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Biology with Nawaz Abbas, Karachi (2026)

09/12/2024

The formation of twins in humans, can occur in different ways depending on how the egg and s***m interact during fertilization. In this video, Here's a simplified explanation of how s***m pe*******on into an egg can lead to the formation of twins:

***m Pe*******on into the Egg,

When s***m enters the egg (oocyte), it releases its genetic material (DNA) into the egg's cytoplasm. The egg has a protective layer around it called the zona pellucida. The s***m must pe*****te this layer to reach the egg's membrane and fuse with it. Once fertilization occurs, the egg's genetic material combines with that of the s***m, forming a fertilized egg or zygote.

# Two main types of twins.

*1. Monozygotic (Identical) Twins:*
*
Monozygotic twins occur when a single fertilized egg (zygote) splits into two embryos during early development, typically within the first week after fertilization,
This split can happen at different stages of development, leading to different types of identical twins (e.g., sharing a placenta or separate placentas).

The genetic material is identical because both embryos originate from the same fertilized egg, making the twins genetically identical.

*2. Dizygotic (Fraternal) Twins:*

Dizygotic twins are formed when two separate eggs are released during ovulation (often in the case of multiple eggs being ovulated) and each is fertilized by a separate s***m.

This leads to the formation of two zygotes, each with its unique genetic material from its respective s***m and egg. These twins share about 50% of their genetic material, just like any other siblings.

3. How S***ms Influence Twin Formation:

In the case of dizygotic twins, two s***m fertilize two eggs, resulting in fraternal twins.

In the case of monozygotic twins, one s***m fertilizes the egg, and after fertilization, the zygote undergoes a division process that creates two embryos. This division is usually random and not influenced by the s***m, but it can occur due to genetic or environmental factors, leading to identical twins.

:

S***m pe*****tes the egg to fertilize it, leading to the formation of a zygote. If the zygote divides into two embryos (monozygotic twins), the twins will be genetically identical. If two separate eggs are fertilized by two s***m (dizygotic twins), the twins will be genetically distinct but share the same gestation period.

.

18/02/2024

The different types of cells of the human body and their functions!

1.Red blood cells:
Erythrocytes are the most common type of cell of human body.
and their main job is to transport oxygen, carbon dioxide, nutrients and other substances throughout the body.

2.White blood cells; also known as leukocytes,
these cells fight against infection, inflammation, and other disease. They also help your immune system to detect things that shouldn’t be in your body. White blood cells are further classified into:

i.Agranulocytes;
This type of WBC has no distinct granules in their cytoplasm, hence the name. Examples include monocytes and lymphocytes.

ii.Granulocytes;
Unlike agranulocytes, this type of WBC has granulated structures in its cytoplasm. Examples include basophils, eosinophils and neutrophils.

3.Platelets;
Also called as thrombocytes, these are tiny, colourless cell fragments. When you have a cut or a bruise, platelets stick to the injured area and help stop bleeding.

4;Skin cells;
Skin is the largest organ in our bodies, and it’s made up of two different types of cells:

i.Keratinocytes; Keratinocytes are a type of skin cells that make up the epidermis. They form a tough, protective layer for the body and protects us from infections

ii.Melanocytes; Melanocytes are types of skin cells that are found in the skin, hair, and eyes. They produce the pigment melanin, which is responsible for skin color and protection from the sun’s UV rays.

iii.Langerhans cells; Langerhans cells are a type of “antigen-presenting cell” that play an important role in skin immunity. They are found in the upper layers of the epidermis and are activated by pathogens. They contain organelles called Birbeck granules, which are formed from inflammasomes (a type of protein) and help to produce cytokines to fight infection.

iv.Merkel cells;
Also called Tactile epithelial cells or Merkel-Ranvier cells, are found in the human skin (right below the epidermis) and are believed to be essential for sensing touch.

5.Heart Muscle Cells;
Also called cardiomyocytes, these are the cells that make up the cardiac muscles.

6.Stem Cells;
Stem cells are cells that have not differentiated into any particular type yet. They can either become a particular cell type of divide and become more stem cells. They are usually found in embryos as well as adult tissues such as bone marrow,
Stem cells can be classified into the following:

i.Totipotent cells; Totipotent cells are cells that can form any cell in the body.

ii.Pluripotent cells; Pluripotent cells are cells that may become any cell except an egg or s***m.

iii.Multipotent cells;
This type of cell can develop into more than one type of cell but are generally more limited than pluripotent cells.

7.Bone Cells;
As the name indicates, these are the cells which make up the bone tissue.
Bone cells are further classified into the following types based on their function.

i.Osteoclasts:
Osteoclasts are one of the types of bone cells that break down and reabsorb bone tissue. These are important cells as they are used to initiate bone remodelling.

ii.Osteoblasts:
Osteoblasts are a type of cell that builds new bone tissue. They are also produced in the bone marrow and spread to the surface of bones.

iii.Osteocytes:
Type of cells that are found inside the substance of fully developed bones.
The functions of osteocytes include responding to mechanical stress and signalling bone resorption or formation, modification of the microenvironment, and regulating local and systemic mineral homeostasis.

iv.Myocytes:
Also called muscle cells, are long and tubular cells that are essential for a wide variety of functions including support, internal, external movement and more.
For example, peristalsis is a type of internal movement which is important for digestion.

V.Chondrocytes:
This type of cells are found in cartilage. These cells produce a matrix which primarily consists of collagen and proteoglycans.

8.Nerve Cells;
Nerve cells, also called neurons, are the fundamental building blocks of the nervous system. They enable communication between different areas of your body and brain. These cells can carry messages from your brain to other parts of your body via electrical impulses.

9.Neuroglial cells,
They are also known as glial cells, are found in our brains and spinal cord and are tasked with the optimum functioning of the nervous system.

10.Fat Cells
A person’s weight is determined by the number and size of their fat cells.
They're of two types,
i.White adipocytes.
White adipocytes store energy as triglycerides

ii.Brown adipocytes – Brown adipocytes burn energy as heat (thermogenesis). Moreover, as people age, they produce less white fat cells and more brown fat cells.

11.Sex cells;
S***matozoa and Ova are the main s*x cells of humans. They're of two types. S***matozoa and ova.

i.S***matozoa/S***m.
It is the male's s*x cell that is develoved in the testicles within a system of tiny tubes called seminiferous tubules.
The job of s***m is to fertilize an egg in order to create an embryo.

ii.Ovum/Egg
It is the female's s*x cell that is develoved in female ovaries. It also non-motile female gamete that fuses with the motile s***m during fertilization and results in the formation of a zygote.

18/02/2024

S***m is the smallest cell of the human body.

18/02/2024

1.Which is the largest cell of the human body?

A.S***m
B.Neuron
C.Ovum
D. Ostrich egg

10/02/2024

"Fathers of 50th important branches of Biology".

1. Father of Comparative Anatomy,
George Cuvier.

2. Father of Ethology,
Konrad Lorentz.

3. Father of Indian Ecology,
R. Mishra.

4. Father of Modern Palaeontology,
Cuvier.

5. Father of Anatomy,
Andreas Vesalius.

6. Father of Antibiotics,
Alexander Flemming.

7. Father of Antiseptic Surgery,
Joseph Lister.

8. Father of Bacteriology,
Robert Koch.

9. Father of Biochemical/Human Genetics,
Archibald Garrod.

10. Father of Biochemistry,
Justus Von Leibig.

11. Father of Blood Circulation,
Williams Harvey.

12. Father of Blood Groups,
Landsteiner.

13. Father of Botany,
Theophrastus.

14. Father of Conditional Reflex,
Ivan Pavlov.

15. Father of DNA Finger Printing,
Alec Jeffrey.

16. Father of ECG,
Einthoven.

17. Father of Embryology,
C.F. Wolff.

18. Father of Endocrinology,
Addison.

19. Father of Eugenics,
Francois Galton.

20. Father of Evolutionary Idea,
Empedocles.

21. Father of Genetic Engineering,
Paul Berg.

22. Father of Genetics,
Mendel.

23. Father of Histology,
Bichat.

24. Father of Immunology,
Edward Jenner.

25. Father of Indian Embryology,
P. Maheshwari.

26. Father of Indian Green Revolution,
M.S. Swaminathan.

27. Father of Indian Palaeobotany,
Birbal Sahni.

28. Father of Medicine,
Hippocrates.

29. Father of Microbiology,
Louis Pasteur.

30. Father of Microscopic Anatomy,
Marcello Malpighi.

31. Father of Microscopy,
Antony van Leeuwenhoek.

32. Father of Modern Botany,
K. Bauhin.

33. Father of Modern Cytology,
Swanson.

34. Father of Modern Embryology,
Von baer.

35. Father of Modern Genetics,
Bateson.

36. Father of Experimental Genetics,
Morgan.

37. Father of Mutation,
Hugo de Vries.

38. Father of Mycology,
Micheli.

39. Father of Palaeontology,
Leonardo da Vinci.

40. Father of Parasitology,
F. Platter.

41. Father of Plant Anatomy,
N. Grew.

42. Father of Plant Pathology,
De Berry

43. Father of Radiation Biology,
Muller.

44. Father of Taxonomy,
Carolus Linnaeus.

45. Father of Virology,
W.M. Stanley.

46. Father of Zoogeography,
P.L. Sclater.

47.Father of Zoology,
Aristotle.

48. Father of evolution,
Charles Darwin.

49. Father of chemotherapy,
Paul Ehrlich.

50. Father of cloning,
Ian Willmut.

By;
Nawaz_abbas ( Zoologist).

06/02/2024

"The 40th_Branches_of_biology".

1.Actinobiology;
the branch of biology concerned with the effects of radiation on living organisms.

2.Aerobiology;
the study of airborne organisms, spores, etc.

3.Agrobiology;
the science of plant growth and nutrition in relation to agriculture.

4.Astrobiology;
the branch of biology that investigates the possibility of life elsewhere in the universe.

5.Bacteriology;
the branch of science concerned with the study of bacteria.

6.Biochemistry;
the study of the chemical compounds, reactions, etc, occurring in living organisms.

7.Biodynamics;
the branch of biology that deals with the energy production and activities of organisms.

8.Biogeography;
the branch of biology concerned with the geographical distribution of plants and animals.

9.Biometry;
the analysis of biological data using mathematical and statistical methods.

10.Biophysics;
the physics of biological processes and the application of methods used in physics to biology.

11.Biostatics;
the branch of biology that deals with the structure of organisms in relation to their function.

12.Botany;
the study of plants, including their classification, structure, physiology, ecology, and economic importance.

13.Chronobiology;
the branch of biology concerned with the periodicity occurring in living organisms.

14.Cryobiology;
the branch of biology concerned with the study of the effects of very low temperatures on organisms.

15.Cytogenetics;
the branch of genetics that correlates the structure, number, and behaviour of chromosomes with heredity and variation.

16.Cytology;
the study of plant and animal cells, including their structure, function, and formation.

16.Ecology;
the study of the relationships between living organisms and their environment.

17.Genetics;
the branch of biology concerned with the study of heredity and variation in organisms.

18.Histology;
the study, esp the microscopic study, of the tissues of an animal or plant.

19.Microbiology;
the branch of biology involving the study of microorganisms.

20.Morphology;
the branch of biology concerned with the form and structure of organisms.

21.Oceanography;
the branch of science dealing with the physical, chemical, geological, and biological features of the oceans and ocean basins.

22.Organography;
the description of the organs and major structures of animals and plants.

23Organology;
the study of the structure and function of the organs of animals and plants.

24.Palaeontology;
the study of fossils to determine the structure and evolution of extinct animals and plants and the age and conditions of deposition of the rock strata in which they are found.

25.Parasitology;
the branch of biology that is concerned with the study of parasites.

26.Photobiology;
the branch of biology concerned with the effect of light on living organisms.

27.Photodynamics;
the branch of biology concerned with the effects of light on the actions of plants and animals.

28.Radiobiology;
the branch of biology concerned with the effects of radiation on living organisms and the study of biological processes using radioactive substances as tracers.

29.Sociobiology;
the study of social behaviour in animals and humans, esp in relation to its survival value and evolutionary origins.

30.Somatology;
the branch of biology concerned with the structure and function of the body.

31.Stoichiology;
the branch of biology concerned with the study of the cellular components of animal tissues.

32.Taxonomy;
the branch of biology concerned with the classification of organisms into groups based on similarities of structure, origin, etc.

33.Teratology;
the branch of biology that is concerned with the structure, development of monsters.

34.Zoology;
the study of animals, including their classification, structure, growth, physiology, and history.

35. Anatomy;
It is the study of the internal structure of living organisms.

36. Biomathematics;
It is use of mathematics in study of living things.

37. Endocrinology;
It is the study of endocrine system, hormones and their functions.

38. Embryology;
It is the study of bio formation and development of living things from fertilization to birth as an independent organism.

39. Pharmacology;
It is the study of actions of drugs or chemicals on and in living things.

40. Phytopathology;
It is the study of diseases in plants.

By;
Nawaz Abbas (Zoologist)

05/02/2024

Biological classification of humans.

05/02/2024

What is biology?
Biology is a branch of science that deals with living organisms. Biology encompasses diverse fields, including Botany, Conservation, Ecology, Evolution, Genetics, Marine biology, Microbiology, Molecular biology, Physiology, Medicines and Zoology.

*The concept of biology*
The word biology is derived from the Greek words/Bios/ meaning/ life and/ Logos/ meaning/Study and it is defined as the science of life and living organisms. An organism is a living entity consisting of one cell e.g
Bacteria, Diatoms, Protozoa and Amoeba or several cells e.g Animals plants and fungi.

By;
Nawaz Abbas (Zoologist)

Biology with Nawaz Abbas

09/12/2024

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