General Biology I Q1 Reviewer PDF

GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Q1W2 Biotechnology biological organisms and its use and applicat...

GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Q1W2 Biotechnology biological organisms and its use and application for 1.0 INTRODUCTION TO BIOLOGY industrial and medical purposes Biology Science of Life From the Greek words; 1.2 PIONEERS IN BIOLOGY bios (life) and logos (study of/science of) Anton van Leeuwenhoek - microscopes/animacules Carolus Linnaeus - taxonomy 1.1 BRANCHES OF BIOLOGY Jean Lamarck - naturalist evolution / adaptation / use Botany & disuse study of plants, its taxonomy and morphoanatomy Louis Pasteur - disproved abiogenesis and discovered Zoology pasteurization study of classification and morphoanatomy of animals Gregor Mendel - Mendelian genetics; used pea plants Anatomy study of structures of living organisms Charles Darwin - law of natural selection Taxonomy Thomas Hunt Morgan - genetics for fruit flies study of classifications and systematics of living (chromosome theory of heredity) organisms Sir Alexander Fleming - discovered Cytology penicillin/antibiotics by accident study of cell parts and their functions James Watson and Frederick Crick - discovered the Genetics DNA’s structure (double helical) study of genes, heredity, and genetic disorders Microbiology study of microorganisms 1.3 SCIENTIFIC METHOD Parasitology Scientific Method study of parasites The logical & systematic way of solving a scientific problem Entomology study of different insects, biology and taxonomy Steps in the Scientific Method 1. Define the problem Embryology/Developmental Biology 2. Collection of data study of the development of living organisms from 3. Hypothesis fertilization to death 4. Experimentation 5. Observation Physiology 6. Recording of data or documentation study of body functions 7. Drawing of conclusion 8. Reporting Ecology study of the environment and interrelationship of the environment and the organisms living on it Histology/Pathology study of tissues at microscopic level @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 1 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Homeostasis 1.4 LIFE the ability of an organism to maintain constant internal conditions despite environmental changes Life Absence of death Examples: thickening of fur in winter, darkening of skin in sunlight, seeking for shade in heat, production of A person may be dead, but their body organs/cells more red blood cells at high altitude, dog panting to could still be alive. release body heat, etc. Homonculus Unique Structural Organization (order) Man the seed, woman the incubator Cell > Tissue > Organ > Organ System > Organism Latin for “little man” or “little person.” 1.6 ABIOGENESIS & BIOGENESIS Believed to have the capacity to increase in size, giving rise to an adult human. Spontaneous Generation (Abiogenesis) Theorized/sketched by Nicolaus Hartsoeker (1964) Also called Free Cell Formation/Abiogenesis States that certain non-living material has the ability to change into living organisms 1.5 CHARACTERISTICS OF LIFE Questioned by Francesco Redi Metabolic Process Nutrient Uptake, Nutrient Processing, and Waste Disproved by Louis Pasteur and approved Redi’s Elimination experiment refers to the total of all chemical reactions and Law of Biogenesis associated energy changes taking place within an In nature, life comes only from life and that of its kind organism Living things came from living organisms Energy processing; Energy = ability to do work Generative Process Q1W2 Growth, reproduction, and development 2.0 CELL THEORY Growth = increase in the size of an individual Zacharias Jensen Reproduction = increase in the number of individuals Made the compound microscope (first microscope) in a population of organisms; could be sexual or asexual Anton Van Leeuwenhoek Father of microbiology, Responsive Process Sensitivity or response to stimuli Improved the microscope and used it to make some of the earliest recorded observations of single-celled When organisms respond to changes within their organisms, including bacteria and protists. bodies and their surroundings Found bacteria in his dental scrapings called Irritability = reaction to stimuli “animalcules” Control Process Robert Hooke mechanism that ensures an organism will carry out Coined the term “cell” after observing cork tissue metabolic activities in the proper sequence (coordination) and at the proper rate (regulation) Laid foundation for cell theory @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 2 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Isaac Newton Q1W2 Newton’s laws of motion and universal gravitation 3.0 ENDOSYMBIOTIC THEORY indirectly influenced the study of biology by fostering systematic and scientific approach to understanding the natural world, including living organisms Endosymbiotic Theory Explains how eukaryotic cells may have evolved from Matthias Schleiden prokaryotic cells Proposed the idea that all plants are made of cells Ancient (prokaryotic) cells lacked chloroplast and Emphasized the importance of cells in structure mitochondria; these cells engulfed aerobic bacterium and function of plants and cyanobacterium which evolved into the aforementioned organelles Believed in free cell formation or abiogenesis It proposes that mitochondria (aerobic bacteria) and Theodore Schwann chloroplasts (cyanobacteria) were once separate All animals are made of cells, thus completing the prokaryotic bacteria that were consumed into the foundational aspects of the cell theory membrane of another prokaryotic bacteria (“blob” bacteria), forming a symbiotic system that evolved into Opposed free cell formation or abiogenesis eukaryotic cells. Rudolf Virchow The process of prokaryotes combining/absorbing one "Omnis cellula e cellula," meaning that every cell arises another to make complex cells or how they evolved from a pre-existing cell. This idea emphasized the continuity of life and became a crucial component of cell theory. Proved law of biogenesis Robert Remack Emphasizing the role of cell division and embryology, further supporting the idea that cells are fundamental to life. Claimed that he proved law of biogenesis 2.1 POSTULATES OF CELL THEORY Evidences that relate chloroplast and mitochondria as prehistoric bacteria 1. Chloroplast and mitochondria divide the same way 1st Postulate as the prehistoric bacteria; All living organisms are composed of one or more cells 2. The two organelles have their own circular DNA and ribosomes similar to prehistoric bacteria but different 2nd Postulate from the eukaryotic cells. The cell is the basic unit of structure and organization of life 3. The presence of a double membrane which indicates that engulfment has happened. 3rd Postulate All cells came from pre-existing cells @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 3 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM DNA 3.1 TYPES OF CELL Genetic material of the cell According to Number of Cell/s 1. Unicellular - single-celled organisms (amoeba, Ribosomes bacteria, paramoecium) Molecular machines that synthesize proteins 2. Multicellular - organism consisting of many cells Nucleoid Region (plant, animals) Majority of prokaryotic DNA is found in a central region called the nucleoid According to Presence of Nucleus 1. Prokaryotes - (Pro) Ancient, (Karyo) Nucleus Typically consists of a single large loop called a 2. Eukaryotes - (Eu) True, (Karyo) Nucleus circular chromosome Peptidoglycan 3.2 COMPONENTS FOUND IN ALL CELLS Polymer composed of linked carbohydrates and small proteins Plasma Membrane Outer covering that separates the cell's interior from its Cell Wall surrounding environment Provides an extra layer of protection Cytoplasm Helps the cell maintain its shape, and prevents Consists of jelly-like cytosol inside the cell, plus the dehydration cellular structures suspended in it. Made of peptidoglycan – polymer composed of linked In eukaryotes, cytoplasm specifically means the region carbohydrates and small proteins outside the nucleus but inside the plasma membrane Bacteria cell walls have peptidoglycan DNA Plant cell walls are made of cellulose Genetic material of the cell Fungi have chitin Ribosomes Capsule Molecular machines that synthesize proteins Outermost layer of carbohydrates Sticky mucus that helps the cell attach to surfaces in 3.3 COMPONENTS OF PROKARYOTIC CELLS its environment Prokaryote a simple, single-celled organism that lacks a nucleus and membrane-bound organelles Three Basic Bacterial Shapes: 1. rod — bacilli 2. sphere — cocci 3. spiral — spirillum Plasma Membrane Outer covering that separates the cell's interior from its surrounding environment Flagellum Cytoplasm Note: Not all prokaryotes have flagella Consists of jelly-like cytosol inside the cell, plus the cellular structures suspended in it. Used by prokaryotic cells to move around In eukaryotes, cytoplasm specifically means the region outside the nucleus but inside the plasma membrane @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 4 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Fimbriae Q1W3 Numerous, hair-like structures that are used for 4.0 CELL STRUCTURE AND FUNCTIONS attachment to host cells and other surfaces Class of cell surface protrusions that are numerous, Cell relatively short and involved in attachment to surfaces The basic and fundamental unit of life Pilus/Pili (pl.) They are small in order to optimize surface Rod-like structures area-to-volume ratio. Allows bacteria to transfer DNA molecules to other Eukaryote bacteria, some are involved in bacterial locomotion multi-celled organism that has a nucleus and (bacterium movement) membrane-bound organelles Less numerous, longer, more specialized cell surface protrusions 4.1 EUKARYOTIC CELL COMPONENTS FIMBRIAE PILUS Plasma /Cell Membrane (Plasmalemma for plants) Cell Surface Protrusions Phospholipid bilayer with embedded proteins numerous less numerous Phospho – PO4/phosphate group Lipid – fatty acid shorter longer Bilayer – two layers attaches to surfaces more specialized purpose Exhibits fluid mosaic model Phosphate head is hydrophilic and Fatty acid tail is hydrophobic. Referring to the figure below, the green parts are cholesterol. (cholesterols are only present in humans; for animals, only sterol.) Cholesterol serves as the steroid for plasma membrane stability that maintains the fluid mosaic model Functios: Selective permeability, Diffusion, Osmosis, Transport by carriers, Endocytosis and exocytosis Glycolipids and glycoproteins are responsible for cell-cell recognition @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 5 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Nucleus Nucleoplasm Stores genetic information that determines the Semifluid medium of nucleus characteristics of cells pH is different from cytoplasm (NP more acidic & Controls cell activities heavier than CP) Genetic information > DNA > chromosome Ribosomes Small organelles where protein synthesis takes place Parts of the Nucleus Nuclear Envelope/Membrane May be found in: For protection Cytoplasm as polyribosomes ER as bounded ribosomes Double membrane with pores continuous with the ER Nuclear Pore Permits passage of proteins into, and ribosomal units out of the nucleus Nucleolus Contains ribosomal units which forms subunits of ribosomes Synthesizes RNA Chromatin (in the nucleoplasm) Undergoes coiling that forms chromosomes Chromatin = uncoiled Chromatid = coiled Endomembrane System (Compartmentalization) Chromosome Genetic makeup of the organism Formed by DNA bound to proteins For humans, 46 chromosomes in somatic cells, 23 in sex cells Male = XY, Female = XX Consists of: 1. Nuclear Envelope 2. Endoplasmic Reticulum 3. Golgi Complex 4. Lysosome 5. Vesicle Endoplasmic Reticulum (ER) Series of saccules (flattened vesicles) and tubules (membranous channels) connected to nuclear envelope @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 6 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Two Types of Endoplasmic Reticulum Lysosomes Rough ER (Saccular) Specialized vesicle containing hydrolytic digestive Bounded by ribosomes enzymes - lysozymes Synthesizes protein and packages them in vesicles Breaks down worn out cell parts and substances that transport it to Golgi Complex entering the cell, as well as the bad products sent by the golgi complex Smooth ER (Tubular) Connected to rough ER but has no ribosomes When inactive or missing, causes Tay-Sachs disease Synthesizes Lipids, Detoxifies, Metabolizes Mitochondria Carbohydrates and Produces Hormones The powerhouse of the cell Prevalent in Liver Cells Cell Respiration/ATP Production (Adenosine Triphosphate) process: 1. Glycolysis ROUGH ER SMOOTH ER 2. Krebs Cycle 3. Oxidative Phosphorylation/ Electron Transport Chain Bounded by Continuous (produces the most ATP) (Chemiosmosis) ribosomes with rough that faces the ER Have their own DNA (mtDNA which is from our cytoplasm mother’s egg cell) Saccular Tubular shape shape Parts of Mitochondria: 1. Inner and Outer Membrane protein lipid 2. Cristae - Infoldings synthesis; synthesis, 3. Matrix - contains mtDNA then detoxification, packages carbohydrate proteins in metabolism, vesicles for hormone transport to production the golgi complex No ribosomes Prevalent in liver, endocrine glands Golgi Complex Discovered by Camillo Golgi Stack of flattened and curved saccules Processes, packages and secretes proteins from the ER (also modifies lipids) If good, make vesicles. If bad, make lysosomes @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 7 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Cytoskeleton Locomotory Organelles (Cilia and Flagella) Cyto (cell) + Skeleton (framework) Hair-like structures projecting from cell surface Network of microtubules and filaments Capable of cell movement and moving material along the surface of the cell Shapes the cell, & gives organelles capacity to move NOT present in plant cells Made up of mostly proteins Cillia Made up of: Short, numerous hairs 1. Microtubules (For Shape) [Tubulin] 2. Microfilaments (For Movement) [Actin and Myosin] Crawling Movement 3. Intermediate Filaments - Also has proteins such as collagen and elastin Present in Uterus (sperm cells hide in uterus cells’ cilia to wait out ovulation) ADDITIONAL NOTE: Red Blood Cells are biconcave and have an abundance of tubulin Flagella Long, few hairs Example for microtubules for shaping Red blood cells are biconcave due to the lack of nucleus (nucleus is Propelling Movement (Prokaryotes) replaced by hemoglobin), and it cannot maintain its structure due to the lack of cytoskeleton Undulating/Whip-Like Movement (Eukaryotes) Types of Flagella (refer to image): Protein Type of Function 1. Monotrichous - one tail on one end Framework 2. Lophotrichous - multiple tails on one end 3. Amphitrichous - one tail on each end Tubulin Microtubules Shape 4. Peritrichous - multiple tails everywhere Actin Microfilaments Movement Myosin Microfilaments Movement Various Intermediate Network, Support filaments (both shape and movement) Centrosomes “Cell center” with small rod-like structures called centrioles Holds the spindle fibers during mitosis Facilitates chromosome segregation during mitosis Centrioles Cillia Flagella Organizes microtubules to form spindle fibers in cell division short long Small rod-like structures numerous few Self-duplicating Crawling movement Prokaryotes - propelling Eukaryotes - undulating NOT present in plant cells (whip-like) @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 8 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Vacuoles Storage of food, ions and water CANNOT burst (It knows when it’s full) Plant Cell vacuoles are much larger than animal cells’ Plant cells shrivel up if vacuoles lack water (reason why we can visually tell if plants are dehydrated) As visible as the nucleus under the microscope Cell Wall Only present in Plant Cells (cellulose or if woody, lignin), Fungi Cells (chitin), and Bacteria (peptidoglycan) Surrounds cell membrane Protects and supports the cell Composition For… Cellulose For most plant parts; purely polysaccharides PLANT VS ANIMAL CELL Ligmin For hard parts of plants ANIMAL PLANT (e.g., bark) Cell Membrane YES YES Chitin For fungi Cell Wall NO YES Peptidoglycan For bacteria Endomembrane YES YES Plastids System Mostly in plant cells Locomotory YES YES Chemical factory of pigments Organelle Chloroplast – chlorophyll Mitochondria YES YES Chromosomes YES YES Centrosome YES NO Plastids NO YES Vacuoles YES YES @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 9 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Visual of Animal Cell Visual of Plant Cell @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 10 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Q1W4 Histology Study of tissues using microscopy. 5.0 MICROSCOPY Produces 2-dimensional images; orientation when sectioned affects what is seen. Microscopy The tool that serves to progress the study of cells. Uses a microscope to magnify objects and measure their clarity. History of the Microscope Early Microscopes First microscopes were constructed in the Netherlands during the late 1500s. Inventor uncertain; often credited to Zacharias Janssen, Hans Lippershey, or Hans Janssen. Anthony van Leeuwenhoek Developed the first microscope with high magnification and good image quality around 1670. Microscopy Concepts Used beads formed from drops of molten glass as Magnification lenses, mounted in a metal plate with an adjustable Refers to how much larger the object appears stage. Natural light or candle flame was used for compared to its real size. illumination. Essential for observing small details. Evolution of Microscope Design Microscope design evolved from simple microscopes Resolving Power (Resolution) (one lens) to compound microscopes (more than one Measures the clarity of the image. lens in series). Adequate resolution is necessary to distinguish Improved image quality and magnification. between two objects. Importance of Microscopy Types of Microscopes Biomedical Sciences Light Microscope Used to observe overall morphological features of Uses compound lenses and light to magnify objects. specimens; a quantitative tool. Commonly found in schools; lenses bend or refract Advances in fluorochrome stains and monoclonal light to make objects appear closer. antibody techniques have led to explosive growth in fluorescence microscopy. Electron Microscope Uses a beam of electrons to magnify objects. Physical and Materials Sciences Used to observe surface features of high-tech Two kinds: Scanning Electron Microscope (SEM) and materials and integrated circuits. Transmission Electron Microscope (TEM). Important in the semiconductor industry. Scanning Electron Microscope (SEM) Forensic Sciences Uses electrons to magnify objects up to two million Used to examine hairs, fibers, clothing, blood stains, times. bullets, and other items associated with crimes. Allows scientists to view the surface of cells. Essential tool for forensic scientists. @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 11 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Transmission Electron Microscope (TEM) Uses electrons to pass through very thin specimens. Allows scientists to view the internal ultrastructure of cells. Brightfield Microscope Uses light to illuminate the specimen. Commonly used in basic microscopy. Darkfield Microscope Uses a special condenser to block direct light, making the specimen appear bright against a dark background. Useful for observing live, unstained specimens. Phase-Contrast Microscope Enhances contrast in unstained cells. Useful for studying living cells. Fluorescent Microscope Uses selective wavelengths of light to illuminate biological specimens. Reveals self-luminescence of naturally occurring fluorescent dyes bound to particles, components, or antibodies of cells. Microscopy Units of Measurement Units used to measure microscopic objects. Micrometer – 1μm – 0.001 μm – 10,000A Nanometer – 1nm – 0.001 μm – 10A Angstrom unit – A – 0.1 nm – 0.0001 μm Limits of Resolution Various components that make up a microscope. 1. Eyepiece (Ocular Lens) This is the lens you look through at the top of the microscope It typically has a magnification of 10x or 15x 2. Objective Lenses These are the lenses located on the revolving nosepiece Parts of a Microscope They come in different magnifications (usually 4x, 10x, 40x, and 100x) determines how much the specimen will be magnified @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 12 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Different magnifications: Q1W5 a. scanning objective (4x) 6.0 CELL ORGANIZATION (QUIPPER) b. low power objective (10x) c. high power objective (40x) d. oil immersion objective lens Cell Structure and Function The hierarchy of biological organization includes the 3. Stage assemblage of life from the smallest biomolecules to The flat platform where the slide holding the specimen the interacting ecosystems of the biosphere. is placed Covers various levels of biological organization. It often has clips to hold the slide in place Levels of Biological Organization 4. Light Source Chemical This provides illumination to the specimen Atoms and molecules that make up the basic unit of life. It can be a mirror that reflects light from an external source or an electrical light bulb Includes four types of biomolecules associated with 5. Coarse Focus Knob life: carbohydrates, proteins, lipids (fats), and nucleic This knob is used for making large adjustments to the acids. focus of the microscope Organelle It moves the stage up and down to bring the specimen Distinct and specialized subcellular structures that into view contribute to the cell’s maintenance and reproduction. 6. Fine Focus Knob Membrane-bound structures in eukaryotic cells, e.g., This knob is used for making small adjustments to mitochondria, nucleus, Golgi apparatus, endoplasmic focus the image more clearly after using the coarse reticulum. focus knob Cell 7. Arm The smallest, basic, functional unit of life formed when The part of the microscope that connects the base to different atoms and molecules combine and function the head and supports the eyepiece and objective together. lenses Examples include skin cells, blood cells, muscle cells It is also used to carry the microscope. (fibers), and neurons. 8. Base Tissue The bottom part of the microscope that provides Groups of cells that work together to perform a stability and support specialized function. 9. Diaphragm Four types of animal tissue: epithelial tissue, Located under the stage, this part controls the amount connective tissue, muscle tissue, nervous tissue. of light that reaches the specimen, allowing for better visibility Organ Groups of tissues that work together to perform a 10. Revolving Nosepiece specialized function. This is the part that holds the objective lenses and allows you to switch between them easily Examples include skin, heart, leg muscle, brain. Organ System Groups of organs that work together to perform a certain process in the body. Examples include the integumentary system, circulatory system, muscular system, nervous system. @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 13 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Organism Q1W5 Formed by different organ systems that create 7.0 ANIMAL TISSUE complex interactions with one another to maintain balance (homeostasis) and sustain life. Tissue Examples include humans, grasses, dogs, cats, Composed of specialized cells of the same type that mushrooms. perform a common function in the body Population Types of Animal Tissue: Organisms that belong to the same species and live in 1. Epithelial tissue the same area. 2. Connective tissue 3. Muscular tissue Examples include humans living in the same house, 4. Nervous tissue koalas living in an area of the forest. Community 5.1 EPITHELIAL TISSUE Different populations living in the same area. Epithelial Tissue Examples include humans, cats, and dogs living in the Covers body surface and lines body cavities same house; koalas, kangaroos, and various tree species in an area of the forest. Tightly packed cells that form continuous layer/sheets Functions: protection, secretion, absorption, excretion, filtration Ecosystem Includes all the communities interacting with one forms the inner and outer lining of organs, the covering another and with their environment. in surfaces, and the primary glandular tissue of the body. Examples include humans, cats, dogs, and grasses getting resources from nonliving things like soil, water, Epithelial tissues are avascular, which means that they and sunlight. do not have a blood supply of their own. Biosphere They acquire nutrients and release waste materials Includes all the different kinds of ecosystems. through diffusion from the capillaries in the underlying connective tissue. Example is the entire surface of Earth where life thrives. Another distinct characteristic of epithelium is its ability to regenerate easily. Apical Surface One side of an epithelial cell that is unattached and is exposed to the body’s exterior or to the cavity of an internal organ. Some apical surfaces are smooth, but some have surface modifications, such as cilia or microvilli. Can be classified according to number of layers: Simple - single layer Stratified - many layers piled on top of each other Pseudostratified - appears to be stratified, but are actually simple since they touch the baseline; Pseudo=false @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 14 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Can be classified according to cell type: Squamous - flattened; found in lining of lungs and blood vessels, turtles & tortoise = squamates Cuboidal - cube-like in longitudinal section; found in lining of kidney tubules; forms a circle (like a tube) Columnar - pillars; have nuclei at the bottom (appears to be of different color due to difference in ph) Transitional - combination of at least 2 cell types; cuboidal when relaxed and squamous when stretched; found in urinary bladder ACCORDING TO NUMBER OF LAYERS Simple Single layer Stratified Layers of cells piled-up *Pseudostratified = appears to be layers, but all cells touch the baseline ACCORDING TO NUMBER OF LAYERS Squamous Flattened cells Lines lungs and blood vessels Cuboidal Cube-shaped cells Lining of kidney tubules Columnar Resembles rectangular pillars or columns Nuclei is usually at the bottom Transitional Combination of at least 2 cell types @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 15 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Naming: Example: Simple Stratified Parts of Epithelial Tissue 1. Baseline membrane structureless material secreted by cells in the lower surface of the epithelium joins epithelium to underlying loose connective tissue; neither connective or epithelial tissue made of matrix 2. Glands Epithelial tissue that secrete products a. Exocrine Secretes product into ducts (directly to organ) Outside the body salivary glands, mucus glands, sebaceous glands, sweat glands, sublingual, submaxillary, parotid b. Endocrine secretes product directly into bloodstream ductless hypothalamus, pituitary gland, thyroid gland, pancreas, testes, and ovaries 3. Junctions works to adjoin cells The presence of cell junctions like desmosomes and tight junctions permits the cells of epithelial tissue to absorb and filter different substances Can be classified as Tight, Gap, or Adhesion/desmosomes a. Tight junction Impermeable barrier Adjacent plasma membrane proteins join to produce a zipper-like fastening b. Gap junction Forms when two adjacent plasma membrane channels join Gives strength Allows small molecules, ions, and sugars to pass between molecules / permeation between cells c. Adhesion junction (desmosomes) Adjacent plasma membrane do not touch, but are held together by intercellular filaments attached to cytoplasmic plaques @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 16 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM 5.2 MUSCLE / CONTRACTILE TISSUE Muscle Tissue also known as Contractile Tissue composed of long & extensive cells called muscle fibers that can shorten or contract to produce Striations in the table signifies whether the muscles movements. are striated/non-striated ( +: striated, -: non-striated) which contain protein myosin (myo = muscle) and actin filaments for movement. Three types of muscle tissue: 1. Skeletal / Striated Muscle muscle tissue attached to the skeleton or bones. These muscles can be controlled consciously or voluntarily. Skeletal muscle cells are long, cylindrical, striated (with visible stripes) multinucleated (with more than one nucleus). When they contract, they pull the bone and the skin to cause movement. 2. Smooth / Visceral Muscle A type of muscle tissue commonly found in the walls of hollow organs such as intestines, stomach, bladder, blood vessels, and uterus. It involuntarily contracts slower than the other two types of muscle tissue. Smooth muscles are non striated, uninucleated, and spindle-shaped (have pointed ends) cells. 3. Cardiac Muscle muscle tissue found in the heart. Unlike a skeletal muscle, it is uninucleated (one nucleus) it moves involuntarily (cannot be controlled consciously) However, it has striations like skeletal muscle. Cardiac muscle cells are branching together and fit tightly together at junctions called intercalated disks. These disks contain gap junctions that facilitate the rapid conduction of electrical impulses across the heart. @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 17 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM 5.3 CONNECTIVE TISSUE Connective Tissue Separated by matrix (non-cellular material, protein) The cells are called fibroblast Functions: 1. Binds organs together 2. Provides support/protection 3. Produces blood cells 4. Stores fat Its proteins are collagen and elastin the most abundant tissue in the body Sliding Filament Theory According to the sliding filament theory, a muscle fiber connects body parts. contracts when myosin filaments pull actin filaments closer together and thus shorten sarcomeres within a Unlike the avascularized epithelial tissues, most fiber. connective tissues are vascularized (with constant blood supply from blood vessels) except tendons and When all the sarcomeres in a muscle fiber shorten, the ligaments. fiber contracts. If epithelial tissues have a basement membrane, connective tissues have an extracellular matrix made up of ground substance and fibers The ground substance is mostly made up of water, adhesion proteins, and large polysaccharides or complex sugars. The amount of polysaccharide determines the consistency of the matrix. The amount and type of fiber vary depending on the type of connective tissue. @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 18 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Types of Matrix 2. Adipose Tissue 1. Collagen Fiber has large fibroblasts that store fat, used for energy, white, contains collagen that gives flexibility and insulation, and organ protection strength (fibrillin) Adipocytes = fat cells “malutong” supports, connects, and protects other body tissues It also serves as a water reservoir because of its ability to absorb large amounts of water 2. Reticular Fiber very thin collagen fibers that are highly branched and 3. Reticular Connective Tissue form delicate supporting networks serves as the supporting meshwork of lymphatics Soft parts of the body (e.g. breasts, spleen) 4. Cartilage separated by a matrix that is solid yet flexible; usually oriented randomly, forming mesh-like structures its cells lie in small chambers called lacunae; Heals slowly due to lack of blood supply 3. Elastic Fiber yellow, and contains elastin that gives elasticity cartilage cells called chondrocytes (capacity to stretch and recoil) Has different types: a. Hyaline Cartilage Types of Connective Tissues most common type; 1. Fibrous Connective Tissue has fibroblast (secretes collagen) that has a jellylike contains very fine collagen fibers found in the nose, matrix ends of long bones, fetal skeleton, and in rings of the Respiratory Tract has two kinds, loose (thin, more elastic, mostly matrix, few cells) and dense (thick, more collagen, few matrix, b. Fibrocartilage few cells) matrix has strong collagen fibers found in areas that could withstand pressure and tension (such as pads between vertebrae and backbones and wedges in knee joints) c. Elastic Cartilage has more elastin fiber; more flexible a. Dense Fibrous Connective Tissue Matrix is predominantly made up of collagen fibers Found in the framework of the outer ear and has lesser cells. 5. Bone / Osseous Tissue This is a fibroblast or a fiber-forming cell. most rigid connective tissue; b. Loose Fibrous Connective Tissue has a very hard matrix of inorganic/calcium salts for Matrix contains more cells and fewer fibers than dense rigidity, deposited around protein fiber, and collagen connective tissue so it is softer. fibers especially for elasticity Tendon : muscle - bone consists of bone cells (osteocytes and osteoclasts) Ligament : bone - bone found in cavities called lacunae @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 19 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Has 2 types: a. Compact Bone makes up the shaft of long bones has cylindrical structural units called osteons (Haversian system) b. Spongy Bone found in ends of long bones has numerous bony bars and plates separated by irregular spaces 6. Blood plasma, a liquid matrix Cellular components consist of blood cells with fibers that are only visible during clotting because 5.4 NERVOUS TISSUE they are made of soluble proteins Functions: Nervous Tissue a. transports nutrients and oxygen to tissue fluids Receives stimuli and conducts nerve impulses b. removes CO2 and waste products c. helps distribute heat and fluids/ions, and for pH Makes up the central nervous system (CNS) and balance peripheral nervous system (PNS) d. gives protection Composed of neurons and neuroglia (supporting cells) a) Erythrocytes (Red Blood Cells) b) Large lymphocyte (NK Cells) Nerves – fibers bounded by connective tissues c) Neutrophil (White Blood Cells) d) Eosinophil Functions: sensory input, integration of data, motor e) Monocyte (Macrophages) output f) Thrombocyte (Platelets - from megakaryocytes) g) Lymphocyte (Killer T Cells) Central Nervous System - brain + spinal cord h) Neutrophil, band cell i) Basophil Peripheral Nervous System - nerves @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 20 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Neurons nerve cells found in the brain and spinal cord Basic structural unit of the nervous system. Composed of the cell body (soma), dendrite, and axon. Two basic characteristics: 1. Irritability Allows neurons to be sensitive and responsive to various stimuli 2. Conductivity Allows for the transmission of electrochemical signals from one part of the body to another Parts of a Neuron: Cell Body (Soma) Contains the nucleus and specialized organelles that produce molecules needed by the neuron. Central part of the neuron. Dendrite Three types of neurons based on function: Receives electrochemical signals from external stimuli Sensory Neuron or adjacent neurons. Usually unipolar or pseudounipolar with an axon that branches into two extensions. Transmits incoming signals towards the cell body. One extension is connected to the dendrite that Axon receives sensory input, and the other transmits Transmits electrochemical signals away from the cell information to the CNS. body. Interneuron Surrounded by the myelin sheath for quick and efficient Bipolar or multipolar neurons with one axon and signal transmission. multiple dendrites. Myelin Sheath Connects sensory neurons to motor neurons. Insulating layer around the axon. Motor Neuron Allows impulses to transmit quickly and efficiently Multipolar neurons that carry electrochemical signals along the neuron. from the CNS to muscles or glands. Nodes of Ranvier Responsible for initiating movement or glandular Periodic gaps between myelin sheaths on an axon. activity. Important for rapid signal transmission. Synapse Neural junction where the transmission of electrochemical signals occurs. Located between two neurons or between a neuron and a muscle/gland. Aside from neurons, nervous tissues also contain neuroglia or supporting cells. @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 21 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Types of Neuroglia (Supporting Cells) Neuroglia (Glial Cells) Support, protect, or insulate neurons. Do not conduct nerve impulses. Six types—four in the CNS and two in the PNS. Astrocytes Star-shaped cells that support and control the chemical environment around neurons. Most abundant glial cells in the CNS. Neuroglia or glial cells in the central nervous system Microglial Cells Ovoid cells that can transform into phagocytic macrophages. Clean neuronal debris and wastes in the CNS. Ependymal Cells Ciliated cells that line the central cavities of the brain and spinal cord. Form a permeable membrane between cavities with Neuroglia or glial cells in the peripheral nervous system cerebrospinal fluid and CNS tissues. Oligodendrocytes Responsible for the production of the myelin sheath in Nervous System Components the CNS. Central Nervous System (CNS) Consists of the brain and spinal cord. Similar function to Schwann cells in the PNS. Integrates and processes information. Satellite Cells Surround the cell body of a neuron in the PNS. Peripheral Nervous System (PNS) Consists of nerves distributed throughout the body. Provide support and protection. Connects the CNS to limbs and organs. Schwann Cells Surround all nerve fibers in the PNS and produce the myelin sheath. Similar function to oligodendrocytes in the CNS. @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 22 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Q1W6 Increase plant rigidity and sturdiness 8.0 PLANT TISSUE Roots searching for water Tissue Types: vascular cambium and cork cambium group of cells performing the same function 3. Intercalary Meristems cells that are structurally/functionally similar found at the bases of young leaves and internodes (pagitan ng dahon) Types of Plant Tissue: Meristematic Tissue (Meristems) responsible for leaf and stem length Permanent Tissue 8.1 MERISTEMATIC TISSUE Meristematic Tissue (Meristems) composed of actively dividing/growing cells, responsible for the reproduction of cells As cells leave the meristem, they undergo differentiation to form specific cell types Meristematic cells are undifferentiated or incompletely 8.2 PERMANENT TISSUE differentiated responsible for growth Found in growing areas of plants (roots, stems) Permanent Tissue tissues that attained their mature form and perform Young specific functions Three Types of Meristematic Tissue they stop dividing/growing (according to location and type of growth) : 1. Apical Meristems Old found at the tip of stems and roots Two Types of Permanent Tissue: moves towards the source of food 1. Simple Permanent Tissue (meristems) Permanent tissues composed of one kind of cell responsible for height Does not have the capability to divide and give rise to Shoot system - going against gravity, vertical new cells. growth/elongation Provide support, aid in the transport of water and Produce primary meristems (protoderm, procambium, minerals, and act as storage of plant food. and ground meristem) a) Dermal/Surface Tissue external tissues 2. Lateral Meristems Also known as cambia (s: cambium) forms a protective covering of the plant body found along the sides of roots and stems Meristems that cause growth in diameter and girth known as secondary growth @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 23 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM i. Epidermis b) Ground Tissues the outermost layer of the primary plant body Cells that are neither dermal or vascular, considered as fillers of plants and form the bulk of plants covers the leaves, floral parts, fruits, seeds, stems, and roots i. Parenchyma general purpose cells rounded shape; generally only one layer thick with cuticle (wax; hydrophobic) uniformly thin walls at all parts of the plant Upper epidermis living at maturity more chlorophyll content Darker in color Has large vacuoles Slow transpiration (release of water vapor) Location: Leave, stem (pith), roots, fruits Lower epidermis More stomata (for oxygen release & CO2 absorption) all fruit insides have parenchyma Chlorenchyma Specialized parenchyma; Monocot/Monocotyledon found in green parts of the shoot — if the body is hard at maturity — only epidermis performs photosynthesis — fleshy — parallel venation (hibla ng dahon is the same with veins) Dicot/Dicotyledon — both epidermis and periderm ii. Periderm outermost layer of stems and roots of woody plants such as trees ii. Collenchyma kolla = glue; Greek cells are elongated (~2mm long) uneven thick walls alive at maturity @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 24 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM iii. Sclerenchyma non-living lack protoplasts at maturity thick, lignified secondary walls provides strength and support in parts that have ceased elongating or mature Types: 1) Sclereids or Stone Cells (grittiness of pear) Strengthen seed coats and contribute to the gritty texture of some fruits. 2) Fibers Used commercially in making rope and flax fibers. 2. Complex Permanent Tissues Vascular Tissues specialized for long-distance transport of water and dissolved substances. contain transfer ceIIs, fibers in addition to parenchyma and conducting ceIIs location, the veins in Ieaves Dicot and Monocot Roots: Vascular bundles arranged like a stellar. Monocot Stems: Vascular bundles are scattered. Dicot Stems: Vascular bundles are circular. @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 25 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Types of Complex Permanent Tissues XYLEM PHLOEM a. Xylem water-conducting tissue Made of Dead Cells Living Cells responsible for distributing water and minerals Cell Wall Thick Thin absorbed by the roots Thickness Composed of tracheids and vessel elements Cell Wall Lignin (rigid) Cellulose Material Tracheids Thin, elongated cells with thick secondary walls and Permeability Impermeable Permeable pits for water transport. Cytoplasm None Cytoplasm Vessel Elements Lining Thin-walled cells with perforated plates for water Transports Water & Food transport through vessels. Minerals Secondary walls provide rigidity against water Flow One - Way Two - Way transport tension. b. Phloem food-conducting tissue responsible for distributing sucrose and other inorganic compounds throughout the plant Composed of sieve tubes consisting of sieve-tube elements Sieve-Tube Elements Cells that transport nutrients, sucrose, and organic compounds; lack nucleus and ribosomes. Sieve Plates Contain pores to regulate nutrient flow between cells. Companion Cells Assist in nutrient transport through the phloem. @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 26 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Q1W7 Cholesterol regulates fluidity of membrane and changes based on 9.0 PLASMA MEMBRANE environment temperature Functions of Plasma Membrane acts as antifreeze and is more abundant in animals in Selective permeability, diffusion, osmosis, transport by cold climates carriers, endocytosis, exocytosis Separates components of a cell from its environment Helps maintain homeostasis (stable internal balance) Molecules of Plasma Membrane Phosphate hydrophilic head; Water-loving molecules of phospholipid Fatty Acid hydrophobic tail; Water-hating molecule of the phospholipid The 1st major component Q1W7 Protein 10.0 TRANSPORT MECHANISM second major chemical component that may serve as enzymes, structural attachments for cytoskeleton fibers, or recognition sites Cell Membrane All cells have cell membrane made up of proteins, a. Integral Protein ccarbohydrates, and lipids; some also have cell walls embedded in the plasma membrane and may span all or part of the membrane, that may serve as channels Separates the cell from its environment or pumps to move materials into or out of the cell Selectively permeable protein that makes up the 2nd major chemical component of plasma membranes “Gatekeeper” of the cell b. Peripheral Protein regulates the flow of materials into and out of cell found on the exterior or interior surfaces of membranes, attached either to integral proteins or to Helps cell maintain homeostasis phospholipid molecules Bacteria: Peptidoglycan Both integral and peripheral proteins may serve as Fungi: Chitin enzymes, as structural attachments for the fibers of Plants: Cellulose (fiber) the cytoskeleton, or as part of the cell’s recognition sites Cell membranes and cell walls are porous – which allows water, carbon dioxide, oxygen and nutrients to Carbohydrate pass through easily third major chemical component that are always found on the surface of cells There are two types of transport: passive, active a. Glycoprotein Carbohydrates bounded to proteins Concentration Gradient Gradual change in concentration of solutes in a b. Glycolipid solution from one region to another Carbohydrates bounded to lipids Lower concentration yields greater entropy @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 27 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Tonicity 10.1 PASSIVE TRANSPORT the capability of a solution to modify the volume of cells by altering their water content Passive Transport A process that does not require energy / use ATP a. Hypotonic (low concentration of solute) Water goes inside the cell, causing it to swell moves molecules from a HIGH to LOW concentration Cells under hypotonic solutions undergo cytolysis along the “CONCENTRATION GRADIENT” contain a low concentration of solute relative to Types of Passive Transport another solution (e.g. the cell's cytoplasm) 1. Diffusion Movement of particles across the semipermeable When a cell is placed in a hypotonic solution, the water membrane (e.g. cell membrane) until equilibrium in diffuses into the cell, causing the cell to swell and concentration is reached. possibly explode These particles move from a high to low concentration b. Isotonic (balanced) areas contain the same concentration of solute as another NOT affected by gravity solution (e.g. the cell's cytoplasm) When a cell is placed in an isotonic solution, the water diffuses into and out of the cell at the same rate. The fluid that surrounds the body cells is isotonic c. Hypertonic (high concentration of solute) Water is drawn out of the cell Red blood cells under hypertonic solution undergo 2. Osmosis crenation Diffusion of water through the semipermeable membrane For plant cells, they undergo plasmolysis High to low concentration contain a high concentration of solute relative to another solution (e.g. the cell's cytoplasm) Rate of osmosis depends on the types of solution the cell is situated in When a cell is placed in a hypertonic solution, the water diffuses out of the cell, causing the cell to shrive @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 28 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM 3. Facilitated Diffusion Sodium-Potassium Pump Movement of larger molecules (like glucose) with “help” Primary active transport Proteins in the cell membrane form channels or pores 3 Sodium (Na+) ions out of the cell and 2 Potassium for large molecules to pass through (K+) ions into the cell Protein channels - pores or holes for flow through 2 K : 3 Na + ATP diffusion Carrier proteins - binds to molecules or ions on one side of the membrane, releases to the other side 10.2 ACTIVE TRANSPORT Endocytosis Active Transport movement of very large molecules into the cell; the movement of molecules from LOW to HIGH requires energy concentration Exocytosis Energy is required movement of very large molecules out from the cell; requires energy Uses ATP (primary) or electrochemical gradient (secondary) molecules are pumped against the “CONCENTRATION GRADIENT” Protein pumps - proteins that work as pumps Body cells must pump carbon dioxide out into the surrounding blood vessels to be carried for the lungs to exhale Pinocytosis Blood vessels are high in carbon dioxide compared to cell membrane opens and “drinks” or ingests the cells, so energy is required to move the carbon surrounding dioxide across the cell membrane from LOW to HIGH concentration Phagocytosis cell membrane grabs or “engulfs” or ingests solid material (ex. White blood cells) @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 29 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Q1W8 2. S (Synthetic Phase) DNA is copied/synthesized 11.0 CELL CYCLE AND ITS CHECKPOINTS each chromosome consist of two chromatids attached at the centromere Cell Cycle describes the life of a eukaryotic cell The centrosome is duplicated (2 each cell and 2 centrioles each centrosome) Happens in the nucleus the two chromosomes will give rise to the mitotic life of a eukaryotic cell is shown in a cycle a repeating spindle (spindle fiber) sequence of cellular growth and division Mitotic spindle - the apparatus that orchestrates the movement of chromosomes during mitosis 3. G2 (Second Growth Phase / Gap 2) preparations are made for the nucleus to divide Microtubules are assembled Microtubules - hollow protein fibers that move chromosomes during mitosis M Phase the cell division proper Apoptosis the process during cell division in which the nucleus of Programmed cell death a cell is divided into nuclei Phases of Cell Cycle makes an identical copy of another cell 1. Interphase a. G1 phase M stands for Mitosis/Meiosis b. S phase c. G2 phase Karyokinesis (nuclear division) and Cytokinesis 2. M Phase (cytoplasm division) a. Karyokinesis (Mitosis) - Prophase Cleavage furrow for animal cells - Metaphase Cell plate for plant cells - Anaphase - Telophase b. Cytokinesis - Cleavage Furrow (Animal Cells) - Cell Plate (Plant Cells) Interphase the longest phase accounts for 90% of the time elapsed during each cycle G0 PHASE cell cycle arrest cell growth and production of copies of chromosomes a state where the cell rests should they not continue 1. G1 (First growth phase) the cell cycle Rapid cell growth If cells no longer want to divide, they exit G1 and enter occupies major portion of the cell’s life G0 @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 30 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM they either stay in this phase till death or wait to be Kinetochor - point of attachment of spindle fiber reactivated M-checkpoint decides if the cell will undergo repairing May be permanent (neurons) or may re-enter cell cycle or apoptosis (programmed cell death) (hepatocytes) if there is no go-signal, the cell just waits in that state Examples include neurons conducting signals or till the spindles are connected storing carbohydrates as a live cell if it passed through the checkpoint but does not meet Most cells in the human body are in G0 the requirements, an abnormal cell or cancer cell may be produced Cell Cycle Checkpoints the control system driven by a built-in clock that can be Kinases (Cyclin-Dependent Kinases or CDKs) adjusted by external stimuli (chemical stimuli) Used by checkpoints checkpoints are critical points where ‘stop’ and Protein that activates or deactivates another protein by ‘go-ahead’ signals can regulate the cell cycle phosphorylating them cell cycle has 3 major checkpoints Give the “go” signals at G1 and G2 checkpoints G1 Checkpoint Kinases must be activated by cyclin to function the restriction point that ensures that the cell is large enough to divide and that enough nutrients are Cyclin – protein that is cyclically fluctuating the available to support the resulting daughter cells concentration in the cell determines whether all conditions are favorable for cell Cyclins accumulate during G1, S, and G2 phases division to proceed Mitosis-promoting Factor (MPF) – functions by if a cell receives a ‘go-ahead’ signal at the G1 phosphorylating key proteins in the mitotic sequence checkpoint, it will usually continue with the cell cycle MPF switches itself off during mitosis by initiating if the cell does not receive the ‘go-ahead’ signal, it will process that destructs cyclins exit the cell cycle and switch to a non-dividing state called G0 The non-cyclin aprt of MPF, CDKs, persist in the cell as inactive until it associates with new cyclin molecules checks for cell size, nutrients, growth factors and DNA synthesized during interphase damage Phosphorylating – to introduce a phosphate group into G2 Checkpoint a molecule or compound ensures that DNA replication in the S phase has been successfully completed DNA replication checked by repair enzymes If passed, the proteins help trigger mitosis If the cell does not have requirements for the checkpoint, it waits in that state checks for cell size, and DNA replication M Checkpoint also known as metaphase or spindle assembly checkpoint ensures that all the chromosomes are attached to the mitotic spindle by a kinetochore @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 31 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Chromatid pairs place themselves onto individual fibers aligned along the center of the spindle they are aligned at the center of the cell (equatorial plate) Cyclin-Dependent Kinase Cyclin Activated Complex nuclear membrane is completely gone Q1W8 Under a microscope, you will see the spindle fibers 12.0 MITOSIS aligning the chromosomes in the middle of the cell Anaphase Mitosis A - AWAY -Type of cell division resulting in two daughter cells with the same number and kind of chromosomes Chromatid pairs split into two due to the movement of spindle fibers Also known as karyokinesis Chromatid pairs travel to opposite ends on the spindle Karyo - nucleus, kinesis - movement Halved chromatids = chromosomes division of the nucleus Cell grows due to the start of cytokinesis Cell division of somatic (body) cells Cytokinesis (division of cytoplasm) starts 1 division that produces 2 diploids (46 chromosomes) daughter cells Cytoplasm expands Singular cycle of PMAT (Prophase, Metaphase, Under a microscope, cell is wider than in prophase and Anaphase, Telophase) metaphase and the chromosomes are visibly being pulled apart: Produces identical copies of parent Telophase Diploid – complete chromosomes; T - TWO Haploid – halved chromosomes Two new nuclei are formed when chromosomes reach Prophase opposite poles of the cell P - PREPARATION Nuclear membrane is formed and the nucleolus Nucleolus and nuclear membrane breaks down reappears Centrioles move to opposite sides of the nucleus Chromosomes disperse in the nucleus Chromatin (unraveled DNA) condenses into cleavage furrow/cell plate is visible chromosomes Under a microscope, two nuclei are visibly being Under a microscope, you will see the nucleus formed although still sharing the same cytoplasm disintegrating and the DNA condensing. Basically, reverse prophase Metaphase M - MIDDLE Spindle becomes fully developed spindle fibers are connected to the kinetochore of the chromatid pairs @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 32 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Q1W8 13.0 MEIOSIS Meiosis Type of cell division resulting in gametes (sex cells) Two cycles of PMAT Has two rounds of division: Meiosis I, Meiosis II Diploid parent splits into two haploid daughter cells that each split into two haploid daughter cells Does NOT produce identical copies of parent Involves two successive cell divisions without interphase that leads to no replication of genetic material or DNA Results in reduction of chromosome number from diploid to haploid Gametes contain half the number of chromosomes from the parent cell Sexual reproduction requires fusion of haploid gametes to produce a diploid zygote Zygotes undergo mitosis to form offspring Homologous Chromosomes Homologues are held by proteins in a synaptonemal complex Pair of chromosomes (maternal and paternal) that are similar in shape and size During meiosis I, they become closely associated with each other through synapsis. Homologues are held by proteins in a synaptonemal complex, forming a tetrad Tetrads (homologous pairs) carry genes that control inherited traits Humans have 23 pairs of homologues: 22 autosomes, 1 sex chromosomes Example of Defects: → Down Syndrome (Trisomy 21) – 21st chromosome has an extra chromosome → Cri du Chat (5p-) – 5th chromosome has an extra chromosome @zaerijoy STEM / 12 | SEMESTER 1 | QUARTER 1 GENBIO | EJSV PAGE 33 GENERAL BIOLOGY I S.Y. ‘24 - ‘25 | MRS. SUZZETH U. DIZON REVIEWER FOR Q1 PERIODICAL EXAM Metaphase I Tetrads align in the middle in random orientation Terminal chiasmata hold homologues following the crossing over Kinetochore Microtubules on poles attach to each homologue (not each chromatid) Homologues are aligned at metaphase plate side-by-side Crossing Over Spindle fibers hold the entire chromatin to one side, Genetic recombination between non-sister chromatids and not just a chromatid like for mitosis in a tetrad Anaphase I Physical exchange of regions of chromatid regions Homologues are separated from each other, sister called Chiasmata chromatids remain together at centromeres allows variation between the Microtubules of the spindle shorten daughter cells during meiosis Telophase I Chiasmata – site for crossing over Two nuclei are formed around each new set of chromosomes Crossing over means that the daughter cells are no longer identical Daughter cells are now haploid Nuclear envelopes form around each set of chromosomes Cytokinesis may occur After Meiosis I, immediately proceed to Meiosis II. There is NO interphase in between. 13.1 MEIOSIS I Prophase I Standard prophase procedure but with Synapsis and Crossing over Chromosomes coil tighter (Chromosomes condense, spindle microtubules form) Nuclear envelope disso