Molecular Basis of Inheritance - Class 12 Revision

Molecular Basis

Fundamental molecular mechanisms of genetic inheritance.

Inheritance

Transmission of genetic information across generations.

DNA

Deoxyribonucleic acid, carrier of genetic information.

Gene

Segment of DNA coding for a trait.

Chromosome

Structure containing DNA and associated proteins.

Allele

Different forms of a gene at a locus.

Genotype

Genetic constitution of an organism.

Phenotype

Observable characteristics resulting from genotype.

Homozygous

Having two identical alleles for a trait.

Heterozygous

Having two different alleles for a trait.

Dominant allele

Allele that expresses its trait in phenotype.

Recessive allele

Allele that expresses its trait only in homozygotes.

Punnett Square

Diagram predicting genetic variation in offspring.

Mendelian inheritance

Patterns of inheritance established by Gregor Mendel.

DNA replication

Process of copying DNA before cell division.

Transcription

Synthesis of RNA from a DNA template.

Translation

Synthesis of proteins from RNA.

Mutation

Change in DNA sequence affecting genetic information.

Chromatid

One of two identical halves of a duplicated chromosome.

Centromere

Region where two sister chromatids are joined.

Karyotype

Number and appearance of chromosomes in a cell.

Genetic variation

Diversity in gene frequencies within a population.

Sex-linked traits

Traits associated with genes on sex chromosomes.

Polygenic inheritance

Trait controlled by multiple genes.

Epigenetics

Study of heritable changes not involving DNA sequence.

Nucleotide

Basic building block of DNA and RNA.

RNA

Ribonucleic acid, involved in protein synthesis.

Transposons

DNA sequences that can change positions within the genome.

Genetic drift

Random changes in allele frequencies in small populations.

Natural selection

Process where organisms better adapted survive and reproduce.

Gene flow

Transfer of genetic material between populations.

Chromosomal aberration

Structural changes in chromosomes affecting genetic information.

Genetic engineering

Manipulation of an organism's DNA using biotechnology.

Cloning

Creating a genetically identical copy of an organism.

Biotechnology

Use of biological processes for industrial and other applications.

CRISPR

Gene-editing technology using targeted DNA modification.

Genetic counseling

Guidance for individuals regarding genetic disorders.