Plant and Animal Cell Biology Notes PDF

PLANT AND ANIMAL CELLS Prepared by: Ianna Tacleran-Cid  OBJECTIVES Describe the structure and function of a plant cell Describe the structure of an animal cell Compare and contrast the plant and animal cell plant Cell Animal Cell  A ph...

PLANT AND ANIMAL CELLS Prepared by: Ianna Tacleran-Cid  OBJECTIVES Describe the structure and function of a plant cell Describe the structure of an animal cell Compare and contrast the plant and animal cell plant Cell Animal Cell  A phospholipid bilayer with embedded proteins that separate the internal contents of the cell from its surrounding environment The plasma It has two fatty acid chains and a phosphate-containing group membrane It controls the passage of organic molecules, ions, waste products, water, and oxygen into and out of the cell Sample Footer Text CYTOPLASM The cell’s entire region between the plasma membrane and the nuclear envelope Comprised of organelles in the gel-like cytosol, the cytoskeleton, and various chemicals Consists of 70 to 80% water, but has a semi- solid consistency Other components include proteins, glucose and other simple sugars, polysaccharides, amino acids, nucleic acids, fatty acids, and 8/9/2024 ions (Na+, K+, Ca2+) 5 Sample Footer Text THE NUCLEUS (Information center) Most prominent organelle in the cell It houses the cell’s DNA (chromatin) and directs the synthesis of ribosomes and proteins Nucleoplasm is a gel-like substance Nucleolus is a condensed chromatin region where ribosome synthesis occurs Nuclear envelope is also of phospholipid bilayer Nuclear membrane is continuous with the endoplasmic reticulum Nuclear pores allow substances to enter and exit the 8/9/2024 nucleus 6 Sample Footer Text THE NUCLEUS: Nuclear Envelope The nuclear envelope is double-membrane structure that constitutes the outermost portion of the nucleus Punctuated with pores that control passage of ions, molecules, and RNA between nucleoplasm and cytoplasm Nucleoplasm is the semi-solid fluid inside the nucleus, where we find the chromatin and nucleolus 8/9/2024 7 Sample Footer Text THE NUCLEUS: CHROMATIN AND CHROMOSOMES DNA is the hereditary material Chromosomes are linear structures, and every eukaryotic species has specific number of chromosomes in the nucleus of each cell – they are only visible and distinguishable from one another when the cell is about to divide Chromatin is when proteins attach to chromosomes during the growth and maintenance phase of its life cycle – it describes the material that makes up the chromosomes both when condensed and decondensed 8/9/2024 8 Sample Footer Text THE NUCLEUS: NUCLEOLUS Directs the synthesis of ribosomes Ribosome synthesis is done by some chromosome which have sections of DNA that encode ribosomal RNA Nucleolus is a darkened area in the nucleus that aggregates the ribosomal RNA with associated proteins to assemble the ribosomal subunits that are then transported out through the pores in the nuclear envelope to the cytoplasm 8/9/2024 9 Sample Footer Text RIBOSOMES (Protein Factories) Responsible for protein synthesis Under SEM, they appear as clusters, or single, tiny dots that float freely in the cytoplasm They may be attached to plasma membrane cytoplasmic side, the ER’s cytoplasmic side, or the nuclear envelope’s outer membrane They consists of two subunits: large and small They receive “orders” for protein synthesis from the nucleus where the DNA transcribes into messenger RNA, the mRNA then travels to ribosomes which translate the code provided by the sequence of nitrogenous bases in the 8/9/2024 mRNA into specific order of amino acids in a protein Amino acids are the building blocks of proteins 10  Responsible for making the cell’s energy currency Sample Footer Text called adenosine triphosphate (ATP) Cellular respiration takes place in this organelle where glucose is transformed into ATP using oxygen while producing carbon dioxide as a byproduct They are oval-shaped, double-membrane organelles that have their own ribosomes and DNA, each membrane is a phospholipid bilayer embedded with proteins The inner layer has folds called cristae The area surrounded by the folds is the mitochondrial MITOCHONDRIA matrix (Cell’s powerhouse) There is an inner membrane and an outer 8/9/2024 membrane, and between these two, there is an intermembrane space where ATP synthesis takes place 11 Peroxisomes (Oxidation) They are small, round organelles enclosed by single membranes They carry out oxidation that break down fatty acids and amino acids, detoxify many poisons that may enter the body The oxidation processes releases hydrogen peroxide (H2O2) which can damage the cells; however, they are broken down by enzyme catalase into water and oxygen molecules  Specialized peroxisomes in plants are responsible for converting stored fats into sugars glyoxysomes Plant cell contain many different types of peroxisomes that play a role in metabolism, pathogen defense and stress response  VESICLES AND VACUOLES They are membrane-bound sacs that function in storage and support Vacuoles are somewhat vesicles, and have very little distinction between them Vesicle membranes can fuse with either the plasma membrane or other membrane systems within the cell Some agents such as enzymes within plant vacuoles break down macromolecules. The vacuole’s membrane does not fuse with the membranes of other cellular components  PLANT VS ANIMAL CELL PLANT CELLS Has microtubule organizing centers (MTOCs) They have cell wall, chloroplasts, and other specialized plastids Has a large central vacuole ANIMAL CELLS Has microtubule organizing centers (MTOCs) and centrioles associated with the MTOC: a complex called centrosome Have centrosome and lysosomes CENTROSOME A microtubule-organizing center (MTOC) found near the nuclei of animal cells Contains a pair of centrioles, two structures that lie perpendicular to each other Each centriole is a cylinder of nine triplets of microtubules In cell division, centrosomes replicate themselves before a cell divides, and the centrioles appear to have same role in pulling the duplicated chromosomes to opposite ends of the dividing cell  LYSOSOMES The “garbage disposal” of animal cells, in contrast, vacuoles perform this function in plant cells It contains enzymes that aid in breaking down (through phagocytosis) proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles (autophagy) The pH within the lysosome is much lower than the cytoplasm Also, a part of the endomembrane system when needed to ingest a pathogen Cell wall External to the plasma membrane, which is a rigid covering that protects the cell It provides structural support, rigidity, and gives shape to the cell Fungal and other protistan cells (slime molds, algae, and seaweeds) also have cell walls. Prokaryotic cell wall consists of peptidoglycan, plant’s and of most protists is of cellulose, and fungal cell wall is of chitin Cellulose of cell wall in plants is a polysaccharide comprised of glucose units  CHLOROPLAST Plant cell organelles that carry out photosynthesis, a process that allows plants to be photoautotrophs They have their own DNA and ribosomes, and like mitochondria, they also have inner and outer membrane Inside the inner membrane there is a fluid called stroma, within the stroma, there is a set of interconnected and stacked fluid-filled membrane sacs called thylakoids; each thylakoid stack is called a granum (plural=grana) Chloroplasts contain the green pigment, chlorophyll, which captures the light energy and drives the reactions of photosynthesis  Occupies majority of the plant cell’s area Plays a key role in regulating the cell’s CENTRAL VACUOLE concentration of water in changing environmental conditions When the water concentration in the central vacuole is low, the cell wall becomes unsupported making the plant look wilted THE ENDOMEMBRANE SYSTEM AND PROTEINS It is a system consisting of group of membranes and organelles in eukaryotic cells that works together to modify, package, and transport lipids and proteins Includes nuclear envelope, lysosomes, vesicles, the endoplasmic reticulum, Golgi bodies, and the plasma membrane does not include mitochondria and chloroplasts ENDOPLASMIC RETICULUM (ER) A series of interconnected membranous sacs and tubules that collectively modifies proteins and synthesizes lipids Consists of the rough and smooth ER The ER tubules’ hollow portion the lumen or cisternal space The ER’s membrane, which is a phospholipid bilayer embedded with proteins, is continuous with the nuclear envelope ROUGH ER Named rough ER because of the ribosomes attached to its cytoplasmic surface, giving it a studded appearance under microscope Newly synthesized proteins from ribosomes are transferred into the RER lumen where they undergo structural modifications, such as folding or acquiring side chains Proteins processed in the RER incorporate into cellular membranes – the ER or other organelles’ membranes RER also makes phospholipids for cellular membranes RER mainly modifies proteins (e.g., enzymes) so they are most abundant in cells that secrete protein like in the liver SMOOTH ER Continuous with the RER but has few to no ribosomes on its cytoplasmic surface Functions include synthesis of carbohydrates, lipids, and steroid hormones; it also detoxifies medications and poisons and stores calcium In muscle cells, a specialized SER, the sarcoplasmic reticulum, is responsible for storing calcium ions that are needed to trigger the muscle cells' coordinated contractions GOLGI APPARATUS Sorting, tagging, packaging, and distributing lipids and proteins take place in the Golgi apparatus which is a series of flattened membranes The Golgi has a cis and trans face Transport vesicle from the ER arrives at the cis face, fuse with it, and empty their contents into the Golgi bodies’ lumen. These proteins and lipids undergo further modification that allow them to be sorted (usually adding sugar molecule chains) These newly-modified proteins and lipids then tag with PO4 groups to travel to their proper destinations Then, these modified and tagged molecules are packaged into secretory vesicles that bud from Golgi’s trans face Some of these packaged vesicles deposit their contents into other cell parts where they are used, they may also fuse with plasma membrane and release their content outside of the cell THE ENDOMEMBRANE SYSTEM  THE CYTOSKELETON Collective network of protein fibers that help maintain the cell’s shape, secure some organelles in specific positions, allow cytoplasm and vesicles to move within the cell, and enable cells within multicellular organisms to move There are three types of fibers within the cytoskeleton: microfilaments, intermediate filaments, and microtubules  The narrowest type of protein fiber in the CYTOSKELETON: cytoskeleton MICROFILAMENTS Function in the cellular movement they have a diameter of about 7 nm, and are comprised of two globular protein intertwined strands, which we call actin Also called actin filaments They are powered by ATP to assemble their filamentous form that becomes the track for the movement of a motor protein called myosin, allowing cell division They provide rigidity and shape to the cell They can depolymerize (disassemble) and reform quickly, thus enabling a cell to change its shape and move, as seen in white blood cells’ movement to an infection site  CYTOSKELETON: INTERMEDIATE FILAMENTS Several strands of fibrous proteins that are wound together comprise intermediate filaments No role in cellular movement but function purely in the structure – they bear tension to maintain cell shape, anchor the nucleus and other organelles in place The intermediate filaments are the most diverse group of cytoskeletal elements Several fibrous protein types are in the intermediate filaments, like keratin, the fibrous protein that strengthens the hair, nails, and the skin's epidermis. CYTOSKELETON: They are small hollow tubes, with a diameter of about 25 nm, microtubules are cytoskeletons' widest components MICROTUBULES they help the cell resist compression, provide a track along which vesicles move through the cell, and pull replicated chromosomes to opposite ends of a dividing cell; they can also disassemble and reform quickly the structural elements of flagella, cilia, and centrioles flagella are long, hair-like structures that extend from the plasma membrane and enable an entire cell to move. When present, the cell has just one flagellum or a few flagella. Cilia are composed of many extensions along the plasma membrane’s surface – they are short, hair-like structures that move entire cells, or substances along the cell's outer surface like in the fallopian tubes  PLANT AND ANIMAL CELLS’ COMPONENTS  PLANT AND ANIMAL CELLS’ COMPONENTS  PERFORMANCE TASK #1 Create a 3D model of animal and plant cells using recyclable materials