• Genetics,  Q & A

    Q & A ON CELL CYCLE AND CELL DIVISION

    Q 1. Define cell cycle Ans. The sequence of events by which cell duplicates its genome, synthesis of other constituents of the cell and eventually divides into two daughters cell. Q2. Name the phases of cell cycle Ans. A) Interphase B) M Phase Q3. What is the G1phase of the interphase? Ans. The G1 phase Corresponds to interval between mitosis & initiation of DNA replication. Q4. Which phase follows the S phase in the cell cycle? Ans. G2 Phase Q5. What is mitosis? Ans. Cell divides equally to produce identical daughter cell so that they receive an equal number of chromosomes as that of its parents cell.  Q6. What is meiosis? Ans. It…

  • Q & A

    Q & A ON REPRODUCTION IN ORGANISMS

    Q1. What is life span? Ans: Life span is the period from birth to natural death of an organism. Q2. Define clone. Ans: The individuals that are morphologically and genetically similar to the parent are called clone. Q3. Mention the different means/ methods of asexual reproduction with example. Ans:  Cell division – Protista, Monera Binary fission – Amoeba, Paramecium Budding – Yeast Zoospores (microscopic motile endogenous spores) – aquatic fungi, chlamydomonas Conidia (microscopic immotile exogenous spores)- pencillium External buds – hydra Internal buds like gemmules – sponges (spongilla) Q4.Unicellular organisms are immortal. Justify. Ans: Single celled organisms like amoeba & bacteria reproduce by cell division and there is no natural…

  • Biochemistry

    Meiosis

    Meiosis is the type of cell division by which gametes (eggs or sperm) are formed. It involves two divisions and results in four different daughter cells that have 23 chromosomes. This ensures that, when an egg and a sperm unite during fertilization, the resulting embryo will have 46 chromosomes – the normal number for a human. The first meiotic division is called Meiosis I, and the second meiotic division is called Meiosis II. Meiosis I Meiosis one is identical to the stages of mitosis. The only difference is that each stage ends with an “I” to identify it is occurring during Meiosis I. please click here for mitosis Meiosis II…

  • Biology,  Genetics

    Mitosis

    Mitosis is a type of cell division by which a eukaryotic cell divides into two by a special method. In this process, the nucleus and chromosome are divided once and the number, structure and properties of the chromosome in the newly formed cell remain just like the mother. cell. Mitosis is also termed as equational division. Normally this division occurs in the somatic cell. As a result of this division, the plant and animal increases in length and breadth. Mitosis occurs in all meristematic cells of plants. Pre-Mitosis (Interphase): The chromosomes are duplicated just before mitosis, so there are two identical (‘sister’) copies of each one. This gives a total of…

  • Biology,  Cell biology,  Genetics

    CELL DIVISION

    Every living body is composed of the cell. Some living bodies are made of only one cell. They are called unicellular organism, e.g. Bacteria, Amoeba, Plasmodium, some Fungi and some Algae. Some living bodies are made of more than one cell. These are called the multicellular organism. There are many living bodies, which are made of millions of cells. Living bodies like a human. beings or mango tree etc. are composed of millions of cells. Unicellular organisms increase their number (multiple) by cell division. In this process, one cell divides into two, two to four and so on. In multicellular organisms, a large body consisting of millions of cells develops…