Molecular basis of inheritance

The sequence of bases in DNA determines the genetic information of an organism.

Transcription

<p>Translation</p> Signup and view all the answers

<p>DNA polymerase</p> Signup and view all the answers

<p>Origin of replication</p> Signup and view all the answers

<p>mRNA, tRNA, and rRNA.</p> Signup and view all the answers

<p>Introns</p> Signup and view all the answers

<p>Splicing</p> Signup and view all the answers

<p>Translation</p> Signup and view all the answers

<p>Ribosome</p> Signup and view all the answers

<p>Gene regulation</p> Signup and view all the answers

<p>Lac operon</p> Signup and view all the answers

<p>The three structural genes in the lac operon are z, y, and a.</p> Signup and view all the answers

<p>Lac repressor</p> Signup and view all the answers

<p>Lactose</p> Signup and view all the answers

<p>DNA fingerprinting</p> Signup and view all the answers

<p>Microsatellites</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Human Genome Project (HGP)</p> Signup and view all the answers

<p>20,000-25,000 genes</p> Signup and view all the answers

<p>3 billion base pairs</p> Signup and view all the answers

<p>Bioinformatics</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Single nucleotide polymorphisms (SNPs) are variations in a single nucleotide at a specific location in the genome. They are widespread in the human genome and play a significant role in individual differences, disease susceptibility, and population genetics studies.</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Semiconservative replication</p> Signup and view all the answers

<p>Translation</p> Signup and view all the answers

<p>Gene</p> Signup and view all the answers

<p>Transcription</p> Signup and view all the answers

<p>Promoter</p> Signup and view all the answers

<p>Terminator</p> Signup and view all the answers

<p>Transfer RNA (tRNA)</p> Signup and view all the answers

<p>Ribosomal RNA (rRNA)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>RNA world hypothesis</p> Signup and view all the answers

<p>Operon</p> Signup and view all the answers

<p>Polymorphism in human genetics refers to the existence of multiple variations or alleles of a gene within a population. These variations often occur in non-coding regions of DNA and are usually harmless.</p> Signup and view all the answers

<p>DNA fingerprinting is a technique that uses differences in the length of repetitive DNA sequences, called variable number tandem repeats (VNTRs), to identify individuals.</p> Signup and view all the answers

<p>Bioinformatics is an interdisciplinary field that combines biology, computer science, and statistics to analyze and interpret biological data, particularly genetic data. It involves developing and applying computational tools and algorithms to manage, analyze, and interpret complex biological data sets.</p> Signup and view all the answers

Deoxyribonucleic acid (DNA) is a long polymer of deoxyribonucleotides that stores genetic information in most living organisms.

The length of a DNA molecule is often measured by the number of nucleotides or base pairs it contains.

A nucleotide is composed of three parts: a nitrogenous base, a pentose sugar (either ribose or deoxyribose), and a phosphate group.

Adenine (A), Guanine (G), Cytosine (C), and Thymine (T) are the four nitrogenous bases found in DNA. Adenine and Guanine are purines, while Cytosine and Thymine are pyrimidines.

A nucleoside is formed when a nitrogenous base links to the OH group of the 1' carbon of a pentose sugar via a N-glycosidic linkage.

A nucleotide is formed when a phosphate group is linked to the OH group of the 5' carbon of a nucleoside through a phosphoester linkage.

Two nucleotides are joined through a 3'-5' phosphodiester linkage to create a dinucleotide. Many nucleotides can be linked together to form a polynucleotide chain.

The backbone of a polynucleotide chain is formed by the alternating sugar and phosphate groups. The nitrogenous bases project outwards from the backbone.

In DNA, the two polynucleotide chains are antiparallel, meaning they run in opposite directions (5' to 3' and 3' to 5').

The two strands of DNA are held together by hydrogen bonds between the nitrogenous bases. Adenine pairs with Thymine (A-T) and Guanine pairs with Cytosine (G-C).

The double helix structure of DNA provides stability. The bases stack on top of each other, and the hydrogen bonds between the bases contribute to the overall structure.

The process by which DNA makes a copy of itself is called replication. This ensures that each new cell receives a complete set of genetic information.

During replication, the two strands of DNA separate, and each strand serves as a template for the synthesis of a new complementary strand. This results in two identical DNA molecules, each with one old and one new strand.

DNA polymerase is the primary enzyme involved in DNA replication. It uses a DNA template to catalyse the polymerisation of deoxyribonucleotides.

The replication process takes place within a small opening of the DNA helix called the replication fork. This is where the two strands are separated and new strands are synthesized.

On one strand of DNA, replication is continuous, while on the other strand, it is discontinuous. This is because DNA polymerase can only add nucleotides in the 5' to 3' direction.

The process of copying genetic information from a DNA strand into RNA is called transcription. It is also guided by the principles of complementarity, but uracil (U) replaces thymine (T) in RNA.

Only a segment of DNA is copied during transcription, and only one of the strands is used as a template. This is because both strands acting as templates would lead to two different RNA molecules, which would cause complications.

A transcription unit in DNA is defined by three regions: the promoter, the structural gene, and the terminator. The promoter is the binding site for RNA polymerase, the structural gene contains the coding sequence, and the terminator signals the end of transcription.

The template strand in a transcription unit is the one with the polarity 3' to 5', which is read by RNA polymerase in the 5' to 3' direction. The coding strand has the same sequence as the transcribed RNA (except for thymine being replaced by uracil).

RNA polymerase is the enzyme that catalyses transcription. It binds to the promoter, unwinds the DNA, and adds nucleotides to the growing RNA chain following the rules of complementarity.

The three main types of RNA are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). Each type plays a crucial role in protein synthesis.

Translation is the process of converting the genetic code from mRNA into a polypeptide chain. This involves decoding the mRNA sequence to determine the order of amino acids in the protein.

Ribosomes are the cellular machines responsible for protein synthesis. They bind to mRNA and provide binding sites for tRNAs, which carry amino acids that assemble into a polypeptide chain.

tRNA molecules act as adapters during translation. They have an anticodon loop that binds to a specific codon on mRNA and an amino acid acceptor end that carries the corresponding amino acid.

Gene regulation refers to the process of controlling the expression of genes. This allows cells to express the genes needed for specific functions and to adapt to changing environments.

The Lac operon is a classic example of gene regulation in bacteria. This operon contains genes involved in lactose metabolism, and its expression is controlled by the presence or absence of lactose in the environment.