Test: Botany Mock Test - 1

Megaspore mother cell is diploid so meiosis occurs in it.

Meiosis:

• In the metaphase stage, all the chromosomes are arranged at the cell equator. All the chromosomes have two chromatids, joined at the centromere. These are called sister chromatids. 
• The centromere splits in the anaphase stage and the two sister chromatids go to opposite poles. They are now called as chromosomes. They have single chromatid which will duplicate into two sister chromatids in the S phase. 
• Thus, at the anaphase stage number of chromosomes remains the same even as the number of chromatids is reduced to one-half due to the splitting of the centromere.

So, the correct answer is option D.

• Hybrid generally refers to any offspring resulting from the breeding of two genetically distinct individuals, which usually will result in a high degree of heterozygosity. 
• Offspring resulting from the interbreeding between two animal species or plant species, also called a hybrid.

► Cell division is the basic requirement for the growth and development of the body, if the cells top dividing the body will eventually die.

There are two types of cell divisions:

• One occurs in the gamete cell and is necessary for reproduction as this cell division leads to genetic material exchange, this is meiosis or the reductional division.
• The other one is mitosis also known as Equational division which occurs in the somatic cells of the body and this cell division is employed in the repair of the body and increasing the number of cells for growth and development.

► In plants, mitosis occurs in the meristems which have the ability to divide continuously.

Meristems in plants are of two types:

• Apical meristems which are present on the tips of roots and shoots and they help in the elongation of length of the plant.
• The other is lateral meristem which helps in increasing the width of the plant.

Plants don’t repair or replace their damaged parts like leaves, branches but for new ones due to the continuous production of new cells in the meristems.

Mitosis in Onion Root Tips:

Leucaena leucocephala (Subabul) is a social foresting species with multiple utility like green manure, biomass production, food for humans, pulpwood for paper industry etc

Triticale is the only cereal obtained from hybridization, where the required character of 2 different or similar species and merged to form new individual.

• The kangaroo rat or the dessert rat is one of the common animal found in the arid regions.
• The animals and the plants which live in the desserts have certain adaptations which enable the organism to survive in the extreme climate.
• The water which is produced as the product of the metabolic reactions is known as the metabolic water.
• The kangaroo rat uses the metabolic water which is produced by the reactions in the body rather than the less amount of water which is available in the environment.

It is because they are the primary source of energy and every food chain starts with a producer because they produce their own food and pass energy for the other tropical level.

Sun is the ultimate source of energy and plants (producers) are the only ones who can convert sunlight into chemical energy. Hence producers bring energy into the ecosystem.

• Integrated pest management (IPM) combines the use of biological, cultural and chemical practices to control insect pests in agricultural production.
• It seeks to use natural predators or parasites to control pests, using selective pesticides for backup only when pests are unable to be controlled by natural means.

Monoecious” is translated as “single house,” meaning that male and female flowers are found on a single individual. This contrasts with the translation of dioecious, which is “double house.” This means that male flowers are on one plant and female flowers are on another plant.

• DNA helicase is responsible for opening up our DNA to allow for replication as well as the transcription of our DNA.
• A DNA helicase is an enzyme that functions by melting the hydrogen bonds that hold the DNA into the double helix structure. It is also known as Unwindase.
  

• Kornberg's success in unraveling the process of coenzyme synthesis established him as a biochemist by the early 1950s.
• It had also suggested to him that other large molecules such as the nucleic acids RNA and DNA would be synthesized in a similar way.
• He began his investigations into nucleic acid synthesis during the same years that James Watson and Francis Crick, among others, were trying to work out the likely structure of DNA.

• Exon is a part of gene that will become a part of final mature RNA produced by that gene after introns have been removed by RNA splicing.
• Cistron is the smallest unit of genetic material that must be intact to function as a transmitter of genetic information.
• A  codon is a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid (or stop signal) during protein synthesis.

• Two prothallial cells are present in pinus.
•  In pinus prothallial cells start disintegrating even prior to pollination.
• Pollination takes place at 4-celled stage in pinus, i.e. two prothallial cells, a generative cell and a tube cell.

An alternative form of a character in a pair, controlled by a single gene is called Allele. It is dominant either in a homozygous or heterozygous state.

The reason is simple. it was due to the monohybrid cross that Mendel could find that characters that we are not expressed in the F1 generation where expressed in the F2 generation .this could mean gametes independently contained alleles.

A white flower Sweet Potato(CCpp) is crossed with another white flowered Sweet Potato(ccPP). In the F1 generation, Purple flowered Sweet potato plants are formed. When these plants are subjected to self pollination, in the F₂ generation, 9 plants with purple flowers and 7 plants with white flowers are formed. It is complementary genes.

PS II occurs mostly on the granal lamellae of the chloroplast. PS II uses light energy for photolysis of H2O molecules, or oxidizing H2O molecules producing electrons, protons (H+) and O2.

Plants respond to heavy metal toxicity in a variety of different ways. Such responses include immobilization, exclusion, chelation and compartmentalization of the metal ions, and the expression of more general stress response mechanisms such as ethylene and stress proteins. Phytochelatins are oligomers of glutathione, produced by the enzyme phytochelatin synthase. They are found in plants, fungi, nematodes and all groups of algae including cyanobacteria. Phytochelatins act as chelators, and are important for heavy metal detoxification. They are abbreviated PC2 through PC11.

C2 cycle or photo respiration will begin and PGA &Phosphoglycolate is formed so,option D..

Photosynthesis in plants converts solar energy into chemical energy using electrons and protons from water.

Fungi are classified as per their modes of  nutrition as 
1. Saprophytic
2. Parasitic
3. Symbiotic (Mycorrhiza)
Saprophytic Fungi:
These fungi feed on dead organic matter and decaying matter.
Parasitic Fungi:
Parasitic fungi live or colonise animals, plants and other fungi living on their expenses, inflict diseases or even death.
Symbiotic (Mycorrhiza):
The mycelium feeds on organic compounds in the soil substrate through decomposition or through particular associations with plants.

When light is incident on chloroplast, firstly exciting of an electron and then next reactions will occur.

The Volvox is a green algae that you can’t see without a microscope that obtains its own nutrients through photosynthesis, thus it’s a plant. But wait it breathes like an animal and has two flagella that allow it to move, so it’s an animal. But it can’t be both unless it’s neither, so it’s a protist, with characteristics of both plants and animals!

Agent Orange is an herbicide and defoliantchemical, one of the "tactical use" Rainbow Herbicides. It is widely known for its use by the U.S. military as part of its herbicidal warfare program, Operation Ranch Hand,during the Vietnam War from 1961 to 1971.It is a mixture of equal parts of two herbicides, 2,4,5-T and 2,4-D. In addition to its damaging environmental effects, traces of dioxin (mainly TCDD, the most toxic of its type) found in the mixture have caused major health problems for many individuals who were exposed.

Heliotropism is a growth movement or bending of stem in the direction of the light. It is also called as solar tracking. Photoperiodism is the phenomenon in which various physiological reactions like flowering response to the relative length of dark or light periods. Photonasty is nastic movement of plant towards sunlight. Hydrotropism is a growth movement of plant part in response to water.

Plants are able to detect and respond to light, gravity, changes in temperature and chemicals. Plants respond to the changing seasons to initiate their development and flowering. The photoperiodic stimulus is found to be responsible for flowering, light quality, vernalization, autonomous and GA pathways are also responsible for regulating the flowering time in plants. While vernalization and photoperiodic pathways are environmental dependents, the autonomous pathway promotes flowering in all conditions. Hence for a tree that flowers thrice a year, the plant has to be both photo and thermo-insensitive.

Nitrogen fixation occurs in some bacteria as rhizobium,cyno bacteria as nostok , anabaena , in node of root of legumes.

Parenchyma have primary cell wall and retains the ability for future cell division. They form 'filler' tissues in soft part of plants and are usually present in medullary rays and hence are called living cells.

It is an air pollutant and it affects metabolic activity of cell and disrupts the transport system of the cell and hence affect the whole membrane system.

Lead always impaire our nervous system when anyway it enters in our body.

Tapetum synthesizes callase enzyme which dissolves callose. It produces many hormones ,amino acids and nutrious substances that are needed for pollen grains.

Embryology is defined as the branch of biology and medicine that studies embryos and how they develop. The study of how human embryos develop from fertilization to birth is an example of embryology.

Asexual plant propagation methods produce new plants from vegetative parts of the original plant, such as the leaves, stems and roots. These methods are generally referred to as vegetative propagation.

Adenosine triphosphate (ATP) is a complex organic chemical that provides energy to drive many processes in living cells, e.g. muscle contraction, nerve impulse propagation, and chemical synthesis. Found in all forms of life, ATP is often referred to as the "molecular unit of currency" of intracellular energy transfer

• Cytochromes P-450 are proteins of the superfamily containing heme as a cofactor and, therefore, are hemeproteins.
• CYPs use a variety of small and large molecules as substrates in enzymatic reactions. They are, in general, the terminal oxidase enzymes in electron transfer chains, broadly categorized as P450-containing systems.
• The term "P-450" is derived from the spectrophotometric peak at the wavelength of the absorption maximum of the enzyme (450 nm) when it is in the reduced state and complexed with carbon monoxide. 
• Most CYPs require a protein partner to deliver one or more electrons to reduce the iron (and eventually molecular oxygen). 
• Depending on the substrate and enzyme involved, P-450 enzymes can catalyze any of a wide variety of reactions.
• After the product has been released from the active site, the enzyme returns to its original state, with a water molecule returning to occupy the distal coordination position of the iron nucleus. 

So the correct option is 'it is a coloured cell'.

Velamen is a spongy tissue found in aerial or hanging roots of epiphytes (eg : Orchids-Vanda ) It absorbs atmospheric moisture by imbibition.

Cladodes are the modification of stem in leaves which contains chlorophyll for the process photosynthesis in xerophytes plants.

Wheat has animophilly mode of Pollination, and feathery stigma is a characteristic of animophillus flower

This is due to sodium pottasium pump hence when sodium go out of the pottasium ions took the inside place and vice versa.

A potometer is a device used for measuring the rate of water uptake of a leafy plant shoot. The main reason for water uptake by a cut shoot is transpiration (evaporation in plants) and is affected by the transpiration stream.

Transpiration lowers the temperature as during transpiration liquid water is absorbed by the plant. In the cells surrounding the substomata chamber, water evaporates from the cell wall into the chamber. When the stomata are open water vapour diffuses out into the chamber Transpiration cooling energy is needed to evaporate liquid into vapour. Energy is absorbed into liquid water and this reduces the temperature of the surrounding plant tissue and nearby atmosphere