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☆☆☆☆☆As we learn more about genetics, this begins to look like an overly simplistic view of the concept of gene. The exact definition of the term gene is in debate at the moment, as is the use of the term at all in the future. The discovery of very short RNA's (miRNA, siRNA's) which influence gene expression (without translation into peptides) are part of this debate.
Definitions
A gene is a unit of heredity in a living organism. It is normally a stretch of DNA that codes
for a type of protein or for an RNA chain that has a function in the organism. All proteins and functional RNA chains are specified by genes. All living things depend on genes. Genes hold the information to build and maintain an organism's cells and pass genetic traits to offspring. A gene is a unit of in a living organism. It is normally a stretch of DNA that codes for a type of protein or for an RNA chain that has a function in the organism.
Genes hold the information to build and maintain an organism's cells and pass genetic traits to offspring. A gene is a part of a DNA molecule that codes for a particular trait of an organism. It provides instructions on how to make a polypeptide. For example, one gene may code for the production of tyrosinase, which is an enzyme (protein) used in the synthesis of melanin (a pigment responsible for dark colors in skin and fur).
By the traditional definition, a gene is 'transcribed' into mRNA which is then 'translated' into a protein, which will produce the desired effect in an organism's cell. Some genes may contain instructions for the production of RNA that is not translated into a protein, such as tRNA, rRNA, miRNA and siRNA.
Conclusion
In essence, a gene is a section of a DNA molecule that has a unique and specific biological function.
A chromosome is a threadlike strand of DNA in the cell nucleus that carries the genes in a linear order. It is also known as tightly wound DNA. It is a structure that DNA wraps around.
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A chromosome is an organized structure of DNA and protein that is found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.
Chromosomes vary widely between different organisms. The DNA molecule may be circular or linear, and can be composed of 10,000 to 1,000,000,000 nucleotides in a long chain.
Cells may contain more than one type of chromosome; for example, mitochondria in most eukaryotes and chloroplasts in plants have their own small chromosomes.
Chromosomes are the essential unit for cellular division and must be replicated, divided, and passed successfully to their daughter cells so as to ensure the genetic diversity and survival of their progeny.
Chromosomal recombination plays a vital role in genetic diversity. If these structures are manipulated incorrectly, through processes known as chromosomal instability and translocation, the cell may undergo mitotic catastrophe and die, or it may aberrantly evade apoptosis leading to the progression of cancer.
In practice "chromosome" is a rather loosely defined term. In prokaryotes and viruses, the term genophore is more appropriate when no chromatin is present. However, a large body of work uses the term chromosome regardless of chromatin content. The simplest genophores are found in viruses: these DNA or RNA molecules are short linear or circular genophores that often lack structural proteins.
Chromosomal DNA encodes most or all of an organism's genetic information; some species also contain plasmids or other extrachromosomal genetic elements.
Structure in nucleus made of DNA and protein. Sections of a chromosomes are genes.
structure in a cell's nucleuse thaat contians genetic material
A chromeosome is organized structure of DNA and protein that is found in cells.
coiled strands of genetic material
coiled strands of genetic material
a form of a gene apex
DNA doubles and produces sister chromatids before meiosis begins.
the chromosomes must replicate
Using the Polymerase Chain Reaction, scientists can amplify even the smallest amount of DNA, by constant cycles of separation and replication.
They pull the cell membrane in.
They Split The Cell During Cytokinesis.
Anaphase
An example of science fiction is Isaac Asimov's books about robots. He invented the Three Laws of Robotics to explain how robots would be programmed.
A trait with four alleles
If crossing over didn't happen during meiosis in humans, the haploid daughter cells would all have the same genes. The crossing over creates variation and causes each daughter cell to have slightly different genes.
Iceberg concept of viral infection best describes how common cold spreads in the human body.
mitosis only has to do with celluar reproduction
meiosis has to do with sex cells reproducing
Mitosis creates new cells that are used for development, repair, asexual reproduction and growth. Meiosis creates cells in order for organisms to reproduce sexually.
the likelihood that something will happen
