General Biology
BIOLOGY is the study of life and living organisms, including their functions, growth evolution, distribution, and taxonomy.
Cell:
-basic unit of life
-forms all of the living things.
-unicellular and multicellular.
-macroscopic and microscopic
-organelles with different Functions
The invention of the cell and the discovery of the cell
LENS IS DERIVED FROM LATIN WORD LENTIL (LENTIL BEAN)
THESE LENSE CAN MAGNIFY OBJECTS ONLY AT 6X-10X
HOOKE USE A CORK AND CALL THE AMALL COMPARTMENTS CELLULLA (CELL)
LEEUWENHOEK OBSERVED BACTERIA, BLOOD CELLS, PROTISTS (ANIMACULES)
LEEUWENHOEK WAS THE FIRST SCIENTIST TO OBSERVE SPERM CELLS AND EGG CELLS.
LEEUWENHOEK DISCOVERED THAT EGG CELL AND SPERM CELLS UNDERGO FERTILIZATION WHICH DISPROVED THE THEORY OF SPONTANEOUS GENERATION
Cell Theory
AFTER THE IMPROVEMNTS OF MICROSCOPE, MATTHIAS JAKOB SCHLEIDEN AND THEODORE SCHWANN USE THE MORE ADVANCE MICROSCOPE TO OBSERVE ORGANISMS.
SCHLEIDEN PUBLISHED A RESEARCH ABOUT THE PLANTS SCHWANN RESEARCH ANIMALS SLIDES. THEY CONCLUDE THAT…
1. ALL ORGASIMS ARE MADE UP OF CELL.
2.THE BASIC UNIT OF LIFE IS CELL.
RUDOLF BLUDWIG KARL VIRCHOW (1858) NOTICE THAT THE EXISTENCE OF DISEASES IN THE ORGANS AND TISSUES COME FROM AFFECTED CELLS. FROM THIS HE STEATED THAT “OMNIS CELLULA E CELLULA” MEANS ALL CELLS ARISE FROM PRE-EXIXTING CELLS. IT WAS BELIEVED HOWEVER, THAT THIS DISCOVERY WAS INITIALLY MADE BY ROBERT REMAK, A JEWISH SCIENTIST IN 1855 WHEN HE TRIED TO PROVE THE IDEA OF CELL DIVISION BY HARDENING THE CELL MEMBRANE.
The theory states that: All living organisms are made up of cells. Cells are the basic structural/organizational unit of all organisms. All cells come from pre-existing cells
THE THEORY OF SPONTANEOUS GENERATION
Spontaneous generation is a superseded scientific theory that held that living creatures could arise from nonliving matter and that such processes were commonplace and regular. It was hypothesized that certain forms, such as fleas, could arise from inanimate matter such as dust, or that maggots could arise from dead flesh. IT STATES THAT LIVING THINGS CAN ARISE FROM NON LIVING THINGS. IT WAS GENERALLY ACCEPTED UNTIL THE 19TH CENTURY.
Francesco Redi (1626-169) Experimented on fresh meats in jars. He concluded that maggots can only came from something alive.
John Needham (1713-1781) He boiled the chicken broth and then sealed it. He presented it as an evidence that Spontaneous Generation Theory is real.
Lazzaro Spallanzani (1729- 1799) He thought that Needham’s experiment is flawed because the microorganism may have entered the broth through the air. He set another experiment with a sealed chicken broth in a flask and another that is not sealed. He concluded that the theory of Spontaneous Generation may not be
Louis Pasteur (1822-1895) He experimented meat broth in a 2 s-shaped flask, 1 without sealed and the other is not. The 1ˢᵗ flask was entered by the microorganisms while the 2ⁿᵈ flask did not. He concluded that the microorganism did not came from the broth itself
CELL
The cell is the basic unit of life and the structural building block of living organisms.
Cell Membrane(plasma membrane) -is found in all cells and separates the interior of the cell from the outside environment.
Cytoplasm is the gelatinous liquid that fills the inside of a cell. It is composed of water, salts, and various organic molecules. Some intracellular organelles, such the nucleus and mitochondria, are enclosed by membranes that separate them from the cytoplasm.
Centrioles are paired barrel shaped organelles located in the cytoplasm of animal cells near the nuclear envelope
Nucleus controls and regulates the activities of the cell (e.g., growth and metabolism) and carries the genes, structures that contain the hereditary information.
Nucleolus is the largest structure in the nucleus of eukaryotic cells. It is best known as the site of ribosome biogenesis,which is the synthesis of ribosomes. The nucleolus also participates in the formation of signal recognition particles and plays a role in the cell's response to stress.
Ribosomes are macromolecular machines, found within all cells, that perform biological protein synthesis. Ribosomes link amino acids together in the order specified by the codons of messenger RNA molecules to form polypeptide chains. Ribosomes consist of two major components: the small and large ribosomal subunits.
Endoplasmic reticulum is a part of a transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits –rough endoplasmic reticulum, and smooth endoplasmic reticulum
Golgi apparatus, also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells. Part of the endomembrane system in the cytoplasm, it packages proteins into membrane-bound vesicles inside the cell before the vesicles are sent to their destination.
Lysosomes are membrane enclosed organelles that contain an array of enzymes capable of breaking down all types of biological polymers— proteins, nucleic acids, carbohydrates, and lipids.
Mitochondria is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate,which is used throughout the cell as a source of chemical energy.
Cellwall is a structural layer that surrounds some cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, and functions as a selective barrier.
Flagellum is a hair-like appendage that extends from certain cells, including sperm cells of animals and plants, fungal spores, and various microorganisms. It primarily functions in movement or motility. Many protists that possess flagella are called flagellates. A microorganism may have one or several flagella.
Cilium is membrane bound organelle found in most types of eukaryotic cell. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projection that extends from the surface of the much larger cell body
Cilium — singular
Cilia — plural
Flagellum — singular
Flagella — plural
Chitin is a natural and abundant biopolymer. It is commonly found in the cell walls of fungi, exoskeletons of insects,shells of crustaceans, and in other lower eukaryotic organisms. Chitin and its derivative, have structures similar to cellulose.
Root hair, or absorbent hairs, are outgrowths of epidermal cells, specialized cells at the tip of a plant root. They are lateral extensions of a single cell and are only rarely branched. They are found in the region of maturation, of the root.
Chloroplast is an organelle that contains the photosynthetic pigment chlorophyll that captures sunlight and converts it into useful energy, thereby, releasing oxygen from water.
Vacuole is a membrane-bound cell organelle. In animal cells, vacuoles are generally small and help sequester waste products.In plant cells, vacuoles help maintainwater balance. Sometimes a single vacuole can take up most of the interior space of the plant cell.
CLASSIFICATION OF CELLS
Cells can be classified as:
•Eukaryotic or Prokaryotic cells
•Plant Cells or Animal Cell
•Unicellular and Multicellular
Eukaryotic cells:
•contains membrane- bound organelles such as a nucleus, mitochondria, and an endoplasmic reticulum.
•larger and more complex than prokaryotic cells found in domains Archaea and Bacteria.
Prokaryotic cells:
• does not have a true nucleus or membrane bound organelles.
• Mostly are microorganisms and unicellular.
• It is the first kind of cell to develop about 3.5 billion of years ago
• Simple organisms possessing cells that are smaller in size with simple internal structures
Prokaryotes- simple life forms such as bacteria,blue-green algae, and archaeans possess the simple cellular componets of prokaryotic cells. Small size and simple structure allow the to reproduce fast
• Prokaryotic cells has a nucleus which is not enveloped by nuclear membrane called nucleoid
• The prokaryotic cell membranes is compose of phospholipids which serve as a semipermeable barrier to the cell’s outside environment.
• Prokaryotes contain plasmids.
• Prokaryotes have cilia and flagella that enable them to move.
Eukaryotes
• Larger size and more complex structural components.
• Unicellular or multicellular
• (True cells) and have a well-organized internal condition because of their membrane.
• Bigger than prokaryotes and contain more DNA encased with in nucleus, making them capable of more protein production.
Has organelles that is effecient for different roles and functions
Cellular processes and organizes space
Unicellular
• These are organisms composed of only a single cell.
• Reproduction occurs through asexual methods.
• Their mode of nutrition is through phagocytosis, which takes place by engulfing food.
Multicellular Organisms
• Examples include plants and animals.
• They are capable of processing nutrients and digesting food.
• Their cells have different functions and roles in the body.
• Their cells are organized to form complex structures.
• They undergo cell division for growth, repair, and replacement of damaged or old cells.
