CELLS.pdf

College of Nursing Academic Year 2023-2024...

College of Nursing Academic Year 2023-2024 2024-2025 Anatomy and Physiology Bachelor of Science in Nursing LESSON 2: THE CELL, CELLULAR STRUCTURE, FUNCTIONS, METABOLISM AND REPRODUCTION CELL 4. REPRODUCTION Smallest/Basic unit of Life A cell aids in reproduction through the processes called Basic structural, functional, and biological unit of all mitosis and meiosis. Mitosis is termed asexual known organisms. reproduction where the parent cell divides to form Contains many biomolecules such as proteins and daughter cells. Meiosis causes the daughter cells to be nucleic acids. genetically different from the parent cells. FINEST FUNCTIONS STRACTURAL CLASSIFICATIONS OF CELL 1. CELL METABOLISM AND ENERGY USE 1. Prokaryotic cell (before nucleus) Cellular metabolism is the set of chemical reactions o absent of nucleus simple/primitive type of cell that occur in living organisms in order to maintain o lacks some organelles (Centrioles, Endoplasmic life. Cellular metabolism involves complex sequences of Reticulum, Golgi complex, Lysosomes, controlled biochemical reactions, better known as Mitochondria, Cytoskeleton) an independent single metabolic pathways. celled organism. These processes allow organisms to grow and ▪ ex. Bacteria reproduce, maintain their structures, and respond to 2. Eukaryotic cell (after nucleus) environmental changes. Cells require energy to carry o present of nucleus out various chemical processes. This energy is produced o complex by the cells through a process called photosynthesis in o multicellular organisms plants and respiration in animals. ▪ Ex. Plants, animals, humans 2. SYNTHESIS OF MOLECULES Cells synthesize various types of molecules, including proteins, nucleic acid, and lipids. The different cells of the body do not all produce the same molecules. Therefore, a cell’s structural and functional characteristics are determined by the types of molecules the cell produces. 3. COMMUNICATION Cells produce and receive chemical and electrical signals that allow them to communicate with one another. Their survival depends on receiving and processing information from the outside environment, whether that information pertains to the availability of nutrients, changes in temperature, or variations in light levels. Cells can also communicate directly with one another — and change their own internal workings in response — by way of a variety of chemical and mechanical signals. In multicellular organisms, cell signaling allows for specialization of groups of cells. Multiple cell types can then join together to form tissues such as muscle, blood, and brain tissue. In single-celled organisms, signaling allows populations of cells to coordinate with one another and work like a team to accomplish tasks no single cell could carry out on its own. o Neurons communicate with each other as well as with other cells through electric signals (nerve impulses), which in turn allows effector organs to respond to the appropriate stimuli. TRANSCRIBED BY MARIONNE LABANDARA BSN1 Y1-2 1  LESSON 2: CELL, CELLULAR STRUCTURE, FUNCTIONS, METABOLISM AND REPRODUCTION 2 PROPERTIES OF THE CELL PHYSICAL PROPERTIES Perceptible to the senses a. size – micron is the unit of measurement. b. color – grayish/ translucent c. consistency – colloidal, viscous d. odor – odorless e. taste – tasteless colloidal CHEMICAL PROPERTIES it contains organic and inorganic substances that are important for the various functions of the cell. o A. (4) Inorganic compounds ▪ Water – most abundant of all compounds in cell, about 60-90% of most living organisms ▪ Oxygen and Carbon dioxide - are present as gases in the respiratory organs of the organisms and in the tissue fluids such as the blood and lymph. ▪ Mineral Salt - are present in skeletons, ex. Calcium carbonate, and calcium phosphate ▪ Organic Salts - are present in skeletons sodium chloride and other salts are present in very small amounts. o B. Organic Compounds ▪ Carbohydrates - are the simplest and most abundant organic compound. ▪ Proteins - are the most important organic compound. ▪ Lipids - are fats soluble only in organic fluids. ex. Chloroform ▪ Nucleic acids - large and most complex organic molecules - DNA – found only inside the nucleus, for heredity - RNA – found in and out of the nucleus for protein synthesis CELL MEMBRANE/PLASMA MEMBRANE The Cell Membrane is primarily made up of two major types of molecules: (1) Phospholipids and (2) Proteins. o The Polar, phosphate-containing ends of the phospholipids are hydrophilic (water loving) and therefore face the extracellular fluid and the (2) TYPES OF ANIMAL CELL cytoplasm of the cell. o In contrast, the Nonpolar, fatty acids ends of the phospholipids are hydrophobic (water fearing) and Somatic cells are the cells in the body other than therefore facing away from the fluid on the other side sperm and egg cells (which are called germ cells). In of the membrane, toward the center of the double humans, somatic cells are diploid, meaning they layer of phospholipids. contain two sets of chromosomes, one inherited from The plasma membrane is the outer boundary of the cell. each parent. It separates the internal metabolic events from the o body cells ex. Blood cell, bone cell, neuron environment and allows them to proceed in organized, controlled ways. The plasma membrane also has specific receptors for external molecules that alter the cell’s Sex Cells function. A reproductive cell of the body. Germ cells are egg o Barrier cells in females and sperm cells in males. o Control o Signaling TRANSCRIBED BY MARIONNE LABANDARA BSN1 Y1-2 2  LESSON 2: CELL, CELLULAR STRUCTURE, FUNCTIONS, METABOLISM AND REPRODUCTION CYTOPLASM & THE ORGANELLES o Manufacture of certain macromolecules is the portion of the cell outside the nucleus. The semifluid LYSOSOME portion of the cytoplasm is called the cytosol. Suspended Digestive Compartments within the cytosol are the organelles. A lysosome Viscous fluid containing organelles. o Is a membranous sac of hydrolytic enzymes o Components of cytoplasm o Can digest all kinds of macromolecules o Interconnected filaments & fibers Lysosomes carry out intracellular digestion by o Fluid = cytosol Phagocytosis Organelles (not nucleus) Autophagy is the body's way of cleaning out damaged o storage substances cells, in order to regenerate newer, healthier cells. NUCLEUS VACUOLES Genetic Library of the Cell Diverse Maintenance Compartments – Contains most of the genes in the A plant or fungal cell eukaryotic cell. o May have one or several vacuoles – The eukaryotic cell’s genetic instructions are housed in Food vacuoles the nucleus and carried out by the ribosomes. o Are formed by phagocytosis – Carries the genetic material that contains information for Contractile vacuoles cell activities and cell division. o Pump excess water out of protist cells Three distinct parts: Central vacuoles Nuclear Envelope - encloses the nucleus, separating its o Are found in plant cells contents from the cytoplasm. o Hold reserves of important organic compounds and water Nucleolus - Responsible for making ribosomes which contains small units of RNA. THE ENDOMEMBRANE SYSTEM: A REVIEW Chromatin - In a non-dividing cell, the genetic material is Is a complex and dynamic player in the cell’s spread out in the form of chromatin, which encompasses compartmental organization. the last part of the nucleus. Whereas in a dividing cell, the Relationships among organelles of the endomembrane genetic system RIBOSOMES - Protein Factories in the Cell - Carry out protein synthesis. Ribosomes are particles made of ribosomal RNA and protein. ENDOMEMBRANE SYSTEM The endomembrane system regulates protein traffic and performs metabolic functions in the cell. The endomembrane system Includes many different structures. THE ENDOPLASMIC RETICULUM Biosynthetic Factory The endoplasmic reticulum (ER) accounts for more than half the total membrane in many eukaryotic cells Is continuous with the nuclear envelope. There are two distinct regions of ER: o Smooth ER, which lacks ribosomes. MITOCHONDRIA AND CHLOROPLASTS o Rough ER, which contains ribosomes. Change energy from one form to another Mitochondria THE SMOOTH ER o Are the sites of cellular respiration Synthesizes lipids o Are found in nearly all eukaryotic cells Metabolizes carbohydrates Stores calcium Mitochondria are enclosed by two membranes Detoxifies poison o A smooth outer membrane o An inner membrane folded into cristae THE ROUGH ER Chloroplasts Has bound ribosomes o Found only in plants, are the sites of photosynthesis Produces proteins and membranes, which are distributed by transport vesicles o Is a specialized member of a family of closely related plant organelles called plastids GOLGI APARATUS o Contains chlorophyll Shipping and Receiving Center Are found in leaves and other green organs of plants and Receives many of the transport vesicles produced in the in algae rough ER Consists of flattened membranous sacs called cisternae Functions of the Golgi apparatus include: o Modification of the products of the rough ER TRANSCRIBED BY MARIONNE LABANDARA BSN1 Y1-2 3  LESSON 2: CELL, CELLULAR STRUCTURE, FUNCTIONS, METABOLISM AND REPRODUCTION CILIA AND FLAGELLA Contain specialized arrangements of microtubules. Are locomotor appendages of some cells. o Flagella being pattern CYTOSKELETON The cytoskeleton is a network of fibers that organizes structures and activities in the cell. Gives mechanical support to the cell. Is involved in cell motility, which utilizes motor proteins. There are three main types of fibers that make up the cytoskeleton. MICROTUBULES MICROFILAMENTS Shape the cell. Are built from molecules of the protein actin Guide movement of organelles Are found in microvilli Help separate the chromosome copies in dividing cells. CENTROSOMES AND CENTRIOLES Is considered to be a “microtubule-organizing center” o Contains a pair of centrioles. INTERMEDIATE FILAMENTS Support cell shape Fix organelles in place TRANSCRIBED BY MARIONNE LABANDARA BSN1 Y1-2 4  LESSON 2: CELL, CELLULAR STRUCTURE, FUNCTIONS, METABOLISM AND REPRODUCTION CELL TRANSPORT SOLUTE – a substance that is being dissolved in the various fluids. SOLVENT – a fluid or gas in which solute is being dissolved. CONCENTRATION – the amount of solute dissolved in given volume of solvent. CONCENTRATION GRADIENT – the difference in concentration of a substance between two areas TRANSCRIBED BY MARIONNE LABANDARA BSN1 Y1-2 5  LESSON 2: CELL, CELLULAR STRUCTURE, FUNCTIONS, METABOLISM AND REPRODUCTION CELL CYCLE Diploid - A cell possessing two copies of each chromosome (human body cells). Homologous chromosomes - are made up of sister chromatids joined at the centromere. Haploid - A cell possessing a single copy of each chromosome (human sex cells). MEIOSIS Gametes o Sexual Reproduction Ensures that all living organisms will maintain both Genetic Diversity and Genetic Integrity IMPORTANCE OF CELL DIVISION You are a living organism, made of cells. In order to keep living your cells must stay alive. In order for cells to keep living, they must divide and multiply MEIOSIS FACTS ✓ START WITH 46 DOUBLE STRANDED CHROMOSOMES (2N) ✓ AFTER 1 DIVISION - 23 DOUBLE STRANDED CHROMOSOMES (N) ✓ AFTER 2ND DIVISION - 23 SINGLE STRANDED CHROMOSOMES (N) ✓ OCCURS IN OUR GERM CELLS THAT PRODUCE GAMETES TRANSCRIBED BY MARIONNE LABANDARA BSN1 Y1-2 6 LESSON 2: CELL, CELLULAR STRUCTURE, FUNCTIONS, METABOLISM AND REPRODUCTION TRANSCRIBED BY MARIONNE LABANDARA BSN1 Y1-2 7