Plant Systems Flashcards
Multicellular organisms are organized in a structural hierarchy
Specialized cells —> tissues —> organs —> organ systems —> organism
Specialized cells
Each cell type has a different structure and function
Tissues
Are composed of groups of cells of similar structure that perform a particular, related function
Organs
Definite form and structure, comprised of two or more tissues
Organ systems
An association of organs with a common function
Organism
A complex, functioning whole that is comprised of all its component parts
Photosynthesis
The process of plants capturing light energy from the sun, and converting that as well as water and carbon dioxide into chemical energy stored in sugar and other organic molecules
Occurs in chloroplasts
Photosynthesis formula
6CO2 + 6H2O + light energy —> C6H12O6 + 6O2
Organ systems
- Root system
- Shoot system
Root system
Absorbs water and minerals from below ground
Roots — anchor the plant in the soil, absorb minerals and water, store carbohydrates
Shoot system
Absorbs CO2 and light from above the ground
Stems — support the leaves and reproductive structures
Leaves — main photosynthetic organ of the plant
Plant tissues
3 types: dermal, vascular and ground
Dermal tissue
Plants outer protective covering
Vascular tissue
Carries out long distance transport of materials between the root and shoot systems
Ground tissue
Includes cells specialized for storage, photosynthesis and support
Cuticle
Dermal tissue
Waxy substance that coats the epidermal cells
Helps prevent water loss
Upper/Lower Epidermis
Dermal tissue
One cell thick layer of tightly packed transparent cells on the upper/lower side of the leaf
Protects the leaf against physical damage and pathogens
Stomata (stoma singular)
Dermal tissue
Small openings in the epidermal layer that can open and close to allow gases in and out of the leaf
Guard cells
Dermal tissue
Cells in the upper/lower epidermis that flank a stomata pore, and control its diameter by changing shape
Palisade Cells
One or more layers of tightly packed long and narrow cells with many chloroplasts
Site of most of the leafs photosynthesis
Ground tissue
Spongy tissue cells
Ground tissue
Layers of round loosely packed cells containing chloroplasts
Located just below the palisade tissue cells
Carry out photosynthesis
Air spaces between the cells allows for gas exchange
Vascular bundle
Vascular tissue
A series of tubes that are visible as leaf veins
Contain xylem and phloem
Xylem
Vascular tissue
Dead tubular elongated cells with no end walls
Transport water and dissolved minerals up from the roots to the leaves
Made up of two types of cells: tracheids and vessel elements
Phloem
Vascular tissue
Long narrow cells that are alive
Transport sugars produced by the leaves to various parts of the plant where they are needed
Made up of sieve tube elements and companion cells
Water and mineral transport steps
Roots —> xylem —> stem —> leaves
#1. Roots and xylem: water through osmosis and minerals through facilitated diffusion or active transport
#2. Leaves: xylem sap is transported against gravity through bulk transport (root pressure, cohesion and adhesion and transpiration pull)
Root pressure
Created by the accumulation of water and minerals in the root xylem
Pushes the xylem sap up the stem towards the leaves
Minor contributor to moving xylem sap
Transpiration pull
Water is pulled up the xylem tissue to replace the water that is lost through transpiration in the leaves
Cohesion and adhesion
Due to the properties of water
Cohesion - the tendency of water molecules to stick to other water molecules due to hydrogen bonding — pulls a column of water molecules up to the leaves
Adhesion - the tendency of water molecules to stick or adhere to certain hydrophilic surfaces due to hydrogen bonding — resists the force of gravity, preventing xylem sap from falling back to the roots
Sieve tubes
Transport sugars
Companion cells
Transport sugar to sieve tube and perform metabolic functions for phloem
Sugar transport steps
