2-1 Plant Cells, Tissues, and Organs

Figure 2: Plant Tissues Figure 3: Flower Structure 2-1 Plant Cells, Tissues, and Organs

Learning Goals • To learn about plant cells • To label the parts of a plant • To discuss where photosynthesis takes place

2-1 Plant Cells, Tissues, and Organs Cell Specialization– the process where cells develop from similar cells into cells that have specific functions Cell Differentiation – a stage of development of a living organism during which specialized cells form

Diagram 2.1-1 Specialized Cells and Tissues in Plants Meristematic Cell – an unspecialized plant cell that gives rise to a specific specialized cell Tissue– a cluster of similar cells that share the same specialized structure and function Organ– a combination of several types of tissue working together to perform a specific function

Repair , Replacement , and Growth Plants can continuously form new organs and tissues. A bud is a swelling of the stem that contains meristem for new tissues and organs such as leaves, roots and flowers. A plant’s most active growth occurs near the terminal bud. Lateral buds are dormant, but they have the potential to produce new branches, leaves and flowers.

“Buds” and “Type of Growth” The plant grows upward, “getting taller.” The plant grows outward or “thickens.” Diagram 2.1-3

Tissues Working Together - Plant Organs Three types of organs make up the body of a plant: Leaves Stems Roots A fourth organ is the reproductive organ. In many but not all plants, this is the flower.

Leaves • Leaves are designed to capture maximum light and minimize water loss in order to conduct photosynthesis • The main parts of a leaf are: • epidermis • palisade mesophyll • chloroplasts • spongy parenchyma • veins (xylem & phloem) • stoma & guard cells

Diagram 2.1-4 Parts of a Leaf

Epidermis • secrete a waxy cuticle that helps reduce the amount of water that evaporates from the leaf's surface

Palisade Mesophyll • perform most of the photosynthesis in a leaf • arranged so that the Sun’s rays pass through the length of the cell and hit chloroplasts, (where photosynthesis takes place)

Diagram 2.1-6 Chloroplasts • organelles within plant cells that use the Sun’s energy to chemically convert CO2 into glucose (photosynthesis)

Spongy Parenchyma • a layer of cells with open spaces (like a sponge) that contain gases for photosynthesis: H2O, O2, CO2.

Veins - Xylem & Phloem • found in vascular bundles in the centre of the leaf (form leaf veins) • Xylem delivers water vapour to the photosynthesizing cells • Phloem picks up the produced glucose and delivers it to the rest of the plant

Xylem UP Phloem DOWN

Guard Cells • allow gases to move in and out • can change their shape to control the pore openings (stoma) • CO2 enters, while O2 and H2O exit the stoma

Stems A plant’s stem has two main functions: 1.physical support 2. transportation of sap

Roots A plant’s root has three main functions: 1. to anchor the plantin the ground 2. to take up water and mineralsfrom the soil 3. to store energy and nutrient supplies for later use

Types of Roots Tap Root Fibrous Root • one main root that grows larger and thicker than the rest • anchors the plant firmly in the ground • spread out horizontally near the surface • stabilizes soil and prevents erosion and landslides

Flowers The main function of a plant’s flowers is reproductive Flowers: • produce sperm and eggsfor sexual reproduction • attract insects and other animals for pollination • produce seeds and sometimes fruit after pollination Pollination Video

Section 2.1 Review • Things you should now know: • how meristematic cells differentiate into specialized plant cells • the characteristics of dermal, ground, and vascular tissues • the four types of plant organs: root, stem, leaf, and flowers • the process of photosynthesis

 Homework  • Read Section 2.1 Pg 57-68 • Complete 2.1 Worksheet • Complete Pg 69 # 1, 3, 5

2-1 Plant Cells, Tissues, and Organs