Biology-PPT-Q1W2-SY24-25-for-student.pptx

CELL: TYPES, FUNCTIONS AND MODIFICATION  OBJECTIVES K: distinguish prokaryotic and eukaryotic cells according to their distinguishing features; S: classify different cell types (of plant/animal tissues) and specify the functions of each; and A: relate the importance of some cell modific...

CELL: TYPES, FUNCTIONS AND MODIFICATION  OBJECTIVES K: distinguish prokaryotic and eukaryotic cells according to their distinguishing features; S: classify different cell types (of plant/animal tissues) and specify the functions of each; and A: relate the importance of some cell modification by describing their adaptation to carry out specialized function (e.g., microvilli, root hair). Label Me! The illustration below shows some parts of a cell. Identify which of the following is prokaryotic and eukaryotic cell. Label Me! The illustration below shows some parts of a cell. Identify which of the following is prokaryotic and eukaryotic cell. Prokaryotes Prokaryotes come from the Greek term pro meaning “before” and karyon meaning “kernel” referring to the nucleus. Prokaryotes Prokaryotic cells have no nucleus, and their genetic material (DNA) is concentrated in a region called the nucleoid which does not have a membrane separating it from the rest of the cell. Prokaryotes The major parts of a prokaryotic cell include cell wall, cell membrane, ribosomes, and a nucleoid. Prokaryotes Two domains of organisms comprise prokaryotes: Bacteria and Archaea. Bacteria make up most of the prokaryotes. In addition, Archaea are found in extreme environments such as hot springs or near volcanoes. Prokaryotes The difference between Bacteria and Archaea is their type of cell wall. Archaea have a thicker cell wall that is very strong and protects it from the heat and chemicals found in harsh environments, while Bacteria have a more permeable cell wall that provides less protection from high Prokaryotes The difference between Bacteria and Archaea is their type of cell wall. Archaea have a thicker cell wall that is very strong and protects it from the heat and chemicals found in harsh environments, Prokaryotes The difference between Bacteria and Archaea is their type of cell wall. while Bacteria have a more permeable cell wall that provides less protection from high temperatures or extreme pH, but takes less Prokaryotes Both Bacteria and Archaea consist of unicellular organisms. Prokaryotes are important to all life on Earth for a number of Prokaryotes 1.They play a critical role in the recycling of nutrients by decomposing dead organisms and allowing their nutrients to be re- used. Prokaryotes Bacteria in our guts and mouth help with the digestion of food by breaking down difficult to digest carbohydrates and other compounds. Prokaryotes A prokaryotic cell is a simple, single-celled (unicellular) organism that lacks a nucleus, or any other membrane-bound organelle. Prokaryotes Prokaryotic DNA is found in the central part of the cell: a darkened region called the nucleoid. Eukaryotes The oldest fossil evidence of eukaryotes is about 2 billion years old. Eukaryotes are combination of two Greek terms eu meaning “true” and karyon meaning “nucleus.” Thus, eukaryote means “true kernel” or “true nucleus,” Eukaryotes The word organelle means “little organ,” and organelles have specialized cellular functions, just as the organs of your body have specialized functions. Eukaryotes A cell has a membrane- bound nucleus and other membrane bound compartments or sacs, called organelles, which have specialized functions. Eukaryotes The major organelles found in a eukaryotic cell are cell membrane, cell wall, ribosomes, nucleus, mitochondria, endoplasmic reticulum, and lysosomes. They are both unicellular and Eukaryotes The four kingdoms of eukaryotic organisms are Kingdom Plantae, Kingdom Animalia, Kingdom Fungi, and Kingdom Protista. Eukaryotes Plants are photosynthetic organisms containing cell walls and specialized reproductive tissue. Animals are organisms that lack cell walls, are capable of locomotion, and have a digestive tract. Eukaryotes Fungi digest their food externally and then absorb it through their cell walls. Plants, animals, and fungi are all multicellular organisms. Protists are single-celled motile organisms that can be either photosynthetic or Eukaryotes Eukaryotes Animals are capable of movement, although not all animals have muscles used for movement. In the most commonly encountered animals, the mobile stage is the adult, although some animals (such as corals and sponges) have Eukaryotes Both animal and plant evolutionary history show the development of multi- cellularity and they move from water to land (as well as a secondary adaptation back to water, for example dolphins, whales, duckweed, Eukaryotes Animals developed external or internal skeletons to provide support, skin to prevent or lessen water loss, muscles that allowed them to move to search for food, brains and nervous systems for Animal tissues are divided into four main types: 1. Epithelial Tissue This type of tissue is commonly seen outside as coverings or as linings of organs and cavities. It is characterized by closely- joined cells with tight junctions. Animal tissues are divided into four main types: 1. Epithelial Tissue Being tightly packed, tight junctions serve as barriers for pathogens, mechanical injuries and fluid loss. Cells that make up epithelial tissues have distinct arrangements: Animal tissues are divided into four main types: 1. Epithelial Tissue A.Cuboidal- for secretion B. Simple columnar - brick-shaped cells; for secretion and active absorption C. Simple squamous - plate-like cells; for exchange of material through diffusion D. Stratified squamous - Animal tissues are divided into four main types: 1. Epithelial Tissue E. Pseudo-stratified columnar - single layer of cells; may just look stacked because of varying height; for lining of respiratory tract; usually lined with cilia (i.e., a type of cell modification that sweeps the mucus). 2. Connective Tissue These tissues are composed of the following: A. BLOOD - made up of plasma (i.e., liquid extracellular matrix): contains water, salts and dissolve proteins, erythrocytes that carry oxygen (RBC), leukocytes 2. Connective Tissue B. CONNECTIVE TISSUE PROPER (CTP)- made up of loose connective tissue that is found in the skin and fibrous connective tissue that is made up of collagenous fibers found in tendons and ligaments. Adipose tissues are also examples of loose connective tissues that store fats which functions to insulate the 2. Connective Tissue C. CARTILAGE - characterized by collagenous fibers embedded in chondroitin sulfate. Chondrocytes are the cells that secrete collagen and chondroitin 2. Connective Tissue D. BONE - mineralized connective tissue made by bone-forming cells called osteoblasts which deposits collagen. Blood vessels and nerves are found at a central canal surrounded by 3. Muscle Tissue These tissues are composed of long cells called muscle fibers that allow the body to move voluntary or involuntary. It gives rise to muscles' ability to contract. This is opposed to other components or tissues in muscle such as tendons or perimysium. It is formed during embryonic development through a process known as myogenesis. Muscle tissue consists of elongated cells 3. Muscle Tissue Movement of muscles is a response to signals coming from nerve cells. In vertebrates, these muscles can be categorized into the following: A.Skeletal - striated: voluntary movements, attached to the skeleton B. Cardiac - striated with 3. Muscle Tissue C. Smooth - not striated; involuntary, located in walls of hollow visceral organs 4. Nervous Tissue These tissues are composed of nerve cells called neuron and glial cells that function as support cells. These neurons sense stimuli and transmit electrical signals throughout the animal body. Neurons connect to other neuron that receives impulses from other neurons, while 4. Nervous Tissue Structure of a typical neuron. Plant cells with similar structure and functions form plant tissue. Plant tissues come in several forms: vascular, epidermal, ground, and meristematic. Each type of tissue consists of different types of cells, has different functions, and is located in different places. 1. Meristematic tissue 1. Meristematic tissue - is actively dividing to produce new cells. Meristematic tissue consists of undifferentiated small cell, with dense cytoplasm and large nuclei. The cells differentiate into new tissue of the plant. Meristematic tissue is found 1. Meristematic tissue A.Apical Meristem - are located at the growing points at the tips of roots and stems and results in an increase in the length of these structures. B. Lateral Meristem - results in the growth in thickness or width of woody roots and stems. This tissue is also called cambium; cork cambium divides to form the cork cells that form the outer bark of a woody plant. Vascular 1. Meristematic tissue 2. Permanent Tissue These are specialized in function and do not divide constantly. Differentiation of cells begins as soon as cells have been formed by cell division, and results in changes in structure. There are three groups of permanent tissue: 2. Permanent Tissue A. Epidermal Tissue - This is the outermost layer of cells that covers the roots, stems, and leaves. They are tightly packed, with no intercellular air spaces. The main function of the epidermal cells is to protect the underlying tissue from injury. 2. Permanent Tissue A. Epidermal Tissue a. Guard cells - are bean- shaped epidermal cells that occur on either side of a stoma which is the opening that occurs on the surface of a leaf. The guard cells function to open and close the stoma, thus controlling 2. Permanent Tissue A. Epidermal Tissue b. Hair cells - are formed by an extension of the cell wall. The hair functions to increase the surface area of the root to maximize the uptake of water and nutrients. 2. Permanent Tissue B. Vascular tissue - functions to transport and support. a. Xylem Tissue - transport water and mineral salts from the ground water through the roots to the stems and leaves. It consists of vessels and tracheids - both cells have cell walls that are 2. Permanent Tissue B. Vascular tissue - functions to transport and support. b. Phloem Tissue - transport food from the leaves, where photosynthesis takes place, to areas undergoing growth or storage sites. Phloem tissue consists of long columns of sieve tubes and companion cells. 3. Ground Tissue This type of tissue forms the body of the plant and is responsible for support, storage, and photosynthesis. There are three types of ground tissue: A. Parenchyma - thin walled and alive at maturity; often multifaceted Anatomy of flowering plant tissue systems. What is cell modification?. Cell specialization or modification occurs after cell division wherein newly formed cells are structurally modified so that they can perform their function efficiently and effectively. What is cell modification?. Apical modification It is a cell modification found on the apical surface of the cell. Cilia and flagella  Cilia are usually short, hair- like structures that move in waves.  Flagella are long whip-like structures.  Formed from microtubules Villi and microvilli  Villi are finger-like projections that arise from epithelial layer in some organs. They help to increase surface area allowing for faster and more efficient adsorption.  Microvilli are smaller projections that arise from the cell’s surface that also Villi and microvilli Villi and microvilli These projections increase the surface area of the small intestine for the absorption of nutrients, and as a higher surface area = higher rate of transportation processes such as Pseudopods  Temporary, irregular lobes formed by amoebas and some other eukaryotic cells  Bulge outward to move the cell or engulf prey  From the Greek word pseudes and podos, Extracellular matrix (ECM)  Compound secreted by the cell on its apical surface  Cell wall in the extracellular structure in plant cells that distinguishes them from animal cell  Glycoprotein is the main ingredient of ECM in animal cells.  They cover external surface, line up internal organs, take up Basal Modification  Cell modification found on the basal surface of the cell desmosomes/hemidesmoso mes  Anchoring junction on the basal surface of the cell Rivet-like links between cytoskeleton and extracellular matrix components such as the Lateral modification A cell junction that provides contact between neighboring cells or between the cell and extracellular matrix. Tight Junction  Acts as barriers that regulate the movement of Adhering Junction  Anchoring junction on the lateral surface of the cell  Very similar to the anchoring junction of the basal surface of the cell Gap Junction  Also known as communicating junctions  Closable channel that connect the cytoplasm of adjoining animal cells  Presence of connexon that allow direct exchange of chemical between the cytoplasm Evaluation