Genetics Definition

What Is Genetics?

Genetics is the branch of biology that deals with the inheritance of traits and characteristics from the parents to their offspring. It can be defined as a study which focuses on genes, which are the units of heredity. Genes can carry information about things like eye colour, height, and even certain behaviours. The ability to understand living organisms in terms of how they inherit their traits and how individuals become unique can be achieved through studying genetics.

History of Genetics

This history of genetics can be traced back to the 19th century by an Austrian monk Gregor Mendel who is rightly known as the "Father of Genetics." He observed how certain traits were being passed on from generation to generation after conducting experiments on pea plants. His work laid the foundation for modern genetics, to study DNA, genetic disorders, and even genetic engineering. Mendel's findings revealed that heredity is a deterministic process, hence establishing an example for scientists to predict the patterns that could be followed in acquiring specific traits.

Central Concepts of Genetics

The central concept of genetics is that:

• Genes determine the transmission of traits from generation to generation.

• Genes are located on what are called chromosomes.

• Half of the genes come from one parent and half from the other.

• These genes in combination create a determinate of a person's phenotype, from basic body structure to practical abilities or even health.

Basic Concepts in Genetics

The basic concepts used in genetics are:

Genes and Chromosomes

• Genes are segments of the chromosomes that contain sequences responsible for a particular characteristic in an organism.

• Chromosomes are filamentous bodies present in the nucleus of the cells associated with the transmission of hereditary characteristics.

• This is a molecule that carries the codes which determine the characteristics of an individual, it is known as deoxyribonucleic acid or DNA for short.

• DNA has a double helix structure

• It includes nucleotide bases adenine (A), thymine (T), cytosine (C), and guanine (G) in the middle part.

Genetic Code

• The genetic code is a set of rules that determine how DNA makes up proteins.

• Three consecutive nucleotides in the mRNA is called a codon which represents a particular amino acid or allows the process of translation to stop.

• It means transcription (formation of mRNA from DNA) forms the basis of cell activities and translation (building of proteins from mRNA) helps in deciding the characteristics of an individual.

Mutation and Variation

• Mutations are the changes within genes.

• It leads to variation in traits

• They can be beneficial, harmful, or neutral.

• Sometimes mutations are carried into the development stage to cause genetic disease.

Importance of Genetics

Importance of genetics:

• Helps understand inheritance patterns

• Explains genetic diseases

• Basis of genetic engineering and biotechnology

• Useful in agriculture, medicine, and evolution studies

• Enables prediction of traits in offspring

Genetics NEET MCQs (With Answers & Explanations)

Important questions asked in NEET from this topic are:

• History of genetics

• Basic concepts in genetics

Practice Questions for NEET

Q1. Alleles are:

1. different molecular forms of a gene

2. heterozygotes

3. different phenotype

4. true breeding homozygotes

Correct Answer: 1) different molecular form of gene

Explanation:

Alleles are different gene variants or molecular forms that occur at the same location (locus) on a chromosome and are caused by mutations. Different characteristics or variances in an organism can be caused by alleles.

People who have two distinct alleles at a specific gene locus (such as Aa) are known as heterozygotes.
Various phenotypes Although alleles are not distinct phenotypes, phenotypes are the observable qualities or characteristics of an organism that arise from the expression of alleles.
Although this is not the definition of alleles, true-breeding homozygotes are organisms that have two identical alleles for a particular attribute (AA or aa, for example).

Hence, the correct answer is option 1)different molecular forms of a gene.

Q2. What is a phenotype?

1. The genetic makeup of an individual

2. The physical characteristics of an individual

3. The reproductive cells of an individual

4. The expression of a single gene

Correct Answer: 1) different molecular form of gene

Explanation:

A phenotype is the observable physical and biochemical traits of an individual, such as height, hair color, and blood type. It is the result of the interaction between an individual's genetic makeup (genotype) and the environment. The phenotype can also include behavioral characteristics and susceptibility to certain diseases. The genotype refers to the genetic makeup of an individual, including all of the individual's genes and genetic variants. The reproductive cells of an individual are called gametes, and the expression of a single gene is just one part of the complex process that leads to the development of a phenotype.

Hence the correct answer is option 2, The physical characteristics of an individual.

Q3 What is a gene?

1. A unit of heredity that is passed from parent to offspring

2. A type of protein that regulates gene expression

3. A section of DNA that codes for a specific protein

4. A type of RNA that carries genetic information

Correct Answer: 3) A section of DNA that codes for a specific protein

Explanation:

A gene is a specific sequence of DNA that encodes the information required to make a functional protein or RNA molecule. This sequence of DNA contains the instructions for the sequence of amino acids that make up the protein, as well as the regulatory sequences that control when and where the gene is expressed. These proteins perform various functions in the body, such as enzymes that catalyze chemical reactions, structural proteins that form the framework of cells, and signalling proteins that regulate cellular communication. Mutations in genes can lead to changes in protein function, which can result in genetic disorders or diseases. In summary, a gene is a fundamental unit of heredity that carries the genetic information necessary to produce a functional protein or RNA molecule.

Hence, the correct answer is option 3) A section of DNA that codes for a specific protein.

Also Read:

• MCQs on Mendelian Genetics

• Mendel’s Laws of Inheritance

• Complementary Genes

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