Overview of plant cells - Part 1 Structure and function (Cell wall and Pits)

Plant cells

Structure and function

Introduction

Plants are endowed with very unique structures and techniques that help them live a different way of life than us, they have their own immune system and way of defenses methodologies, way of taking up their nutrients, the source of their nutrients, different organs that we do not have and much more we are going to explore in this episode and the upcoming ones as well....

So to begin with, the term cell was firstly used by the English Botanist Robert Hooke to determine the individual unit of the honeycomb-like structure in cork under the compound microscope in 1665.
(Read more about his biography at ---> http://www.ucmp.berkeley.edu/history/hooke.html)

Botany is the scientific study of plants ( and many organisms previously thought to be plants). There are various subfields or sub-disciplines of Botany which may be pure or applied Botany.

Pure Botany
Morphology ( study of plant form)
Physiology ( study of the functions of plant organs)
Anatomy ( study of plant structure)
Taxonomy ( is the science that finds, describes, classifies, identifies, and names plants)
Ecology ( interactions with the environment)
Phytogeography ( The study of the geographic distribution of plants. Also called geobotany)
Genetics ( the study of heredity and variation in organisms)

Applied Botany: Study of the relation of plants with man.
Agriculture The science, art, and business of cultivating the soil, producing crops, and raising livestock; farming.
Horticulture The science or art of cultivating fruits (Pomology), vegetables (Olericulture), flowers (floriculture), or ornamental plants.
Agronomy Is the science and technology of producing and using plants for food, fuel, feed, fiber, and reclamation.
Phytopathology ( plant pathology) is the scientific study of plant disease.
Forestry - The art and science of managing forests, tree plantations, and related natural resources.
Plant breeding - The art and science of changing the genetics of plants for the benefits of mankind.

What are plant cells?
Plants are eukaryotic ( true cells meaning they have organelles) multicellular organisms that composed of millions of cells each of which has its own specialized functions.

What makes plant cells differ from animal cells? 
Plant cells have some distinct organelles and structures that aren't found in animal cells. For example,
1)Chloroplasts which are just one type of the various plastids that can be found in a plant cell, Basically, these powerful organelles that are essential for every plant and mainly contributes to the color of the plant which is the green color that everyone sees due to the pigment contained within the chloroplasts' thylakoids the chlorophyll.
Chloroplasts are spherical to oval-shaped structures, double-membraned, green in color due to pigments contained in such as Chlorophyll A and B, etc..
(Pic. source: http://journal.frontiersin.org/article/10.3389/fpls.2013.00114/full)

Chloroplast

Also, it can vary in shape in many species, For example, Zygnema sp. a type of algae in Phylum: Chlorophyta, has a star shaped chloroplast

Zygnema sp.

Cup-shaped chloroplast in Chlamydomonas sp., Phylum: Chlorophyta

Chlamydomonas sp.

Spiral-shaped chloroplast in Spirogyra sp., Phylum: Chlorophyta

Spirogyra sp.

Besides its various types, it also has a major role in plant cells in their life cycles since it performs one of the processes that is ONLY unique amongst plants and some other bacterial cell types which is the Photosynthesis '' Photo = light, synthesis= manufacture or to make something out of'' ****We will have a complete topic about it discussing anything concerned with plastids, chloroplasts, photosynthesis, and Calvin cycle.**** However, We can define photosynthesis briefly in this well-known equation:

6CO2 + 6H2O + Light (energy coming in the form of photons)---> C6H12O6 + 6O2

Photosynthesis

2)Central vacuole, in plant cells the vacuoles are pretty much large in size which also contributes to the shape and rigidity of plant cells due to its large size relatively compared to that of in animal cells which are very small in size and sometimes they lack a vacuole in animal cells, so the central vacuole is large in size irregular in shape to ovale, membrane-bound by a Tonoplast - Functions as enzyme storage and waste removal.

(Pic.,source: http://fig.cox.miami.edu/~cmallery/255/255hist/255methods.htm)

3)Cell wall is what gives a plant its rigid texture, erect structure ( there are exceptions e.g. weak stemmed plants which have some modifications to hold itself erect)and strong structure.

The cell wall is composed of polysaccharide compounds such as mainly cellulose ( Monomeric unit: Beta 1-4, D-glucose units) thousands of them making up the cellulose, hemicellulose, and lignin.

The cell wall is made up of middle lamella, primary wall, and secondary cell wall.

The middle lamella is the first layer formed during cell division, it is shared by adjacent plant cells, consist of pectic compounds and proteins.

Primary wall of the cell wall, made up of cellulose microfibrils embedded in a gel-like matrix of pectic compounds, hemicellulose, and glycoproteins - the primary wall have thinner areas in their structure which are called pit fields, they contain small openings in the wall through which cytoplasmic extensions are known as plasmodesma (singular word., plural is plasmodesmata) by which a very process is carried out through it..... cell-to-cell communication.

Secondary cell wall which is three-layered and by far is the thickest one amongst all cell wall components due to the more cellulose, hemicellulose and lignin content making the plant which developed a secondary cell wall extremely rigid and tough.

In comparison to animal cell, they have relatively small vacuoles, sometimes they lack it, they have centrioles which are used during cell division to form the spindle fibers.

Pits and their types
The pits again are due to the primary walls which form the holes or openings in the plant cells for cell-to-cell communication ''plasmodesmata'', pits have various types and some are subdivided into other types ( simple pits and bordered pits)
(Pic., source: https://sites.ualberta.ca/~hacke/Lenka-profile.html )

Simple and bordered pits

(Pic.,source: http://www.biologydiscussion.com/eukaryotic-cell/cell-wall-of-eukaryotic-cells-structure-and-function/5890)

Note:

If 2 simple pits opposite to each other= simple pit pairs 

   2  bordered pits opposite to each other= bordered pit pairs

   simple pit + bordered pit opposite to each other= half bordered pit pair

   A simple or bordered pit with no complementary pit field in front of it= blind pit

Different types of bordered pits

Side view of a bordered pit structure

Simple pits - showing transportation within the cell

Upper view of bordered pits structure

Half-bordered pit pair

Pit borders are due to the bending or overarching of the secondary wall of the cell wall, semi-enclosed making a mouth like structure which is the Pit aperture through which the communication happens.

My newly released video is about this overview in case anyone finds it easy to learn from videos 

Link - https://youtu.be/t02MT4heQEA

Some other educational videos that might help you which I don't own - copyrights goes to the owners

Khan academy - https://www.youtube.com/watch?v=zdvKhaQxvag (Plant cell walls)

Shomu's Biology - https://www.youtube.com/watch?v=V-Y-FOexHXE ( Plant cell wall structure and function)