Nutrition

• The process of photosynthesis is an endothermic reaction in which energy from sunlight is transferred to the chloroplasts in green plants.
• Green plants use the energy from sunlight to make the carbohydrate glucose from the raw materials carbon dioxide and water.
• During photosynthesis, oxygen is made and released as a waste product.
• Photosynthesis can be defined as the process by which plants manufacture carbohydrates from raw materials using energy from light.
• Plants are Autotrophs, meaning they can make complex molecules (glucose) from simple molecules (carbon dioxide and water).
• Producers are plants that can make their own food and are the first organism at the start of all food chains.
• The products of photosynthesis are used by plants as a source of energy in respiration and for various other functions.
• In the section of the graph where the rate is not increasing, the limiting factor will be something other than what is on the x axis, which can be temperature, light intensity, or carbon dioxide concentration.
• The more chloroplasts a plant has, the faster the rate of photosynthesis.
• In the section of the graph where the rate is increasing, the limiting factor is whatever the label on the x axis of the graph is.
• The number of chloroplasts, which contain the pigment chlorophyll that absorbs light energy for photosynthesis, affects the rate of photosynthesis.
• Plant leaves have complex structures with layers of different tissues containing specially adapted cells.
• The specialised cells in leaves have adaptive features which allow them to carry out a particular function in the plant.
• The amount of chlorophyll can be affected by diseases such as tobacco mosaic virus, lack of nutrients, and loss of leaves.
• Interpreting graphs of limiting factors can be confusing for many students, but it’s quite simple.
• The different structures in a leaf and their functions are described in a Leaf Structures Table.
• The concentration of carbon dioxide affects the rate of photosynthesis.
• Adaptations of Plant Leaves for Photosynthesis are described in a table.
• The fate of glucose produced in photosynthesis is determined by the needs of the plant.
• The method of testing a leaf for starch can also be used to test whether chlorophyll is needed for photosynthesis by using a variegated leaf (one that is partially green and partially white).
• Malnutrition can cause a variety of different health problems in humans.
• A balanced diet consists of all of the food groups in the correct proportions.
• The method involves dropping the leaf in boiling water, transferring it into hot ethanol in a boiling tube for 5-10 minutes, rinsing it in cold water, spreading it out on a white tile and covering it with iodine solution.
• When working with practical investigations, remember to consider your CORMS evaluation.
• Having an unbalanced diet can lead to malnutrition.
• Causes & Effects of Malnutrition Table.
• The necessary key food groups in a balanced diet are: Carbohydrates, Proteins, Lipids, Dietary Fibre, Vitamins, Minerals (mineral ions), Water.
• The white areas of the leaf contain no chlorophyll and when the leaf is tested only the areas that contain chlorophyll stain blue-black.
• Starch is stored in chloroplasts where photosynthesis occurs, so testing a leaf for starch is a reliable indicator of which parts of the leaf are photosynthesising.
• The areas that had no chlorophyll remain orange-brown as no photosynthesis is occurring here and so no starch is stored.
• Plants obtain these elements in the form of mineral ions actively absorbed from the soil by root hair cells.
• Photosynthesis provides a source of carbohydrates, but plants contain and require many other types of biological molecules such as proteins, lipids and nucleic acid (DNA).
• Mineral is a term used to describe any naturally occurring inorganic substance.
• Mineral ion function and deficiencies in plants are important topics in plant science.
• Although plants synthesise glucose during photosynthesis, their leaves cannot be tested for its presence as the glucose produced is quickly used up, converted into other substances and transported or stored as starch.
• Carbohydrates contain the elements carbon, hydrogen and oxygen but proteins, for example, contain nitrogen as well (and certain amino acids contain other elements too).
• As photosynthesis occurs, oxygen gas produced is released.
• Two fundamental mineral ions required by plants are nitrogen and magnesium, without a source of these elements, plants cannot photosynthesise or grow properly.
• The evolution of oxygen from a water plant can be demonstrated in an experiment.
• The evolution of oxygen from the process of photosynthesis can be demonstrated using water plants such as Elodea or Cabomba, types of pondweed.