1. Describe the difference between a primary metabolite and a secondary metaboli
ID: 193796 • Letter: 1
Question
1. Describe the difference between a primary metabolite and a secondary metabolite. Make sure to provide a description and examples of primary metabolites. Name and describe the three classes of secondary metabolites and describe an example of each. 2. List, illustrate, and describe the parts and functions of cell wall components. You must include, but are not limited to the following terms: primary wall, secondary wall, pits, plasmodesma(ta), middle lamella, cell membrane, cellulose, hemicellulose, pectin.Explanation / Answer
1. Primary metabolite is key substance involved in growth, development and reproduction of cells. it is also called as central metabolite in some independently living organisms. Most of the microorganisms such as bacteria use primary metabolites for their growth. The examples of primary metabolites include alcohols, lactic or other organic acids and amino acids.
In contrast, a secondary metabolite is not having any metabolic functions but is produced to perform some ecological functions. Organisms like bacteria, fungi and plants etc produce the secondary metabolites as byproducts during their metabolism. The common examples of secondary metabolites are antibiotics, alkaloids, nucleosides, peptides and growth factors and these are produced mostly by microorganisms.
Plant secondary metabolites are produced as indirect metabolites that regulate the processes of primary metabolism. These are categorized into 3 classes and are called Flavonoids and phenolic and polyphenolic compounds,Terpenoids and nitrogen-containing alkaloids and sulphur-containing compounds. These three classes of compounds are produced in various plants either individually or in combination of two or more substances.
Examples of flavonoids include Luteolin, tannic acid and polyphenol compounds.
Examples of terpenoids include Azadirachtin, Artemisinin, Tetrahydrocannabinol etc.
Examples of alkaloids include cocaine, caffeine, morphine, atropine and ephidrine etc.
2.
The cellwall is the outer protective layer to the cell membrane. In plant cells, the cellwall has wide variety of functions. the cellwall in plant cells is made up of cellulose. Cellulose is a polysaccharide that provides rigidity the the cellwall. Numerous cellolosic fibers form the bundles of microfibrils to provide strength to the cellwall. Plant cellwalls also contain carbohydrates like hemicellulose, pectin and lignin to provide structural framework of cellwall along with proteins. These are found in various proportions in young and mature plant cells. Mature plant cells are composed of more pectin and lignin to provide mechanical strength to cellwall.
Young plant cells contain cellwall called primary cellwall and mostly composed of cellulose and hemicellulose. The mature or completely grown plant cells produce cellwall called secondar cellwall with large proportions of pectin and lignin. The secondary cell wall is a thick layer formed inside of the primary cell wall. Middle lamella is the layer between two plant cells and is composed of pectin. The middle alamella provides strength and also enables the plant cells to bind together.
Plant cellwalls contain gaps called plasmodesmata that allow the passage of nutrients into cells and waste materials to exterior of the cells.
The plant cellwall provides support and strength to cells. It maintains the turgor of cells. it provides protection against mechanical damge and pathogen attack. The plant cellwall prevents the loss of water and helps to maintain the shape of cells.
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