Cycling of Matter in Living Systems 3.1 Cells, Tissues, and Systems and 3.2 The Leaf and Photosynthesis

Plant Structure Plants are multicellular organisms Living systems made up of many parts Groups of cells performing the same function together are called tissues Tissues contributing to the same function form organs which are part of a system The plant has two organ systems: the shoot system (everything above ground) and the root system (everything below ground)

Plants grow, or increase in size by cell division in the – Shoot apical meristem,or – Root apical meristem There are 3 main types of plant tissues: – Dermal tissue: epidermis – Ground tissue: woody material – Vascular tissue: xylem and phloem

Dermal Tissue Dermal tissue or epidermis is the outer layer of cells that covers all herbaceous (non-woody) plants. Responsible for the exchange of matter and gases into and out of the plant In woody plants, the epidermis is replaced by cork and bark, the leaves and stem are responsible for gas exchange of carbon dioxide and oxygen Protects the plant from disease Dermal tissue of the root system is responsible for the uptake of water and mineral salts from the soil.

Ground Tissue Makes up the majority of the plant, found beneath the epidermis In the stem they provide strength and support to the plant In the roots they are involved in food and water storage In the leaves it is the location where photosynthesis occurs Cells are loosely packed and allow gases to diffuse rapidly through the ground tissue.

Vascular Tissues Vascular tissue is responsible for moving materials around the plant. Water from the roots to the leaves, and sugars from the leaves to the roots for storage

Xylem Tissue Moves water and dissolved minerals from the roots up the stem to the leaves where these substances are used in photosynthesis. Thick walled tubes of various diameters

Phloem Tissue Transports sucrose and other dissolved sugars from the leaves to other parts of the plant Formed from individual long sieve tube cells, which have perforated end walls

Specialization in Plant Cells Cells that become part of the root system and are responsible for the movement of water and minerals from the soil, produce tiny hair-like projections called root hairs Root hairs increase the surface area

Dermal cells of the shoot system produce cuticle to protect the cells from water loss Lower epidermal surface of leaves develops specific cells, called guard cells Guard cells form tiny pores called stomata for gas exchange Guard cells contain chloroplasts

Photosynthesis Leaves perform photosynthesis in plants, and this process supports all life on earth. Chloroplasts are found in the leaves of plants and contain all the chlorophyll, which is responsible for photosynthesis. Photosynthesis is a chemical process that transforms CO 2 and H 2 O into useable materials such as C 6 H 12 O 6 and O 2.

Balanced Chemical Equation : 6 H 2 O + 6 CO 2 + energy ->C 6 H 12 O 6 + 6O 2 Plants can now use this simple sugar to undergo normal life processes. (Energy).

Cellular Respiration This is the description of the normal activities inside the plant. (Growing, breathing, waste excretion, etc) These processes require energy, and that energy comes from the sugars (glucose) produced during photosynthesis. The process of cellular respiration occurs in the mitochondrion

The plant transforms some of the glucose produced as follows: C 6 H 12 O 6 + 6O 2  6 H 2 O + 6 CO 2 + energy

Homework: Check and Reflect Page 302 #1-3, 5 Check and Reflect Page 308 #1-5