Plants evolved from ancestral green algae that belong to the kingdom Protista.
What makes a plant? The following characteristics |
Plants are divided into two general categories: ·Non-tracheophytes (plants lacking a vascular system) A vascular system enables plants to
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There are three different ·Liverwort All of these plants are really small, and they |
There are three different ·Flowering Plants (angiosperms) Flowering plants and conifers have |
There are several important organelles in a plant cell.
The nucleus is the largest organelle in a plant
cell.
It is enclosed by a double membrane called the "nuclear envelope".
The nucleus serves to protect DNA information and is perforated with holes called
nuclear pores.
Inside the nucleus is a special structure called the nucleolus.
The nucleolus is responsible for assembling ribosomes.
Ribosomes are composed of proteins and ribosomal RNA.
They are found in four areas of the plant cell: the cytoplasm,
the surface of the endoplasmic reticulum, the mitochondria, and on chloroplasts.There are two main types of ribosomes: free ribosomes and attached ribosomes.
Attached ribosomes are attached to the endoplasmic
reticulum and serve as sites for protein synthesis.
Proteins synthesized on these ribosomes will be exported from the cell,
moved into other organelles of the endomembrane system, or incorporated into membranes.Plant cells are unique because of their chloroplasts and their cell wall.
Chloroplasts process energy for the plant cell.
The cytoskeleton is a series of intracellular
proteins that aid in
the
support, shape, and movement of the cell.
Three Basic Cell Types in Plants
Parenchyma
Parenchyma cells operate while alive.
They are large vacuoles with
thin walls that pack nicely.
A parenchyma cell is a 14-sided cell structure that is
not specialized.
In leaves, they contain chloroplasts and are called chlorenchyma.
Sclerenchyma
Sclerenchyma function as dead cells.
They have thick cell walls
impregnated with lignin and provide rigid support.
Collenchyma
Collenchyma cells function while alive.
They make a very flexible
support tissue and have visibly thick cell walls.
Elements and Plants
Four main elements are found in plants
Macronutrients are nutrients needed in high amounts
within a plant.
Plants also have micronutrients.
These elements
are found in extremely small quantities within the plants.
Some plant micronutrients are Fe, Zn, Cu, B, and Mn.
Tissue Systems
Plants transport materials via their plant tissues.
A tissue is a group of cells that work together to do a specialized
function.
The meristem,
ground
system, dermal
system, and
vascular
system
are all tissue systems that compose a plant.
A
plant's shoot system involves leaves and
stems.
Leaves are sites of photosynthesis in plants.
They are involved in exchange
with the environment via the evaporation of water.
Leaves are also used in competition among
plants.
Stems help a plant with structural support, transport, and growth.
They are also photosynthetic.
A node is where the leaves are An internode is the space between
attached to the shoot. the nodes on a shoot
Meristems are groups of cells that retain the ability to produce new organs indefinitely.
The shoot system involves the lateral bud meristem and the apical bud meristem.
If you cut off the apical bud meristem, then lateral bud meristem growth is encouraged.
A plant's root system involves roots
Plants can have either a monocot root or a dicot root.
The monocot root has a pith, whereas the dicot root does not.
The endodermis in both monocot and dicot roots is the
most inner layer of cells in the outer region.
It is waxy and can be selectively
permeable.
It controls the access of water and dissolved substances to the inner
vascular tissues.
The vascular bundle or the stele consists of three tissues: the pericycle, the xylem, and the phloem.
The pith is found only in the monocot root.
It is
a region of parenchyma cells that are internal to the xylem.
Water is important for plants for various reasons.
