#40 Photosynthesis investigations – chlorophyll, CO2, light tests

 Investigations to see if chlorophyll, light and CO2 are needed for photosynthesis. 

#39 Photosynthesis investigations - Principles and Starch test

Experiments can be used to find out what factors (CO₂, light, cholorophyll) are needed for photosynthesis. But first of all you need to destarch the plants. To be certain that they are thoroughly destarched, test a leaf for starch before you begin your investigation. 

#38 The equation for photosynthesis

Photosynthesis is the fundamental process by which plants manufacture food molecules (carbohydrates) from raw materials CO₂ and H₂O) using energy from light. 

# 37 Food additives - uses, benefits and health hazards

Food additives are used for a number of purposes, mainly to extend the life of processed foods so they can be transported, stored or kept on the shop shelf for longer, maintain a standard quality, and make the products more attractive to the consumer. Additive groups include antioxidants, colourings, flavourings and preservatives.

# 36 Using microorganism in making yoghurt and single cell protein

In the production of yoghurt, we use microorganisms to change one substance into another, which we use as food. But we can also use the microorganisms themselves, e.g. mycoprotein as food.

#35 Using yeast to make bread and beer

Yeast is a single celled, microscopic fungus which uses sugar as food. It is widely used in food industries such as baking and brewing.

#34. Other Nutrients: Vitamins, Minerals, Fiber and Water

Vitamins and minerals, although needed only in small quantities, are important for maintaining good health. A shortage can result in a deficiency disease. Fibre is needed in much larger quantities. Although it has no nutritional value to us, but long term deficiency can lead to bowel cancer. Water is also a vital part of our dietary requirements.

#33 Food test 4 - Biuret test for Proteins

The Biuret Test is done to show the presence of peptide bonds, which are the basis for the formation of proteins. These bonds will make the blue Biuret reagent turn purple. 

#32 Food test 3 - Emulsion (ethanol) test for Fats

This test is done to show the presence of lipids in a substance. The substance is first dissolved in ethanol. This solution is then dissolved in water. If lipids are present in the mixture, it will precipitates and forms an emulsion.

#31 Food test 2 - Benedict's test for Reducing Sugars

All simple sugars (e.g.glucose) are reducing sugars. They will react with a blue liquid called Benedict's solution to give a brick red color. We can use this reaction to find out if a food or other substance contains a reducing sugar.

#30 Food test 1 - Starch test

The brown Iodine solution reacts with starch and changes it to a blue-black color. This test helps you to find out if a food contains starch. 

#29 Main nutrients: carbohydrates, fats and proteins

Nutrition: taking in of nutrients which are organic substances and mineral ions, containing raw materials or energy for growth and tissue repair, absorbing 

assimilating them.

03. Enzymes pdf

#28 Summary of Enzymes

Enzymes are specialized protein molecules facilitating most of the body’s metabolic processes – such as, supplying energy, digesting foods, purifying your blood, ridding the body of waste products. Enzymes are vital to our health and change the rate at which chemical reactions happen, but without any external energy source added or by being changed themselves.

#27 Use of microorganisms to manufacture antibiotic penicillin

Three colonies of a Penicillium mold growing on an agar medium. 

Antibiotics are substances which kill bacteria without harming human cells. They help to cure bacterial infections. Penicillin is made by growing the fungus Penicillium in a large fermenter.

#26 Use of microorganisms and fermenter to manufacture enzymes

We obatain many enzymes from microorganisms. The enzymes that are used in industry are usually obtained from microorganisms. These include bacteria and microscopic fungi, such as yeast. The microorganisms are grown inside large vessels called fermenters.

#25 Use of enzymes in the food industry

Enzymes are an integral component of modern fruit juice manufacturing and are highly suitable for optimising processes. Fruit juices are extracted using an enzyme called pectinase.

#24 Use of enzyme in biological washing powders

Biological washing powders contain protease and lipase to remove protein stains and fat/grease from clothes. The enzymes break down proteins or fats on the fabric, forming water-soluble substances that can be washed away.

# 23 Role of enzymes in germinating seeds

Seeds contain stored food in the cotyledons to provide energy and materials for growth. This is usually in the form of starch – a large, insoluble molecule (long chain of glucose), that keeps the food immobile. The starch needs to be changed into a soluble molecule (sugar) with help of enzymes for the seeds to make use of.

#22 Enzymes - 'Lock and key' model

Enzymes are very specific, each kind of enzyme catalyse one kind of reaction only. To catalyse a reaction, enzyme molecule and substrate molecule need to meet and joint together by a temporary bond.

#21 Enzymes and reactions

Many chemical reactions can be speeded up by substances called catalysts. Within living organisms, these reactions (metabolic reactions) are controlled by catalysts called enzymes. Enzyme molecules are proteins.

02. Cells pdf

# 20 Summary of Cells

Here is a brief summary of previous topics. 

#19 Active transport

Sometimes substances are required to be move against the Concentration Gradient, or faster than they would by Passive Transport. In these cases, Active Processes are used, which require energy.

#18 Osmosis

Osmosis is the diffusion of water molecules from a region of their higher concentration to a region of their lower concentration, through a partially permeable membrane.