independent variable. We tried to keep all of the other variables constant by controlling them. Such as the room temperature; the volume of caffeine; the type of water fleas ect. Our hypothesis is that as the caffeine increases so will the heat rate of the daphnia. This is because caffeine is a stimulant that increases the amount of neurotransmitters being released and therefore the production of the heart. Equipment: * A culture of Daphnia in a beaker of water * A microscope- with two cavity slides * Two dropping pipettes- one with a large mouth and one with a small opening * Cooled Distilled water * Cotton wool * Paper towels * A stop clock Method: . We picked out a couple of daphnia from the culture in the beaker with the pipette that has a big mouth. 2. Then, we got rid of the excess water, by squeezing the pipette to get rid of the extra water onto a paper towel. 3. Then, one of the daphnia was placed onto the small bit of wool which was on the cavity slide. 4. After that, we placed a small amount of cooled distilled water onto the second cavity slide before putting that
The Carbon Cycle
The Carbon Cycle The Carbon Cycle is a complex series of processes through which all of the carbon in existence rotates. Carbon is an essential element which is used in life process like photosynthesises which occurs in daytime in the presence of sunlight and carbon in the gaseous form of carbon dioxide. All green plants are known as producers because they can produce their own food via the process of photosynthesis. The green plant is always the start of any food chain and is consumed by the primary consumer. Photosynthesis occurs in the green part of a plant, usually the leaf as chlorophyll is present here, were the carbon dioxide is absorbed from the atmosphere through the stomata which are pores caused by guard cell and is stored in the spongy mesophyll layer of the plant were it used alongside light and the green pigment chlorophyll which produces glucose, water and oxygen as the products of the process. The glucose is used by the plant as a food source and the water is mainly lost via transpiration to the atmosphere and oxygen is secreted by the processes of simple diffusion. Plants are autotrophic as they produce their own food. As explained above carbon dioxide is absorbed from the atmosphere into the plant for photosynthesis. Another life process which occurs in animals all the time but in plants only in night time in the absence of sun light is Respiration.
Biological Importance of Water
Biological Importance of Water: Water is a truly incredible molecule, biological life as we know it evolved from the water. It is the main constituent of all organisms and we humans are made up of around 70% of it. In order to understand why the water molecule is so important, we have to examine its structure. The Structure: A molecule of water consists of two hydrogen and one oxygen atoms (see diagram left). The atoms are joined covalently and the water molecule formed is very stable. Water is a polar molecule, and since it has two charges it is dipolar which means that it has negative ends (Oxygen) and positive ends (Hydrogen) as shown in the diagram. This dipolar quality gives an electrostatic, albeit weak, force and allows adjacent molecules to bond together resulting in water having a high boiling point. Water as a Solvent: Water is an exceptional solvent in particular when dissolving salts, simple alcohols and sugars all otherwise known as polar substances. For example an ionic salt such as potassium chloride would dissolve because the charged particles (ions) will dissociate within the water. The positive ions attract to the negative oxygen atom and the negative ions to the positive hydrogen. Substances that are non polar however, for example lipids, do not mix with water and consequently can be easily separated from aqueous solutions. For example, when droplets
Summarising the differences between deciduous and coniferous woodland.
Ecology Report: Summarising the differences between deciduous and coniferous woodland. This report will attempt to explain some differences in energy flow and nutrient cycles between two types of woodland: deciduous and coniferous, using secondary data, and primary data collected during fieldwork. I predict that a greater amount of energy passes through a deciduous woodland ecosystem than a coniferous one. I think that as leaves fall from deciduous trees, primary consumers use them to create energy. At these times the canopy disappears and more sunlight reaches lower levels, also creating more energy. These factors mean more all-round energy, more animals and a more 'alive' ecosystem. The world's coniferous woodlands are generally in colder areas that receive less sunlight, and the permanent canopy prevents sunlight from reaching lower levels. The fieldwork site, Constitution Hill Viewpoint, is set on a hill in a residential area in Poole. It is mixed woodland, containing small areas of deciduous and coniferous woodland. Conifers at the site are mainly Scots Pine, whilst Oak is the dominant broad-leaved deciduous tree. Being mixed woodland, our samples might not show clearly contrasting results because of an overlap of the woodland, but samples were taken from as clearly defined areas as the site would allow. We used quadrats, and sampled each of the areas randomly. This
The effect of light on plant activities
The effect of light on plant activities In this essay I will look at the different effects that light has on plant activities, in particular the effect it has on the flowering of plants. I will discuss the role of phytochrome in plants and how the two different types are dependant on the length of day. Light affects plant activities in various ways, but in order for these activities to take place, the plant must first have a method of absorbing and then utilizing the light - this is where phytochrome comes into play. Phytochrome is a blue-green pigment that is present in very small amounts throughout the plant, particularly at the growing tips. There are two types: phytochrome red (Pr) and phytochrome far-red (Pfr), with phytochrome red absorbing red light and phytochrome far-red absorbing far-red light. Sunlight contains a lot more red light than far-red light. Therefore, during the day, phytochrome exists in the form Pfr. At night it gradually changes back into the Pr form. Phytochrome is involved in a range of plant responses to light, including the germination of seeds, elongation of seedlings, the size, shape and number of leaves, the synthesis of chlorophyll, and the straightening of the epicotyl or hypocotyl hook of dicot seedlings. In particular, many flowering plants use phytochrome to regulate the time of flowering based on the length of day and night (the
The effect of temperature on the survival of yeast cells
Biology Planning Exercise - The effect of temperature on the survival of yeast cells Aim: To investigate the lowest temperature that kills all the yeast cells in a sample of yeast. Scientific Background Enzymes tend to work best at an optimum temperature (the temperature at which the reaction is most rapid) which varies depending on the enzyme and the conditions it requires. The general rule for enzymes is the higher the temperature the faster the reaction. However this is only up until a certain point where the enzyme begins to denature. An enzyme denatures when the temperature is above the optimum temperature for the enzyme and it begins to vibrate violently so all the bonds which make up the tertiary structure of an enzyme break therefore changing the shape of the enzyme making it unable to function. (The enzyme which catalyses this reaction is dehydrogenase) Enzyme performance depends on the active site, an area on the enzyme molecule in which the substrate fits into. This is what makes enzymes very specific as each enzyme only catalyses one reaction. Enzymes are tertiary globular proteins and their structure is held together by different types of bonds the strongest; the disulphide bridge which forms when two sulphur containing cysteine residues react together. Hydrogen bonds are also present in enzyme structure which bind the substrate to the active site and are
An Experiment to Show the Rate of Respiration In a Locust.
An Experiment to Show the Rate of Respiration In a Locust Aim The rate of respiration in an organism can be determined either by measuring the volume of oxygen taken in, or the volume of carbon dioxide produced. The aim of this experiment was to determine the rate of respiration of a locust using an instrument called a respirometer. Method * The respirometer consisted of 2 equal chambers- an experimental one containing the respiring organism, and a control one, containing an equal volume of non-respiring material (in this case a marble). * The 2 chambers were connected by a U-shaped manometer tube that had a diameter of 1mm, containing a coloured fluid (manometer fluid)- this differential respirometer ensured that any fluctuations in temperature or pressure affected both sides of the manometer equally and so they cancel each other out. * An equal volume of some soda lime (a carbon dioxide absorbing material) was added to each chamber. * I then left the apparatus in a water bath filled with water of approximately 32 degrees for about 5 minutes to allow it to reach the desired temperature. * I left screw clips A and B open at these times to allow air to escape as it expands. * I closed both screw clips after 5 minutes, allowing the experiment to start. * The carbon dioxide given off by the respiration of the locust was absorbed by the soda lime, hence a reduction in
Pulse Rate-Lab Report
BIOLOGY INVESTIGATION Research Question: What is the effect of physical exercise on Pulse Rate of the human heart? Hypothesis: As the level of physical exercise increases, the pulse rate will also increase. Females will have a higher pulse rate difference compared to that of males, of the same age group. Variables: Independent Variable: Climbing Stairs, Using the treadmill Dependent Variable: Heart Beat Rate Control Variables: The following factors were controlled, or kept the same in this test: -Room temperature: In the gym: 220C ±0.5, On stairs: 250C ±0.5; measured using Thermometer -Time over which subject was under experiment: 2 minutes ±0.5 -Time of the day: Period 3, 10.45-11.45am -Time over which subject was allowed to rest before pulse was measured: 20 seconds ±0.05, this was measured using a stopwatch -Same equipment used to measure pulse rate in order to have standardized results, that is, pulse rate monitor and stop watch, to the accuracy of ±00.5 -Same method used to measure pulse rate -Time over which pulse rate was measured, after exercising: 1 minute ±0.05 -Speed on treadmill: Level 6, was kept constant throughout -Same person for tests -Time for person to rest between trials: 2 minutes ±0.05 Materials Needed: -Thermometer -Stopwatch -Pulse Rate monitor -Recording Sheet -Stairs -Treadmill Procedure for Controlling Variables:
Renewable and non-renewable energy sources.
Renewable and non-renewable energy sources Energy resources can be described as renewable and non-renewable. Renewable energy sources are those which are continually being replaced such as energy from the sun (solar) and wind. If an energy resource is being used faster than it can be replaced (for example, coal takes millions of years to form) then it will eventually run out. This is called a non-renewable energy source. Renewable energy sources: Solar Power: Solar energy is light and heat energy from the sun. Solar cells convert sunlight into electrical energy. Thermal collectors convert sunlight into heat energy. Solar power is used in watches, calculators, water pumps, space satellites, for heating water, and supplying clean electricity to the power grid. There is enough solar radiation falling on the surface of the earth to provide all of our energy needs. Advantages Disadvantages * There is enough solar radiation falling on the earth to provide for all of our energy needs. * It is a lot cleaner than using fossil fuels and does not harm the environment. * It is good to use for heating water (Solar thermal electric generating plants) * Solar power does not store or travel well. It looses a lot of energy when done so. * At the moment, solar power is more expensive than using fossil fuelled power stations. * Solar power would only be effective in some places in
The Role of the Respiratory and Circulatory Systems in the Provision of Oxygen and the Removal of Carbon Dioxide from the Body
The Role of the Respiratory and Circulatory Systems in the Provision of Oxygen and the Removal of Carbon Dioxide from the Body The purpose of breathing is to supply a continuous supply of fresh oxygen into the body and to remove carbon dioxide. Oxygen is essential for cells to function. Blood acts as the transport mechanism for gases to move between the lungs and tissues by passive diffusion. These gases will diffuse down their pressure gradient from areas of high pressure to areas of lower pressure. Atmospheric air contains approximately 79% nitrogen and 21% oxygen plus negligible amounts of water vapour, carbon dioxide and pollutants (Boyle & Senior, 2008). Air needs to enter and leave the body in a continuous, rhythmic pattern to sustain the body. Cardiac muscles rhythmically contract and relax to empty and refill the heart; respiratory muscles also act in a rhythmic pattern to fill and empty the lungs with air. These two actions are performed involuntary - the heart by means of a pacemaker and the respiratory muscles at a brainstem level. Specialised neurones called dorsal medullary respiratory neurones produce a cycle of activity that occurs every few seconds to establish the basic routine of respiration When air is breathed in, the external intercoastal muscles, of which there are eleven on each side of the body, contract and pull the ribcage upwards and outwards
