STM 007 General Biology 1 Notes PDF

1st achievement test reviewer Topic: The Theories About the Origin of Life Six Major Theories: 1.) Divine Creation Theory. (Theory of Special Creation) It states that life on earth is created by a supernatural being (depends on the religion). According...

1st achievement test reviewer Topic: The Theories About the Origin of Life Six Major Theories: 1.) Divine Creation Theory. (Theory of Special Creation) It states that life on earth is created by a supernatural being (depends on the religion). According to Christian belief, God created the universe, planets, animals, plants, and human in six natural days. These points are as follows:  All living organisms were created in the same day  They were created in the present form (no evolution)  Their bodies and organs are fully developed to meet the requirements to run life. Objections to the Theory of Special Creation:  Purely based on religious belief.  No experimental evidence to support assumptions.   Age of fossils proves that living organisms appear on Earth in different time frames. 2.) Abiogenesis Theory (Spontaneous Generation Theory). Assumes that non-living material in a spontaneous manner gives rise to life. Van Helmont claimed that he could produce mice on a dirty shirt and handful of wheat grains kept in a dark cupboard in 3 weeks. 3.) Biogenesis Theory. Opposite of Abiogenesis Theory. It says that life can arise from pre- existing living things. Some scientists performed well-designed scientific experiments to disprove the theory of spontaneous generations:  Francisco Redi – He used jars with meat inside: uncovered, covered, and with gauze. He left those jars for several days and when he got back on them, he found out that there were maggots in the jar where there was no lid. From this, Redi suggested that life did not originate from non-living matter (meat), but instead from a living matter like the flies who laid eggs which eventually turned into maggots.   Lazarro Spallanzani – Same process as Francisco Redi but he just used broth and 2 bottles: covered and uncovered. He waited for several days and turns out that the unsealed bottle has the presence of the microbial growth. He concluded that a longer heating period and high temperature had killed all microorganisms.  Louis Pasteur – Also same with Spallanzani’s experiment but he just used a swan-necked flask (a flask that traps any airbone coming from the air to enter into the flask). 4.) Theory of Catastrophism. Extension of the theory of special creation. It is a cycle of catastrophe/creation. This theory assumes that life originated by catastrophe due to geographical disturbances. Each round of catastrophe is responsible for the growth of different types of organisms. No scientific experiment to support the hypothesis and most are based on imaginary concepts. 5.) Theory of Cosmozoic (Theory of Panspermia or Apore Theory). This theory was put forward by Richter and strongly supported by Arrhenius. This theory states that life did not arise in our planet. Microorganisms from space (resistant spores – cosmozoa) came to earth along with the meteorites and comets then later on evolved into higher organisms with water. There were no details about the spores, their origin, and their mechanism of crossing space and reaching Earth. No scientific experiments support this theory. 6.) Theory of Eternity of Life (Steady State Theory). It explains that life has no beginning or end. That life has always existed and will continue to be so. Also known as the Steady State Theory by Hermann Bondi, Thomas Gold, and Fred Hoyle. 1st achievement test reviewer Topic: The Levels of Organization of Living Things Living Organism – It is anything that has life and consists of cells. It has the ability to respire, grow, excrete, reproduce, metabolize, move, and be responsive to the environment. Levels of Organization of Living Things 1) Atom – It is the smallest scale and fundamental unit of matter. 2) Molecule – When atoms combine, they form molecules. It is a chemical structure consisting of at least two atoms held together by one or more chemical bonds. Examples of molecules are: proteins, lipids, carbohydrates, and nucleic acid like the DNA. 3) Organelle – When molecules join together, they form an organelle. It is a structure that has a specific function within a cell. Examples are the mitochondria and chloroplasts, these two organelles carry out indispensable functions. 4) Cell – All living things are made of cells. Cell is the basic building block of all organisms. It is the structural and functional unit of life. Cells are classified into two:  Prokaryotic – These are single-celled organisms that do not have membrane-bound organelles. Examples are: bacteria, protozoa, algae etc.  Eukaryotic – Have membrane-bound organelles like the nucleus. Example organisms are: humans, plants, and some fungi. 5) Tissue – It is a group of similar cells performing specific functions within an organism. Four types of tissues are:   Epithelial tissues – can be found in the linings of the organs  Connective tissues – supports, protects, and gives structure to other tissues and organs in the body  Muscle tissues – responsible for movement of muscles  Nervous tissues - found in the brain, spinal cord, and nerves. It is responsible for coordinating and controlling many body activities. 6) Organs – Collection of tissues grouped performing a common function. 7) Organ System – It is formed when organs combine together. It is a higher level of organization that consists of functionally related organs. 8) Organisms – Simply defined as any living thing that is composed of various organ systems that function altogether. 9) Population – A group of organisms of the same species living together within a specific are/habitat. 10) Community – A group of organisms composed of different species living together and interacting in a certain area or habitat. 11) Ecosystem – A group of organisms having an interaction or interrelationship with the non-living environment such as air, nitrogen in the soil, or rainwater. 12) Biosphere – At the highest level of organization. It is the global sum of all ecosystem, and it represents the zones of life in Earth which means a part of the planet that is capable in supporting life. 1st achievement test reviewer Topic: The Development of Cell Theory How did the Cell Theory develop? 1590 – Two Dutch spectacle makers Zacharias Janssen and his father Hans started experimenting with lenses. They put several lenses in a tube, turns out that the object near the end of the tube appeared to be greatly enlarged. Because of this, both of them created the forerunner of the compound microscope and the telescope. 1665 – English Scientist Robert Hooke used a microscope to examine a thin slice of cork (dead oak tree bark). He described it as consisting of “great many little boxes” and coined the term “cells”. 1674 – Anton Van Leeuwenhoek, a Dutch scientist, was the first man to witness live cells. He described the Algae Spirogyra as animalecules “little animals”. He was also the first scientist who observe and describe bacteria. 1838 – Matthias Jacob Schleiden, German botanist, proposed that structures and morphological features, not processes, give organic life its character. Also proved that a nucleated cell is the first element of the plant embryo. 1839 – Theodor Schwann, German Psychologist, proposed that in animal too, every structural element is composed of cells and cell products. He together with Schleiden proposed the first two principles of cell theory. 1855 – German Pathologist, Rudolf Virchow, published the biogenic law and coined the phrase “omnis cellula e cellular” meaning cells originate from cells which became the third principle of cell theory. Also stated that all diseases involve changes in normal cells. The three principles of cell theory: 1. All living things are composed of one or more cells 2. The cell is the basic unit of life 3. All cells arise from pre-existing cells. 1st achievement test reviewer Topic: Introduction to Cell Structures and Functions of a Bacterium Cell Bacteria – Are single-celled organisms that lack nucleus or any membrane-bound organelle. Bacteria Cell Structures: Cell Wall:  It gives shape to the cell and surrounds the cytoplasmic membrane protecting it from the environment.  It is made up of PEPTIDOGLYCAN - protein-sugar molecule (Polysaccharide).  Its main function is it helps in providing support, mechanical strength and rigidity to cell. Capsule:  Protective covering of the bacteria made up of polysaccharides  Keep the bacteria from drying out  Protects the bacteria from PHAGOCYTOSIS of larger organisms  A slime layer that sticks the cells together, it is slippery Cytoplasm:  for cellular growth, metabolism, replication of genetic material of bacterial cell  store house of all chemicals and components used to sustain the life of a bacteria Plasma Membrane:  semi-permeable membrane that regulates what goes in and out of the cell  composed of phospholipids, proteins and carbohydrates  transportation of substances, removal of wastes, and providing a mechanical barrier to the cell Ribosomes:  for protein synthesis  helps in transferring the genetic material of bacterial cells   where antibiotics act upon Flagella:  is a cellular component that can only be found mostly in prokaryotes like bacteria  hair-like structure that provides a means of locomotion  helps the bacterium to move clockwise or counter-clockwise and forward  found on one end or both ends of the bacteria Pili:  hair-like projections emerging from the surface of the bacterial cell  assist the bacteria in adhering or attaching itself on a surface and sometimes to a HOST  involved in gene transfer mechanism (fertility pili)  CONJUGATION - gene is transferred through the pilus of the donor to the recipient cell Plasmid:  small circular DNA  exchange DNA between bacterial cells Nucleoid:  irregularly-shaped section of the bacterial cell where the DNA is housed  lacks the MEMBRANE found in nucleus  contains RNA, proteins and enzymes for cellular processes  1st achievement test reviewer Topic: Introduction to Cell Structure and Functions of Animal and Plant Cell Plasma Membrane:  The outer covering of the cell  A phospholipid bilayer made up of 2 parts (Heads and Tails)  The Heads are Hydrophilic (agree with water)  The Tails are Hydrophobic (disagree with water)  It regulates what goes in and out of the cell (that's why it is  also called "SEMI-PERMEABLE MEMBRANE") Endoplasmic Reticulum: collectively modifies proteins and synthesizes lipids Rough Endoplasmic Reticulum - "rough" due to the RIBOSOMES attached to the membrane, also for PROTEIN synthesis. Smooth Endoplasmic Reticulum - "smooth" because there are NO RIBOSOMES attached to it, also for CARBOHYDRATE, LIPIDS, STEROID HORMONE synthesis. Cytoplasm - entire region between plasma and the nuclear envelope, fluid portion of the cell where organelles appear to be floating. Cytosol - maintains shape to the cell, hold cell organelles and, carry out metabolic processes (glycolysis, cell division, protein synthesis, etc.) Ribosomes - are very essential for PROTEIN SYNTHESIS. PROTEINS help in the production of enzymes, hormones, antibodies, pigments, structural components and, surface receptors. Golgi Bodies/Apparatus - sorting, tagging, packaging and, distribution of lipids and proteins destined to leave the cell or for use within the cell. Peroxisomes - carries out enzymes which are involved in oxidation reactions that break down fatty acids and amino acids. Mitochondria - "powerhouse" of the cell - responsible for making ATP (Adenosine Triphosphate), also cells' main energy carrying molecule. ATP - short term stored energy of the cell - produced through the process called CELLULAR RESPIRATION. Cytoskeleton - network of protein fibers that: 1. maintain the shape of the cell 2. secure organelles in specific positions 3. allows cytoplasm and vesicles to move within the cell 4. enable cells within multicellular organisms to move Nucleus - "governor" of the cell, controls all the activities of every organelle inside the cell, also house the genetic material called DNA (contains instructions for the structure and function of all living organisms). NUCLEAR ENVELOPE - outermost portion of the nucleus that separates the nucleus from cytoplasm, phospholipid bilayer. NUCLEOPLASM - semi-solid fluid inside the nucleus, also where we can find the chromatin and the nucleolus NUCLEOLUS - region of intensive synthesis of Ribosomal RNA Lysosomes - contains high levels of degrading (digestive/hydrolytic) enzymes for rapid breakdown of proteins, nucleic acids, lipids and, carbohydrates. "SUICIDE BAGS" of the cell * when a cell is about to die - lysosome bursts. Release of digestive enzymes- to eat up the dying cell- creates space for new cells. Destroy pathogens that might enter the cell through phagocytosis or endocytosis. PLANT CELL Cell Wall - outermost covering of the plant cell. Made up of CELLULOSE which is a type of carbohydrate. Protects the cell, structural support, gives shape to the cell. Chloroplast - plant cell organelles that carry out PHOTOSYNTHESIS, also contains CHLOROPHYLL (photosynthetic pigment which gives plants their green color). Vacuole - regulates the plant cell's water concentration in constantly changing environmental conditions.