Hormones secreted by Pituitary Gland mnemonic.

Hello everyone.

Staph here:D

So, as I have said earlier that I have completed studying the nervous system.

And now I have started with my next topic i.e. Endocrinology.

Yippiee :'D

Oxidation - reduction mnemonic.

Hey guys..
So a lot of times I have observed that inspite of knowing redox reactions and the flow of electrons, I sometimes forget whether oxidation is loss of electrons or gain?
And what is more painful, that it always happens at absolutely crucial times, like..

G protein coupled receptors and signalling.

Ola everyone..

Today the topic that we will be discussing is kinda lengthy, so let's not waste time.

We will be learning about G protein coupled receptors today. This is considered as a monstrous topic in cell biology with most students finding it either boring or difficult and they skip it. But as this topic is gaining interest, it won't take long to appear in your vivas or your multiple choice questions. Hence let's have a simple introductory session on it so that we at least don't assume the question is from planet X when we see it.

First discussing the receptors we will talk about G proteins.

I hope this post builds your interest into G proteins. Go.

Types of hormones in cell signalling

Hello to all readers.
Today we will be learning about different types of hormones involved in cell signalling. As of now just to start we will get to know the names and their source. Detailed mechanism will be discussed in later posts.
Because these hormones are too many and remembering them is not easy. Hence we will be doing it by our flash card method.
You can refer it here. Do let me know if it helps.
Tadaa.
-Staph <3

Oh oh, forgot about the high six. Let's do it mates :D

Levels of structural Organisation

Hello everyone,

Today I will be writing a brief description of Levels of structural Organisation

The human body is incredibly complex but it does have an underlying organization. Learning this organizational structure can really help you visualize and understand how the human body is built and how it functions. 

In unicellular (single-celled) organisms, the single cell performs all life functions. It functions independently. However, multicellular (many celled) organisms have various levels of organization within them. Individual cells may perform specific functions and also work together for the good of the entire organism. The cells become dependent on one another.

The levels of organization start at the most basic level and end at the most complex  level, from the  cellular level to the  whole organism.  Let's start working our way down through these levels.

Multicellular organisms have the following 6 levels of organization ranging from simplest to most complex, these include

1. Chemical level;
2. Cellular level; 
3. Tissue level; 
4. Organ level; 
5. System; and 
6. Organism

Levels of structural Organization in Human body can be can be Compared to to the written language tools which we commonly use in daily life

  

1. Chemical level : Includes atoms organized into molecules (example: DNA, glucose) . Atoms and Molecules can be Compared to LETTERS of  Alphabet.
2. Cellular level: molecules are organized into cells which are the basic structural and functional living units an organism (example: muscle cells, nerve cells, blood cells) .Cellular level  can be compared to a WORD. Cells, the smallest living units in the human body can be compared with WORDS, the smallest Element of language.
3. Tissue level: are organized into tissues to perform a particular function .Tissue level can be compared to a SENTENCE. Cells join together to form tissues similar to the way words are put together to form SENTENSES
4. Organ level : Structures that are composed of 2 or more different types of tissues, that have specific functions and usually have recognizable shapes (example: liver, stomach, heart, lungs, brain) . Organ level can be compared to a PARAGRAPH. Tissue join  together to form organs similar to the way sentences are put together to form PARAGRAPHS.
5. System level or organ-system level :consists of related organs with a common function
   (example: digestive system, which breaks down and absorbs food, and includes the mouth, salivary glands, stomach, small intestine, large intestine, liver, gallbladder and pancreas). System level can be compared to a CHAPTER. Organs join together to form systems similar to the way paragraphs are put to form CHAPTERS.
6. Organism level: all the systems are structurally integrated and function cooperatively to constitute the total organism (example: the human body) .The Organism level can be compared to a BOOK. Systems join together to form an Organism similar to the way chapters are put together to form a BOOK.

Here's a Mnemonic to remember Levels of Structural Organization in human body

In summary Levels of Structural Organization are 

Atom Molecule Macro-molecules  Organelles  Cell  Tissue  Organ  Organ system  Organisms

Auguti Mouse Mated Once Creating Transgenic Organism Oneby One

With Love

-Dixy

PeROXIsomes!!

Hey everyone, welcome to the cell...

not a jail cell, cell biology.

Today we will learn something about peroxisomes.

Pero in latino means but't' so I guess it basically means buttsome :p. Just kidding.

No filthy jokes, please.

Alright alright.

Peroxisomes unfortunately doesn't refers to any kinky stuff :(

Peroxisomes are found in all and any type of eukaryotic cell. They house variety of oxidative enzymes like catalase or oxidase. Just like mitochondria, they are the sites for oxidation utilization.

Peroxisomes are so named because they usually contain one or more enzymes that use molecular oxygen to remove hydrogen atoms from specific organic substrates (designated here as R) in an oxidative reaction that produces hydrogen peroxide (H2O2):

RH2 + O2 = R + H2O2

• This type of oxidative reaction is particularly important in liver and kidney cells, where the peroxisomes detoxify various toxic molecules that enter the bloodstream. About 25% of the ethanol we drink is oxidized to acetaldehyde in this way. 

• Breakdown of fatty acid molecules.

• Catalyzes the first reactions in the formation of plasmalogens, which are the most abundant class of phospholipids in myelin Deficiency of plasmalogens causes profound abnormalities in the myelination of nerve cells, which lead to neurological disease.

• Two different types in plants. One type is present in leaves, where it catalyzes the oxidation of a side product of the crucial reaction that fixes CO2 in carbohydrate.
• Second in seeds, known as glyoxysomes as they carry out break down of fats to sugars by glyoxylate pathway.

• The last added benefit is that they require shorter signal sequences for protein transportation.

That's all, hope it helps you. Disorders related to peroxisomes to come shortly.
Till then have fun with pero :p
Be amazing <

-Staph. 

TOM and TIM complexes.

Hello everyone, it's Staph here. 

Sorry I was away for a few days, thanks to the unstable internet connection :(

My internet for a few days was in it's full speed only at night, but that time I cannot blog because everyone sleeps at my home, and that's when I use internet for watching some....

...

...

Come on I am young and you know what youngsters watch late night on internet :p

...
...
...

Narutoooooooooooooooo!!!!!

Jeez! What were you thinking??

Jerk -_-

Anyways, it's two minute into the blog and I am off topic already.

Back to subject.

TOM and JERRY.

It's TOM and TIM.

Oh yeah.

TOM and TIM unlike you think are not puppies, neither they are cats, nor rats.

Sadly, TOM and TIM are mitochondrial multi-subunit complexes, duh.

They are protein translocators, and carry out protein translocation across the mitochondrial membranes;

TOM: Translocase for outer membrane.

TIM: For inner membrane. There are basically two types pf TIM known as dual TIM, nah just kidding.They are TIM 22 and TIM 23.

The TOM complex is required for the import of all nucleus-encoded mitochondrial proteins. It initially transports their signal sequences into the intermembrane space and helps to insert transmembrane proteins into the outer membrane. 

The TIM23 complex then transports some of these proteins into the matrix space, while helping to insert transmembrane proteins into the inner membrane. The TIM22 complex mediates the insertion of a subclass of inner membrane proteins, including the carrier protein that transports ADP, ATP, and phosphate. 

A third protein translocator in the inner mitochondrial membrane, the OXA complex, mediates the insertion of inner membrane proteins that are synthesized within the mitochondria. It also helps to insert some proteins that are initially transported into the matrix by the TOM and TIM complexes. 

It is thought that the TOM complex first transports the mitochondrial targeting signal across the outer membrane. Once it reaches in the intermembrane space, the targeting signal binds to a TIM complex, opening the channel in the complex through which the polypeptide chain either enters the matrix or inserts into the inner membrane. 

Although the functions of the TOM and TIM complexes are usually coupled to allow protein transport across both membranes at the same time, both protein types of translocator can work independently.

Here's a small diagram to show you the mechanism.
P.S.Do not draw this in the exam, your examiner might get cataract :p

Hope this helps.
-Staph <3
And always remember, that you are amazing :D

Ion Channels

Hello everyone,

Today I will be writing about Ion Channels

Certain cells, commonly called excitable cells, are unique because of their ability to generate electrical signals. Although several types of excitable cells exist — including neurons, muscle cells, and touch receptor cells — all of them use ion channel receptors to convert chemical or mechanical messages into electrical signals.

Ion channels are pore-forming membrane proteins whose functions include establishing a resting membrane potential, shaping action potentials and other electrical signals by gating the flow of ions across the cell membrane, controlling the flow of ions acrosss ecretory and epithelial cells, and regulating cell volume. Ion channels are present in the membranes of all cells. Ion channels are considered to be one of the two traditional classes of ionophoric proteins, with the other class known as ion transporters (including the sodium-potassium pump, sodium-calcium exchanger, and sodium-glucose transport proteins, amongst others)

The three main groups of ion channels are

 1) the voltage-gated channels such as the sodium and potassium channels of the nerve axons and nerve terminals,

 2) the extracellular ligand-activated channelswhich includes channels such as GABA and glycine receptor channels, most of which are regulated by ligands that are "neurotransmitters". These channels are often named according to the ligand they bind to. 3) Intracellular ligand-gated ion channels.

     

 Ion channel Receptors are usually multimeric proteins located in the plasma membrane. Each of these proteins arranges itself so that it forms a passageway or pore extending from one side of the membrane to the other. These passageways, or ion channels, have the ability to open and close in response to chemical or mechanical signals. When an ion channel is open, ions move into or out of the cell in single-file fashion. Individual ion channels are specific to particular ions, meaning that they usually allow only a single type of ion to pass through them. Both the amino acids that line a channel and the physical width of the channel determine which ions are able to wiggle through from the cell exterior to its interior, and vice versa. The opening of an ion channel is a fleeting event. Within a few milliseconds of opening, most ion channels close and enter a resting state, where they are unresponsive to signals for a short period of time.

Function of Ion channels

•        Mediate the generation, conduction and transmission of electrical signals in the                   nervous system.
•        Control the release of neurotransmitters and hormones
•        Initiate muscle contraction
•        Transfer small molecules between cells (gap junctions)
•        Mediate fluid transport in secretory cells
•        Control motility of growing and migrating cells
•        Provide selective permeability properties important for various intracellular organelles.

     -Dixy

Different ways of protein transport.

Heyo homiees..
Protein transportation is the topic of discussion for today.

To understand the general principles by which sorting signals operate, it is important to distinguish three fundamentally different ways by which proteins move from one compartment to another.

GATED TRANSPORT:

The protein traffic between the cytosol and nucleus occurs between topologically equivalent spaces, which are in continuity through the nuclear pore complexes.

VESICULAR TRANSPORT:

Membrane-enclosed transport intermediates which may be small, spherical transport vesicles or larger, irregularly shaped organelle fragments ferry proteins from one compartment to another. The vesicles load with the contents that are supposed to be transported from the donor compartment. Then the vesicles separate and travel via cytosol to the target compartment and merge with them thus transporting the contents within.

TRANSMEMBRANE TRANSPORT:

Membrane-bound protein translocators directly transport specific proteins across a membrane from the cytosol into a space that is topologically distinct. The transported protein molecule usually must unfold to snake through the translocator. This type of transport usually occurs between cytosol and mitchondrion or ER lumen.

Thus these are the three ways for protein transport. Further protein sorting will be discussed later.

Hope this helps.

Thanks a lot.

-Staph.

Lichens

Hello everyone ,

 Today I will be writing about lichens

Lichens are unusual creatures. A lichen looks like a single organisms, but a lichen is not a single organism the way most other living things are, but rather it is a combination of two organisms which live together intimately. lichens actually a form of  symbiotic relationship between an alga and fungus.

It is composed of a fungal partner (Mycobiant) and one or more photosynthetic partner (Photobiont), generally green algae or cyanobacteria. there are about 20,000 species of lichens on the earth. Lichens will grow almost anywhere that a stable and reasonably well-lit surface occurs. This may include soil, rock, or even the sides of trees. A lichen may absorb certain mineral nutrients from any of these substrates on which it grows, but is generally self-reliant in feeding itself through photosynthesis in the algal cells. Thus, lichens growing on trees are not parasites on the trees and do not feed on them, any more than you feed on the chair you sit in. Lichens growing in trees are simply using the tree as a home. 

Mutualistic or Parasitism.

It is debated whether the relationship in a lichen is mutualistic or part of a controlled parasitism. On one hand, the fungus and photobiont seem to be in a mutualistic relationship because when they combined, they have the ability to deal with ecological  conditions, it also seem that  neither partner is damaged by other . Upon taking a closer look at a lichens, some might say that the photobiont is captive of the mycoboint, not a partner . the fungal partner 'enslaves ' the photobiont to feed from the photobionts photosynthesis.

Lichens; as biological indicator of pollution

Lichens absorbs most of it's mineral nutrients from air and rainfall. They have been used to monitor the amount of pollutants in an environment. This is done by  observing condition of lichens as well as their chemical composition sulfur dioxide is lethal to lichens as it damage chlorophyll  that cause photosynthesis to cease. 

Lichens are often strikingly colorful because of presence of pigments that protects the photosynthetic partner .

Lichens occur in one of four basic growth forms, as illustrated below:

• crustose - crustlike, growing tight against the substrate.
• squamulose - tightly clustered and slightly flattened pebble-like units.
• foliose - leaflike, with flat sheets of tissue not tightly bound.
• fruticose - free-standing branching tubes.
• leprose- powdery
• gelatinous – jelly like
• byssoid – whispy, like teased wool
• structureless.

-Dixy

Specialization of plant cells

Hello, everyone 

You all must have a seen seed germinating into a whole plant. But what are the mechanism or process which take place to change seed into a plant or tree. So in this section I will be explaining  about cell SPECIALIZATION IN PLANT  with help of image.

When seed begins to germinate it is a long way from redeeming it's promise of becoming a majestic tree . At initial stage of growth rapid cell division occurs leading to cluster of identical cells wit no root , stem and leaves. It is much later that roots begin their exploratory voyage and the stem embarks on it's cautious journey skyward.

Cell maturation involves development and specialization.the ultimate appearance and function of each cell depends on change it undergoes during specialization or differentiation. After differentiation only cells in certain specific apical areas such as root and stem tips retain their ability to divide.

Specialization is a one way street

Thank You,

with love 

-Dixy