General Biology 1 Lecture Notes (PDF)

Colegio San Agustin-Makati Senior High School Department First Semester - AY 2024-2025 GENERAL BIOLOGY-1 TOPICS Cell theory Cell organelles Prokaryotic Vs. Eukaryoti...

Colegio San Agustin-Makati Senior High School Department First Semester - AY 2024-2025 GENERAL BIOLOGY-1 TOPICS Cell theory Cell organelles Prokaryotic Vs. Eukaryotic cells Cell types Cell modifications Cell cycle Cell division Cell Theory Francesco Redi’s experiment depicts how maggots can grow through different set ups.This experiment supported the idea that the cells come from living organisms. John Needham’s experiment was about boiling a broth and sealing it to see if there will be growth of microorganisms, which was eventually observed. This experiment supported the idea of spontaneous generation, that cells can come from inanimate matters. Lazaro Spallanzani’s experiment modified Needham’s experiment by boiling the broth longer and sealing the flask tighter. This does not show growth of microorganisms. This experiment supported the idea that cells can’t come from nonliving things. Louis Pasteur’s experiment used a swan-neck flask, eventually showing microorganisms did not grow on the flask. Then the curved neck was removed, eventually showing microorganisms grow on the flask. It supported the idea that cells came from living organisms. Theodore Schwann - all animals are made up of cells Mattias Schleiden - all plants are made up of cells Rudolf Virchow - diseases start with the problem with cells. Cells came from pre-existing cells. Cell Theory 1st Tenet - All organisms are composed of one or more cells.  Cell Theory 2nd Tenet - Cells are the smallest and most basic unit of structure and function of organisms. Cell Theory 3rd Tenet - Cells came from previously existing cells. Cell Organelles Organelle Structure/Composition Function Cell Membrane Phospholipid Bilayer: Act as a barrier of the cell, Head - Phosphate and separating and protecting it Glycerol from the outside environment Tail - Fats of the cell. Cell Wall Plant - Polysaccharide cellulose A rigid layer that acts as a Bacteria - Peptidoglycan secondary protective layer of Fungi - Chitin various organisms. Cytoplasm Cytosol - jelly-like portion Site of different chemical  reactions and suspends organelles. Nucleus Nuclear Membrane Storehouse of DNA. Protects Nuclear Pore genetic materials. Nucleolus Membrane - protects the nucleus and the DNA Pore - entry and exit points of substances such as proteins Nucleolus - helps in the production of protein that codes characteristics Endoplasmic Reticulum Smooth Endoplasmic Smooth - responsible for Reticulum synthesizing lipids Rough Endoplasmic Reticulum Rough - responsible for synthesizing proteins Golgi Apparatus Cis face Involved in modifying, sorting, Trans face and packaging proteins Cis - receiving area Trans - releasing area Vesicles Small membrane-bound sac Encloses substances like Pinched off part of ER proteins and lipids for transport. Vacuoles Animals - numerous but small Store water, nutrients, and in size other substances necessary for Plants - one central and big in survival size Lysosome Round-shape Contains lysozyme to breakdown substances Peroxisome Contains digestive enzymes Breakdown hydrogen peroxide into water and oxygen  Breakdown alcohol Mitochondria Double membrane Produce small molecules of Folds energy Produce ATP through cellular respirations Plastids Double membrane Produce energy for plants With own DNA and ribosomes Centrosome and Centrioles Pair of centrioles Primary microtubule organizing center CIlia and Flagella Cilia: 5-10 micrometer Cilia - move fluid or move through fluid Flagella - 15-25 micrometer Flagella - makes the cell propel faster Cytoskeleton Network of protein filaments Provide structural support, and tubules shape, and organization to the cell. Prokaryotic Vs Eukaryotic Cells Prokaryotic Eukaryotic Definition Type of cell that lacks distinct Type of cell that contains nucleus and membrane-bound distinct nucleus and organelles. membrane-bound organelles Nucleus None Present Genetic Material Present in the nucleoid Present inside the nucleus Plasmid - extrachromosomal DNA Organelles No membrane bound Membrane bound organelles organelles  Examples Bacteria such as E.coli, Yeast, amoeba, fungi, animal Streptococcus pneumoniae, cells, and plant cells Salmonella enterica, and Staphylococcus aureus Cell Types 1. Animals Epithelial Cells - line surfaces of organs that act as protective barriers. Consists of receptors for detection of environmental agents and tissue repair. Nerve Cells - consist of soma (body cell), axon covered by myelin sheath, dendrites, and axon terminals. Transmits signals from the body to the brain and vice versa. Capable of receiving sensory information from the environment. Muscle Cells - generate force and movement through contractions 1. Skeletal - aids in the movement of the bones 2. Smooth - control functions of various organs 3. Cardiac - pump blood through the heart Connective Tissue Cells - support and bind tissues 1. Fibroblast - collagen, tissue repair 2. Osteocytes - bone 3. Adipocyte - stores fats 2. Plants Parenchyma - youngest among collenchyma and sclerenchyma, thin-walled, and used for storage of substances and tissue repair. Collenchyma - younger than sclerenchyma but older than parenchyma, with thick walls for strength and stability Sclerenchyma - oldest among parenchyma and collenchyma, with thick walls for strength and stability Xylem - transports water and minerals Phloem - transports water and food Cell Modifications Microvilli - increase surface area for nutrient absorption in the intestines of animals Root Hairs - increase surface area for water and nutrient absorption of the plants Cilia and Flagella - enable movement of organisms through fluid and movement of fluid.  Adipocytes - stores energy in the form of fats Osteocytes - found in the bound matrix, responsible for regulating bone density Secretory Cells - responsible for the release of hormones and enzymes in the body Nerve Cells - transmit electrical signals to communicate with other cells Erythrocytes - biconcave in shape for more efficient gas exchange even in narrow capillaries Myocytes - facilitate contraction for movement Cell Cycle Cell Process Phases / Checkpoints Key Ideas Cell Cycle 1 G1 Phase Duplication of organelles Start of duplication of centrioles 2 S Phase Replication of DNA 3 G2 Phase Duplication of centrioles is completed 4 M Phase Process of cell division occurs 5 G0 Phase Resting phase Cell is not dividing  6 G1/S Checkpoint Evaluate DNA damage 7 G2/M Checkpoint Ensure successful DNA replication 8 M Checkpoint Spindle assembly checkpoint Ensure spindle fiber is properly attached to the centromere of the chromosome Cell Division Mitosis Cell Phases Illustration Key Ideas Process Mitosis Interphase Cell growth Preparation for cell division G1 Phase, S Phase, and G2 Phase Prophase Nuclear envelope disintegrate Centrioles move to opposite poles Spindle fiber starts to form  Metaphase Chromosomes align at the center Spindle fiber attaches to the centromere Anaphase Sister chromatids are pulled to the opposite poles with the use of spindle fiber Telophase Cleavage furrow forms Reappearance of nuclear envelope Spindle fiber breaks down Cytokinesis Mitosis is completed Cell membrane completely separates 2 identical daughter cells are produced. Meiosis Cell Phases Illustration Key Ideas Process Meiosis I Interphase Cell growth Preparation for cell division G1 Phase, S Phase, and G2 Phase Prophase I Nuclear envelope disintegrate Centrioles move to opposite poles Spindle fiber starts to form Homologous chromosome pair-up Crossing-over happens Metaphase I Homologous chromosomes align at the center Spindle fiber attaches to the centromere Anaphase I Homologous chromosome are pulled to the opposite poles with the use of spindle fiber Telophase I Homologous chromosome arrive at the opposite poles Cleavage furrow forms Reappearance of nuclear envelope Spindle fiber breaks down Cytokinesis Meiosis I is completed Cell membrane completely separates 2 unique daughter cells are produced. Meiosis II Prophase II Nuclear membrane breaks down Spindle fiber starts to form Chromosomes condense Metaphase II Chromosomes align at the cell equator. Spindle fibers attach to the centromeres. Anaphase II Sister chromatids are pulled to opposite poles of the cell Telophase II Chromatids arrive at opposite poles and decondense. Nuclear envelopes reform Cytokinesis Meiosis II is completed Results in 4 genetically distinct haploid cells.