General Q&A for Class 12 · Page 31
5,215 free answers in General for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
what is species in biology class 11
Living world is organised and categorised by various systems. Carolous Linnaeus divided all organisms into large groups called kingdoms. Kingdoms were further classified and subdivided. The criteria of such classification was variety of factors like similarity in structure, function etc. Later systems included evolutionary relationships to establish categories. The idea was that features might be lost, gained or modified according to time. Towards this the categories were arranged in a hierar
- GeneralClass 12All
what is protoplasm in biology
The concept of protoplasm is old and dates to a time when little was known about the cell. The cell was known to have a boundary- the plasma membrane. The inside of the membrane is known as the protoplasm. Later on the nucleus was identified and the protoplasm was said to be divided into the cytoplasm, the region outside the nucleus, and the nucleoplasm, the region inside the nucleus. The protoplasm is the seat of metabolic reactions. There are several enzymes which catalyse reactions like th
- GeneralClass 12All
what is oxidation in biology
Oxidation is the loss of electrons, addition of oxygen, or loss of hydrogen. This process also happens in biological systems. This process yields energy that is used to drive metabolic reactions. When light hits the assembly of chlorophyll molecules we call as photosystems, we call it photoxidation, as the energy is used to kick out electrons (oxidation), with high energy. These high energy electrons are used to reduce NADP+ to NADPH (reduction). In the dark reaction NADPH is oxidised to make
- GeneralClass 12All
What is variation in biology class 10
Variation in a different form or combination of characteristic that is found in our population. We refer to these variants as trait. Variations can arise due to various reasons Copying fo DNA is done by enzyme DNA polymerase. Being a biochemical reaction, it cannot have 100 accuracy. The errors when made are attempted by the enzyme’s exonuclease activity but even then several discrepancies seep in Variation could result from the transfer of DNA between organisms
- GeneralClass 12All
what is nomenclature in biology class 11
Nomenclature means a system of identifying and naming organisms. While there have been old systems which used common usage or property to name organisms scientifically this process dates back to Carolus Linnaues who gave the Binomial nomenclature. Binomial nomenclature is the system that assigns a 2 part name to each organism. The first part represents the name of the Genus and the second part stands for the species. Genus must be capitalized where as species name must be not. When written th
- GeneralClass 12All
What is systematics in biology class 11
Systematics is a branch of biology that deals with the classification of organisms by understanding evolutionary relationships. Classification systems scientifically started with Carolus linnaeus when he gave is two kingdom classification system using the external characteristics. Eventually, more systems by Hackael, Copeland, and Whittaker came into being. With the understanding of evolution, scientists could figure that the characteristics they used may not be true measure as it shifts with
- GeneralClass 12All
what is notochord in biology
The notochord is a tube-shaped structure filled with extracellular fluid and cells. The origin of this structure had huge implications for the movement and locomotion of organisms. This provided some strength to organisms to move around and use muscles effectively. The evolution of notochord gave rise to a new set of organisms we call Chordates. This allowed them advantages that further strengthened them. Later on, the notochord got replaced by a cartilaginous vertebral column. This later on
- GeneralClass 12All
What is taxonomy in biology class 11
Taxonomy is the science of identifying, naming and categorising organisms based on several characters. Several systems of classification has been developed. Carolous linnaeus gave the Two kingdom classification which grouped organisms into plants or animals. Ernst Hackel gave the third kingdom Protista. Kingdoms are largest categories. This was followed by Copeland who introduced Monera, the kingdom of prokaryotes. Whittaker gave the 5 kingdoms classification which added fungi and was followe
- GeneralClass 12All
What is the full form of pan in biology
Peroxyacyl nitrates are chemical compounds which are markedly present in photochemical smog. They irritate lung surfaces and also the eye. Besides they are believed to be mutagenic and a possible cause of skin cancer in people exposed to them. They are secondary pollutants meaning they are not emitted directly rather are released as volatile organic compounds from power plants or internal combustion engines. Ultra violet light catalyses the reaction that leads to formation of peroxyacyl nitra
- GeneralClass 12All
What is genus in biology
According to old surveys, around 5 million varieties of organisms existed. Modern estimates place the count at 8.7 million. It becomes difficult to study this huge variety of organisms. That is why we divide the organisms into categories. This was started by Carolous linnaeus who divided all organisms into 2 kingdoms, thus giving the two-kingdom classification system. Kingdoms are future categorised into Phyla which are further categorised into Classes. Classes are categorised into o
- GeneralClass 12All
What is plasticity in biology
Plasticity is the term used to describe brain’s behaviour over its course of development. Plasticity stands for modification in neuron distribution or even function over time depending upon usage.. People who use a certain area of the brain more may have more connections in that area of the brain compared to others. This has been recorded multiple times. Certain areas of brain involved in spatial understanding increase in size for cab drivers. People who can’t hear or see, dedicat
- GeneralClass 12All
What is growth in biology
Growth could be defined as an increase in mass or number of cells in living organisms. In unicellular organisms like bacteria growth and reproduction is synonymous as bacterial cells divide and reproduce and also grow in size. For multicellular organisms, growth is defined by increase in mass. This growth however is internal as external growth can happen for even non-living organisms. A mountain can grow by accumulation of snow over it. FAQ What is growth in organism?</p
- GeneralClass 12All
What is lichen in biology
Lichen is a symbiotic association between algae and fungi. Algae are photosynthetic and hence fix carbon and energy needs for the lichen. They are referred to as phycobiont. Fungi are saprotrophic in nature. They absorb inorganic substances for lichen. They are often referred as mycobiont. Both of these are very often the pioneer species, which means they are the first to inhabit a particular ecosystem, given their ability to be least dependent on other organisms. Lichens are also highly susc
- GeneralClass 12All
What is organism in biology
An organism or a living organism has been challenging to define. Most popular definitions group several characteristics as definitions. A comprehensive definition states that a living organism is a self-maintained chemical entity capable of response, reproduction and evolution. All living organisms- a bacterium or a dinosaur had perfect organised structures ranging from that of the plasma membrane’s bilayer nature to the chambers of the heart (in higher organisms). But these structures
- GeneralClass 12All
What is locomotion in biology
Locomotion stands for change of position. Not all but many organisms possess body parts to help them locomote. Several evolutionary events have occurred directed by advantages obtained by efficient locomotory structures. The reason for the same is very simple- many organisms are heterotrophs; if they can locomote they can obtain food to fulfil their needs. Locomtory structures could include simple subcellular structures like cilia and flagella which help several organisms like bacteria and pa
- GeneralClass 12All
What is conjugation in biology
Bacteria lacks true sexual reproduction. In such case it largely depends on errors in DNA replication (copying DNA) for variation. Still they are among the most versatile organisms when it comes to metabolism or habitat. Much of this is contributed by easy mechanisms of exchange of DNA- transformation, transduction and conjugation. Conjugation is a mechanism of DNA exchange where a bacterium can pass on circular pieces of DNA, called plasmids, to another bacterium by pipe like structures call
- GeneralClass 12All
What is plastid in biology?
Plastid are pigments present in plant cell.Therese pigments are further classified into three categories namely, Chloroplast, chromoplast and leucoplast. Chloroplast contains chlorophyll and carotenoid pigments. It assist in photosynthesis process and appear as green coloured pigment. Chromoplast provides colour to the petals and fruits. Carotenoids and xanthophylls are responsible for the colour in the chromoplast. Leucoplast are the colorless pigmen
- GeneralClass 12All
What is monera in biology?
Carl Linaaeues gave two kingdom classification and classified the organisms into two major kingdoms, plant and animal kingdom namely. But this system classification was not accepted much as it combines all the unicellular, multicellular, eukaryotic and prokaryotic organisms. Very later R.H whittaker gave five kingdom classification and placed each of the organisms on basis of cellular organization, reproduction, cell wall composition and so on. Amongst the classification of whittaker the very
- GeneralClass 12All
What is a carrier in biology?
An organism or a person that is infected with a disease and tends to spread the same to other organisms is called a carrier. It is often used in genetics.The carrier is infected with the disease but may or may not show the symptoms. Carrier holds the potential to transfer the disease to a healthy individual FAQ What is an example of carrier. An organism or a person that is infected with a disease and tends to spread the same to other organisms is c
- GeneralClass 12All
What is barr body in biology?
The somatic cells in females have an extra X chromosome which remains inactive throughout.Generally the sex cell in female have two X-chromosomes , whereas males have one X and one Y chromosome. In case of somatic cells one of the X chromosomes becomes inactive and is called a barr body. Barr body is absent in the genetic material of males.Every time the number ofBarr bodies in a cell is always one less than the number of X chromosome. For example male with Klinefelter’s syndrom