<h2> What are proteins made of?</h2><h3>Proteins are made up of smaller building blocks called amino acids, joined together in chains. There are 20 different amino acids. Some proteins are just a few amino acids long, while others are made up of several thousands. These chains of amino acids fold up in complex ways, giving each protein a unique 3D shape. Some, like keratin, the hair protein, form long fibres. Others, like haemoglobin, the protein that carries oxygen around your body, are roughly spherical.</h3>
Meiosis is a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells. This process is required to produce egg and sperm cells for sexual reproduction. During reproduction, when the sperm and egg unit to form single cell for sexual reproduction. During reproduction, when the sperm and egg unit to form a single cell, the number of chromosome is restored in the offspring.
Meiosis begins with a parent cell that is diploid, meaning it has two copies of each chromosome. The parent cell undergoes one round of DNA replication followed by two separate cycles of nuclear division. The process results in four daughter cells that are haploid, which means they contain half the number of chromosomes of the diploid parent cell.
Essential amino acids cannot be made by the body. As a result, they must come from food. The 9 essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Galaxy is a collection of stars, gas, and dust bound together by gravity. The smallest galaxies may contain only a few hundred thousand stars, while the largest galaxies have thousands of billions of stars.
