• Biology

    What is the function of hemoglobin?

    Hamoglobin is a protein found in red blood cells that is responsible for transporting oxygen from the lungs to the body’s tissues and carrying carbon dioxide from the tissues to the lungs for elimination. It is one of the most important proteins in the human body and plays a vital role in maintaining homeostasis. The structure of hemoglobin is composed of four protein chains, two alpha chains, and two beta chains, each of which contains a heme group. Each heme group consists of an iron atom that can bind to one molecule of oxygen. When oxygen binds to hemoglobin, the molecule undergoes a conformational change that makes it easier for…

  • A level biology,  A level biology,  Biochemistry,  Biology,  Cell biology,  O level biology,  Q & A

    What is enzyme and characteristics?

    Enzymes are biological catalysts that facilitate chemical reactions in living organisms. They are typically proteins, although some RNA molecules also have catalytic activity. Enzymes are essential for life because they speed up the reactions that are necessary for cells to function properly. Without enzymes, many biochemical reactions in the body would occur too slowly to support life. Enzymes work by lowering the activation energy required for a chemical reaction to occur. Activation energy is the amount of energy needed to start a reaction, and enzymes reduce this energy barrier, allowing the reaction to occur more quickly. Enzymes do this by binding to specific molecules, called substrates, and positioning them in…

  • Biology,  MCQ

    MCQ on Breathing and Exchange of Gases-2

    Visiting high mountains may cause altitude sickness in men living in plain areas. Prime cause of this is (a) excess of CO2 in blood (b) decreased efficiency of haemoglobin (c) decreased partial pressure of oxygen (d) decreased proportion of oxygen in air. Increase in body temperature makes oxygen haemoglobin dissociation curve (a) shift to left (b) shift to right (c) hyperbolic (d) parabolic. Bohr’s effect is related with (a) reduced carbon level in lymph (b) reduced oxygen level in haemoglobin (c) oxidised phosphorus level in blood (d) reduced carbon dioxide level in blood. After deep inspiration, capacity of maximum expiration of lung is called (a) total lung capacity (b) functional…

  • A level biology,  Biology,  O level biology,  Zoology

    Why Earthworms Are a Gardener’s Best Friend

    Earthworms are considered a gardener’s best friend for several reasons: Soil aeration: Earthworms burrow through the soil, creating tunnels and air pockets that allow air, water, and nutrients to penetrate the soil more easily. This improves soil aeration, which is important for plant root health. Soil structure: Earthworms also help to improve soil structure by breaking down organic matter and creating channels for water to flow through. This creates a more hospitable environment for plant roots to grow. Nutrient cycling: As earthworms eat their way through the soil, they break down organic matter and release nutrients that plants can use. They also excrete castings (worm poop) that are rich in…

  • A level biology,  Biology,  Fun Fact,  Zoology

    Koala Has Human Like Fingerprints!

    The discovery that koalas have human-like fingerprints was a surprising revelation that has captured the attention of the scientific community and the general public alike. In this essay, I will explain this discovery in detail, including the methods used by researchers to uncover this fact and the potential implications of this discovery for the field of biology and beyond. The discovery that koalas have unique fingerprints that resemble human fingerprints was made in 2016 by a team of researchers from the University of Adelaide in Australia. The researchers were studying koala genetics in an effort to find ways to protect the species from disease and habitat loss. As part of…

  • plasma-membrane
    A level biology,  A level biology,  Biochemistry,  Biology,  Cell biology,  O level biology

    Plasma membrane

    Delimiting membrane or boundary of all cells providing the characteristic shape to the cell. Structure ● Composed of approx. 7 nm thick phospholipid bilayer with hydrophilic heads facing outward from both sides into aqueous environment and hydrophobic tails facing inside the bilayer. ● A symmetrical the presence of proteins, floating in the bilayer imparts a fluid mosaic pattern which comprises of (a) Integral/Intrinsic proteins spanning through the lipid bilayer, protruding both extracellular and cytoplasmic sides of membrane. (b) Peripheral/Extrinsic proteins located on outside either extracellular or cytoplasmic surface. (c) Lipid anchored proteins covalently linked to a lipid molecule of bilayer but present outside to it. ● Some oligosaccharides are covalently…

  • oyster
    Biology,  Fun Fact

    How do oysters make pearls?

    Pearls are formed in the body of a sea oyster as a response to an irritant that enters its shell. The irritant can be a foreign object such as a grain of sand or a parasite that makes its way into the oyster’s shell. In response to the irritant, the oyster secretes a substance called nacre (also known as mother-of-pearl) around the irritant to protect its soft body. Over time, multiple layers of nacre are deposited around the irritant, forming a pearl.The process of pearl formation is complex and involves a series of biological and chemical reactions. When the irritant enters the oyster’s shell, the oyster’s mantle (a soft tissue…

  • mutation
    A level biology,  A level biology,  Biochemistry,  Biology,  Cell biology,  Genetics,  O level biology


    Mutation is a change in the DNA sequence of an organism’s genetic material. DNA, or deoxyribonucleic acid, is the molecule that carries the genetic instructions for the development and function of all living things. DNA is made up of four chemical bases, adenine (A), cytosine (C), guanine (G), and thymine (T), which are arranged in a specific sequence to form genes. Genes are the functional units of DNA that encode specific traits and are passed on from parent to offspring. In biology, mutations can occur naturally or as a result of exposure to certain environmental factors such as radiation or chemicals. Natural mutations can arise from errors during DNA replication…

  • chromosome
    A level biology,  A level biology,  Biochemistry,  Biology,  Cell biology,  Genetics,  O level biology


    A chromosome is a structure found in cells that is made up of a long strand of DNA, which is the genetic material that contains the instructions for the development and function of all living organisms. Chromosomes are found in the nucleus of eukaryotic cells and play a crucial role in the cell cycle, replication, and transmission of genetic information. Chromosomes are tightly coiled, compact structures that can be seen under a microscope during cell division. The DNA in chromosomes is organized into segments called genes, which contain the instructions for making proteins and other essential molecules for life. Proteins play a critical role in many cellular processes, such as…

  • A level biology,  Biology

    Defences Against Diseases

    The body has three main lines of defence against disease. These involve mechanical barriers, chemical barriers and cells. Mechanical barriers Although many bacteria live on the surface of the skin, the outer layer of the epidermis seems to act as a barrier that stops them getting into the body. But if the skin is cut or damaged, the bacteria may get into the deeper tissues and cause infection. Hairs in the nose help to filter out bacteria that are breathed in. However, if the air is breathed in through the mouth, this defence is by-passed. Chemical barriers The acid conditions in the stomach destroy most of the bacteria that may…