- Branchiostoma, commonly known as the lancelet, is a small marine chordate found in shallow waters.
- It displays the simple primitive chordate condition, possessing the three defining chordate characteristics - notochord, dorsal nerve cord, and pharyngeal slits.
- The elongated and laterally compressed body has a pointed snout and tail, with dorsal, caudal, and ventral fins. The transparent body wall encloses myotomes and gonads.
Insects, spiders, crabs, shrimp, millipedes, and centipedes are all arthropods. Arthropods have jointed feet, a segmented body, and an exoskeleton, a cuticle on the outside of their body. Arthropods have by far the greatest number of species of any animal group, at around 900,000 species
Chordata is the last phylum of kingdom Animalia.
Which is further subdivided into subphylums, divisions and classes.
The Slides shows the classification of the phylum along with the basis on which it is classified.
(includes examples along with pictures for easy understanding and memorizing)
Insects, spiders, crabs, shrimp, millipedes, and centipedes are all arthropods. Arthropods have jointed feet, a segmented body, and an exoskeleton, a cuticle on the outside of their body. Arthropods have by far the greatest number of species of any animal group, at around 900,000 species
Chordata is the last phylum of kingdom Animalia.
Which is further subdivided into subphylums, divisions and classes.
The Slides shows the classification of the phylum along with the basis on which it is classified.
(includes examples along with pictures for easy understanding and memorizing)
Periplanata americana
morphology, sense organs
anatomy - digestive system
respiratory system
excretory system
nervous system
circulatory system
reproductive system
Useful for NEET 12 th
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
2. Branchiostoma (=Amphioxus): The
Lancelet
The members of the subphylum Cephalochordata are small, marine and superficially
fish-like chordates.
They are of special significance because they possess the three distinctive or primary
chordate characters such as notochord, dorsal tubular nerve cord and pharyngeal gill
slits, in simple condition throughout life.
Thus, they display the simple primitive chordate condition and are considered a
blueprint of the phylum Chordata.
The most extensively studied cephalochordate type, and also the best known
example of protochordates is Branchiostoma (= Amphioxus) commonly called as
'lancelet' or 'lancet'.
It was first described by the German scientist Pallas in 1778. He considered it
to be a slug (phylum Mollusca) and named it Umax lanceolatus.
An Italian scientist Costa (1834) first recognized its chordate nature and described it
as Branchiostoma lanceolatum. Two years later (1836), Yarrel named it as
Amphioxus lanceolatus.
3. Systematic Position
Phylum : Chordata
Group : Acrania
Subphylum : Cephalochordata
Class: Leptocardii
Family : Braachiostomidae
Type : Branchiostoma (=Amphioxus) (The Lancelet)
Derivation of Names
Cephalochordata (Gr., kephale=head + chorde= cord) ;
Acrania (Gr., «=absent + kranion = skull);
Amphioxus (Gr., amphi= double + oxys = sharp)
'lancet* or 'lancelet' (a little lance) refer to both
Geographical Distribution
Branchiostoma is a cosmopolitan, reported different ocean of the world.
Habit And Habitat :-
Branchiostoma is a marine animal commonly found in shallow waters, preferably
brackish or salt water, on the sandy coasts. It leads a double mode of life. Mostly it is
buried in sand in an upright condition with only the anterior end protruding above the
sand.
4. External Features:-
Shape, Size and colour:- It is small elongated narrow and fish-like animal 5 to 8 cm in length.
Body is whitish, somewhat translucent, laterally compressed and pointed at both the ends, hence
the common name “lancelet” which means “a little lance”. The streamline body is well-suited for
burrowing as well as swimming. The posterior end is more tapering and pointed than the anterior
end.
Division of body:- A true head is degenerate and absent. The body is divisible only in two
regions. The greater anterior region constitutes the trunk and a much shorter postanal posterior
region is the tail. The anterior end of trunk projects in front as a pointed snout or rostrum.
5. Apertures:- the trunk bears three openings : mouth, atriopore and anus.
• Anterior below the rostrum is a tentaculated structure, the oral hood, formed by
dorsal and lateral projections of the body. It shall be described later as a part of the
digestive system.
• Mouth is a very wide anteroventral aperture, bordered by the free margin of oral
hood. Atriopore is a small mid-ventral rounded aperture, laying just in front of the
ventral fin. The large atrial cavity surrounding the pharynx opens to outside through
atriopore. Another small aperture, the anus, lies somewhat asymmetrically to the left
of mid-ventral line at the base of caudal fin. The small posterior body region behind
the anus is the tail.
Fins and folds:-
• Branchiostoma bears three longitudinal median or unpaired fins: dorsal, caudal and
ventral.
• The dorsal fin runs as a low, mid-dorsal fold along the entire length of trunk.
Myotomes and gonads:-
• On each lateral side of body a series of shaped muscle bands, called myotomes or
myomeres can be seen through the transparent body wall.
• Between mouth and atriopore, can also be seen on either side below the myotomes,
a series of gonads.
6. Body wall
The body wall includes from outside
1. Skin. The skin or integumert consists of an outer thin epidermis made of a single layer of
columnar epithelial cells resting on a basement membrane. It is ciliated in young individuals, but
in mature individuals the cilia are lost and a thin layer of non-pigmented, chitin-like cuticle,
perforated at places, is secreted externally.
The epidermis contains sensory cells but gland cells and pigment cells are absent. Immediately
beneath the epidermis is a tough thiri, and compact, fibrous connective tissue layer, called cutis.
Underneath cutis is a thick spongy subcutis made of a gelatinous matrix, containing nerve fibres,
cells and blood vessels. A few scattered distributed nomadic cells, similar to fibroblasts of
vertebrates, secrete both these layers.
2. Musculature: The muscles lying just
beneath the skin form the greater part of
body wall. The muscles show distinct
metameric segmentation and arranged
throughout the length of body in a series of
characteristic V-shaped muscle blocks or
segments, called myotomes or myomeres.
60-62 in numbers.
3. Peritoneum. The muscle layer is lined
internally by a thin layer of parietal
paritoneum. It is not continuous in the
pharyngeal region but restricted to a few
patches.