Lesson 2 - Cell Types and Modification PDF

Recap Lesson 2: Cell Types and Modification Presented by: Sir. Roy R. Piloneo Learning Objectives 1 2 Classify different cell types Describe some cell (of plant / animal tissues) modifications that lead to and s...

Recap Lesson 2: Cell Types and Modification Presented by: Sir. Roy R. Piloneo Learning Objectives 1 2 Classify different cell types Describe some cell (of plant / animal tissues) modifications that lead to and specify the function(s) adaptation to carry out of each. specialized functions (e.g., microvilli, root hair) Table of Contents Stem Cell Plant Tissues Animal Tissues 01 Stem Cell  What are Stem Cells? Stem cells are undifferentiated cells that can differentiate and multiply into 200 cell types that form a human being. It’s All about Potential It’s All about Potential Variations of Stem Cells (Potency) Totipotent Pluripotent Multipotent Unipotent fertilized egg and can give rise to differentiate can differentiate the first four any of the cell into a limited into one type of divisions types in the body range of cell cell only can develop into types a new individual if placed in a womb Variations of Stem Cells (Potency)  0 2 Plant Tissues Permanent Tissues Three Main Types Ground Tissues make up most of the plant’s body. Vascular Tissues (Xylem and Phloem) transport materials within the plant. Dermal Tissues cover the plant’s body. Permanent Tissues Ground Tissue Ground Tissue consists of three main cell types: 1. Parenchyma 2. Collenchyma 3. Sclerenchyma “The cells that compose the ground tissue are important sites of photosynthesis, respiration, storage, and support.” Permanent Tissues Vascular Tissue Vascular Tissues transport water, minerals, carbohydrates, and other dissolved compounds. Permanent Tissues Vascular Tissue Xylem tissue transports water and minerals from the roots to other plant parts. It consists of long, narrow cells called tracheids and wide, barrel- shaped cells called vessel elements. Permanent Tissues Vascular Tissue Phloem tissue transports dissolved organic compounds like sugars. Sieve tube elements are the conducting cells; companion cells transfer materials in and out of sieve tubes. Permanent Tissues Dermal Tissue Dermal tissue covers the plant; it consists of the epidermis, which is coated with a waxy cuticle. Permanent Tissues Dermal Tissue The cuticle conserves water and protects the plant. Pores in the cuticle, called stomata (singular stoma), allow leaves to exchange gases with the atmosphere. Permanent Tissues Dermal Tissue Guard cells surround each stoma and control its opening and closing. Tissues Build Stems, Leaves, and Roots “The three tissue types make up the stems, leaves, and roots of the plant. Let’s look at each of these organs, starting with the stem.” Permanent Tissues Stem Ground tissue occupies most of the stem of an herbaceous plant. Vascular bundles are embedded in the ground tissue. Dermal tissue covers the stem. Permanent Tissues Stem Monocots and Eudicots have different arrangements of vascular tissue and ground tissue in stems. Permanent Tissues Stem In monocots, vascular bundles are scattered throughout the stem. In eudicots, vascular bundles are arranged in a ring near the epidermis. Permanent Tissues Leaf Ground tissue occupies most of a leaf. Vascular bundles are embedded in the ground tissue. Dermal tissue covers the leaf. Permanent Tissues Leaf Leaves are flattened blades supported with a stalk-like petiole. Permanent Tissues Leaf Simple leaves have undivided blades. Compound leaves are divided into leaflets attached to one petiole. Permanent Tissues Leaf Veins on typical Veins are vascular bundles inside the eudicot leaf leaves. Many monocots have parallel veins; most eudicots have netted veins. Veins on typical monocot leaf Permanent Tissues Leaf The ground tissue inside a leaf is called mesophyll, which consists of cells with abundant chloroplasts that produce sugars by photosynthesis. Permanent Tissues Leaf Mesophyll cells also exchange materials with vascular tissues. Permanent Tissues Root In a root, ground tissue surrounds a central core of vascular tissue. Dermal tissue forms the root epidermis. Permanent Tissues Root Roots might form a fibrous root system or a taproot system. Fibrous roots are slender, shallow, and arise from the stem base. Taproots are thick, deep, and have fewer branches. Permanent Tissues Root Near each root’s tip, root hairs are extensions of the epidermis that absorb water and minerals. Meristematic Tissues Plants grow by adding units, or modules, consisting of repeated nodes and internodes. Growth occurs at meristems, regions of active cell division. Meristematic Tissues Apical meristems produce tissues that lengthen the tips of shoots and roots. Meristematic Tissues Primary growth occurs at the apical meristems. New cells can differentiate into any tissue type. Apical meristems Meristematic Tissues Secondary growth thickens roots and stems; this growth occurs at lateral meristems. Meristematic Tissues Secondary growth occurs in woody plants. Two types of lateral meristems produce wood and bark: Vascular cambium Cork cambium Meristematic Tissues The vascular cambium (highlighted green) produces a secondary xylem toward the inside of the stem and a secondary phloem toward the outside. Meristematic Tissues The cork cambium (highlighted white) produces parenchyma cells toward the inside and dense, waxy cells called cork toward the outside. Cork is the outer protective layer of bark. Meristematic Tissues The secondary xylem eventually becomes unable to conduct water, forming heartwood. The lighter sapwood transports water and dissolved minerals. Meristematic Tissues Tree rings arise from alternating moist and dry seasons. Wood that forms in the spring has larger cells than wood that forms in the summer. Animal Tissues 0 3 Animal Tissues Animal Tissues fall into FOUR categories: Epithelial, Connective, Muscle, and Nervous Epithelial Tissues Epithelial tissues are tightly packed cells that coat the body’s internal and external surfaces. Epithelial Tissues Each epithelial tissue has a free (exposed) surface. The opposite side is anchored to a layer of extracellular matrix called a basement membrane. Free surface Epithelial Tissues Simple epithelial tissues consist of one layer of cells. Stratified epithelial tissues have multiple cell layers. Epithelial Tissues Simple squamous epithelial tissue is a single layer of flattened cells that allows substances to pass by diffusion and osmosis. The lining of blood vessels Alveoli of lungs Epithelial Tissues Simple cuboidal epithelial tissue is a single layer of cube-shaped cells that secrete and absorb substances. Glands Lining of kidney tubules  Epithelial Tissues Simple columnar epithelial tissue is a single layer of column-shaped cells that secrete and absorb substances. Lining of the digestive tract Bronchi Uterine tubes Epithelial Tissues Stratified squamous epithelial tissue is multiple layers of flattened cells that protect areas subject to abrasion. The outer layer of the skin Epithelial Tissues Connective Tissues Connective tissue consists of cells scattered within an extracellular matrix, rather than being connected to one another. Connective Tissues Loose connective tissue consists of cells in a loose matrix of protein fibers (elastin and collagen). It holds organs in place and attaches epithelial tissues to other tissues. Under skin Between organs  Connective Tissues Dense connective tissue consists of cells in a dense matrix of protein fibers. It connects muscle to bone and bone to bone. Tendons Ligaments Connective Tissues Adipose tissue is fat cells in a minimal extracellular matrix. It stores fat for energy and insulation. Beneath skin Between muscles Around heart Around joints Connective Tissues Blood consists of red blood cells, white blood cells, and platelets in a liquid matrix (plasma). It transports gases, hormones, wastes, and nutrients. Flows inside blood vessels Connective Tissues Cartilage consists of cells in a matrix of fine collagen fibers. It provides flexible support. Ears Joints Bone ends Respiratory tract Connective Tissues Bone consists of cells in a matrix of collagen and minerals. It provides firm support. Skeleton Muscle Tissues Muscle tissue consists of cells that contract when electrically stimulated. Muscle tissue attaches to soft tissue or bone. When the cells contract, the body part moves. Muscle Tissues Skeletal muscle is striated and consists of elongated cells with many nuclei. It moves bones under voluntary control. Attached to bones Muscle Tissues Cardiac muscle is striated and consists of short, branched cells, each with one nucleus. It contracts the heart chambers under involuntary control. Walls of the heart Muscle Tissues Smooth muscle consists of spindle- shaped cells, each with one nucleus. It produces slow, involuntary movements. Digestive tract Arteries Nervous Tissues Nervous tissue uses electrical signals to transmit information within an animal’s body rapidly. Nervous tissue comprises cells called neurons, which form communication networks, and neuroglia, which support neurons. Brain Spinal cord Nerves  References: Rey, J. D. & Ramos, J. M. (2018). Senior High School: General Biology 1. Oxford Publishing (Malaysia). Russell, P. J., Et. Al (2017). General Biology 1. JO-ES Publishing House, Inc. Hoefnagels, M. (2016). Biology: The Essentials. McGraw-hill Education (International) Thanks for listening! Do you have any questions?