how many genes do human have?

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By nclexnursing

Genes are DNA segments that contain the instructions for making a specific protein that operates in one or more types of cells in the body. Chromosomes are cellular structures that house a person’s genes.

Chromosomes, which are establish in the cell nucleus, contain genes. Hundreds to thousands of genes are found on a single chromosome. Each normal human cell has 23 pairs of chromosomes, totaling 46 chromosomes. A trait is any attribute that is determined by a gene, and it is generally determined by multiple genes. Some features are caused by mutated genes that are passed down through the generations or that arise as a result of a new gene mutation.

Chromosomes, which are establish in the cell nucleus, contain genes. Hundreds to thousands of genes are found on a single chromosome. Each normal human cell has 23 pairs of chromosomes, totaling 46 chromosomes. A trait is any attribute that is determined by a gene, and it is generally determined by multiple genes. Some features are caused by mutated genes that are passed down through the generations or that arise as a result of a new gene mutation.

A person’s genotype (or genome) is their unique set of genes or genetic makeup. As finding, the genotype is an entire collection of instructions for how a person’s body synthesizes proteins and, as a result, how that person’s body should be created and function.

The phenotype is a person’s physical structure and function. The phenotype is how the genotype manifests in a person; not all of the genotype’s instructions may be followed (or expressed). The environment (including sicknesses and diet) and other factors, some of which are unknown, play a role in determining if and how a gene is expressed.

A karyotype is a representation of a person’s complete set of chromosomes in their cells.

Genes

Humans have somewhere between 20,000 and 23,000 genes.

DNA

Deoxyribonucleic acid (DNA) makes up genes (DNA). The coding, or blueprint, utilized to make a protein is found in DNA. The size of genes varies based on the size of the proteins they code for. Each DNA molecule is a lengthy double helix with millions of steps, similar to a spiral staircase. The stairwell’s steps are made up of pairs of four different sorts of molecules known as bases (nucleotides). The base adenine (A) is coupled with the base thymine (T) in each step, or the base guanine (G) is paired with the base cytosine (C) in each step (C). Inside one of the chromosomes, each incredibly long DNA molecule is coiled up.

DNA’s structure

DNA (deoxyribonucleic acid) is the genetic material of the cell, and it is base in chromosomes in the nucleus and mitochondria.

The cell nucleus, except for some cells (such as sperm and egg cells and red blood cells), includes 23 pairs of chromosomes. A chromosome carries a large number of genes. A gene is a piece of DNA that contains the instructions for making a protein.

The DNA molecule is a spiral staircase-like long, coiled double helix. Two strands of sugar (deoxyribose) and phosphate molecules are joined by pairs of four molecules known as bases, which comprise the staircase’s steps. Adenine is paired with thymine in the stages, and guanine is paired with cytosine. A hydrogen bond holds each pair of bases together. A gene is composed of a series of bases. Three-base sequences can represent an amino acid (amino acids are the building blocks of proteins) or other data.

Producing proteins

Proteins are made up of a long chain of amino acids that are joined together one by one. There are 20 distinct amino acids that can be utilized in protein synthesis, some of which must be obtained from food (essential amino acids) and others which are produced by body enzymes. When you put together a chain of amino acids, it folds in on itself to form a complicated three-dimensional structure. The folded structure’s function in the body is determined by its shape. Because the particular sequence of amino acids determines the folding, each sequence results in a different protein. Some proteins (for example, hemoglobin) have several folded chains.

Coding

The order in which the bases (A, T, G, and C) are placed in DNA encodes information. Triplets are used to write the code. In other words, the bases are grouped in threes. Specific three-base DNA sequences code for specific instructions, such as adding one amino acid to a chain. GCT (guanine, cytosine, thymine) denotes the addition of alanine, while GTT (guanine, thymine, thymine) denotes the addition of valine. As a result, the arrangement of triplet base pairs in the gene for that protein on the DNA molecule determines the amino acid sequence in that protein. The process of converting genetic information into a digital format.

Transcription and translation

The process by which information encoded in DNA is transferred (transcribed) to ribonucleic acid is known as transcription (RNA). The basic uracil (U) substitutes the base thymine (T) in RNA, making it a lengthy chain of bases similar to a strand of DNA (T). As a result, RNA, like DNA, includes triplet-coded information.

When transcription begins, a section of the double helix of DNA opens and unwinds. One of the unwound DNA strands serves as a template for the formation of a complementary strand of RNA. Messenger RNA is the complementary strand of RNA (mRNA). The mRNA splits from the DNA, leaves the nucleus, and moves into the cytoplasm (the part of the cell outside the nucleus) of the cell. The mRNA then connects to a ribosome, a small component in the cell that performs protein synthesis.

The mRNA coding (from DNA) instructs the ribosome on the order and type of amino acids to bind together during translation. A much smaller kind of RNA called transfer RNA transports the amino acids to the ribosome (tRNA). Each tRNA molecule contributes one amino acid to the developing protein chain, which is folded into a complex three-dimensional structure under the influence of neighboring molecules known as chaperone molecules.

Gene expression regulation

A person’s body contains several different types of cells, including heart cells, liver cells, and muscle cells. These cells differ in appearance and behavior, as well as the chemical molecules they generate. Every cell, on the other hand, is a descendent of a single fertilized egg cell and hence has essentially the same DNA. Because different genes are expressed in different cells, cells have extremely distinct looks and activities (and at different times in the same cell). DNA also contains information about when a gene should be expressed.The kind of tissue, the person’s age, the presence of certain chemical signals, and a variety of other factors and methods all influence gene expression. Although our understanding of the various variables and mechanisms that affect gene expression is quickly expanding, many of these factors and mechanisms remain unknown.

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The mechanisms through which genes regulate one another are extremely complex. Chemical markers on genes indicate where transcription should start and stop. Various chemical compounds in and around the DNA block (such as histones) allow transcription. In addition, an RNA strand known as antisense RNA can link with a complimentary strand of mRNA and prevent translation.

Replication

Cells divide in half to reproduce. The DNA molecules in the original cell must recreate (replicate) themselves during cell division because each new cell requires a complete set of DNA molecules. Replication works similarly to transcription, with the exception that the complete double-strand DNA molecule unwinds and splits in two. After splitting, the grounds on each strand bind to complementary bases floating nearby (A with T, and G with C). When this procedure is finished, two identical double-strand DNA molecules are produced.

Mutation

Cells feature a “proofreading” activity that helps guarantee that bases are linked correctly during replication. Chemical methods can also be used to repair DNA that hasn’t been replicated correctly. However, due to the billions of base pairs involved in the protein synthesis process and its intricacy, errors are possible. Such errors can happen for a variety of reasons (including radiation, medications, or viruses) or for no apparent reason. Minor variations in DNA are extremely prevalent and can be found in almost everyone. The majority of genetic variants have no effect on successive copies of the gene. Mutations are errors that are reproduced in successive copies.