Exploring the Wonders and Importance of Biology

Importance of Biology

• Biology is the science of life, concerning the study of plants, animals, and microorganisms.
• Understanding biology is crucial, as unknowingly disturbing nature's balance can lead to infectious disease outbreaks, weather changes from global warming, overfishing, overhunting, and deforestation.
• A lack of biological knowledge can exacerbate problems related to feeding a growing population and result in species extinction.
• Biology plays a role in animal breeding, agriculture, and medicine.
• Biology helps protect nature, feed nations, and improve the world for future generations.

Links Between Biology and Other Sciences

• Biology consists of many disciplines.
• Pure sciences within biology study basic facts, such as morphology (structure and form of organisms) and cytology (cell structure and function).
• Applied sciences use biological knowledge for practical applications, including biotechnology, medicine, veterinary science, agriculture, and animal husbandry.
• Biology is linked to physics, chemistry, geology, geography, mathematics, and computer science.
• Biophysics applies physics to understand biological processes like bird flight and bat echolocation.
• Biochemistry studies chemical substances and processes in cells and organisms.
• Biogeography explains the distribution of plants and animals across space and time.

Identification and Classification of Living Things

• Identification classifies organisms and assigns scientific names.
• Taxonomy involves studying and classifying living things.
• Biologists group organisms with similar characteristics and separate dissimilar ones.
• Classification is arranged in a hierarchical order, known as hierarchical classification.
• The eight taxonomic groups include three domains (Archaea, Bacteria, and Eukarya) at the top.
• Each domain is subdivided into seven levels or taxa: Kingdom, Phylum/Division, Class, Order, Family, Genus, and Species.
• Cladistics, another classification method, uses techniques like DNA comparison to determine species relatedness.
• Biologists use morphology and anatomy as keys to identify organisms.

Construction of Dichotomous Keys for Identification

• Dichotomous keys classify unknown organisms into proper taxa through a series of questions with two possible answers.
• The term "dichotomous" means "divided into two parts".
• This method repeatedly divides organisms into two categories, progressing from general to specific characteristics.
• Organisms are identified and placed in their taxonomic level by following the sequence of questions and making correct choices.

How Electron Microscopes Work

• Electron microscopes require a vacuum for the electron beam, specimen, and fluorescent screen.
• An electron gun and anode emit a high-velocity electron beam.
• A condenser electromagnetic lens focuses the electron beam onto the specimen.
• An objective electromagnetic lens focuses and magnifies the first image.
• Projector electromagnetic lenses focus the magnified image onto the screen, where it is recorded in black and white on a screen or photographic plate.

Comparison of Light and Electron Microscopes

• Light microscopes use light as a radiation source, while electron microscopes use electrons.
• Light microscope images are projected on the eye or photographic film, whereas electron microscope images are projected on a screen or photographic film.
• Light microscope specimen preparation is simple, but electron microscope preparation is lengthy and complicated.
• Light microscopes magnify up to 2000x, while electron microscopes magnify up to 500,000x.
• Light microscopes can examine dead or alive specimens, but electron microscopes can only examine dehydrated and dead specimens.
• Light microscopes are inexpensive to purchase and operate, but electron microscopes are expensive.

Magnification

• Magnification increases the size of an object's image to make microscopic organisms visible.
• Magnification is the number of times larger an image is compared to the object's real size.
• The formula for magnification is: Magnification = Observed size / Actual size
• M = Magnification, I = Observed size, A = Actual size.

Resolution

• Resolution is the ability to distinguish between closely positioned objects.
• Resolving power shows the smallest detail a microscope can resolve.
• Increasing magnification does not always result in a more detailed image; it may only increase the size, causing blurriness.
• Greater resolution results in greater detail.

Biotechnology

• Biotechnology combines biological sciences with engineering technologies.
• Biotechnology uses living systems and organisms to produce chemicals, products, or carry out industrial work.
• Traditional biotechnology has been practiced for centuries in making wine, bread, cheese, and breeding livestock without scientific knowledge.

Traditional Biotechnology

• Traditional biotechnology began thousands of years ago with the discovery of microorganisms like bacteria and yeast.
• Seven thousand years ago, Mesopotamians used bacteria to convert wine into vinegar.
• Traditional examples include making wine, cheese, yogurt, bread, and beer.

Modern Biotechnology

• Modern biotechnology is a scientific study of biochemical processes that contributes to the advancement of biotechnology.
• It produces a range of materials from medicines like penicillin to chemicals like enzymes and fuel.
• Gene technology allows scientists to modify organisms by transferring genes, creating transgenic plants and animals.
• Transgenic goats produce antibodies and blood clotting agents in their milk, and plants are engineered to produce vaccines.

Microorganisms and Biotechnology

• Microorganisms (microbes) are small organisms seen with a microscope, including protists, archaea, fungi, bacteria, and viruses.
• Archaea and bacteria are prokaryotes, while protists and fungi are eukaryotes.
• Viruses are not cellular and reproduce inside host cells using the host's genetic material.
• Protists are single-celled organisms in wet environments.
• Fungi have hyphae or filamentous cells, except for yeasts, which have single spherical cells.
• Microbes are used in manufacturing to produce useful products for food technology, baking, brewing, drug production, textile and mining, and the production of biological washing powder and biofuel.
• Microorganisms are cultured easily in fermenters, reproduce profusely, and grow rapidly under optimum conditions.
• They need cheap nutrients and can be fed with waste products.

Making of Biofuels

• Raw or unrefined sugar is used as a nutrient for anaerobically respiring yeasts.
• This fermentation produces ethanol, which is distilled to obtain pure ethanol.
• Ethanol is mixed with petrol to make gasohol for driving cars.
• Brazil, Zimbabwe, and the USA use ethanol and gasohol as energy sources.
• Biofuel can also be produced from oil from rapeseeds or sunflower seeds.

Bread Making

• Yeast is used in bread making.
• Flour, water, oil, and yeasts are mixed and kneaded.
• Water activates amylase enzymes to break down starch into sugar.
• Yeast ferments the sugar anaerobically into carbon dioxide and ethanol.
• The dough ferments at 27°C for a few hours.
• Gluten, a sticky protein, holds carbon dioxide gas bubbles, making the dough rise.
• The dough is baked at 200°C, killing yeasts and evaporating ethanol, resulting in a light cellular texture.

Making Yogurt and Cheese

• Both yogurt and cheese are made from milk.
• Milk is pasteurized at 90°C to kill bacteria and homogenized to break up fat globules.
• At 40-45°C, a starter culture of Streptococcus thermophilus and Lactobacillus bulgaricus are added.
• Bacteria turn lactose into lactic acid which coagulates milk protein casein and produces creamy yogurt.
• Cheese making follows similar processes as yogurt.
• Rennet, a mixture of enzymes, is added to coagulate milk casein further to form solid curds.
• Liquid whey is drained off, and the solid curds are dried and compressed, then allowed to ripen and mature.

Making Wine and Beer

• To make wine, grapes are crushed, and the juice is treated with sulphur dioxide to kill natural occurring yeast.
• A starter culture of yeast (Saccharomyces cerevisiae) is added, respiring aerobically until oxygen is used up.
• Yeast cells then respire anaerobically, fermenting the grape sugar (glucose) to alcohol and carbon dioxide.
• When the alcohol content reaches 15%, the yeast cells die, and the juice becomes wine.
• Beer is made from barley grains that are wetted and germinated to activate starch-digesting enzymes.
• Seeds are dried to kill the seed but keep the enzymes.
• The dried grains are mixed with water and starch from wheat or rice.
• Barley enzymes digest starch to maltose and glucose, forming 'wort'.
• Wort is filtered and boiled with hops to give the beer a bitter flavor.
• Yeast is added to act on maltose and glucose to produce ethanol.
• Fermentation takes 5-15 days to make beer.

Fermentation

• Respiration is a chemical reaction carried out by all living organisms to get energy out of food.
• Anaerobic respiration breaks down glucose to alcohol and carbon dioxide (alcoholic fermentation).
• Louis Pasteur described alcoholic fermentation as "life without air".
• Fermentation is defined as chemical changes in organic substances brought about by microorganisms in the presence or absence of oxygen.

Fermenters

• Fermenters are large containers that maintain optimum environment for culturing microorganisms to manufacture commercially.
• Fermenter tanks are made of stainless steel to withstand the corroding effect of acidic waste.
• Hot steam is passed into the fermenter to sterilize it.
• Nutrients are added to the tank.
• Filtered air is passed through the air inlet if the microorganisms need to respire aerobically.
• Temperature and pH are monitored.
• Cold water is circulated through a water jacket to prevent overheating.
• Stirring paddles are used to keep even temperature and keep microorganisms expose to the nutrients.
• Products are collected from the harvesting outlet when the fermentation process is finished.

Extracting Fruit Juice

• Fungi produce pectinases enzymes used in extracting fruit juices.
• Enzymes break down pectin between cell walls and separate fruit cells.
• Polysaccharides are released during the breakdown, causing the juice to become cloudy.
• Pectinases continue to break them down to sugar making the juice sweeter and clearer.
• In commercial fermentation, batch culture involves fixing the volume of culture medium and collecting products when maximum products accumulate.
• In continuous culture, the fermenter kept running for extended periods adding fresh nutrients while products are harvested continuously.

Enzymes Use in Industry

• Enzymes are protein molecules that are biological catalysts for metabolic processes.
• Enzymes isolated from the cell retain their ability to function, and for industrial processes, they're cheaper and require less fuel to function.
• Enzymes are used in baking, brewing, dairy, textile, medicine, and pharmaceutical industries.
• Microbial trypsin is used to treat blood clotting and pancreatic trypsin for inflammation

Biological Washing Powders

• Commercial fermentation produces enzymes useful to man, like proteases and lipases.
• These enzymes are used to make biological washing powder to remove stains caused by blood, egg, gravy, and grease.
• Proteases act on red haemoglobin and break it down into colorless molecules which dissolve in water.
• Proteases and lipases together digest protein and fat molecules into small, soluble substance.