KINGDOM FINGI

KINGDOM FUNGI

General Characteristics

1. Fungi are achlorophyllous, spore bearing and non-vascular organisms.
2. Fungal cell wall is made up of chitin-the fungal cellulose.
3. They are usually filamentous with branched somatic bodies.
4. They are heterotrophic and reproduce generally by spores.
5. They can be parasitic, saprophytic or symbiotic.
6. They occur in long lasting beneficial association with the roots of gymnosperms. This association is called mycorrhiza.
7. They range from unicellular forms to thread like structures known as mycelium.
8. The interconnected filaments of mycelia are called hyphae.
9. Each hypha is bounded by a chitinous cell wall.
10. Multinucleate forms are known as coenocytic.

Cell Structure

1. Fungal cell is eukaryotic with a chitinous cell wall.
2. Hyphal or fungal cell wall encloses the protoplast which is differentiated into plasma membrane, cytoplasm and nucleus/ei.
3. Reserve food is in the form of glycogen and lipid globules.
4. Membranous vesicles called lomasomes are found attached to the cell membrane.
5. Cytoplasm is colourless and vacuolated.
6. Fungal hyphae may be septate or aseptate with one, two or more nuclei.
7. In case of aseptate hyphae the the cross wals are not formed after nuclear divisions and hence such forms are multinucleated or coenocytic.
8. In case of septate hyphae the cross walls are laid down after nuclear divisions and such forms are called acoenocytic forms.
9. Septa are generally perforated with pores, which can be simple or dolipores.
10. Dolipores are barrel shaped with swollen edges.

Stages in the development of  a branched hypha

Phases in the life cycle of Fungi

Reproduction in Fungi

1. Vegetative Reproduction

(a)    Fragmentation- Vegetative hyphae get broken into fragments accidentally and the fragments develop into new mycelia eg. Rhizopus, Mucor.

(b)   Fission- In this case, the parent cell splits into two daughter cells by constriction eg. Yeasts.

(c)    Budding- A small outgrowth appears in the vegetative cell and enlarges in size eg. Yeasts.

(d)   Sclerotia- These are more or less rounded,cushion-like cylindrical or irregular structures. They grow under favourable conditions to produce mycelia eg. Claviceps.

(e)    Rhizomorphs- They are rope like twisted subterranean masses of several interwoven hyphae with well-defined apical growing point.

2. Asexual Reproduction

  

 

3. Sexual Reproduction

Classification of Fungi

S.No.	Group	General Features	Examples	Diagrams
	Phycomycetes (Algal fungi)	Mycelium is coenocytic. Wall of hyphae contains cellulose. Asexual reproduction involves formation of sporangia, which produce zoospores, aplanospores. Sexual reproduction is by gametangial contact. Gametes are usually nonflagellete. Ptroduct of sexual reproduction is oospore. Hence, they are also called as oomycetes. They may be parasites or saprophytes.	Phytophthora, Albugo,Pythium
	Zygomycetes (Conjugation Fungi)	Mostly saprophytes, some may be parasites on plants and animals. Cell wall is mainly composed of fungal chitin. Mycelium is well developed, profusely branched, filamentous and coenocytic. Asexual reproduction takes place by sporangiospores, aplanospores or by conidia. Sexual reproduction takes place by conjugation and hence are called conjugation fungi. Sexual reproduction produces a resting diploid zygospore. Zygospore produces germ sporangiophore which bears terminal germ sporangium, which in turn produces meiospores called germ spores.	Rhizopus, Mucor
	Ascomycetes (Sac Fungi)	Saprophytes or parasites. Are haploid fungi and their mycelium is composed of septate hyphae. Cell wall is made up of fungal cellulose. Motile structures are absent throughout their life cycle. Most distinctive feature of this group is the formation of sac like structure, the ascus, in which eight ascospores are produced. Asexual reproduction occurs by oidia, conidia nad chlamydospores. Sexual reproduction occurs by gametangial copulation, gametangial contact, spermatisation and somatogamy. Fertilisation involves plasmogamy and karyogamy.	Saccharomyces, Penicillium, Neurospora
	Basidiomycetes (Club Fungi)	The mycelium is perennial, septate and multicellular composed of branched hyphae. Mycelia are of two type- primary and secondary. Primary mycelia develop by the germination of basidiospores and its cells are monokaryotic. Primary mycelium is short and multiplies by oidia or conidia. Motile structures are all together absent. Sexual reproduction occurs between + and – strains in three steps- plasmogamy, karyogamy and meiosis. Secondary mycelium is long lived and consists of profusely branched, filamentous hyphae which are septate and binucleate. Septa consist of dolipores. Secondary mycelia multiply by chlamydospores, ascidiospores etc. They penetrate into the soil or wood by sclerotia or rhizomorphs. Karyogamy and meiosis takes place in the basidia.	Agaricus campestris, Puccinia, Amanita
	Deuteromycetes (Fungi Imperfectii)	They are saprophytes or parasites. Mycelia consist of septate and branched hyphae. Septa are perforated and multinucleate. Reproduction is by conidia, oidia or chlamydospores. Sexual reproduction is absent	Alternaria solani, Fusarium

MOTIVATION FOR SUCCESSFUL LIFE

Staying motivated

Staying motivated is a struggle — our drive is constantly assaulted by negative thoughts and anxiety about the future. Everyone faces doubt and depression. What separates the highly successful is the ability to keep moving forward. There are 3 primary reasons we lose motivation.

1. Lack of confidence – If you don’t believe you can succeed, what’s the point in trying?
2. Lack of focus – If you don’t know what you want, do you really want anything?
3. Lack of direction – If you don’t know what to do, how can you be motivated to do it?

The first motivation killer is a lack of confidence. When this happens to me, it’s usually because I’m focusing entirely on what I want and neglecting what I already have. When you only think about what you want, your mind creates explanations for why you aren’t getting it. This creates negative thoughts. Past failures, bad breaks, and personal weaknesses dominate your mind. You become jealous of your competitors and start making excuses for why you can’t succeed. In this state, you tend to make a bad impression, assume the worst about others, and lose self confidence. The way to get out of this thought pattern is to focus on gratitude. Set aside time to focus on everything positive in your life. Make a mental list of your strengths, past successes, and current advantages. We tend to take our strengths for granted and dwell on our failures. By making an effort to feel grateful, you’ll realize how competent and successful you already are. This will rejuvenate your confidence and get you motivated to build on your current success. The second motivation killer is a lack of focus. How often do you focus on what you don’t want, rather than on a concrete goal? We normally think in terms of fear. I’m afraid of being poor. I’m afraid no one will respect me. I’m afraid of being alone. The problem with this type of thinking is that fear alone isn’t actionable. Instead of doing something about our fear, it feeds on itself and drains our motivation.
If you’re caught up in fear based thinking, the first step is focusing that energy on a well defined goal. By defining a goal, you automatically define a set of actions.

The final piece in the motivational puzzle is direction. If focus means having an ultimate goal, direction is having a day-to-day strategy to achieve it. A lack of direction kills motivation. The key to finding direction is identifying the activities that lead to success. For every goal, there are activities that pay off and those that don’t. Make a list of all your activities and arrange them based on results. Then make a make an action plan that focuses on the activities that lead to big returns. t’s inevitable that you’ll encounter periods of low energy, bad luck, and even the occasional failure. If you don’t discipline your mind, these minor speed bumps can turn into mental monsters. By being on guard against the top 3 motivation killers you can preserve your motivation and propel yourself to success.

STEM CELLS

STEM CELLS

Stem cells are how we all begin: undifferentiated cells that go on to develop into any of the more than 200 types of cell the adult human body holds.

Stem cells are cells that have the potential to develop into many different or specialized cell types. Stem cells can be thought of as primitive, "unspecialized" cells that are able to divide and become specialized cells of the body such as liver cells, muscle cells, blood cells, and other cells with specific functions. Stem cells are referred to as "undifferentiated" cells because they have not yet committed to a developmental path that will form a specific tissue or organ. The process of changing into a specific cell type is known as differentiation. In some areas of the body, stem cells divide regularly to renew and repair the existing tissue.

The best and most readily understood example of a stem cell in humans is that of the fertilized egg, or zygote.

Stem Cell Uses

A potential application of stem cells is making cells and tissues for medical therapies. Today, donated organs and tissues are often used to replace those that are diseased or destroyed. Unfortunately, the number of people needing a transplant far exceeds the number of organs available for transplantation.So far, only a few organs have been made and transplanted, and they are relatively simple, hollow ones — like bladders and a windpipe, which was implanted in June 2011. But scientists around the world are using similar techniques with the goal of building more complex organs .Researchers are making use of advances in knowledge of   basic cells that can be transformed into types that are specific to tissues like liver or lung.

Why are stem cells important?

Stem cells represent an exciting area in medicine because of their potential to regenerate and repair damaged tissue. Some current therapies, such as bone marrow transplantation, already make use of stem cells and their potential for regeneration of damaged tissues. Other therapies are under investigation that involves transplanting stem cells into a damaged body part and directing them to grow and differentiate into healthy tissue.

What are the different types of stem cells?

1.Adult stem cells

2.Fetal stem cells

3.Embryonic stem cells

3.Peripheral blood stem cells

4.Umbilical cord stem cells

Tissue engineers caution that the work they are doing is experimental and costly, and that the creation of complex organs is still a long way off. But they are increasingly optimistic about the possibilities.

Fun filled Activity With Satyans

Secondary Growth in Dicot Stem and Roots-Must Read

Secondary Growth in Dicot Stem and Roots

Description: The secondary growth of vascular bundles in dicot stem and root are made as the plant grows in order to incorporate changes for the required nutrition and mechanical support for the plant growth. The changes in secondary growth of stem include formation of bark and lenticels.
Vascular Cambium
The vascular cambium is present as patches between the vascular tissues xylem and phloem in younger stems which later develops into a complete cambial ring. The cells of cambium present between the xylem and phloem is called as intrafascicular cambium. The cells of medullary rays adjoining intrafascicular cambium are converted to meristematic cells to form the interfascicular cambium.
The cambial ring develops by cutting off new cells present in the inner and outer sides. The cells cut off towards pith later on mature to become secondary xylem and the cells cut off towards periphery mature into secondary phloem. The cambium is active on the inner side thus resulting in more production of secondary xylem thus forming a compact mass. As the secondary xylem gradually develops the primary and secondary phloem gets crashed. However, the primary xylem remains intact around the centre. At some places, the cambium forms a narrow band of parenchyma which passes through the secondary xylem and secondary phloem in radial directions. This cambium arranged in radial pattern is known as the secondary medullary rays.

Cork Cambium:
Once the cambium ring formation is active and spreading eventually in dicot stems, the cortical layers and epidermis are replaced by new protective layers of meristematic tissue called cork cambium or phellogen. The cork cambium develops in the cortex region and is couple of layers thick composed of narrow rectangular cells. The phellogen cuts off the outer cells to form cork or phellem and the inner cells to differentiate in to secondary cortex and phelloderm. The phellogen, phellem and phelloderm together constitute the periderm. As the cork cambium continues to expand, the pressure builds up in the periphery phellem resulting in death of the layers and sloughing off which is referred to as bark that is soft during younger stages of stem and woody later. 
At certain regions of cork cambium, the parenchymatous cells on the outer side are ruptured to form lens-shaped openings called lenticels. The lenticels permit the exchange of gases between the outer atmosphere and the internal tissue of the stem.

A. Lenticel B. Bark

Secondary growth in dicot roots:
In dicot roots, the events of secondary growth are quite similar to that of dicot stem. However, the vascular cambium is secondary in origin as it originated from the tissue located just below the phloem bundles, which is a portion of pericycle tissue thus resulting in formation of complete and continuous wavy ring.