General Biology 1 Notes PDF

GENERAL BIOLOGY 1 processes. It is a type of nucleic acid, similar to DNA The branch of science that study living things are but with some key differences. referred to as the life sciences. It is under the natural ADENOSINE TRIPHOSPHAT...

GENERAL BIOLOGY 1 processes. It is a type of nucleic acid, similar to DNA The branch of science that study living things are but with some key differences. referred to as the life sciences. It is under the natural ADENOSINE TRIPHOSPHATE (ATP) – is a molecule science. Bio came from Greek word “bio” means life that stores and transfers energy within cells, playing and “logus”, means study of. Experts in this field of a central role in numerous biological processes and science are known as biologists. serving as a key energy currency in living organisms. Some life sciences focus on a specific study such as zoology(study of fauna/animals),and botany(study of MICROSCOPE 1. Hans and Zacharias Janssen: flora/plants). There are also some specific studies in The official credit for the invention of the biology linked to medicine, agriculture, and other sciences at present. compound microscope is often given to Hans Janssen and his son Zacharias Janssen, who were Here are some of the examples: Dutch spectacle-makers in the late 16th century. ANATOMY - study of forms in plants and animals, or Around the 1590s, they created a compound specifically in human being microscope that consisted of two lenses—an BIOTECHNOLOGY - manipulation of living matter objective lens and an eyepiece. This design such as genetic modification allowed for greater magnification than previous BIOENGINEERING - application of knowledge in magnifying glasses. biotechnology by means of engineering CELL BIOLOGY - study of cell molecular as well as the 2. Robert Hooke's Contribution: chemical interactions that occur in it. In the 1663-1665, Robert Hooke, an English ECOLOGY - interactions of living things with each scientist, made significant contributions to other and their relationships within the environment microscopy. ENTOMOLOGY- focus on insects The scientist who is often referred to as the ETHOLOGY - focus on animal behavior "Father of Microscopy" for his pioneering work GENETICS - study on genes and heredity with microscopes, including the observation of MICROBIOLOGY - focus on microorganisms and their cork cells. Hooke used a microscope to observe interactions within their environment cork slices and coined the term "cell" to describe MYCOLOGY - study on fungi the tiny, box-like structures he saw. PALEONTOLOGY - fossils and geographic proofs of early life 3. Anton van Leeuwenhoek: PATHOLOGY - nature and causes, processes and Antonie van Leeuwenhoek, a Dutch draper and development of diseases amateur scientist, played a pivotal role in PHYSIOLOGY - functions of living matter together advancing microscopy in the mid-17th century. with its organs and parts He designed single-lens microscopes with TAXONOMY - naming and classifying organisms remarkable magnification capabilities. These microscopes were handcrafted and achieved Other Terminologies: magnifications of up to 300 times. CELL – Basic unit of life. Leeuwenhoek's meticulous observations of MICROSCOPE - A tool used to magnify and observe microorganisms, such as bacteria and protozoa, objects or specimens that are too small to be seen using his microscopes significantly advanced the with the naked eye. field of microbiology. PROKARYOTES – are predominantly single-celled microorganisms belonging to the domains Bacteria 3 Main Parts of Microscope and Archaea. Mechanical Parts EUKARYOTES – are a group of organisms ▪ Used to support and adjust the parts characterized by the presence of complex, Magnifying Parts membrane-bound structures within their cells, ▪ Used to enlarge the specimen including a well-defined nucleus that houses their Illuminating Parts genetic material (DNA). ▪ Used to provide light EVOLUTION - The ability of an organism to change in its characteristics over a period of time. PART OF THE MICROSCOPE MICROSCOPY – A scientific technique used for the observation, study, and analysis of objects or a. Eyepiece (Ocular): The eyepiece is the lens at the top specimens that are too small to be seen with the of the microscope through which you look to observe naked eye. the specimen. It often has a standard magnification HOMEOSTASIS – The state of an organism which it of 10x and is where you place your eye to view the maintains its balance. image. DEOXYRIBONUCLEIC ACID (DNA) - The structure b. Objective Lenses: Objective lenses are located below made from protein and DNA molecules, containing the eyepiece and are mounted on a revolving turret information for protein synthesis of an organism. or nosepiece. They come in various magnification RIBONUCLEIC ACID (RNA) - is a molecule found in powers, such as 4x (low-power), 10x (medium- cells that plays a crucial role in various biological power), 40x (high-power), and sometimes 100x (oil  immersion). Objective lenses are used to magnify the of magnifying objects hundreds of times. Using these specimen. powerful microscopes, he observed single-celled c. Nosepiece: The nosepiece is a rotating mechanism microorganisms, which he called "animalcules" or that holds the objective lenses. It allows you to easily "little animals." Leeuwenhoek's observations switch between different objective lenses to change provided further evidence of the existence of cells the level of magnification. and their incredible diversity. d. Coarse Focus Knob: The coarse focus knob is used for rough adjustments of the focus. Turning this knob 3. Matthias Jacob Schleiden (1804-1881): moves the stage (and the specimen) closer to or Matthias Schleiden, a German botanist, contributed farther away from the objective lenses to bring the to cell theory by focusing on plant tissues. In 1838, specimen into approximate focus. he proposed that all plants were composed of cells, e. Fine Focus Knob: The fine focus knob is used for a theory that laid the foundation for understanding precise and fine adjustments of the focus. It allows the cell as the fundamental unit of plant structure. you to bring the specimen into sharp focus after Schleiden's work, in collaboration with Theodor using the coarse focus knob. Schwann, helped solidify the concept of the cell as a f. Stage: The stage is a flat platform where you place fundamental building block of life. the specimen for observation. It often has clips or holders to secure the specimen slide in place. The 4. Theodor Schwann (1810-1882): stage can be moved vertically (up and down) using Theodor Schwann, also a German scientist, the coarse and fine focus knobs. expanded upon Schleiden's work to include animal g. Stage Clips or Mechanical Stage: Some microscopes tissues. In 1839, he proposed that all animals were are equipped with stage clips or a mechanical stage also composed of cells, extending the concept of cell that allows for precise movement of the specimen theory to the animal kingdom. Schwann's slide in both X and Y directions. contribution, along with Schleiden's, led to the h. Condenser Lens: Located beneath the stage, the formulation of the first two principles of cell theory: condenser lens concentrates and directs light onto that all plants and animals are made of cells. the specimen. Some condenser lenses have an adjustable diaphragm to control the amount of light 5. Rudolf Virchow (1821-1902): passing through the specimen. While not as famous as Hooke, Leeuwenhoek, i. Light Source: The light source provides illumination Schleiden, or Schwann, Rudolf Virchow, a German for the specimen. It is often located beneath the physician and pathologist, made a critical addition to stage and can be an LED, halogen lamp, or other light cell theory. In 1855, he proposed the third principle source depending on the microscope model. of cell theory, stating “Omnis cellula e cellula” means j. Diaphragm: The diaphragm is a part of the that all cells arise from pre-existing cells. This condenser and controls the amount of light that concept countered the earlier belief in spontaneous reaches the specimen. It can be adjusted to regulate generation, which suggested that life could arise the brightness and contrast of the image. from non-living matter. Virchow's principle k. Base: The base of the microscope provides stability completed the foundation of cell theory as we know and support for the entire instrument. it today. l. Arm: The arm connects the base to the head of the microscope. It is used for carrying the microscope Together, the contributions of these scientists form and may also serve as a handle. the basis of cell theory, which consists of the three key principles mentioned earlier: 1. All living organisms are composed of one or CELL THEORY more cells. 2. The cell is the basic unit of structure and SCIENTISTS THAT CONTRIBUTE IN THE function in organisms. FORMULATION OF THE BASIS OF CELL THEORY: 3. All cells arise from pre-existing cells through 1. Robert Hooke (1635-1703): cell division. Robert Hooke, an English scientist, is often credited with laying the foundation for cell theory. In 1665, he Cell theory is a fundamental concept in biology that used a simple compound microscope to examine a describes the basic properties of living organisms and thin slice of cork and made a significant discovery. He their organization. It consists of three key principles: observed small, box-like structures within the cork 1. All living organisms are composed of one or and coined the term "cells" to describe them. more cells: This principle emphasizes that all life, Hooke's work marked the first recorded observation whether it's a single-celled bacterium or a of cells, although he did not fully understand their complex multicellular organism like a human, is significance at the time. made up of cells. Cells are the building blocks of life, and they are the smallest units of life that 2. Anton van Leeuwenhoek (1632-1723): can carry out all the processes necessary for Anton van Leeuwenhoek, a Dutch scientist and survival. microscopist, made groundbreaking contributions to 2. The cell is the basic unit of structure and the field of microscopy. In the late 17th century, he function in organisms: This principle designed and built high-quality microscopes capable underscores the idea that the cell is not just the  smallest structural unit of life but also the 5. Golgi Apparatus: functional unit. It means that the specific Structure: Consists of a stack of flattened structure of a cell determines its function within membranous sacs. an organism. Understanding this principle helps Function: Modifies, sorts, and packages proteins and biologists’ study and appreciate the diversity of lipids synthesized in the ER for transport to their final life at the cellular level. destinations inside or outside the cell. 3. All cells arise from pre-existing cells through cell 6. Mitochondria: division: This principle is a fundamental concept Structure: Double membrane structure with inner of reproduction and growth in living organisms. folds called cristae. It means that new cells are continually being Function: Site of cellular respiration, where glucose produced by the division of pre-existing cells. and other organic molecules are broken down to This process of cell division, often referred to as produce ATP (adenosine triphosphate), the cell's mitosis (in eukaryotic cells) or binary fission (in primary energy source. prokaryotic cells), ensures the continuity of life. 7. Ribosomes: Without the ability of cells to divide and give rise Structure: Small particles made of ribosomal RNA to new cells, life as we know it would not exist. (rRNA) and protein. This principle also refutes the idea of Function: Sites of protein synthesis, where amino spontaneous generation, as it demonstrates that acids are assembled into proteins based on the new life only arises from pre-existing life. information from mRNA. 8. Lysosomes (Rare in Plant Cells but plenty in ANIMAL AND PLANT CELL Animal Cells): Animal cells are eukaryotic cells, meaning they have Structure: Membrane-bound sacs containing a true nucleus enclosed by a nuclear membrane, as digestive enzymes. well as various other membrane-bound organelles. Function: Digests cellular waste, damaged These cells are highly specialized to carry out specific organelles, and engulfed particles, contributing to functions within the body of animals. cellular recycling and waste disposal. 9. Cytoskeleton: Plant cells, like animal cells, are eukaryotic cells with - Structure: A network of protein filaments, including a true nucleus enclosed by a nuclear membrane. microtubules, microfilaments, and intermediate However, plant cells have several unique structures filaments. that are essential for their functions, particularly - Function: Provides structural support to the cell, those related to photosynthesis and maintaining facilitates cell movement, and is involved in rigidity. intracellular transport. 10. Peroxisomes: - Structure: Membrane-bound organelles. CELL ORGANELLES - Function: Break down fatty acids and detoxify harmful substances, primarily hydrogen peroxide, 1. Cell Membrane (Plasma Membrane): using enzymes. Structure: A phospholipid bilayer with embedded 11. Nucleolus: proteins and carbohydrates. - Structure: A dense region within the nucleus. Function: Regulates the passage of substances in and - Function: Involved in the synthesis of ribosomal out of the cell, provides cell structure, and RNA (rRNA) and the assembly of ribosomes. participates in cell signaling and communication. 12. Chromatin: 2. Nucleus: Structure: A complex structure composed of DNA Structure: Surrounded by a double membrane called and associated proteins found within the nucleus of the nuclear envelope, contains chromatin (DNA and eukaryotic cells. proteins). Function: It serves critical functions related to the Function: Houses the genetic material (DNA), storage, organization, and regulation of genetic controls gene expression, and directs cell activities, information. including growth, replication, and division. 13. Centrioles (in Animal Cells): 3. Cytoplasm: Structure: Cylindrical structures composed of Structure: The semi-fluid substance filling the cell's microtubules. interior. Function: Play a crucial role in cell division (mitosis Function: Provides a medium for cellular processes, and meiosis) by organizing the spindle fibers that supports organelles, and enables the movement of separate chromosomes. molecules within the cell. 14. Cell Wall (in Plant Cells): 4. Endoplasmic Reticulum (ER): Structure: A rigid outer layer made primarily of Structure: A network of membranous tubules and cellulose, hemicellulose, and pectin. sacs. Function: Provides structural support, protection, Function: and rigidity to the cell. It also helps maintain cell Rough ER: Studded with ribosomes, involved in shape. protein synthesis and modification. 15. Chloroplasts (in Plant Cells): Smooth ER: Synthesizes lipids, detoxifies drugs and - Structure: Double membrane structure with poisons, and stores calcium ions. internal stacks called thylakoids. - Function: Exclusive to plant cells, chloroplasts are CELL TYPES the sites of photosynthesis. They capture light energy and convert it into chemical energy (glucose) through Prokaryotic Cell a series of biochemical reactions. 16. Central Vacuole (in Plant Cells): The term “prokaryote” is derived from the Greek - Structure: A large, membrane-bound sac that word “pro“, (meaning: before) and “karyon” occupies a significant portion of the cell's volume. (meaning: nucleus). It translates to “before nuclei.“ - Function: Stores water, nutrients, pigments, and Prokaryotes are one of the most ancient groups of waste products. It plays a crucial role in maintaining living organisms on earth, with fossil records dating turgor pressure, which helps support the cell and the plant. back to almost 3.5 billion years ago. 17. Plasmodesmata (in Plant Cells): All prokaryotic organisms are. These includes the - Structure: Channels or pores in the cell wall that members of Eubacteria and Archaebacteria. connect adjacent plant cells. - Function: Facilitate communication and the Prokaryotic cells are comparatively smaller and much exchange of nutrients and signals between plant simpler than eukaryotic cells ranging from 1-10 µm in cells. diameter. Note: A typical cell contains three major parts, the The other defining characteristic of prokaryotic cells cell membrane, cytoplasm and nucleus. is that it does not possess a nucleus but has nucleoid which contains its genetic material. Reproduction happens through the process of binary fission. They may occur singly, in pairs, chains, clusters, aggregates, or colonies. Some species rod-shaped (bacilli), spherical (cocci), spiral (spirilla), etc. Structurally, prokaryotes have a capsule enveloping their entire body, and it functions as a protective coat. This is crucial for preventing the process of phagocytosis (where the bacteria get engulfed by other eukaryotic cells, such as macrophages). The pilus is a hair-like appendage found on the external surface of most prokaryotes and it helps the organism to attach itself to various environments. The pilus essentially resists being flushed, hence, it is also called attachment pili. It is commonly observed in bacteria. Right below the protective coating lies the cell wall, which provides strength and rigidity to the cell. Further down lies the plasma membrane, which Eukaryotic Cell separates the interior contents of the cell from the The term “Eukaryotes” is derived from the Greek outside environment. word “eu“, (meaning: good) and “karyon” (meaning: The cytoplasm helps in cellular growth which is nucleus), therefore, translating to “good or true contained by the plasma membrane. nuclei.” Eukaryotes are more complex and much larger than prokaryotes. They include almost all the Within the cytoplasm, ribosomes exist and it plays an major kingdoms such as kingdom Protista, Fungi, important role in protein synthesis. It is also one of Plantae and Animalia, excluding kingdom Monera. the smallest components within the cell. Structurally, eukaryotes possess a cell wall, which Some prokaryotic cells contain special structures supports and protects the plasma membrane. The called mesosomes which assist in cellular cell is surrounded by the plasma membrane and it respiration. controls the entry and exit of certain substances. Most prokaryotes also contain plasmids, which The nucleus contains DNA, which is responsible for contain small, circular pieces of DNA. storing all genetic information. The nucleus is To help with locomotion, flagella are present, surrounded by the nuclear membrane. Within the though, pilus can also serve as an aid for nucleus exists the nucleolus, and it plays a crucial locomotion. Common examples of Prokaryotic role in synthesizing proteins. Eukaryotic cells also organisms are bacteria and archaea. Also, all contain mitochondria, which are responsible for the members of Kingdom Monera are prokaryotes. creation of energy, which is then utilized by the cell. Present in only plant cells, chloroplasts are the subcellular sites of photosynthesis. The endoplasmic reticulum helps in the transportation of materials. Besides these, there are also other cell organelles that perform various other functions and these include ribosomes, lysosomes, Golgi bodies, cytoplasm, chromosomes, vacuoles and centrosomes. Examples of eukaryotes include almost every unicellular organism with a nucleus and all multicellular organisms.