Plant Structure and Function PDF

Lesson 2: Plant Structure and Function Module 19: Introduction to Plants P. 513 to 522 Think About It All multicellular organisms have cells and tissues that work together to maintain homeostasis. However, plant cells and animal cells are different. Do you recall the difference...

Lesson 2: Plant Structure and Function Module 19: Introduction to Plants P. 513 to 522 Think About It All multicellular organisms have cells and tissues that work together to maintain homeostasis. However, plant cells and animal cells are different. Do you recall the differences and similarities between plant cells and animal cells? How do plant cells and tissues help plants maintain structure and homeostasis? What I Know? What I Want to Know? Focus question: What are the structures and functions of plant cells and tissues? New vocabulary Epidermis Cortex Guard cell Endodermis Xylem Pericycle Vessel element Petiole Tracheid Palisade mesophyll Phloem Spongy mesophyll Sieve tube member Transpiration Companion cell Nastic response Ground tissue Tropism Root cap Plant cells P: 513 Plant cells are identifiable by their cell walls, large central vacuole, and chloroplasts. Plant cells Plants have many types of cells adapted for specific purposes. P: 513 Plant cells P: 513 A. Parenchyma Cell Functions Storage Photosynthesis Gas exchange Protection Tissue repair and replacement Plant cells P: 513 B. Collenchyma Cell Functions Support Transport of material Plant cells P: 513 C. Sclerenchyma Cell Functions Support for surrounding tissues Provides flexibility for plant Tissue repair and replacement Plant tissues P: 514 A tissue is a group of cells that work together to perform a function. There are four different tissue types found in plants: Meristematic Dermal Vascular Ground  21s tC Cri entur tica y l Th Skill ink s: ing What do you think would happen to a plant if the apical meristem were removed? Plant tissues Dermal tissue - the epidermis The outer covering layer Epidermal cells resemble pieces of a jigsaw puzzle with interlocking ridges and dips. P: 515 Plant tissues Dermal tissue - the epidermis _ The cuticle_ made of fatty substance that: - Reduces water loss. - Prevents bacteria from entering the plant. Changes in the shape of guard cells result in the opening and closing of a stomata. _ Stomata _ small openings through which gases pass. P: 515  21s tC Cri entur tica y l Th Skill ink s: ing How might the cuticle of a desert plant be different from the cuticle of a rainforest plant? Plant tissues Dermal tissue - the epidermis _ Trichomes _ hair-like projections that protect the plant from insect and animal predators. The tiny glands at the tip of a trichome can contain toxic substances. P: 515 Plant tissues Dermal tissue - the epidermis _ Root hairs _ fragile extensions of root epidermal cells that increase the root's surface area and enable roots to take in a greater volume of materials. P: 515 Plant tissues Vascular tissues Water, food and dissolved material are transported in a plant by two types of vascular tissue - Xylem and Phloem P: 516 Plant tissues Vascular tissues _ Xylem _ is the water-carrying vascular tissue, composed of specialized cells called vessel elements and tracheids. Vessel elements are tubular cells stacked end-to-end. Lack end walls, allowing free movement Tracheids are tubular cells with of water from one vessel element to pitted ends and end walls. another. Less efficient at moving water P: 516 than vessel elements. Plant tissues Vascular tissues _ Phloem _ is the main food-carrying tissue in vascular plants. Consists of two types of cells: - Sieve tube members - Companion cells P: 516 Plant tissues Vascular tissues Sieve tube members contain cytoplasm but lack nuclei and ribosomes when mature. Companion cells occur next to sieve tube cells and have a P: nucleus. 517 Plant tissues Ground tissue _ Ground tissue _ Plant tissues that are not meristematic, dermal, or vascular tissues. Consist of parenchyma, collenchyma, and sclerenchyma cells Functions include photosynthesis, storage, and support P: 517 Plant tissues Roots P: 517 Plant tissues Roots The tip of a root is covered by the root cap. The root cap consists of parenchyma cells to help protect root tissues as the root grows. The layer between the epidermis and vascular tissue is the cortex. The cortex is composed of ground tissue parenchyma cells that transport or store substances. P: 517 Plant tissues Roots The inner boundary of the cortex is a layer called the endodermis. Each cell of the endodermis is encircled by a waterproof strip called the Casparian strip: forces water and substances to pass through the endodermal cells instead of around them. Directly next to the endodermis, toward the center of the root, is the pericycle, which produces lateral roots. P: 517 Plant tissues Roots Types of Roots: Taproot system Anchors plant, food storage (beets, carrots) Fibrous root systems Anchors plant, good for rapid water storage. P: 518 Plant tissues Roots Types of Roots: P: 518 Plant tissues Roots Other root types are adapted to diverse environments: P: 518 Stems Structure and functions Main function is support of leaves and reproductive structures: - Herbaceous stems are soft, flexible, and capable of photosynthesis. - Woody stems are rigid and fibrous. P: 518 Stems Structure and functions The apical meristem produces cells that increase the length of a stem. As plants grow taller, an increase in stem diameter provide additional support. P: 519 Stems Structure and functions The age of a tree can be estimated by counting the annual growth rings. a r th Science E tion connec P: 518 Stems Types of stem P: 518 Stems Types of stem P: 518 Leaves Leaf structure The main function of leaves is photosynthesis, and they have many adaptations to optimize this purpose. P: 520 Leaves Leaf structure Most leaves have a flattened portion called the blade with a large surface area. The blade is attached to the stem by a stalk called a petiole. The petiole’s vascular tissue connects the stem’s vascular tissues to the leaf’s vascular tissue or veins. P: 520 Leaves Leaf structure The internal structure of most leaves is well-adapted for photosynthesis. - The palisade mesophyll is composed of tightly packed cells with many chloroplasts. - The spongy mesophyll consists of irregularly shaped cells with spaces in between, allowing gases to move between the spaces. P: 520  21s tC Cri entur tica y l Th Skill ink s: ing Can you propose a better arrangement for the palisade cells? Leaves Leaf structure P: 520 Leaves Leaf structure Water evaporates from the inside of a leaf to the outside through stomata in a process called transpiration that helps pull the water column upward. P: 520 Leaves Types of leaf P: 521 Plant responses _ Nastic responses _ A plant response that causes movement that is not dependent on the direction of a stimulus. Nastic responses: - Are not growth responses - Are reversible - Can be repeated P: 521 Plant responses _ Tropism _ a plant’s growth response to an external stimulus. - If growth is toward the stimulus, it is a positive tropism. - If growth is away from the stimulus, it is a negative tropism. P: 522 Plant responses Plant tropism P: 522 Quiz 1- Which plant structure is NOT part of a root? A- Endodermis C- Pericycle B- Root cap D- Stomata Quiz 2- Which control(s) the movement of water vapor through the stomata? A- Bark C- Guard cell B- Pericycle D- Vascular tissues Quiz 3- Which is the vascular tissue that transports water and dissolved minerals from roots to leaves? A- epidermis C- Xylem B- Parenchyma D- Phloem Quiz 4- Which fill(s) the space between spongy mesophyll cells? A- Gases C- Cells B- Chlorophyll D- Vascular tissues Quiz 5- Which describes a positive phototropism? A- The plant grows away from the light. B- The plant grows toward the light C- The plant grows toward gravity. D- The plant grows away from gravity.