Cell: The Basic Unit of Life - PDF

CELL: THE BASIC UNIT OF LIFE Ms. JULIA MHAE B. CELON, LPT. Lecturer I  INTRODUCTION All living things are made up of cells - the basic unit of a living organism. Cells are made up of atom and they are the smallest biologically functioning element of life. Based on the number...

CELL: THE BASIC UNIT OF LIFE Ms. JULIA MHAE B. CELON, LPT. Lecturer I  INTRODUCTION All living things are made up of cells - the basic unit of a living organism. Cells are made up of atom and they are the smallest biologically functioning element of life. Based on the number of cells, organisms can be either unicellular or multi – cellular. Bacteria are unicellular, while humans are multi-cellular. CELL HISTORY Cytology- study of cells Robert Hooke, an English Scientist, is referred as the “Father of Cytology” He used a microscope to examine cork (plant) Hooke called what he saw "Cells" CELL HISTORY Robert Brown discovered the nucleus in 1833. Matthias Schleiden German Botanist ALL PLANTS "ARE COMPOSED OF CELLS". Theodor Schwann Also in 1838, discovered that animals were made of cells CELL HISTORY Rudolf Virchow 1855, German Physician " THAT CELLS ONLY COME FROM OTHER CELLS". His statement debunked "Theory of Spontaneous Generation" CELL THEORY The COMBINED work of Schleiden, Schwann, and Virchow make up the modern CELL THEORY. The Cell Theory states that: 1. All living things are composed of a cell or cells. 2. Cells are the basic unit of life. 3. All cells come from preexisting cells. CELL DIVERSITY Cells within the same organism show Enormous Diversity in: Size Shape Internal Organization NERVE CELL SKIN CELL EGG CELL PLANT CELL BACTERIAL CELL  CELL DIVERSITY CELL SIZE CELLS ARE SMALL FOR TWO REASONS: 1. Limited in size by the RATIO between their Outer Surface Area and Their Volume. A small cell has more SURFACE AREA than a large cell for a GIVEN VOLUME OF CYTOPLASM.  CELL DIVERSITY CELL SIZE CELLS ARE SMALL FOR TWO REASONS: 2. The cell's nucleus (the brain) can only control a certain amount of living, active cytoplasm.  CELL DIVERSITY CELL SHAPE Diversity of form reflects a diversity of function. THE SHAPE OF A CELL DEPENDS ON ITS FUNCTION.  CELL DIVERSITY INTERNAL ORGANIZATION  CELL DIVERSITY INTERNAL ORGANIZATION  CELLULAR ORGANELLES NUCLEUS They are spherical bodies surrounded by the nuclear membrane and contain many organelles, including nucleolus. It is the location for the synthesis of nucleic acids.  CELLULAR ORGANELLES NUCLEOLUS The nucleolus is usually visible as a dark spot in the nucleus. It is the location of ribosome formation and the synthesis of RNA and proteins.  CELLULAR ORGANELLES MITOCHONDRIA Singular: Mitochondrion These are spherical to rod-shaped organelles with a double membrane. The inner membrane is in folded many times, forming a series of projections (called cristae) They are the powerhouses of the cell where oxidative reactions and electron transport occur. They change energy from food to energy for the cell.  CELLULAR ORGANELLES LYSOSOMES They are small and round organelles surrounded by a membrane They contain digestive enzymes that break down materials in the cell. They break down large food particles into smaller ones as well as old cell parts. Lysosomes are the cell's clean- up crew.  CELLULAR ORGANELLES ENDOPLASMIC RETICULUM It is attached to the outside of the nucleus. Smooth ER – no ribosomes embedded on it. Site of lipid synthesis. Rough ER – there are ribosomes embedded on it. Aid the ribosomes in synthesizing proteins. These organelles are very small, made up of 50 proteins and several long RNAs bound together.  CELLULAR ORGANELLES ENDOPLASMIC RETICULUM It carries proteins and other materials from one part of the cell to another.  CELLULAR ORGANELLES GOLGI BODY a flattened, layered, sac-like organelle that looks like a stack of pancakes and is located near the nucleus It produces the membranes that surround the lysosomes and packages proteins and carbohydrates into membrane- bound vesicles for "export" from the cell.  CELLULAR ORGANELLES CELL MEMBRANE Also known as the plasma membrane Electron microscopic examinations of cell membranes have led to the development of the lipid bilayer model (also referred to as the fluid-mosaic model).  CELLULAR ORGANELLES CELL MEMBRANE The most common molecule in the model is the phospholipid, which has a polar (hydrophilic) head and two nonpolar (hydrophobic) tails. These phospholipids are aligned tail to tail so the nonpolar areas form a hydrophobic region between the hydrophilic heads on the inner and outer surfaces of the membrane  CELLULAR ORGANELLES CELL MEMBRANE It functions as a semi-permeable barrier, allowing a very few molecules across it while fencing the majority of organically produced chemicals inside the cell.  CELLULAR ORGANELLES CYTOPLASM This is the jellylike material between the plasma membrane (cell membrane) and the nuclear envelope The cytoplasm is where organelles are located. CELL METABOLIC PROCESS Cell metabolism is the collective set of chemical reactions. They occur within living cells to sustain life and maintain cellular functions. These processes involve the conversion of nutrients into energy, the synthesis of biomolecules, and the regulation of metabolic pathways. Understanding cell metabolism is crucial for comprehending how cells obtain energy, generate building blocks for cellular components, and adapt to changing environmental conditions. CELL METABOLIC PROCESS Cellular metabolic pathways are can be categorized into two – ANABOLIC and CATABOLIC. Anabolic Catabolic they require energy and means that they release use it to build large energy and break apart molecules from small large molecules to make ones. Ex. Photosynthesis smaller ones. Ex. Cellular respiration and Glycolysis.  CELL METABOLIC PROCESS for EUKARYOTES CELLULAR RESPIRATION It is a type of metabolic pathway that breaks down glucose to make adenosine triphosphate, or ATP.  CELL METABOLIC PROCESS in EUKARYOTES CELLULAR RESPIRATION The main reactant are glucose and oxygen, while the main products are carbon dioxide, water and ATP. C6H12O6 + O2 -→ CO2 + H2O + ATP  CELL METABOLIC PROCESS for EUKARYOTES CELLULAR RESPIRATION The different pathways of cellular respiration in eukaryotes are: Glycolysis Pyruvate oxidation Citric acid or Krebs Cycle Oxidative phosphorylation  CELL METABOLIC PROCESS in EUKARYOTES PHOTOSYNTHESIS This metabolism happens in plant cells, some algae and certain bacteria called cyanobacteria. It occurs in chloroplasts and it produces sugar along with oxygen.  CELL METABOLIC PROCESS in PROKARYOTES You can categorized prokaryotes into different groups based on their metabolism. The main types are the following: Heterotrophic Autotrophic Phototrophic Chemotrophic THAT’S ALL. THANK YOU!