How do genes determine the traits of an organism?

The genes, which are part of DNA, contain the genetic information inherited from the parents determine the traits of an organism.

The ‘complete set of all the genes and the DNA’ is called the genome which stores the entire set of information of how an organism is structured and maintained.

The pattern of dominant and/or recessive traits and the genetic variations are determined by the allelles.  

Explanation:

The genetic codes in the genes represent the particular amino acid codes and their linkages specific to particular protein.  The amino acids link together to form long polypeptide chains of protein molecules.  

These proteins determine various traits through various roles like:

Messenger proteins: Hormones like insulin, estrogen etc., control and coordinate various functions of the body

Pigments: Like melanin determines the color of the hair, skin, eyes.

Structural protein: Like keratin gives structure of hair, nails; myosin determines muscle structure

Antibodies: Determine the immunity of a person

Ion channel proteins, messenger proteins, structural proteins, receptor proteins etc.: Determine various physiological traits.

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.