The DNA molecules are not always double stranded helical structures, sometimes they occur in single stranded form called ssDNA. In 1959 Robert Sinsheimer discovered a unique bacteriophage called φX 174 (which infect Escherichia coli) with single stranded DNA as its genetic material. Even though the chemical composition of single stranded and double stranded DNA are the same, they also show some characteristic differences. The present post describes the similarities and differences between dsDNA and ssDNA.s
Similarities between dsDNA and ssDNA
Ø Both dsDNA and ssDNA can acts as genetic material
Ø Both are polymers of nucleic acids
Ø The sugar molecule in both the case is deoxyribose
Ø Both contain purines and pyramidines
Ø Both ssDNA and dsDNA contain the nitrogen bases A, G, T and C
Similarities & Differences between DNA and RNA – A Comparison Table
We wish to suggest a structure for the salt of deoxyribose nucleic acid (DNA).
This structure has novel features which are of considerable biological interest. Watson & Crick, 1953
DNA and RNA are the two types of nucleic acids (a class of macromolecules in the cells) present in all prokaryotic and eukaryotic organisms. Both are essentially the polymers of nucleotides and have immense role in the storage and expression of genetic information in an organism. DNA and RNA allow the storage of genetic information for long period of time without any changes in the genetic constitution of the organism. The presence of two categories of nucleotides also allows the decoding of genetic information during protein synthesis by the process of transcription and translation. The current post describes the similarities and differences between DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Similarities between DNA and RNA
Ø Both DNA and RNA can acts as genetic material.
Ø Both are polymers of nucleotides.
Ø Both DNA and RNA are linear structures with secondary and super-secondary arrangements.
Ø Both contain purines and pyrimidines.
Ø Both DNA and RNA contain pentose sugar.
Ø In DNA and RNA the adjacent nucleotides are connected by 3’-5’ phosphodiester bonds.
Apoptosis vs Necrosis (Similarities and Differences)
Apoptosis and Necrosis are two types of cell death occur in organisms. The cells undergo death when the cell death becomes necessary as a part of developmental process or they fail to adapt to injuries. Both these types of cell deaths differ in their initial cause and progression of the cell death pathway.
Apoptosis definition (programmed cell death): a physiological process by which unwanted or useless cells are eliminated during the development and other normal biological processes. Often found during tissue homeostasis, embryogenesis, immunological reactions and development of nervous systems. During apoptotic cell death, the cells undergo some characteristic events such as chromatin condensation, nuclear and cytoplasmic aggregation and partitions of cytoplasm and nucleus into membrane bound vesicles called apoptotic bodies containing ribosomes and mitochondria. Apoptotic bodies are recognized and phagocytized by either by macrophages or adjacent cells and thus no inflammatory response are elicited during apoptotic cell death.
Necrosis definition: (accidental cell death) a pathological process occurs when the cells are exposed to serious physical or chemical insults. Occur during pathological infections such as bacterial and fungal infections, hypothermia and hypoxia conditions. The cell and cellular organelles swell and ruptures to release the entire cell content including lysosomal enzymes into the extracellular fluid. Due to this, necrotic cell deaths are always associated with severe inflammatory response in the surrounding tissues.
The current post describes the similarities and difference between apoptotic and necrotic cell death with a comparison table.
Sympathetic vs Parasympathetic Nervous Systems (Similarities and Differences between Sympathetic and Parasympathetic Nervous Systems)
The involuntary or reflex functions in the body are controlled by a part of peripheral nervous system called Autonomous Nervous System (ANS). ANS regulate the functions of internal organs (visceral functions) particularly the functions of heart, stomach and intestine. The Autonomic Nervous System composed of two components:
(1). Sympathetic Nervous System (SNS)
(2). Parasympathetic Nervous System (PNS or PSNS)
Sympathetic Nervous System (SNS): They are the part of ANS which originate from the spinal cord of the thoracic and lumbar region. They control the ‘fight-or-flight’ response or the ‘sympatho-adrenal response’ in the body. SNS prime the body for acting in threatening situations for survival. The sympathetic nervous system acts in the body as complementary to the action of Parasympathetic Nervous System.
Parasympathetic Nervous System (PNS or PSNS): Part of ANS originates from the spinal cord and medulla which control the ‘rest-and-digest’ or ‘feed-and-breed’ activities in the body. They act in the body as complementary to the action of SNS.
The present post describes the similarities and differences between Sympathetic Nervous System and Parasympathetic Nervous System
Similarities between Sympathetic and Parasympathetic Nervous System
Ø Both are the part of ANS.
Ø Both originate from the spinal cord.
Ø Both have huge influence on physiological process of the body such as respiration, circulation, digestion, urination and reproduction.
Ø Both have role in maintaining the homoeostasis of the body.
Ø Both composed of pre-ganglionic and post-ganglionic neurons.
Difference between Sympathetic and Parasympathetic Nervous System
Oligotrophic vs Eutrophic Lakes Similarities and Difference between Oligotrophic vs Eutrophic Lakes / Ponds
Lake Ecosystem is an example for a lentic ecosystem. An aquatic ecosystem with stationary or relatively still water is called lentic ecosystem. Based on the trophic state* and productivity, the lake ecosystem is divided into three categories.
(1). Oligotrophic lakes
(2). Eutrophic lakes
(3). Mesotrophic lakes
(1). Oligotrophic lake: a lake with low productivity, low nutrients and clear water with drinking water quality.
(2). Eutrophic lake: a lake with high productivity, high nutrients and with dark water. The water is usually not good for drinking purpose.
(3). Mesotrophic lake: a lake with intermediate nutrient level and productivity.
This post describes the similarities and differences between an Oligotrophic Lake Ecosystem and a Eutrophic Lake Ecosystem as a comparison table.
Similarities between Oligotrophic and Eutrophic Lakes / Ponds
Ø Both are aquatic ecosystems.
Ø Both are natural ecosystems.
Ø Both contain biological and abiological components.
Ø Water in both ecosystems is rich in oxygen.
Ø Both are lentic ecosystems.
Ø Both ecosystems show thermal stratification.
Difference between Oligotrophic and Eutrophic Lakes/Ponds