Biology

• Biology is the area of science dealing with living things and includes biological concepts and process skills, technology and attitudes and values for addressing the needs and problems of society.
• In recent years, the development of techniques in genetic engineering and increased understanding of the molecular basis of cellular processes have led to the emergence of a new and exciting field of scientific research called biotechnology.
• Organic compounds are characterized by the presence of carbon and include carbohydrates, lipids, proteins, and nucleic acids.
• Carbohydrates are made up of carbon, hydrogen, and oxygen (e.g., sugar, starches, and cellulose) atoms and have the general formula C n H 2n O n.
• The sizes of carbohydrates range from the small simple sugars like glucose and fructose to the large and complex forms like starch and glycogen.
• Only the simple sugars (monosaccharides) can easily pass across cell membranes.
• Most carbohydrates serve as energy molecules or energy reserves in living organisms.
• Cellulose gives strength and protection to plant cells.
• Lipids are macromolecules such as fats, oils and waxes made up of carbon, hydrogen, and oxygen.
• The building blocks used to form fats are fatty acids and glycerol.
• Some excess food in the body is stored as fats.
• Lipids that are liquid at room temperature are known as oils.
• Waxes serves as protective body covering to organisms and make plant and animal tissues water-resistant.
• Proteins are made up of repeating units of amino acids and are a component of the muscles and all other tissues.
• In the form of enzymes, proteins control the rate of chemical reactions inside the cell.
• Enzymes are proteins that act as catalysts and are specific in their actions.
• Nucleic Acids are carriers of hereditary information in living organisms.
• Vitamins are substances necessary in very small amount for body growth and activity and are also needed to prevent certain diseases.
• Vitamins are organic substances essential to life but not required as energy sources.
• The sources of most Vitamins are plants and bacteria.
• The Golgi apparatus modifies, packages, and distributes proteins while lysosomes store enzymes for digesting food.
• Eukaryotic cell cytoplasm is similar to that of the prokaryote cell except for one major difference: Eukaryotic cells house a nucleus and numerous other membrane-enclosed organelles.
• Like separate rooms of a house, these organelles enable specialized functions to be carried out efficiently.
• The plasma membrane separates the cell from its surroundings and regulates the traffic across the membrane.
• The plasma membrane that surrounds eukaryotic cells is a dynamic structure composed of two layers of phospholipid molecules interspersed with cholesterol and proteins.
• Phospholipids are composed of a hydrophilic, or water-loving, head and two tails, which are hydrophobic, or water-hating.
• The mitochondria generate energy for the cell.
• The nucleus directs activities of the cell and carries genetic information from generation to generation.
• Ribosomes, also immersed in the cytoplasm, are the only organelles in prokaryotic cells and are the cell’s protein factories.
• Tiny gaps in the membrane enable small molecules such as oxygen to diffuse readily into and out of the cell.
• An animal cell typically contains several types of membrane-bound organs, or organelles.
• The entire cell is wrapped in a lipid membrane that selectively permits materials to pass in and out of the cytoplasm.
• The nucleus of a Cell is the largest organelle in an animal cell and contains numerous strands of DNA, the length of each strand being many times the diameter of the cell.
• The nucleus, present in eukaryotic cells, is a discrete structure containing chromosomes, which hold the genetic information for the cell.
• Eukaryotic animal cells are typically about ten times larger than prokaryotic cells and have a plasma membrane, rather than a cell wall, as their outer boundary.
• Proteins are manufactured by ribosomes, which are bound to the rough endoplasmic reticulum or float free in the cytoplasm.
• The nucleus is separated from the cytoplasm of the cell by a double-layered membrane called the nuclear envelope, which contains a cellular material called nucleoplasm.
• Commensalism is an association between two different kinds of nonparasitic animals, called commensals, that is harmless to both and in which one of the organism benefits.
• Competition occurs when a shared resource is in short supply, and organisms compete, with the more successful surviving.
• Commensalism is most common among marine invertebrates, but it often occurs among land animals, such as in the association of ants with other insects like aphids and beetles.