AOS 2- How do plants and animal systems function? Flashcards
(90 cards)
What are the two systems that plants have?
An above ground shoot system and a below ground root system.
What is a vascular plant?
Plants with xylem and phloem tissue- the majority being flowering plants and conifers.
What is the shoot system?
The above-ground system of plants, the site of photosynthesis transport of sugars and the site of reproductive organs.
What is the root system?
The below the ground system of plants which anchors the plant in the soil, is responsible for the absorption and conduction of water and mineral, and storage of excess sugars (starch).
What organs do the shoot and root system consist of ?
Shoot system organs- the stem and leaves, plus reproductive organs, the flower and fruit
Root system organs- the root, lateral roots and the root hairs.
What is the meristematic tissue?
Meristematic tissues are made of cells that can undergo cell division and can continue to divide for the life of the plant.
Meristematic tissues is usually found in the tips of roots and shoots and is responsible for an increase in the length of the plant stems and roots.
What is permanent tissue?
Permanent tissues are made of cells that can no longer divide. Permanant tissues include several tissue types that differ in function.
What is Permanent tissue: Dermal tissue ?
Protects plants and minimizes water loss. For example, epidermal tissue made of flattened cells form the outer layer of stems and leaves.
A non-cellular layer of wax on top of the epidermal tissue adds further waterproofing.
What does ground tissue include?
Parenchyma, collenchyma, sclerenchyma
What is Ground tissue: Parenchyma?
The most common plant tissue and is composed of living tin- walled cells. In leaves, the parenchyma tissue is the site of photosynthesis.
In roots, tubers and seeds, the parenchyma tissue is the site of storage of starch or oils.
What is Ground tissue: Collenchyma?
The main supporting tissue of elongating stems; this tissue is composed of elongated living cells with thick but flexible primary cells.
What is Ground Tissue: Sclerenchyma?
Confers rigidity and strength to many plant organs and is composed of cells with thickened secondary cell walls; at maturity sclerenchyma cells are dead.
What is the Vascular Tissue: Xylem?
Consists mainly of hollow dead cells with thick cells walls hardened by lignin. This tissue transports water and dissolved mineral throughout a plant.
What is a Vascular Tissue: Phloem?
Consists mainly of living cells that transport sugars, in the form of dissolved sucrose (table sugar), and other organic compounds, including hormones throughout a plant.
What are root hairs?
Root hairs are extensions of cells of the epidermal tissue that forms the out cellular covering of the root, responsible for absorption and uptake of water.
How is there absorption of water through the root hairs?
Water enters the root hairs from the soil solution by osmosis.
From the root hair cells, water moves across the cells of the cortex to the xylem in the vascular bundle from where it will be transported as a fluid to all the living cells of the plants.
Why is xylem a complex tissue and what is present in it?
It is a complex tissue because unlike other tissues it is made of more than one cell.
Present in the xylem tissue are the major water- conducting cells called a tracheid and vessels.
Factors of Tracheid
-Are present in all vascular plants
-Are long thin tubular cells
-Have no cell contents and so are no longer living
-Have both primary and a secondary cell wall
-Have pits in their secondary cell wall enabling lateral movement of water to nearby tissues.
Factors of Vessels
-Are found only in flowering plants
-Lose their cell contents and are dead
-Form a continuous wide pipe-like structure by the joining of vessels end-to-end
-The walls are perforated by pits- these are spots where the secondary wall of the vessel is thin or absent so that water can move laterally and exit the xylem.
What is transpiration?
Loss of water from the surface of a plant.
What is water loss by transpiration?
Water loss by transpiration occurs in the leaves of plants, and the tissue that are involved include:
-the air spaces in the spongy mesophyll tissue of leaves are usually saturated with water vapor
-the stomata located mainly in the lower epidermis of the leaves are the exit point from where water vapor may diffuse out from the leaves into the air.
When will loss of water vapor occur?
-A concentration gradient exists between the water content in the leaf spaces (high) and in the air outside the leaf (low)
-The leaf stomata are open.
What is the stomata?
Pores, each surrounded by two guard cells that regulate the opening and closing of the pores.
Why does water loss occur?
To make sugars during photosynthesis, carbon dioxide is required, taken from the atmosphere. The entry of carbon dioxide to the leaf is through the stoma.
