4th Quarter - General Biology 1

• organ system has two types: shoot and root system
• shoot system: the part of a plant that grows above the ground and produces new plants
• root system: the part of a plant that anchors it to the ground and provides support for the plant
• main types of tissue: meristematic and permanent
• meristematic tissues are composed of actively dividing cells
• permanent tissues are tissues that do not regenerate and are not replaced by new tissue
• meristematic tissues csn be classified into dermal, vascular, and ground tissues
• dermal tissues covers and protects the plant, controls gas exchange and water absorption in roots that is found in the outermost layer of roots, stems, and leaves.
• cells in dermal tissues: epidermal cells, guard cells, and trichomes
• epidermal cells make up the majority of the epidermis and secretes cuticle or the covering on top of the leaves for transpiration
• guard cells surround and control the stoma which controls the entrance and exit of gases in plant
• trichomes are specialized cells that are hair-like in structure in epidermis for defense.
• stoma - one
• stomata - two or more
• vascular tissues transport water minerals and sugars to different parts of the plant
• xylem is a type of vascular tissue that carries water and dissolved ions from the roots to stems to leaves.
• phloem is a type of vascular tissue that carries dissolved sugars from the leaves to other parts of the plant.
• cells in xylem: xylem parenchyma, tracheids, vessel elements
• xylem parenchyma is a storage cell
• tracheids are the main transporting part of xylem
• vessel elements are wider than tracheids that have flat ends perforations
• cells in phloem: sieve-tube elements, companion cells, phloem parenchyma, phloem fibers
• sieve-tube elements are the main cells that has glucose in phloem
• companion cells support sieve elements by cell metabolism and regulation
• phloem parenchyma have the same function to xylem parenchyma as storage cells
• phloem fibers are support cells
• xylem - one way flow of water
• phloem - two way flow of food
• xylem has one way flow of water in osmosis and capillary action
• ground tissues are tissues that make up much of the plant interior and carries out different function including photosynthesis, storage, and support
• cells in ground tissues: parenchyma, collenchyma, scelerenchyma
• parenchyma: photosynthesis and storage
• collenchyma: support the young parts and shoot support in areas of active growth
• scelerenchyma: support in areas where growth has ceased
• bryophytes - vascular
• tracheophytes - non vascular
• cell membrane, a.k.a. as plasma membrane is in the outermost part of the cell
• cell membrane controls traffic into and out of the cell it surrounds
• cell membrane exhibits selective permeability
• polar are hydrophillic that cannot easily pass through a lipid bilayer