by extramarks - Academics - September 2, 2021September 2, 2021 Molecular Basis of Inheritance: Definition and its Types The word inheritance refers to the passing on from one generation to another. The process of heredity is an important part of biology, and it involves the molecular basis that determines how traits are passed on from parents to children. So, when you learn more about the molecular basis of inheritance, you will also get to know its different types. The molecular basis of inheritance can be divided into two types: Mendelian inheritance and non-Mendelian inheritance. In this molecular basis of inheritance class, you will learn everything about it. DNA: The Biological Basis of Inheritance The DNA molecule is the biological basis for inheritance. It carries all molecular basis of genetic information in an organism and is passed from one generation to another by sexual reproduction, e.g., through gametes such as sperm or eggs. The four bases that make up DNA are adenine (A), thymine (T), guanine (G), and cytosine (C). DNA Structure The two strands of DNA are held together by hydrogen bonds between the bases. Each strand is a code for one set of instructions-which can be thought of as an instruction manual. The order in which these letters appear on the base pairs creates a sequence, or string of letters, known as a sequence of nucleotides. DNA Packaging The DNA molecule is two long strands that are twisted into the shape of a double helix and held together by hydrogen bonds between base pairs. These bases bind to each other in specific sequences on one strand with an opposing base on the second strand so they can create this coded instruction manual or sequence of nucleotides. Every molecular basis of inheritance class will tell you about the DNA packaging as it is one of the important fragment of DNA structuring. In this way, DNA carries the instructions for how to build an organism and is passed from one generation to another through sexual reproduction-e.g., via gametes such as sperm or eggs. RNA: The Messenger of Genetic Information After the DNA is created, it needs to be translated into proteins. This process begins with transcription-the first step in translating information from one form to another. In this case, RNA is transcribed from DNA and then used as a template for creating new protein molecules called enzymes that are essential for all living organisms. The RNA molecule is made up of a sequence of nucleotides identical to the DNAs. Process of DNA Replication DNA replication is the process by which DNA makes copies of itself. It occurs during cell division and consists of two main steps: base pairing to form a new strand and RNA transcription from the complementary strand to produce mRNA. The first step in this process is referred to as DNA synthesis or semiconservative replication because it involves both strands being copied to form two identical copies. The process begins with the separation of one DNA molecule into two single strands by breaking apart its hydrogen bonds between nucleic acids, a breakage that allows both molecules to be copied at once. Then, each strand is passed on to an enzyme called the DNA polymerase for replication; this enzyme will not start working until the previous strand is completely copied. However, as it does so, this enzyme creates a new complementary DNA strand to the original molecule that was just replicated. DNA replication can be broken down into two steps: Base pairing RNA transcription The first step in the process is referred to as DNA synthesis or semiconservative replication because both strands are replicated, forming two identical copies. The second step of this process involves RNA transcription from one strand and copying it on a complementary strand-a process that creates mRNA. This type of reproduction does not have to be semiconservative because it does not usually involve the copying of both strands. Genetic Code: The Sequence of Nucleotides The genetic code is the sequence of nucleotides that define a gene or protein. These sequences are what makeup DNA and RNA molecules. A gene will be turned on, meaning it can produce proteins when its corresponding sequence appears by chance in the cell’s nucleus-which then triggers the production of specific enzymes to carry out specific functions in the organism. The genetic code is a series of nucleotides that are able to be translated into proteins through transcription. DNA molecules have two strands, and each strand carries one set of instructions-a sequence of letters known as a sequence of nucleotides or “genetic code.” The order that these base pairs appear to create a sequence, or “genetic code,” which then produces proteins through transcription. Types of Gene Expression Gene expression is the process through which a cell turns on or starts to produce protein for an enzyme. This can be done by messenger RNA (mRNA) that has been transcribed from DNA and carries instructions about how to create specific enzymes and proteins themselves. There are two types of gene expression: Cooperative Non-cooperativeCooperative gene expression is when two genes are linked to each other, and they both need to be turned on for one of them to start producing a protein. Non-cooperative gene expression is when only one gene needs to be activated in order for the cell’s machinery to produce a specific enzyme that can catalyze reactions. Frequently asked questions (FAQ’s) What is the sequence of DNA? DNA replication is a process that occurs during cell division and involves two step-base pairings to form a new strand and RNA transcription from the complementary strand. The first step in this process is referred to as DNA synthesis or semiconservative replication because it involves both strands being copied to form two identical copies. What is the significance of a codon? The genetic code comprises DNA and RNA molecules, which can be translated into proteins through transcription. It is the molecular basis of inheritance that tells us about genetic inheritance. This type of reproduction does not have to be semiconservative because it doesn’t usually involve the copying of both strands. The sequence that these base pairs appear to create this “genetic code,” which then produces proteins through transcription. How does DNA encode information? The genetic code is a series of nucleotides that can be translated into proteins through transcription-DNA molecules with two strands. Each strand carries one set of instructions known as the sequence of nucleotides or “genetic code.” The order these base pairs appear to create a sequence, or “genetic code,” which then produces proteins through transcription. Download our NEET Prep App to learn more topics like this for NEET Exam Preparation. Also, learn some important Science facts that would help to improve your knowledge.