Category: Science

What is a Genome?

Genome: The genome is the entire collection of genes and all other functional and non-functional DNA sequences in an organism in a haploid set of chromosomes. It includes genes, regulatory genes and nonfunctional nucleotide sequences. Therefore, the genome comprises of- The structural genes are DNA segments that code for some specific RNAs or proteins. They encode …

Biological Significance of Watson and Crick’s Double Helical Model of DNA

Biological Significance of Watson and Crick’s Double Helical Model of DNA: The biological significance of Watson and Crick’s double helical model of DNA is as follows: (1) Information Storage- Genetic material is expected to act as a repository of information. Its structure must be related to the intimate features of the gene product, i.e. the protein. …

Functions of Blood Plasma

Functions of Blood Plasma: (1) Transport of food- Plasma transports digested food to different organs and tissues of the body. (2) Removal of Excretory Substances- Waste substances from the tissues is removed and carried by plasma to the kidneys for elimination. (3) Disposal of CO2– Major portion of CO2 from the tissues is removed by plasma, …

Effect of Physical Environment on the Community

Effect of Physical Environment on the Community: A community needs non-living or abiotic components which are obtained from the physical environment. The physical environment includes soil, mineral nutrients, rainfall, humidity, sunlight and temperature. There are different environments in different regions of the earth. Therefore, animal and plant communities also differ from region to region. In any …

Microtubules and their Functions

Microtubules and their Functions: What are Microtubules? Microtubules are elongated unbranched cylindrical tubules of protein, tubulin. They are found in all eukaryotic cells occurring freely in the cytoplasm or forming a part of cilia and flagella. They have indefinite length, but their diameter is about 25μ. Each microtubule contains a light central core consisting of protein-tubulin …

Microfilaments

What are Microfilaments? These are thin, narrow, long cylindrical filaments which occur beneath the plasma membrane in eukaryotic plant and animal cells. They are about 5-10 nm in thickness and show a beaded appearance. They are composed of contractile proteins like actin and myosin and are responsible for forming the contractile machinery of a cell like …

Vacuoles Types and Functions

Vacuoles Types and Functions: What are the Vacuoles? Vacuoles are the non-cytoplasmic areas filled with watery fluid (cell sap) present in the cytoplasm. They remain separated from the cytoplasm by a unit membrane called tonoplast in plant cells whereas, in animal cells, they are bounded by a lipoproteinaceous membrane. In plant cells, they are bigger in …

Ultra Structure of Eukaryotic Nucleus

Ultra Structure of Eukaryotic Nucleus: The eukaryotic nucleus consists of a nuclear envelope, nuclear sap (karyoplasm), chromatin and nucleolus. (1) Nuclear Envelope- The nucleus is separated from the cytoplasm by a nuclear envelope. It is a double membrane structure consisting of proteins and lipids with an outer and inner membrane. The space between two membranes is …

Advantages of Multicellularity to an Organism

Advantages of Multicellularity to an Organism: The following are the advantages of multicellularity to an Organism- The multicellularity to an organism results in producing division of labour amongst its cells. These cells become specialized to perform different functions in a coordinated manner. Each cell of a multicellular organism performs a specific function and avoids the duplication …

Structure of Plant Cell Wall

Structure of Plant Cell Wall: A cell wall is a thick and rigid protective envelope outside the plasma membrane in the cells of plants, bacteria, fungi and algae. It is absent in animal cells. The thickness and composition of the cell wall vary. In bacteria and some fungi, the cell wall is composed of proteins and …