Table of Contents
What is the process when a sperm cell unites with an egg cell to form a zygote?
Fertilization occurs when the nucleus of both a sperm and an egg fuse to form a diploid cell, known as zygote. The successful fusion of gametes forms a new organism.
What are the different factors causing mutations in the DNA of living cells?
Mutations arise spontaneously at low frequency owing to the chemical instability of purine and pyrimidine bases and to errors during DNA replication. Natural exposure of an organism to certain environmental factors, such as ultraviolet light and chemical carcinogens (e.g., aflatoxin B1), also can cause mutations.
What is the importance of cell theory for scientists?
Cell theory – This is crucial for us understanding biology because cells form the basis of all life. We can have unicellular organisms, like bacteria, like yeasts. [And] cell division, the division of a cell from one, to two, to four, forms the basis of growth and development of all living things.
What is the process where in egg cell and sperm cell unite?
When a sperm enters an egg cell, they unite and their chromosomes mingle together. This is called conception or fertilization.
What is the importance of fertilization in humans?
Fertilization has the following significance: 1. Fertilization restores the diploid number of chromosomes, i.e. 46 in human being. 2. It provides stimulus for the ovum to complete its maturation.
Do mutations in body cells contribute to genetic variation?
If a mutation occurs in cells that will make gametes by meiosis or during meiosis itself, it can be passed on to offspring and contribute to genetic variability of the population. Mutations are the sole source of genetic variability that can occur in asexual reproduction.
Why are cubic unit cells important in chemistry?
These unit cells are important for two reasons. First, a number of metals, ionic solids, and intermetallic compounds crystallize in cubic unit cells. Second, it is relatively easy to do calculations with these unit cells because the cell-edge lengths are all the same and the cell angles are all 90.
Why is mitosis important in the reproduction process?
Reducing the number of chromosomes by half is important for sexual reproduction and provides for genetic diversity. Mitosis is how somatic — or non-reproductive cells — divide. Somatic cells make up most of your body’s tissues and organs, including skin, muscles, lungs, gut, and hair cells.
How are the corners of a unit cell defined?
Each corner of the unit cell is defined by a lattice point at which an atom, ion, or molecule can be found in the crystal. By convention, the edge of a unit cell always connects equivalent points. Each of the eight corners of the unit cell therefore must contain an identical particle.
Where does a cell spend most of its time during mitosis?
The Mitosis Cell Cycle. Before a cell starts dividing, it is in the “Interphase.”. It seems that cells must be constantly dividing (remember there are 2 trillion cell divisions in your body every day), but each cell actually spends most of its time in the interphase.