General Biology 1 Review - WVSU College of Medicine - PDF

General Biology 1 Quarter 1 By: 11-STEM 1 OUTLINE 2. Cell is a basic unit of life I. Main Characteristics of an Org...

General Biology 1 Quarter 1 By: 11-STEM 1 OUTLINE 2. Cell is a basic unit of life I. Main Characteristics of an Organism 3. All cells came from pre-existing cells II. The Cell Theory Omnis cellula e cellula Expanded version of III. Cell Structure and Functions the cell theory A. Cell Membrane B. Cytoplasm 4. Cells carry genetic material passed to daughter C. Nucleus cells during cellular division IV. Prokaryotic vs. Eukaryotic Cells 5. All cells are essentially the same in chemical V. Cell Types composition A. Plant Tissue 6. Energy flows (metabolism and biochemistry B. Animal Tissue occurs within cells) VI. Cell Modifications I. MAIN CHARACTERISTICS OF AN ENDOSYMBIOTIC THEORY ORGANISM Lynn Margulis – American Biologist  It is made of cell  Provided evidence that some organelles within the  Requires energy cells were at one-time free-living cells themselves  Able to reproduce  Organelles with their own DNA  Maintains homeostasis  Chloroplasts and Mitochondria  They are organized  Grow and develop III. CELL STRUCTURE AND  Exchanges materials with the surroundings FUNCTIONS  Needs of water  A cell has is divided into three structures: Plasma  Definite lifespan Membrane, Cytoplasm, and Nucleus  Has genes and heredity II. THE CELL THEORY PEOPLE BEYOND THE CELL THEORY Robert Hooke  Published the “micrographia” on 1665  Observed a box-shaped structure which he called “cells” as they reminded of him of the cells or room in monasteries Antonie van Leeuwenhoek  On 1670s, he discovered bacteria and protozoa Matthias Shleiden – German Botanist Figure 1. This generalized cell shows the major organelles  He concluded that all plants are made of cells contained in cells. However, no single cell contains all of these Theodore Schwann – German Zoologist organelle types. Furthermore, one kinde of cell may contain  He concluded that all animals are made of cells many organelles of one type, whereas another kind of cell may Rudolph Virchow contain very few.  Observed under a microscope the cells are dividing A. PLASMA MEMBRANE  He reasoned that all cells came form pre-existing Plasma Membrane/Cell Membrane cells by cell division  Outermost component of the cell PORTIONS OF THE CELL THEORY  Substances outside the cell are called extracellular Modern Cell Theory substances 1. All life is composed of one or more cells WVSU COLLEGE OF MEDICINE | Trans Group # - Surname1, Surname2, Surname3, Surname4, Surname5 1 | 13   While substances inside the cell are called B. NUCLEUS intracellular substances The Central Organelle – Nucleus  Acts a selective barrier that determines what moves  Largest organelle into and out of the cell  Nucleus is bounded by nuclear envelope  Major molecule that makes up the cell membrane  The nuclei of human cells have 23 pairs of are phospholipids and proteins chromosomes, which consists of DNA and proteins  The polar, phosphate-containing ends of the  Controls the normal activities of the cell phospholipids are hydrophilic (water-loving) and  Contains the DNA and chromosome therefore face the extracellular and intracellular fluid Nuclear envelope of the cell  Double membrane surrounding the nucleus  The nonpolar, fatty acid ends of the phospholipid are  also called nuclear membrane hydrophobic (water-fearing) and therefore face away  connected to the rough endoplasmic reticulum from the fluid on either side of the membrane Inside the Nucleus  where the genetic materials is found  DNA is spread out and appears as chromatin in non- dividing cells  DNA is condensed and wrapped around proteins forming as chromosomes in dividing cells What does DNA do?  It is the hereditary material of the cell  Genes that make up the DNA molecule code for different proteins  Composed of proteins and phospholipid bilayer Nucleolus Figure 2. cell membrane  Located inside the nucleus Phospholipids Bilayer  Cell may have one to three nucleoli  Heads  Disappears when cell divides  Contains glycerol and phosphate  Makes ribosomes that makes protein  hydrophilic  Found within the nucleus  Tails  Subunits of ribosomes are formed within the  are made of fatty acids nucleolus  hydrophobic  proteins produced in the cytoplasm move through Cell Membrane Proteins the nuclear pores into the nucleus, and into the  helps more large molecules nucleolus  aids in cell recognition C. CYTOPLASM  Peripheral proteins  Attached on the surface  Cytoskeleton  Integral proteins  Consists of proteins that support the cell, hold  Embedded completely through the membrane organelles in place, and enables the cell to  Glycoproteins change shape  have carbohydrate tails to act as markers for cell  Helps maintain the cell shape recognition  Helps organelles move around Cell Wall  Microtubules, microfilaments, and intermediate  non living organism filaments  made of cellulose in plants  Microfilaments are thread-like made up of Actin  made of peptidoglycan in bacteria   microtubules are tube-like made of chitin in fungi made up of Tubulin  supports and protects cell Centrioles  found outside the plasma membrane Y2 B9 M1 L2 | Lecture Title 2 | 13   is a specialized zone of cytoplasm close to the  lacks of ribosomes on its surface nucleus, where microtubules formation occurs  attached to the end of rough E.R.  only found in animal cells  makes the cell products that are used inside the  paired structure around nucleus cell  made of bundles of microtubules  males membrsne lipids (streroid)  appear during cell division farming mitotic spindle  regulates calcium (muscle cells)  help to pull chromosome pairs apart to opposite  destroy toxic substances (liver) ends of the cell Ribosomes Mitochondria  are the organelles where proteins are produced  singular = mitochondrion  ribosomes may be attached to other organelles such  are small organelles with inner and outer as the RER membranes separated by space.  ribosomes that are not attached to any organelle are  The outer membrane has smooth contour called free ribosomes  The inner membrane has numerous folds, called  protein functions for cell cristae  joins amino acids to make protein  generate cellular energy (ATP)  process called protein synthesis  Adenosine Triphosphate) Golgi Body  Carry out aerobic respiration, a series of chemical  consists of closely packed stacks of curved, reaction that require 2 to break down food membrane-bound sacs molecules to produce ATP  collects, modifies, packages, and distribute proteins  Mitochondria came from cytoplasm in the egg cell and lipids manufactured by the rough ER during fertilization  have trans face and cis face  You inherit your mitochondria from your mother Lysosome  membrane-bound vesicles formed from the Gogi Body  contains variety of enzymes that function as intracellular digestive systems  break down food, bacteria, and warm out cell parts  programmed for all cell death (autolysis)  Lyse (break open) and release enzymes to break down and recycle cell parts  Lysosome Digestion  Cells take in food by phagocytosis Figure 3. mitochondrion Lysosome digest the food and get rid of the Endoplasmic Reticulum waste  Is a series of membrane forming sacs and tubules Cilia and Flagella that extends from the outer nuclear membrane into  Cilia the cytoplasm  Singular; cilium  Hollow membrane tubules  Project from the surface of thecell  Connects to nuclear membrane and plasma  Cilia are cylindrical strucutres that extend from membrane the cell  Functions in synthesis of cell products and transport  Cilia are composed of microtubules, organixed in  Rough E.R. a pattern similar to that of centrioles, which are  has ribosomes on its surface enclosed by the cell membrane  makes membrane protein and protein for exports  Flagella out of cell  Singular; flagellum  protein are made by ribosomes on rough E.R.  Have a similar structure to that Cilia but are  hreaded to the interior of rough E.R. much longer, and they usually occure only one  smooth E.R. per cell Y2 B9 M1 L2 | Lecture Title 3 | 13   Sprerm cells each have one flagellum, whic propels the sperm cell  Made of microtubules  9+2 arrangement – (microtubules)  Function in moving cells, in moving fluids, or in small particles across the cell surface Cilia Flagella shorter Longer Numerous on cells Fewer (usually 1-3) on cells Vacuoles Figure 4. Prokaryotic cell  Fluid filled sacs of storage Prokaryotes  Small or absent in animal cells  The first cells  No vacuoles in bacterial cells  Cells that lack nucleus and membrane-bound  In plant, they store cell sap organelles  Includes storage of sugars, proteins, minerals, lipids,  Simplest type of cells wastes, salts, water, and enzymes  Single, cellular chromosome Contractile Vacuole  Includes bacteria  Found in unicellular protist like paramecia  Nucleoid regions (center) contains the DNA  Regulate water intake by pumping out excess  Surrounded by a cell membrane and cell wall  (homeostasis) (peptidoglycan)  Keeps the cell from lysing (bursting)  Contains ribosomes (no membrane) in their Chloroplast cytoplasm to make proteins  Found only in producers (organisms containing chlorophyll)  Use energy from sunlight to make our food  (glucose)  Stored in chemical bonds of sugar  Double membrane  Inner membrane modified into sacs called thylakoids  Thylakoids in stacks called Grana and interconnected  Stroma – gel like material surrounding thylakoids Figure 5. An animal cell and a plant cell  Contains its own DNA Contains pigment for photosynthesis B. EUKARYOTIC CELLS  Photosynthesis – food making process Eukaryotes  Cells that have a nucleus and membrane-bound IV. PROKARYOTIC VS. EUKARYOTIC organelles CELLS  Includes protists, fungi, plants, and animals A. PROKARYOTIC CELLS  Makes complex cell types of cells  Contains three basic structures:  Plasma membrane or cell membrane  Nucleus  Cytoplasm  Two main types of eukaryotic cells:  Animal cell  Plant cell Y2 B9 M1 L2 | Lecture Title 4 | 13  V. CELL TYPES  Help to increase the length of the internode Tissue – group of cells having a similar structure  Part of the apical meristem and adds to the height of and functions the plant A. PLANT TISSUE  Usually seen in monocotyledonous plants Lateral Meristematic Tissue  Lateral side of the stem and root of a plant  Help in increasing the girth or thickness of the plants  These divide preclinically or radially and give rise to secondary permanent tissues. PERMANENT TISSUE  Permanent tissue cells do not usually divide any further  The tissues that are completely grown and have lost Figure 6. Plant tissue concept map the ability to divide Plant tissue  Meristematic tissues divide and differentiate to form  do not move/static the permanent tissue  growth of plants takes place on a particular region  Three types:  types of plant tissue  Simple  meristematic tissue – group cells that have the  Complex ability to divide  Secretory  permanent tissue – consisting of cells that are Simple Permanent Tissue no longer actively dividing  Also known as homogenous tissue MERISTAMATIC TISSUE  They are made up of a single cell type, usually with  type of tissue found in lants the same origin, structure, and function  consists of undifferentiated cells capable of cell  Has a thick layer of walls and is full of protoplasm. division  It is one of the most abundant and common tissues  meristem classification: that can be found easily in the plant body  apical meristem  Three types:  lateral meristem  Parenchyma  intercalary meristem  Collenchyma Apical Meristematic Tissue  Sclerenchyma  present at the tips of the roots and shoots  helps in the growth and increase of the height of the plants  various cell divisions facilitate the growth of the cells in the roots and shoots and help in cellular enlargement  divided into:  promeristem zone – contains actively dividing cells  meristematic zone – contains protoderm, Figure 7. Three types of simple permanent tissue procambium, and ground meristem. Parenchyma Intercalary Meristematic Tissue  Parenchyma is composed of hemicellulose or  located at the base of the leaves and internodes at cellulose and has several small vacuoles the intercalary position.  In the older parenchyma, smaller vacuoles merge to become a large central vacuole, which may Y2 B9 M1 L2 | Lecture Title 5 | 13  accumulate anthocyanin or tannins, a large central baking. It is also sometimes used to make medicine. vacuole. Pectin binds substances in the intestine and adds up  Parenchyma tissue is a type of simple plant tissue bulk to the stools composed of living cells with thin cell walls  types of Collenchyma:  Its primary function is to perform various metabolic  Angular Collenchyma activities such as photosynthesis, storage of It is the most common type of collenchyma nutrients, and providing structural support to organs. Thickening of walls only occurs at the  Type of Parenchyma: corners  Chlorenchyna Intercellular spaces are absent and they Cells which have chloroplasts and perform have a circular lumen. photosynthesis  Lacunar Collenchyma  Xylem parenchyma Has intercellular spaces It stores food materials like starch, fats and Thickening is more at the places adjacent to other substances such as tannins and intercellular spaces crystals.  Lamellar Collenchyma Storage Parenchyma – these store various They are also called plate collenchyma substances like water, starch, proteins, etc. They have thickened tangential walls and They act as a food and water reservoir are arranged into ordered rows  Prosenchyma  Annular Collencyma These are fiber-like elongated cells, which The ells are uniformly thickened are thick-walled and provide rigidity and strength to the plant.  Arenchyma They contain very large intercellular spaces These are present in aquatic plants Figure 9. Types of collenchyma Sclerenchyma  Sclerenchyma cells have thick, lignified secondary walls, lack of cell contents at maturity, and occur throughout all plant tissues  These features make sclerenchyma tissues hard, rigid, and somewhat brittle  Sclerenchyma cells can occurs as aggregates within Figure 8. Types of parenchyma ground tissues (sclereids or stone cells or as Collenchyma elongated fibers)  Helps in the formation of plant tissue  Sclerenchyma provides mechanical strength to  It helps the plant by giving rigidity, flexibility, and stems (fibers in hemp and flax) and reproductive elasticity structures (the texture in pear flesh, the stony shells  it is made up of thick and strong strands of cellulose of nuts and cherry pits that are twisted with each other Complex Permanent Tissue  cells of collenchyma generally grow constantly that  The complex permanent tissues are made up of is why it is easily found on stems, leaves, shoots of more that one type of cells the plants  They coordinate together to perform the same  collenchyma cells may or may not contain a few specialized functions in the plant body. chloroplasts, and may perform photosynthesis and  Two types store food  Xylem  pectin – is a soluble fiber (polysaccharide) found in  Phloeom fruits. It us used as a thickener in cooking and Xylem Y2 B9 M1 L2 | Lecture Title 6 | 13   The xylem tissue is responsible for the conduction of Permanent ground tissue that will form the bulk of a water and minerals from the roots to the leaves and plant. stem Phloem Fiber Stores compound such as  Xylem is an important plant tissue as it is part of the starch. sclerenchyma cells, which plumbing of a plant. are non-living cells in the  It also provides support to the plants phloem, providing structural support to the  The water-transporting cells of mature xylem are dead, therefore the transport of water is mostly a passive process with a very small active root B. ANIMAL TISSUE pressure  Four elements: Animal tissue Tracheid tubular cells in the xylem  It moves of vascular plants that  Needs more energy play a role in mineral and  Four types of animal tissue: water transport from the  Epithelial tissue roots to the leaves.  Connective tissue Vessels vessels are elongated  Muscle tissue dead cells with punctured  Nervous tissue cell walls through which Tissue Cells ECM Functions water flows. Epitthelial Aggregated Small Lining of Xylem Parenchyma responsible for storing the polyhedral amount surface or prepared food and assists cells body cavities; in the conduction of glandular water. secretion Xylem Fibers protect and provide Connective Several Abundant Support and mechanical support to the types of amount protection of xylem's major water-carrying tissues. fixed and tissues/organs Water is transported through wandering xylem fibers. cells Table 1. Four elements of Xylem Muscle Elongated Moderate Strong contractile amount contrations; Phloem cells body  helps in the translocation of food that is prepared by movements photosynthesis in the leaves to various parts of the Nervous Elongated Very small Transmission plant. contractile amount of nerve  transport system for soluble organic compounds wit impulses within vascular plants. extremely  The phloem is made up of living tissue, which uses fine turgor pressure and energy in the form of ATP to processes actively transport sugars to the plant organs  Four elements: EPITHELIAL TISSUE Sieve Tubes Transport sugars, amino acids and nutrients up  Shapes and dimensions of epithelial cells are quite and down the plants in variable, ranging from tall columnar to cuboidal to sieve cells. low squamous cells Companion Cells Controls the activity of the  Columnar cells sieve tube.  Have elongated nuclei Responsible for transporting assimilates into and out of  Squamous cells the sieve tubes.  Flattened nuclei Phloem Parenchyma Provides mechanical strength to the plant.  Cuboidal (pyramidal) Y2 B9 M1 L2 | Lecture Title 7 | 13   Have more spherical nuclei and thickness are roughly similar) , or columnar  The connective tissue that underlies the epithelia (cells taller than they are wide) lining organs of the digestive, respiratory, and  Stratified Epithelia urinary systems, is called the lamina propria  Contains two or more layers  Forms the outer layer of the body and also lines  Stratified squamous keratinized epithelium is many of the bodies cavities where it has a protective found mainly in the epidermis of skin, where it function. helps prevent dehydration  Epithelial tissue usually consists of a single layer of  Types of Epithelial Tissues cells, however in certain cases there may be more Figure 10. types of epithelial tissue than one layer.  All epithelial tissues are free surfaces attached to the CONNECTIVE TISSUE underlying layers of a basement membrane.  Connective tissues provides a matrix that supports  Functions: and physically connects other tissues and cells  Provides a barrier between the external together to form the organs of the body environment and the organ it covers.  Its major constituent is the extracellular matrix (ECM)  Specialized to function in secretion and  All connective tissues originate form embryonic absorption. mesenchyme, a tissue developing mainly from the  Protects organisms from microorganisms, injury, middle layer of the embryo, the mesoderm. and fluid loss.  Mesenchymal cells are undifferentiated and have  Excretes waste products such as sweat from the large nuclei, with prominent nucleoli and fine skin. chromatin Types of Epithelia  All connective tissue is made up of cells, fibers (such  Epithelia can be divided into main groups: Covering as collagen) and extracellular matrix. (lining) Epithelia and Secretory (glandular) Epithelia  ECM 3 major components Covering (lining) Epithelia  Protein fibers  are organized into one or more layers that cover the  Ground substances – consisting of nonfibrous surface or line the cavities of an organ protein and other molecules  epithelia are classified according to the number of  Fluid cell layers and cell morphology in the outer layer.  Three types of protein fibers  Simple Epithelia  Collagen fibers  Contain one cell layer  Reticular fibers  Simple Epithelia are futher classified as  Elastic fibers squamous (thin cells), cuboidal (cell wideth Functions of Connective Tissue  Enclosing and separating other tissues  Connecting tissues to one another  Supporting and moving parts of the body  Storing compounds  Cushioning and insulating  Transporting  Protecting MUSCLE TISSUE  The main characteristics of a muscle tissue is its ability to contract, or shorten, making movement possible  Sometimes called muscle fibers because they often resemble tiny threads  Three types of muscle tissue: Y2 B9 M1 L2 | Lecture Title 8 | 13   Skeletal  Cell body  Cardiac  Densrites  Smooth  Axons Skeletal muscle  Is what we normally think as a “muscle”  It is the meat of the animals and constitutes about 40% of a person’s body weight  Skeletal muscle attached to the skeleton and enables body to move  Voluntary (under conscious control) Figure 11. nervous tissue  Tend to be long and cylindrical, with several nuclei  Three types of neurons: per cell  Interneurons  Skeletal muscles cells are striated  Motor neurons Cardiac muscle  Sensory neurons  Is the muscle of the heard Sensory Nerves  It is responsible for pumping blood  The sensory nerves or sensory neurons are  Involuntary (unconscious) control responsible to generate impulses or signals in the  Cylindrical but shorter than skeletal muscle cell contrasting directions from another type of nerves  Usually, one nucleus per cell known as the motor neurons Smooth Muscle Motor Neurons  Forms the walls of hollow organs (except heart)  Motor neurons or motor nerves are responsible to  Found in eyes and skin send signals or impulses all the way from the spinal  Smooth muscle om controlled involuntarily cord and brain to all the muscles of the body. The  Single nucleus and striated impulse enables humans to carry out basic activities Autonomic Nerves NERVOUS TISSUE  The autonomic nervous system controls the actions of the muscles of the heart, such smooth muscles  Forms the brain, spinal cord, and the nerves located in the stomach and in the interlining of  It is responsible for coordinating and controlling glands and other organs. many bodies activities  Three components: CARTILAGE AND BONE  Neurons These are the structural and functional units Cartilage of the nervous system. It comprises an axon,  Is a tough, durable form of supporting connective cell body and dendrites. tissue characterized by an ECM with high  Neorolgia concentrations and proteoglycans, interacting with These are special cells found in the brain collagen and elastic fibers and spinal cord. They provide support to the Bone neurons and fibers.  Provides solid support for the body, protects vital  Neurosecretory cells organs such as those I cranial and thoracic cavities These function as endocrine organs. They  Bone (or osseous) tissue serves as the reservoir for release chemicals from the axons directly calcium, phosphate, and other ions into blood  Bone is a specialized connective tissue composed of  Many of these functions depend on the ability of calcified ECM, the bone matrix, and the following nervous tissue cells to communicate with one three major cell types: another and with the cells if other tissues by means  Osteocytes of electrical signals called action potentials (Gr. Osteon, bone + kytos, cells)  Nervous tissue consists of neurons and support cells Which are found in cavities (lacunae)  It is composed of three parts: between bone matrix layers (lamellae), with Y2 B9 M1 L2 | Lecture Title 9 | 13  cytoplasmic processes in small canaliculi  Are minute fragments of cells, each consisting of a that extend to the matrix small amount of cytoplasm surrounded by the cell  Osteoblasts membrane (osteon + Gr. Blastos, germ)  Thrombocytes – scientific name Growing cells with synthesizes and secrete the organic components of the matrix VI. CELL MODIFICATION  Osteoclasts A. MERISTEMATIC TISSUE (osteon + Gr. klastos, broken) Giant, multinucleated cells involved in Cell specialization, modification, differentiation removing calcified bone matrix and  specialized or re-acquired by the cell after cell remodeling bone tissues division that helps different beneficial ways.  process that occurs after cell division where the BLOOD newly formed cells are structurally modified so that they can perform their function efficiently and  Blood is regarded as a specialized form of effectively connective tissue because it originates in the bones  features or structure of the cell that makes it different and has some fibers. from another type of cell and at the same time  Blood is composed of red blood cells, white blood enables it to carry out unusual function cells and platelets. Why does it occur?  These components are suspended in a yellow fluid  Plant and animal cells are specialized to be able to known as plasma. carry out their tasks efficiently Blood helps maintain homeostasis in several ways:  They have particular adaptation to their structure to  Transport of gases, nutrients, and waste productions suit its function.  Transport processed molecules Types of Cell Modification  Transport regulatory molecules  Apical Modification  Regulations of pH and osmosis  Basal Modfication  Maintenance of body temperature  Protection against foreign substances  Clot formation Red Blood Cells  About 95% of the volume of the formed elements consists of red blood cells (RBCs), erythrocytes (erythro-red + kytos, cells)  The remaining % are composed of White Blood Cells and Platlets  120 days – lifepsan  Carries hemoglobin; a protein which carries oxygen White Blood Cells  Lateral Modification Figure 12. cell modification concept map  Are spherical cells that lacks hemoglobin APICAL MODIFICATION  Buffy coat – a thin, white layer of cells between plasma and red blood cells  Apical modification occurs in the apical surface.  Each have nucleus  found in the apical surface of the cell Cilia and Flagella  Protects the body from pathogens  Leucocytes – scientific name  usually short, hair-like structure that moves in waves  Lymphocytes  flagella are long whiplike structures  Are the smallest white blood cells  formed from microtubule Platelets Villi and Microvilli Vili Y2 B9 M1 L2 | Lecture Title 10 | 13   Fingerlike projections rise from epithelial layer Basal Infoldings  Helps increase surface area allowing for faster and  Oten found in epithelium that are known to transport more efficient absorption fluid (kidney) Microvilli  Will often see mitochondria in the basal infoldings  Small projections that arise from cells surface that  Suggests that active transport is occuring also increase surface area allowing faster and more efficient absorption. Stereocilia  Stereocilia are non-motile apical modifications of the cell, which are distinct from cilia and microvilli, but closely related to the latter.  Long microvilli that function in increasing absorption  Found in sensory cells in ear and male reproductive tract  Does not have the true characteristic of true cilia or flagella  Very important in epithelial polarization and stability  Stereocilia are the mechanoenzyme organelles of  Support the epithelium and also functions as a hair cells, which respond to fluid motion in numerous passive molecular sieve or ultra filter types of animals for various functions, including hearing and balance. LATERAL MODIFICATION Pseudopods/Pseudopodium  A type of cell modification that is found in the lateral  Temporary, irregular lobes formed by amoebas and surface of the cell some other eukaryotic cells Tight Junction  Bulge outward to move the cell and engulf prey  Act as a barrier that regulate the movement of water  Used in movement and as a tool to capture prey and solutes between epithelial layers Extracellular Matrix  Prevent leakage of extracellular fluid  Compound secreted by the cell on its apical surface Adhering Junction  Cell wall  It anchors junction on the lateral surface of the cell  Is the extracellular structure in plant cells that  It is similar to the anchoring junction of the basal distinguishes them from animal cells surface of the cell  Glycoprotein  Fasten cells to one another  Is the main ingredient of ECM in animal cell Gap Junction BASAL MODIFICATION  communicating junctions  closeable channels that connect the cytoplasm of  Found in the basal surface of the cell adjoining animal cells Desmosomes/Hemidesmosomes  presence of connexon that allow direct exchange of  Anchoring junction on the basal surface of the cell chemicals between the cytoplasm of two cells  Rivet-like links between cytoskeleton and extracellular matrix components such as the basal VII.CELL CYCLE lamina that underline epithelia Two stages  Primarily composed of keratin, integrins, and  Interphase cadherins  Mitotic phase  Desmosomes are junctions involved in intercellular INTERPHASE adhesion of epithelial cells and hemidesmosomes are junction involved in adhesion of epithelia to  The stage in the development of a cell between two basement membrane successive divisions  Interphase is the longest phase of a cell cycle Y2 B9 M1 L2 | Lecture Title 11 | 13   During this phase the cell grows to its maximum size, around the daughter chromosomes that have performs its normal cellular functions, replicates its gathered at each of the poles. DNA, and prepares for cell division Figure 14. Mitosis  Three stages: Cytokinesis  G1  The cytoplasm then divides during a process called First intermediate gap stage in which the cell cytokinesis. grows and prepares for DNA replication  Cytokinesis is not a stage of mitosis but the process  S phase of the cytoplasm splitting into two. In an animal cell Synthesis stage in which DNA is replicated. the cell membrane constricts.  G2 Second intermediate gap stage in which the cell finishes growing and prepares for cell division. REVIEW  G0 1. Question G0 is not a stage of the cell cycle. Some A. Choice cells no longer need to divide and exit the B. Choice cell cycle. These cells may exit the cell cycle C. Choice permanently. D. Choice 2. Question Figure 13. Phases of cell cycle A. Choice MITOTIC PHASE B. Choice C. Chioice  The period of the cell cycle in which the cell and D. Choice contents divide to create two genetically identical daughter cells Answer key  2 processes: TRANS COMM  Mitosis Why did cell stay in bed? Prophase  It lacks of mitochondria! Metaphase What did one cell said to another cell that stepped Anaphase on her toe? Telophase  My toe sis  Cytokiness What do you call a cell that does not share its Mitotis reviewer? Prophase  Cell-fish  The chromatin material shortens and thickens into Anong cell ang maihrap pegelan? individual chromosomes which are visible under the  Cell-los light microscope.  Each chromosome consists of two strands or GOODLUCK SA MIDTERMS GUYS! KAYA TA NI!! chromatids joined by a centromere. Metaphase  During metaphase, chromosomes line up on the equator of the cell. REFERENCES  The chromosomes appear in a straight line across (Tana, General Biology 1, 2023) the middle of the cell. (VanPutte, Regan, & Russo) Anaphase  During anaphase the chromatids are pulled to opposite poles of the cell by the shortening of the spindle fibers. Telophase  During telophase, a nuclear membrane reforms Y2 B9 M1 L2 | Lecture Title 12 | 13 Y2 B9 M1 L2 | Lecture Title 13 | 13