Summarized biology by Tashenka Ninel

mRNA Vaccinology Next Generation

Advancements in the generation, purification and cellular delivery of RNA have enabled the development of mRNA vaccines across a broad array of applications, such as cancer and Zika virus infection. The technology is cost-effective, relatively simple to manufacture, and elicits immunity in a novel way. Furthermore, the emergence of the COVID-19 pandemic demonstrated that the world needed rapid development of a vaccine that was deployable around the globe. Because of previous research that laid the groundwork for this technology, an effective COVID-19 vaccine was developed, produced, approved and deployed in less than a year. This landscape-changing technology has the potential to be used to manage some of healthcare’s most challenging diseases quickly and efficiently.

Protein Synthesis

Protein synthesis is the process whereby biological cells generate new proteins; it is balanced by the loss of cellular proteins via degradation or export. Translation, the assembly of amino acids by ribosomes, is an essential part of the biosynthetic pathway, along with generation of messenger RNA (mRNA), aminoacylation of transfer RNA (tRNA), co-translational transport, and post-translational modification. Protein biosynthesis is strictly regulated at multiple steps. They are principally during transcription (phenomena of RNA synthesis from DNA template) and translation (phenomena of amino acid assembly from RNA).

The cistron DNA is transcribed into a variety of RNA intermediates. The last version is used as a template in synthesis of a polypeptide chain. Protein will often be synthesized directly from genes by translating mRNA. When a protein must be available on short notice or in large quantities, a protein precursor is produced. A proprotein is an inactive protein containing one or more inhibitory peptides that can be activated when the inhibitory sequence is removed by proteolysis during posttranslational modification. A preprotein is a form that contains a signal sequence (an N-terminal signal peptide) that specifies its insertion into or through membranes, i.e., targets them for secretion.[1] The signal peptide is cleaved off in the endoplasmic reticulum.[1] Preproproteins have both sequences (inhibitory and signal) still present.

In protein synthesis, a succession of tRNA RNA molecules charged with appropriate amino acids are brought together with an mRNA molecule and matched up by base-pairing through the anti-codons of the tRNA with successive codons of the mRNA. The amino acids are then linked together to extend the growing protein chain, and the tRNAs, no longer carrying amino acids, are released. This whole complex of processes is carried out by the ribosome, formed of two main chains of RNA, called ribosomal RNA (rRNA), and more than 50 different proteins. The ribosome latches onto the end of an mRNA molecule and moves along it, capturing loaded tRNA molecules and joining together their amino acids to form a new protein chain.[2]

Protein biosynthesis, although very similar, is different for prokaryotes and eukaryotes.

Trasncription

In transcription an mRNA chain is generated, with one strand of the DNA double helix in the genome as a template. This strand is called the template strand. Transcription can be divided into 3 stages: initiation, elongation, and termination, each regulated by a large number of proteins such as transcription factors and coactivators that ensure that the correct gene is transcribed.

Transcription occurs in the cell nucleus, where the DNA is held. The DNA structure of the cell is made up of two helixes made up of sugar and phosphate held together by hydrogen bonds between the bases of opposite strands. The sugar and the phosphate in each strand are joined together by stronger phosphodiester covalent bonds. The DNA is "unzipped" (disruption of hydrogen bonds between different single strands) by the enzyme helicase, leaving the single nucleotide chain open to be copied. RNA polymerase reads the DNA strand from the 3-prime (3') end to the 5-prime (5') end, while it synthesizes a single strand of messenger RNA in the 5'-to-3' direction. The general RNA structure is very similar to the DNA structure, but in RNA the nucleotide uracil takes the place that thymine occupies in DNA. The single strand of mRNA leaves the nucleus through nuclear pores, and migrates into the cytoplasm.

The first product of transcription differs in prokaryotic cells from that of eukaryotic cells, as in prokaryotic cells the product is mRNA, which needs no post-transcriptional modification, whereas, in eukaryotic cells, the first product is called primary transcript, that needs post-transcriptional modification (capping with 7-methyl-guanosine, tailing with a poly A tail) to give hnRNA (heterophil nuclear RNA). hnRNA then undergoes splicing of introns (noncoding parts of the gene) via spliceosomes to produce the final mRNA.

Translation

The synthesis of proteins from RNA is known as translation. In eukaryotes, translation occurs in the cytoplasm, where the ribosomes are located. Ribosomes are made of a small and large subunit that surround the mRNA. In translation, messenger RNA (mRNA) is decoded to produce a specific polypeptide according to the rules specified by the trinucleotide genetic code. This uses an mRNA sequence as a template to guide the synthesis of a chain of amino acids that form a protein. Translation proceeds in four phases: activation, initiation, elongation, and termination (all describing the growth of the amino acid chain, or polypeptide that is the product of translation).

Micro Biology

What is microbiology?

Rod Shaped bacteria

Microbiology is the study of microorganisms - bacteria, protozoal parasites, viruses and fungi. These organisms can only be seen under the microscope but despite their size these micro-organisms, or microbes for short, have a massive impact on our lives. It has been estimated that there are 5X1030 or 5 million trillion, trillion, microbial cells on Earth. The total amount of carbon in these cells is equivalent to that of all of the plants on the planet! They collectively constitute the largest mass of living material on earth and play a critical role in shaping the environment that we live in. Humans, plants and animals are intimately tied to the activities of microbes which recycle key nutrients and degrade organic matter. Some microbes, however, are pathogenic.

Microbiology and the Evolution of Life on Earth

Microbes have existed on Earth for billions of years and were here long before plant and animal life began. For the majority of its 4.5 billion year history, life on Earth was exclusively microbial. Microbial cells first appeared between 3.8 and 3.9 billion years ago. The fossilised remains of these early bacteria can be detected in stromatolites - rock-like build ups of microbial mats and trapped sediment. When the Earth first formed there was no oxygen present and only bacteria which could grow without oxygen could thrive. Eventually a group of bacteria called cyanobacteria evolved which were able to photosynthesise, thus generating oxygen. At this point the long process of oxygenating the world began, starting the slow, gradual process of the evolution of aerobic forms of life, including animals and plants.

Microbes as Guardians of the Earth

Microbes act as guardians of our planet ensuring that key minerals, such as carbon and nitrogen, are constantly recycled. Even though the Earth is now populated with green plants, microbes still play a crucial role in oxygenating the atmosphere and collectively they carry out more photosynthesis than plants. Microbes degrade dead organic matter, converting the organic carbon in their bodies back into carbon dioxide.

Compost heap

Microbes also play a key role in the nitrogen cycle. Bacteria in the soil convert atmospheric nitrogen into nitrates in the soil. Nitrates are an essential plant nutrient – they need the nitrogen for proteins - and the plants themselves provide food for live stock and other animals. The nitrogen locked in plant and animal proteins is then degraded into nitrates by microbes and eventually converted back into nitrogen by denitrifying bacteria. Compost heaps are a fantastic example of how effectively microbes breakdown organic matter. The mixture of garden weed, grass clippings and mouldy fruit and veg is decomposed rapidly by fungi and bacteria into carbon dioxide and plant compost containing nourishing nitrates and nitrites. Without the recycling power of microbes dead vegetation, carcasses and food waste would start piling up around us! In the UK 6.7 million tonnes of food waste is thrown away every year. Imagine what would happen to the Earth if this waste just sat there and wasn’t degraded…

The Birth of Microbiology

It wasn’t until the 17th century, when the microscope was invented by Robert Hooke, that the existence of microbes was even suspected. Hooke’s microscope, however, could only achieve magnifications of 20-30 times - not powerful enough to see bacteria. Around 1668 Antonie van Leeuwenhoek, an amateur microscope builder, improved microscope design so that he was able to make a microscope capable of magnifications of up to 200 times. Van Leeuwenhoek started examining things like pond water, tooth scrapings and then almost anything he could lay his hands on! In 1683 he described, in a letter to the Royal Society, that he had seen "an unbelievably great company of living animalcules, swimming more nimbly that I had ever seen up to this time” when he had used his microscope to look at the tooth scraping from an elderly man, who had never cleaned his teeth! The animacules were bacteria.

Microbes are everywhere

Microbiologists have discovered that microbes can be found just about anywhere. Microbes are an incredibly diverse group of organisms and can grow in extreme environments that no other living organisms can tolerate. Bacteria have been found to thrive in volcanic hot springs, where temperatures typically reach near boiling point. At the other extreme, living bacteria have also been discovered in Antarctic deserts, where temperatures range from -15 to -30°C. Bacteria can also thrive in salt flats, pools of saturated brine, where salt concentrations range from 120 to 230 grams per litre. Bacteria which live happily in these inhospitable environments have been termed ‘extremophiles’

Hot Springs teaming with swathes of bright, orangey-red thermophillic bacteria

In addition to being a biological curiosity bacteria which grow in these extreme conditions have proved a rich source of enzymes for the biotechnology industry. Fat-degrading and protein-degrading enzymes from bacteria isolated from hot springs have been used to make ‘biological washing powders’. Unlike equivalent enzymes from ‘ordinary’ bacteria these function efficiently at the high temperatures typically used for doing the laundry. Clearing up oil spills that have occurred in cold oceanic environments, the production of ice cream and artificial snow have also benefited from enzymes, produced by bacteria that thrive in near zero temperatures.

Microbes and Food

Microorganisms also provide us with pleasure! They play a hugely important role in producing a whole variety of delicious foods. Who knew that microbes were involved in making chocolate? Cocoa pods are split open and their contents – 20 to 30 bitter seeds in a sweet sticky pulp - are heaped together and covered with banana skins and naturally fermented for 7 days. Over 30 different types of bacteria are involved in this process, along with yeasts and moulds. While in this heap, the sticky pulp becomes a turbid chocolate-coloured broth which gives the cacao seeds both their characteristic chocolate flavour and colour. Microbes play a key role in making wine and beer and foods such as bread, cheese and yoghurt. Salt-loving bacteria, like those found in salt flats, play a key role in the production of Thai fish sauce and Japanese soy sauce. Chinese cooking also depends heavily on microbes which are essential in the production of black bean and yellow bean sauces. Salt-loving bacteria are also important in the production of cured meats and sausages such as salami. Without microbes our culinary repertoire would be smaller and our diets extremely bland.

Colonies of fungi growing on bread. Image courtesy of Matt Wharton

As we all know to our cost, the interaction between microbes and food is not always beneficial. Mouldy bread and rotten fruit caused by microbial degradation is not very appetising. Pizzas and pies which have passed their sell by date may not be obviously full of bacteria, but sell by dates are based on the amount of time it takes for the numbers of bacteria to reach a level where the chances of food poisoning are high. Microbial spoilage makes food unappetising and perhaps foul tasting, but rotten food won’t automatically make you sick – but contamination of food with microbial pathogens will.

The bacterium Campylobacter jejunii is the commonest cause of food poisoning in the UK. In 2010 the Food Standards Agency estimated that 65% of all fresh chickens sold in the UK were contaminated with C. jejunii. Although cooking will kill this bacterium it is still responsible for approximately 300,000 cases of food poisoning in England and Wales each year. For most healthy people, food poisoning, although very unpleasant, is not life-threatening. However for both babies and elderly people food poisoning can be extremely serious as it can cause severe dehydration and kidney failure. Learning how to handle raw meat and to cook poultry and meat properly is therefore essential, particularly during the barbecue season when the incidence of food poisoning, due to poorly cooked food, soars.

Microbes and Disease

Influenza virus

The study of infectious disease is another important branch of microbiology. At the beginning of the 20th century infectious diseases, caused by microbial pathogens, were the major cause of death. Large numbers of children and the elderly succumbed to diseases such as tuberculosis, diphtheria and pneumonia. At this time microbiologists had little idea about how diseases were spread, or how they could be controlled, so epidemics flourished. The "Spanish" influenza pandemic of 1918–1919, caused ˜50 million deaths worldwide - more than the total number of deaths recorded in World War One. Diarrhoeal disease was also common since people regularly ate contaminated food and drank contaminated water.

Microbiology research has, therefore, been concerned with developing antibiotics and vaccines to protect the population from infectious disease. The discovery of penicillin by Alexander Flemming has saved the lives of many millions of people. The development of vaccines which protect against, diphtheria and pneumonia dramatically reduced the number of childhood deaths caused by these diseases. Children in developed countries are also routinely vaccinated against common viral infections such as measles, mumps, rubella and polio. As a direct result of the efforts of microbiologists, smallpox, once a dreadful scourge, is now officially extinct on the planet. However a vaccine against HIV, which in 2009 was reported to infect approximately 33.3 million people around the world, still eludes us.

Friendly bacteria

Babies are colonised by bacteria immediately after birth. It has been estimated that the average person is colonised by 200 trillion bacteria, comprising at least 1,000 different species. This doesn’t mean that we are teaming with potentially pathogenic bacteria, quite the opposite! The bacteria that call the human body home are often essential for our health and well being. Our intestines contain about 100 trillion bacteria and collectively they make up 60% of the dry weight of faeces. These intestinal bacteria play an essential role in helping us to digest food, they provide us with essential vitamins such as vitamin K and biotin and they help to prevent the growth of harmful pathogenic bacteria. The surface of our skin is also home to millions of friendly bacteria which crowd out potential pathogens and prevent them from growing. One bacterium which is abundant on the skin is Staphylococcus epidermidis which produces chemicals called bacteriocins that kill pathogenic bacteria. Friendly bacteria can also be found in our noses but many of these bacteria also carry a health warning. Neisseria meningnitidis which causes meningitis, lives in the noses of millions of people without causing disease, but if the immune system becomes weakened through ill-health then this bacteria can, almost by accident, cause disease which may result in the death of the human that has become its home.

Kingdom Animalia

Kingdom Animalia Characteristics

All animals are multicellular, eukaryotic heterotrophs —they have multiple cells with mitochondria and they rely on other organisms for their nourishment.

Adult animals develop from embryos: small masses of unspecialized cells

Simple animals can regenerate or grow back missing parts

Most animals ingest their food and then digest it in some kind of internal cavity.

Somewhere around 9 or 10 million species of animals inhabit the earth.

About 800,000 species have been identified.

Animal Phyla- Biologists recognize about 36 separate phyla within the Kingdom Animalia.

(We’ll study the 10 major ones!)

Animal Movement

Most animals are capable of complex and relatively rapid movement compared to plants and other organisms.

Organisms that live rooted to one spot are sessile and those that move around are motile. Even the most sessile animals can move at lease part of their bodies. This movement is dependent on how animals obtain food.

Animal Reproduction

Most animals reproduce sexually, by means of differentiated haploid cells (eggs and sperm).

Most animals are diploid, meaning that the cells of adults contain two copies of the genetic material.

Animal Sizes

Animals range in size from no more than a few cells (like the mesozoans) to organisms weighing many tons (like the blue whale).

Animal Habitats

Most animals inhabit the seas, with fewer in fresh water and even fewer on land.

Animal Bodies

The bodies of most animals (all except sponges) are made up of cells organized into tissues.

Each tissue is specialized to perform specific functions.

In most animals, tissues are organized into even more specialized organs.

Cells form tissues, tissues form organs, and organs form organ systems. This is how an organism develops.

These cells have to differentiate and become specialized in various ways.

Cell Structure: The nucleus, nucleolus, ribosomes, smooth ER, rough ER, nuclear membrane, Golgi bodies, lysosomes, mitochondria, centrioles, cytoskeltelton, vacuoles.

Animal Systems

Skeletal-Support, protection-Bones, shells, cartilage; there are some animals that are prokaryotic (invertebrates). Most of them are eukaryotic, and have a backbone (vertebrates).

Muscular-Movement-Muscles; There are many different body plans. Some have radial (starfish as an example), bilateral (humans), unilateral (earthworms)

Digestion-Digestion of food and absorption of nutrients-Mouth, stomach, intestine. This is the process in which the various macronutrients such as carbohydrates, proteins, fats, etc. are broken down and absorbed into the body. There are various sorts of systems that the animals have. Humans have the following (mouth, salivary duct, esophagus, stomach, small and large intestine, pancreas, liver, rectum). Birds for instance have a gullet as part of their digestive system, and then primitive animals such as amoeba, and paramecium have vacuoles on the cell membrane. Then there are sponges that feed for instance, and are filter feeders.

Circulatory-Distribution of nutrients and oxygen; removal of wastes-Heart, blood vessels, blood. some animals have an open and closed circulatory system. The open system they exchange wastes over the cell membrane. With closed circulatory systems such as humans it goes through a number of areas to cleanse the blood. The two organs that “bad blood” goes through is the kidneys and the liver, and they detoxify the blood by filtering the impurities and sending it into the appropriate system to be excreted or defecated. Some of the animals have a 2 chambered heart, and some have a four chambered heart. One example of a double chambered heart is a bird, and then the one that has four chambers is a human.

Respiratory-Absorption of oxygen; removal of CO2-Lungs, gills. Tthis is known as the “gaseous exchange” system. For instance with humans you take in oxygen, and then it filters through the respiratory system into the alveoli, and the alveoli, filters the wastes from the blood (carbon dioxide) back up the respiratory system through the mouth or nose and back into the air. With fish or marine life it is a bit different with the fact that they have gills so it is an open respiratory system, and they exchange their gases through the gills and through their system, and back out.

Excretory-Removal of wastes-Kidneys

Nervous-Perception, control of movement, control and coordination of organ system activities-Brain, spinal cord, nerves

Endocrine-Control and coordination of organ system activities-Glands

Immune-Defense against disease-causing organisms-Blood cells, glands, skin

Reproductive-Production of new organisms-Ovaries, testes. Tthere are some invertebrates that do asexual reproduction through means of budding or fission, and then there are many animals that do the sexual reproduction. There are two types of reproduction in the main animal kingdom. One type of fertilization is external this type is like birds and fish where they lay eggs, and then the male fertilizes them. With internal fertilization, that is what many of the chordates such as marsupials, humans etc. have this type.

Animal Symmetry

The most primitive animals are asymmetrical.

Cnidarians and echinoderms are radially symmetrical.

Most animals are bilaterally symmetrical.

Radial Symmetry

Forms that can be divided into similar halves by more than two planes passing through it.

Animals with radial symmetry are usually sessile, free-floating, or weakly swimming.

Radially Symmetrical

Like a wheel, animals with this spend most of their time floating like a buoy or attached to rocks.

Differences between the dorsal and ventral surfaces allow jellyfish to float upright; sea anemones grip rocks with their ventral surfaces and collect food with their specialized dorsal surfaces.

Advantages: Architects and engineers use radially symmetrical designs for structures such as fire hydrants and lighthouses so that the structures will be accessible or visible from any horizontal direction

Bilateral Symmetry

Animals with bilateral symmetery are most well-suited for directional movement.

Anterior (front end), and posterior (rear) end

The left and right sides of most animals are nearly mirror images.

Advantages:

o This body plan works well for animals, if a body part is damaged, the animal can rely on an identical part on its other side.

o This symmetry provides balance that aids movement.

o Anterior and dorsal defenses such as bones, shells, and horns protect delicate internal organs.

Cephalization

Bilateral Symmetry usually has led to cephalization —

the process by which sensory organs and appendages became localized in the head (anterior) end of animals.

Evolutionary Trends

If we analyze the basic body plans of animals, we find that they illustrate evolutionary trends.

Four major “advances” (in order):

Multicellular body plan

Bilaterally symmetrical body plan

“Tube-within-a-tube” body plan

Pseudocoelomates/ Coelomates

Each plan consists of 3 cell layers: endoderm, mesoderm, ectoderm

Acoelomates

These animals have no other cavity than the gut.

They are often called the “solid worms.”

Pseudocoelomates

These animals have a body cavity (the pseudocoelom) which is not completely lined with mesoderm.

The “tube within a tube” body plan.

This category is also composed of mostly worms.

These animals have a “true coelom” lined with mesodermal peritoneum.

Most animals are coelomate (EARTHWORM)

Major Animalia phylums

Phylum Porifera

Sponges

Very primitive, considered barely animals.

Don’t have true organs or nerve or muscle cells

Phylum Annelida

Segmented Worms (earthworms, leeches)

Segmented Worms

Earthworms, leeches, and other segmented worms live in water or damp soil

Leeches were once used to suck out people’s “excess” blood and reduce harmful high blood pressure.

Leeches are uses today to produce anti-blood-clotting medicines, to suck blood from bruises, and to stimulate blood circulation in severed limbs that have been surgically reattached.

Each segment is separated from its neighbors by a membrane and has its own excretory system and branches of the main nerves and blood vessels that run the length of the animal.

Both segmented and unsegmented worms have definite anterior and posterior ends.

Food travels through the digestive system in one direction; from anterior to posterior.

A cluster of nerve cells at the anterior end serves as a simple brain.

Reproduction occurs by splitting or by mutual fertilization

Mollusks (Mollusca)

Includes snails, clams, slugs, squid, and their relatives.

Mollusks have soft bodies with 3 parts

A mass that contains most of the organs

A muscular “foot” that is used in movement

A thick flap called a mantle, which covers the body and in most species produces a heavy shell of calcium compounds.

Mollusks pump water through gills

This is how food is also ingested for clams and oysters. Squid and octopuses use the pump for jet propulsion through the water in search of prey.

Arthropods (Arthropoda)

The largest animal phylum, and have jointed external skeletons.

1 million species, crabs, shrimp, spiders, scorpions and insects make up this phylum

Arthropods molt, have heads with many sensory organs.

Simple and complex eyes that detect only light intensity and form images

Antennae that smell chemical substances in the environment, arthropods also respond to water vapor, like biting mosquitoes.

They reproduce sexually, where sperm is released inside the female’s body, not in water.

Larvae of many species develop into very different adults, a process called metamorphosis.

Arthropods development of resistance to insecticides demonstrates how quickly they adapt to a changing environment.

Short generations and many offspring increase the chance that random mutations will produce a few resistant individuals

Echinoderms (Echinodermata)

Sea stars and sea urchins.

Reproduce sexually. Sperm and eggs are released in water, where they meet and join.

Movement by seawater into and out of a system of internal tubes.

Chordates (Chordata)

Vertebrates-fish, amphibians, reptiles, birds, and mammals.

Four characteristics

Stiff dorsal rod helps to organize the embryo’s development.

Kingdom plante

Kingdom Plantae Characteristics

chloroplasts with chlorophyll a & b, and carotenoids

cellulose cell walls

formation of cell plate during cell division

starch used for carbohydrate storage

Life cycle - sporic meiosis or haplodiplonic or alternation

of generations

diploid stage (sporophyte) and haploid stage

(gametophyte) are multicellular

dominant stage varies between groups

primitive plants - gametophyte is dominant

advanced plants - sporophyte is dominant

primitive plants have poorly developed systems for

conducting fluids - nonvascular plants

more advanced plants (vascular plants) have well

developed xylem and phloem for conduction

Ten phyla of plants

Three nonvascular (without water conducting vessels)

P. Bryophyta - mosses

P. Hepaticophyta - liverworts

P. Anthocerophyta - hornworts

Nine vascular

Two seedless

P. Pterophyta - ferns, whisk ferns, horsetails

P. Lycophyta - club mosses

Five seeded

P. Coniferophyta - conifers

P. Cycadophyta - cycads

P. Gnetophyta - gnetophyta

P. Ginkophyta - ginkgo

P. Anthophyta - flowering plants - angiosperms

this group is

called the

gymnosperms

Characteristics of nonvascular plants

lack vessels for conducting water and foodstuffs throughout plant

Gametophytes green, nutritionally independent of, and more

conspicuous than sporophyte

Sporophyte attached to gametophyte, partially nutritionally dependent

Homosporous - spores of equal size

Require external water for fertilization, only common in moist places

In total about 24,700 species

Three Phyla -

Bryophyta (mosses),

Hepaticophyta (liverworts),

Antherocerophyta (hornworts)

collectively called the

“bryophytes”

Terms:

Sporophyte - a multicellular diploid organism that produces spores

by meiosis - spores germinate and grow into gametophytes

Gametophyte - a multicellular haploid organism that produces

gametes by mitosis can be either male or female, females produce

eggs, males produce sperms, fusion of gametes produces a zygote

that grow into a multicellular sporophyte

Antheridium - the sperm producing organ of a gametophyte

Archegonium - the egg producing organ of a gametophyte

Homosporous - spores (produced by meiosis) are indistinguishable

in size and may give rise to either male or female gametophytes

Heterosporous - spores differ in size

megaspores produce megagametophytes, which produce eggs

microspores produce microgametophytes, which produce sperms

fusion of an egg and sperm produces a zygote that can grow into a

multicellular sporophyte

Phylum Bryophyta - mosses

Gametophytes small, spiral or alternate arranged

leaves on central axis

Sporophytes grow as stalk from gametophyte

Anchored to substrate by rootlike rhizoids

Consists of several cells that absorb water

Leaves superficially resemble true leaves

green, flattened blade, slightly thickened midrib

one cell thick, lack vascular strands and stomata

Most water used by plant travels up on outside of plant, via

capillary action

Some have specialized food conducting cells

Can withstand long periods of drying

Most abundant plants in Arctic and Antarctic, rare in deserts

Mosses are sensitive to pollutants

Poor competitors in environments favorable to growth of higher

plants

Other “bryophytes”

Phylum Hepaticophyta -

Liverworts

similar reproduction

to mosses

Phylum Anthocerotophyta

Hornworts

among earliest land plants

Sporophyte has stomata, is

photosynthetic, and provides

much of plant’s energy.

Human Digestive System

The digestive system is a group of organs working together to convert food into energy and basic nutrients to feed the entire body. Food passes through a long tube inside the body known as the alimentary canal or the gastrointestinal tract (GI tract). The alimentary canal is made up of the oral cavity, pharynx, esophagus, stomach, small intestines, and large intestines. In addition to the alimentary canal, there are several important accessory organs that help your body to digest food...

Blood clotting

Clotting of blood is considered as the defense mechanism because of following reasons ,

1.It protect the body against the blood loss which can lead to dehydration .

2.It prevent the entry of micro organisms into the blood circulation.

Given below are the main steps of resting blood,

1. Vasoconstriction

Amount of blood which flow along the blood vesicle is reduce

2. Platelet plug formation

Platelets in the damage vesicle adhere with each other and form a mass of platelets which adhere to the vesicle wall that damage.

3. Blood clot formation

Thermoplastin is released by ruptured platelet. It converts plasma protein , prothombin to thrombin . Thrombin converts water soluble plasma protein , fibrinogen to water insoluble fibrin threads . This fibrin threads strengthen the platelet plug and forms a sticky network. RBC and WBC are trapted in fibrin network and form the blood clot. When the blood clot is formed bleeding is completely arrested .

Endoplasmic Reticulum

Endoplasmic Reticulum is an internal system which is formed by cell membrane .It extends from cell membrane to nuclear envelop. Membrane bound compartment which composed of Endoplasmic Reticulum are called CISTERNAE.

Chemicals which decrease the rate of enzyme catalyzed reactions are called inhibition.

There are 3 types of inhibition

1. Competitive inhibition
2. Non competitive inhibition
3. End product inhibition

1. Competitive inhibition

competitive inhibition are some what similar to the specific substrate of the enzyme and they can fit into the active site of enzyme.
competition occurs between the specific substrate molecule and inhibitor molecule to occupy active sites.

2. Non competitive inhibition

Non competitive inhibitors do not combine with the active site of the enzyme instead they fit into ALLOSTERIC SITE. Therefore substrate unable to combine with enzyme . As the enzyme substrate formation is affected reaction rate decreases . This inhibition cam be reversible or irreversible.

3. End product inhibition

When the end product of a series of reaction causes and inhibition over one or more enzyme of the path. It referred as end product inhibition.

1. ARISTORTAL,

Aristortal is the first one who classify organisms scientifically . He divided organisms as PLANTS and ANIMALS.

Animals were further divided according to the criteria such as,

* Mode of locomotion

* Reproduction

* Presence and absence of red blood cells

2.EARNEST HAECKEL

He introduce kingdom protista and Taxam Phylum

3.ROBERT WHITAKER

He classify organisms into 5 kingdoms based on 3 criteria

1.Cellular organization

2. Arrangement of cells

3. Mode of transport

4. CARLWOUS

After the acceptation of DARWIN theory on evolution and with the advancement of molecular biology it became apparent that in early stages of evolution

INHIBITORS

Chemicals which decrease the rate of enzyme catalyzed reactions are called inhibitors.

There are 3 types of inhibitors

1.Competitive inhibition

2.Non-competitive inhibition

3.End product inhibition

1. COMPETITIVE INHIBITION

competitive inhibitors are some what similar to the specific substrate of the enzyme and they can fit into the active site of enzyme.

Therefore competition occurs between the specific substrate molecule and inhibitor molecule to occupy active sites.

When inhibitors join enzyme molecules active sites are blocked temporary hence substrate molecules unable to combine with enzymes as enzyme substrate complex formation is affected the rate of the reaction decreases.

2.NON-COMPETITIVE INHIBITION

Non-competitive inhibitors do not combine with active sites of enzymes instead they fit into ALLOSTERIC SITES of the enzyme then they change the shape of active site. Therefore substrate unable to combine with enzyme further .

3.END PRODUCT INHIBITION

When the end product of a series of reaction causes and inhibition over one or more enzyme of the path.

It referred as end product inhibition.

Enzyme co-factor are non protenious organic or in organic compounds which are essential for efficient function in some enzyme.

Enzyme and co-factor combination is called Holo Enzyme .
The protenious heat unstable enzyme component of holo enzyme is called Apo Enzyme .
Co-factor is non-protenious hence heat stable.

There are 3 types of co-factors
1.Enzyme activators
2.Prosthetic groups
3.Co-enzymes

1.Enzyme activators
Enzyme activators are usually inorganic ions,

2.Prosthetic group
These are non-protenious organic compounds which are firmly integrated to the apo-enzyme.
The bond between apo enzyme and prosthetic group is permanent.
ex; FAD, FMN, HAEN,

3.Co-enzyme
These are non-protenious organic compounds which combines with apo enzyme temporary during the reaction .After the reaction they separate from the enzyme.
ex; NAD , NADP

Mitochondria

* Mitochondria is a long cylindrical double membrane bound organal.

* It's believed that mitochondria originate from AEROBIC bacteria.

* Outer membrane is smooth and inner membrane is folded into cristae .

* In between 2 membranes inter membrane space is present .

* On cristae stalked bodies called oxysomes are present , they contain enzymes.

* Mitochondria is self replicating organal.

* Mitochondrial DNA can be used to identify the mother of a person.

* Inside the mitochondria a gel like medium called mitochondrial matrix is present .

Functions of mitochondria

1. Carries of reaction of aerobic respiration

2. Take part in photo-respiration

Cellular organization

There are 2 types of cellular organizations can be identified in living organisms

1. Prokariyotic cellular organization

2. Eukariyotic cellular organization

This division is based on level of organization of nucleus.

Simple primary organization can be seen in Prokariyotic organisms and advanced structure can be seen in Eukariyotic organisms.

Functions of proteins

1. Important in oxygen transport .

Ex; Hemoglobin in red blood cells

2. Important in blood clotting.

Ex; Fibrinogen

3. Protect the body from foreign particles

Ex; Anti bodies are defensive proteins

4. Important in single transmission

Ex; Insulin

5. Proteins act as a storage food

Ex; Albumin in eggs

6. They are also structural bonds

Ex; Carotene [in hair and finger nails,e.t.c]

7. Proteins act as a respiratory substrate

8. Some proteins are hormones

Ex; Pituitary hormones

9. Important in mussel contraction

Ex; Actin

Proteins

Proteins contain carbon , hydrogen , oxygen and nitrogen.

Proteins are polymers here the monomer is AMINO ACIDS .
Some proteins are macro molecules.
Some proteins are water soluble
Ex; enzymes

Some proteins are water in soluble
Ex; structural proteins

Some proteins can act as catalyst
Ex; enzymes

Factors effects in protein denaturation

1. Hi temperature
2. Strong acids
3. Strong bases
4. Organic solvents
5. Heavy metals
6. Radiation

NUCLEOTIDES

Structural unit of nucleic acid is NUCLEOTIDE

Nucleotide have 3 main components

1.Phosphate group

2. Pento sugar group

3.Nitrogenous based group

PENTO SUGAR GROUP

They are monosaccharides having 5 carbons

There are 2 types of pento sugars

1. Ribose

2. Deoxy ribose

NITROGENOUS BASED GROUP

They are nitrogen containing organic molecule which can be found in nucleic acid.

There are 5 types of nitrogenous bases

1.Adenine

2.Guanine

3. Thiamine

4.Cytosine

5.Uracil

Nitrogenous bases can be divided into 2 groups

1.Purine

2. Pyrimidines

mRNA Vaccinology Next Generation

Protein Synthesis

Micro Biology

Kingdom Animalia

Kingdom plante

Human Digestive System

Blood clotting

Types of Lipids and their functions

Plant tissues

Epithelial Tissue

Bones

Cartilage

Cell junctions

Cytoskeletan

Transportation of materials across Plasma membrane

Lysosomes

Endoplasmic Reticulum

Blood Tissues

INHIBITION

HISTORY OF CLASSIFICATION

INHIBITORS

CO-FACTOR

Mitochondria

Cellular organization

Functions of proteins

Proteins

NUCLEOTIDES

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