EmSAT Biology Mock Test - 3 - EmSAT Achieve MCQ

In detritus food chain, speed of decomposition will be fast if detritus is rich in simple sugar that can be easily decomposed into glucose by saprophytes that includes bacteria and fungi.

Primary productivity is maximum in tropical rain forests due availability of sufficient food and water followed by temperate forests. Savannah grasslands have comparatively less productivity and arid regions have limited biotic component and water.

• tRNA has an anticodon loop that has bases complementary to the code, it also has an amino acid acceptor end by which it binds to amino acids.
• The site lies at the 3' end opposite the anticodon in tRNAs are specific for each amino acid.

Fig: tRNA binding site 
Hence, the correct option is C.
NCERT Reference: Page no. 114 of topic “6.6.2 tRNA– the Adapter Molecule” of chapter 6.

Only 10 % of energy is transferred from one trophic level to the next trophic level of a food chain (ten percent law, given by Linderman). In present case, energy available at producer level is 10 J. Hence energy at primary consumer level would be 1 H (10% of 10 J). Similarly, at secondary consumer level, energy present will be 0.1 J (100 % of 1 J).

The anticodon loop is crucial for the accurate translation of mRNA into protein, as it ensures that the correct amino acid is added to the growing polypeptide chain.

Bt toxin is obtained from Bacillus thuringiensis bacterium that can kill certain insects like tobacco budworm, armyworm, beetles and flies.

The International Day for Biological Diversity is a United Nations–sanctioned international day for the promotion of biodiversity issues. It is held on May 22. The International Day for Biological Diversity falls within the scope of the UN Post-2015 Development Agenda's Sustainable Development Goals.

Analogous organs are those organs which have the same function but are quite different in their fundamental structure and embryonic origin. For example, the wing of an insect and the wing of a bird are analogous organs. Both these organs are used for flying in the air but they re very different in structure. An insect wing is an extension of the integument whereas a bird wing is formed of limb bones covered with flesh, skin, and feathers. Each has evolved from a separate ancestral population as a means of a more efficient mode of locomotion. Similarity developed in distantly related groups as an adaptation for the same function is called analogy or convergent evolution.

Thus, the correct answer is option B. 

The stacks or closely packed thylakoids is called granum. Chlorophyll is present inside the thylakoidsto perform photosynthesis in plant cells.

Introduction of Nile perch (an exotic predatory fish) into lake Victoria (South Africa) threatened the entire ecosystem of the lake by eliminating several native species of the small Cichlid fish species that were endemic to this fresh water ecosystem. 

In non-competitve inhibition, the inhibitor binds at a site other than the active site ob the enzyme surface. This binding impairs the enzyme function. The inhibitor has no structural resemblance with the sunstrate. It does not interfere with the enzyme-substrate binding but the catalysis is prevented, possibly due to a distortion in the enzyme conformation. Non-competitive inhibition is usually irreversible because it cannot be overcome by increasing the substrate concentration. The inhibitor (l) generally binds with the enzyme as well as the ES complex. The overall relation in non.competitve inhibition is represented as :

Transgenic organism is one that has become transformed following the introduction of novel genes into its genome. It is most frequently achieved by integration of cloned DNA sequences following their injection into the fertilized egg. This fertilized egg divides mitotically to form the whole organism so that all the cells of the organism will carry the transferred gene. The transferred genes are known as transgenes.

UGA, UAG and UAAare called termination or stop codon because they do not code for any amino acid. As soon as any one of them codon is located on m-RNA translation process is stopped.

Guanine, cytosine and adenine are all nitrogenous bases that are found in nucleotides. These bases are essential components of DNA and RNA molecules, which are composed of nucleotides. Guanine pairs with cytosine, and adenine pairs with either thymine (in DNA) or uracil (in RNA) through complementary base pairing.
Tyrosine, on the other hand, is an amino acid and not a component of nucleotides. Amino acids are the building blocks of proteins, while nucleotides are the building blocks of nucleic acids.

Vitamin-A deficiency causes night blindness among children. Vitamin-A deficiency often occurs where rice is the staple food since, rice grain does not contain β-carotene. Three transgenes providing phytoene synthase, phytoene desaturase, beta carotene desaturase and lycopene cyclase activities were transferred into rice by Agrobacterium mediated transformation. The resulting transgenic rice popularly called goldern rice contains good guantities of β-carotene.

Flaw savr is genetically modified tomato, which remains fresh and retain their flavour much longer than normal tomato due to the blocking of synthests of fruit softening enzyme polygalacturonase.

Enzyme may be broadly classified into two types depending on their chemical composition-simple enzymes and conjugated enzymes are wholly made up of proteins and any additional substance or group is absent, e.g., pepsin, trypsin, etc. Conjugated enzymes (or holoenzymes) are formed of two parts -a protein part called apoenzyme and a non-protein part named co-factor. The complete conjugated enzyme consisting of an apoenzyme and a co-factor is called holoenzyme. Holoenzyme is the functional unit of enzyme.

Co-factor may be inorgainc or roganic in nature. Catalytic activity is lost when co-factor is removed from the enzyme which indicates that it plays a crucial role in catalytic activity of enzymes.

The correct answer is A: A - (iii), B - (iv), C - (ii), D - (i).

Here's the breakdown of each transgenic organism with its specific characteristics:
- Golden rice: Enriched with vitamin A to address deficiencies.
- Bt cotton: Engineered for high yield and resistance to pests.
- Flavr Savr: Developed for increased shelf life.
- Rosie cow: Genetically modified for protein-enriched milk.

Understanding these associations helps in recognizing the benefits and applications of transgenic organisms efficiently.

Successful graft reaction can be done by using Xenotransplantation to get two kinds of products from single plant.

Jurassic period of Mesozoic era characterized presence of Gymnosperms as dominant plant and first birds evolved from reptiles. Dianasours are also a kind of reptiles.

Productivity is the rate of new biomass production by an individual, population, community within an ecosystem. The productivity of an ecosystem depends on several environmental factors such as light, water, temperature, precipitation, etc.

Brazil has the highest biodiversity because it is located near equator.

• The cell cycle consists of several distinct phases, including interphase and mitosis. Interphase, which is the longest phase of the cell cycle, can be further divided into three subphases: G₁ (gap phase 1), S (synthesis phase), and G₂ (gap phase 2).
• During the S phase, DNA synthesis occurs. This is the period when the cell replicates its DNA to ensure that each daughter cell produced during cell division receives a complete set of genetic information.
• The DNA replication process involves unwinding and separating the two strands of the DNA double helix and synthesising new complementary strands using the existing strands as templates. As a result, each chromosome is duplicated, and sister chromatids are formed, which remain attached at the centromere.
• After the S phase, the cell progresses into the G₂ phase, where it prepares for cell division. The subsequent phase is mitosis, which includes prophase, prometaphase, metaphase, anaphase, and telophase, leading to the separation of sister chromatids and the formation of two identical daughter cells.
• Therefore, DNA synthesis occurs specifically during the S phase of the somatic cell cycle.

Line in NCERT: "S phase marks the period during which DNA synthesis or replication takes place."

• Single-step that causes large mutation is called saltation.
• It is called as such because the mutation occurs suddenly and abruptly that leads to evolution in large scale.
• Hugo de Vries used this term against Darwin’s theory of evolution.

Line in NCERT: "Hugo deVries believed mutation caused speciation and hence called it saltation (single step large mutation)."

The diagram shown is a uracil which is a pyramidine belonging to nitrogen bases.

The secondary structure of a protein refers to regular folding patterns of continuous portions of the polypeptide chain. It is primarily determined by hydrogen bonding interactions between the amino acid residues of the chain. The two most common types of secondary structure are alpha helices and beta sheets.

The term used to refer to the use of bio-resources by multinational companies and other organizations without proper authorization from the countries and people concerned without contemporary payment is Bio-piracy. It happens when biological resources are taken or exploited without official sanction.

Line in NCERT: "At the beginning of the final stage of karyokinesis, i.e., telophase, the chromosomes that have reached their respective poles decondense and lose their individuality. The individual chromosomes can no longer be seen and each set of chromatin material tends to collect at each of the two poles."

In prokaryotes, the genetic material consists of single circular DNA molecule lying entangled in nucleoid. It is not bounded by a definite nuclear membrance. Histones are water-soluble proteins rich in arginine and lysine that help in DNA packaging in chromosomes. Prokaryotic cells lack pistone proteins.

Line in NCERT: "The genetic material is basically naked, not enveloped by a nuclear membrane. In addition to the genomic DNA (the single chromosome/circular DNA), many bacteria have small circular DNA outside the genomic DNA."