The roles water in living organisms and water as a habitat for organisms
The roles water in living organisms and water as a habitat for organisms Introduction Water is the most abundant liquid on the planet. It covers 2/3rds of the earth's surface, and at least 60% of living organisms is water. This value may be as large as 99% - in a jellyfish. The reason for such a large amount of water making up organisms is the fact that it is a major cell constituent - more on that later. Water is a simple molecule yet has many interesting properties which contribute to its importance. Structure The molecule is polar, because the electrons in the bonds between O and H are pulled slightly toward the O. this means that the O atom is slightly negative and the two H atoms are slightly positive (shown by ?+ and ?-). The electrons are shown as small dots; note they are closer to the O. These properties are described more in the solvent section. db. Water is made up of two hydrogen atoms bonded to one oxygen atom. They are covalently bonded and the intramolecular covalent bonds are very strong. The structure is non-linear, due to the electron pair repulsion of the two lone pairs of electrons on the oxygen atom. Major cell constituent Often 2/3rds or more of living cells are water. The water is found mainly in the cytoplasm, and it plays a vital role in many functions of the cell: in all organisms - metabolism, and in plants photosynthesis and support. The
Whether or not the intensity of light would affect the rate of photosynthesis
Biology Coursework Aim The aim of my experiment was to determine whether or not the intensity of light would affect the rate of photosynthesis in a plant. To do this, I placed a piece of Canadian pondweed in varying light intensities, and observed the amount of oxygen being given off. I used Canadian pondweed because of its unusual quality of giving off bubbles of gas from a cut end, when placed in water. Introduction Photosynthesis occurs only in the presence of light, and takes place in the chloroplasts of green plant cells. Photosynthesis can be defined as the production of simple sugars from carbon dioxide and water causing the release of sugar and oxygen. The chemical equation for photosynthesis can be expressed as: (light) 6CO2 + 6H2O À C6H12O6 + 6O2 (in the presence of chlorophyll) The fact that all plants need light in order to photosynthesise has been proven many times in experiments, and so it is possible to say that without light, the plant would die. The reason that light intensity does affect the rate of photosynthesis is because as light, and therefore energy, falls on the chloroplasts in a leaf, it is trapped by the chlorophyll, which then makes the energy available for chemical reactions in the plant. Thus, as the amount of sunlight, or in this case light from a bulb, falls on the plant, more energy is absorbed, so more energy is available for the
The use of fertilisers in farming
The use of fertilisers in farming Fertilisers are the largest item of discretionary expenditure in most arable farm budgets and have been used for centuries to maintain or improve soil fertility. How well the fertiliser pound is spent often has a large impact on farm profitability, which in a modern world is a very important factor. All plants require nutrients to survive, as do animals, so it is only natural that plants gather these nutrients from the ground via the roots, by active transport for movement of mineral ions (e.g. nitrate) against a concentration gradient or by osmosis for movement with the concentration gradient. In a natural environment, with no human intervention plants would usually be eaten by animals, most would die, decompose and return their nutrients to the ground. However, humans break the nutrient recycling chain by removing the entire crop and along with it all the nutrients that the plant had taken up from the soil, leaving it deprived of nutrients, so in order to re-use the same piece of land over and over again and still have an acceptable level of production the nutrients must be replaced. The nutrients are replaced in form of fertilisers. This is why farmers use fertilisers to maintain soil quality and also to supply nutrients that are not present in the soil but may boost crop yield. Natural farmyard manures have long been used as a source
To investigate a factor that affects the rate of photosynthesis.
Aim: To investigate a factor that affects the rate of photosynthesis. A piece of pondweed will be cut and placed into a beaker containing water. A lamp will be shined on to the pondweed and the amount of bubbles released from the plant will be counted. The lamp will be adjusted to different distances from the plant to try and obtain different results. Photosynthesis Equation: 6CO2 + 6H2O light energy & chlorophyll C6H12O6 + 6O2 Variables: Experimental Variable- Light intensity is to be the variable explored in this investigation. Increasing or decreasing the distance from the light source to the plant can vary light intensity. Factors that influence the rate of photosynthesis The rate of photosynthesis is dependent on the following environmental factors: light intensity, temperature, and the availability of carbon dioxide, the water supply, and the availability of certain minerals. A shortage of any one of these factors can limit the rate of photosynthesis, and an increase in the particular rate-limiting factor will, up to a point, speed up the process. The rate also varies with the plant species and its physiological state- for example its health, its maturity and whether or not it is in flower. Fixed Variables- Light Wavelength (color)- Light energy is absorbed by pigments in the leaf such as chlorophyll. Chlorophyll easily absorbs blue light, in the 400-450 nm
To investigate a factor that affects the rate of photosynthesis.
BIOLOGY COURSEWORK- PHOTOSYNTHESIS Aim: To investigate a factor that affects the rate of photosynthesis. Outline: A piece of pondweed will be cut and placed into a beaker containing water and sodium hydrogen carbonate. A lamp will be shined on to the pondweed and the amount of bubbles released from the plant will be counted. The lamp will be adjusted to different distances from the plant to try and obtain different results. Photosynthesis Equation: 6CO2 + 6H2O light energy & chlorophyll C6H12O6 + 6O2 Variables: Experimental Variable- Light intensity is to be the variable explored in this investigation. Increasing or decreasing the distance from the light source to the plant can vary light intensity. Fixed Variables- Light Wavelength (color)- Light energy is absorbed by pigments in the leaf such as chlorophyll. Chlorophyll easily absorbs blue light, in the 400-450 nm range, and also easily absorbs red light in the 650-700 nm range. Chlorophyll does not absorb green light or yellow light effectively but tends to reflect them, decreasing the amount of light absorbed and decreasing the rate of photosynthesis. Why the rate of photosynthesis increases or decreased from the amount of light energy absorbed is what is being investigated in this experiment. The light color can be fixed by using the same lamp throughout the experiment. Carbon Dioxide- CO2 concentration can
To investigate the effect of insulators on the rate of cooling.
AT1 INVESTIGATION By Farah Kazi 10w TITLE: The factors effecting Insulators. . AIM: To investigate the effect of insulators on the rate of cooling. Introduction: I will be investigating the rate of cooing, by using various numbers of layers of insulators round a beaker of hot water. The science which effect my investigation are as follows: Conduction is a transfer of heat energy through a substance from the hotter region to the cooler region without any movement of the substance itself. As the substance is heated, free electrons spread through the substance bumping into other electrons and passing on Kinetic energy. Gradually energy is transferred along the substance. Radiation is the transfer of heat energy through waves. Hot objects emit mainly infrared radiation which can pass through a vacuum i.e. No medium is needed for its transfer. How much radiation is given out or taken in by an object depends on its surface In this experiment I could have many variables. Ranging from colour to size. They are: - The material of my cup (ceramic, metal, glass, polythene, plastic) - The layers of insulators (no layers, 1layer, 2layer etc) [this is what I have chosen to use as my variable] - Different types of insulators (wool, bubble wrap, foam, cotton, paper) - Different colours of insulators. (Black, transparent,) Research and preliminary experiment: For when I
To Investigate The Effect Of Light Intensity On The Rate Of Photosynthesis.
To Investigate The Effect Of Light Intensity On The Rate Of Photosynthesis Introduction We were set an experiment to investigate the effect of light intensity on the rate of photosynthesis; we did this by using an angle poised lamp and shining it on a beaker with some Elodea Cana Densis (Canadian pond weed) in it, measured distances from the bulb to the beaker and counted how many bubbles floated above a marked point on the beaker. Plotted a graph from these results and drew a line of best fit. Carbon Sunlight + Water Glucose + Oxygen Dioxide Chlorophyll 6CO2 + 6H2O C6H12O6 + 6O2 Apparatus: Beaker Spatula Stopwatch Bulldog Clips Canadian Pond Weed Sodium Hydrogen Carbonate Angle Poised Lamp - 60 Watts Prediction I predict that the closer the lamp (bulb) to the pond weed the higher the number of oxygen bubbles given off, as the light source is moved closer the more intense light speeds up the rate of photosynthesis. Plan To do this experiment we had to get a beaker full with water and some Canadian pond weed weighted down with bulldog clips, so the entire weed is covered in water. We had an angle poised lamp with a 60w bulb shining on the beaker, we measured the distances from the pond weed to the bulb every time, then counted the number of oxygen bubbles given off. To make this a fair
Transpiration in Plants
Transpiration in Plants Hypothesis The rate of transpiration in a plant will increase in a windy environment. Justification Transpiration is the process of evaporation of water from plants. This process takes place in the leaves through the stomata. Transpiration is needed to transport the water and minerals ions from the roots in a plant to the leaves, stems and flowers to aid proper growth, Water is absorbed into the plant from the soil through the stem via the roots. It is absorbed by osmosis through the root hair, which supply a large surface area. The water ends up in the Xylem vessels at the centre of the root as a result of travelling through the cortex, endodermis and pericycle, normally through the appoplast pathway. The Xylem Vessels carry the water and mineral irons, which follow the flow of water, up the plant into the leaves. The water molecules form hydrogen bonds and stick together and travel up the plant. This effect is called capillary action. Once in the leaves the water evaporates through the Spongy mesophyll then diffuses through the stomata into the surroundings outside. This process is called transpiration. Plants control the transpiration process by opening and closing their stomata operated by the surrounding guard cells. The rate of transpiration will increase when it is windy because the wind will reduce the water concentration outside
Water is said to have unique properties. Explain what these are and show in what ways these properties are so important to life.
Water is said to have unique properties. Explain what these are and show in what ways these properties are so important to life. Water has many properties which makes it unique to all other lquids. It is one of the most important substances and even make up 80% of the body and 2/3 of the world. Many of the physical and chemical properties that make water so unique is due to its structure. Water is composed of one oxygen atom and two hydrogen atoms. Each hydrogen atom is covalently bonded to the oxygen. Oxygen also has two unshared pairs of electrons which has strong repulsion forces pushing the hydrogens further away. (see diagram 1) The bond angle between these hydrogen bonds is 105. This arrangement results in a polar molecule. This is due to the fact that there is a net negative charge toward the oxygen end of the molecule due to the unshared pairs of electrons and a net positive charge at the hydrogen end. The water molecle is therefore attracted to the opposite side of another water molecule, with each oxygen being able to attract two nearby hydrogen atoms. (see diagram2). Hydrogen Bonding is strong enough to keep water liquid at ordinary temperatures; its low molecular weight would normally tend to make it a gas at such temperatures. Diagram 1 Diagram 2 A water molecule Water as a universal solvent Water is unique in that it dissolves more substances than
What Affects The Rate Of Photosynthesis?
What Affects The Rate Of Photosynthesis? Aim: To investigate the factors that, affect the rate of photosynthesis. Planning: I will get some pondweed and place and place it in a beaker with some water and sodium hydrogen carbonate. Then I will shine a lamp on the pondweed and when it starts to release bubbles, I will start to count the bubbles. Then I will adjust the lamp to distances of 5 cm, 10 cm, 20 cm and 30 cm and try to get different results. Introduction: The experiments in this topic tells us that plants need carbon dioxide, water, light and chlorophyll in order to make food for themselves; and starch and oxygen are produced. Carbon dioxide and water are raw materials of photosynthesis. They react in some way to produce starch and oxygen, the products. We now know that this is not a simple reaction, but takes place in a series of steps. The reaction needs energy, and this comes from the light. The chlorophyll enables the plant to use light energy this way. Light and energy are therefore essential helpers in the process. Although starch is made in the end, it is not the first substance to be formed. Glucose is formed first and then turned into starch. Photosynthesis is therefore a complicated process. However is usually summed up by a simple equation. Light + chlorophyll 6CO2 + 6H2O ⇛ C6H12O6 + 6O2 Carbon + Water
