EmSAT Biology Mock Test - 2 - EmSAT Achieve MCQ

• Structure and Function: Mitochondria are membrane-bound organelles found in the cytoplasm of eukaryotic cells. They are often referred to as the powerhouse of the cell because they are responsible for producing the majority of the cell's ATP, which is the main source of energy for cellular activities.



• ATP Production: Mitochondria carry out aerobic respiration, a process that uses oxygen to convert nutrients such as glucose into ATP through a series of complex biochemical reactions. This ATP is then used by the cell to fuel various processes including growth, repair, and movement.



• Role in Cell Metabolism: In addition to ATP production, mitochondria also play a role in other metabolic processes such as the synthesis of certain molecules and the regulation of calcium levels within the cell. They are also involved in cell signaling and apoptosis (programmed cell death).



• Number and Distribution: The number of mitochondria in a cell can vary depending on the energy requirements of that cell. Cells with high energy demands, such as muscle cells, may have thousands of mitochondria, while cells with lower energy needs may have fewer. Mitochondria are distributed throughout the cell to ensure that energy is readily available wherever it is needed.



• Importance: The proper functioning of mitochondria is essential for the overall health and survival of the cell. Any dysfunction in these organelles can lead to a variety of disorders and diseases, including metabolic disorders, neurodegenerative diseases, and aging-related conditions.

The DNA segment which serves as ON-OFF switch for transcription is called an operator. Operator attach with template strand to initiate transcription process.

Cryopreservation is the method of preserving living organisms or their parts at extremely low temperature. To preserve seeds that rapidly lose viability and cannot survive desiccation are preserved by this method.

NCERT Line: Now gametes of threatened species can be preserved in viable and fertile condition for long periods using cryopreservation techniques, eggs can be fertilised in vitro, and plants can be propagated using tissue culture methods.

The most important form of energy currency in living systems is the bond energy in a chemical called ATP.

Codon AAA code for amino acid lysine but UUA, AUG and CCC do not code for Valine, cysteine and alanine respectively. So, AAA and lysine pair is correct option out of given options.

Evolution is the gradual change of race due to variation is course of time. It is the history and development of race along with variations. Evolution is a continuous process and takes millions of years to evolve a new species.

Primary consumers obtain food from producers or autotrophs. In aquatic ecosystem phytoplankton are main prouder and zooplankton are primary consumers along with frog tadpole , snail and tortoise.

Pachytene: During the third substage of meiosis, the chromosomes continue to condense. Crossing over takes place at this stage and at each point of crossing over a chiasma is formed (singular: chiasma) between non-sister chromatids of homologous chromosomes.

Fig: Stages of Prophase I of Meiosis

Line in NCERT: "During this stage, the four chromatids of each bivalent chromosomes becomes distinct and clearly appears as tetrads. This stage is characterised by the appearance of recombination nodules, the sites at which crossing over occurs between non-sister chromatids of the homologous chromosomes."

Fossils are generally found in sedimentary rocks.

Hereditary diseases are due to defects in gene. Gene can be corrected at embryonic stage by gene therapy technique in which genes are inserted into person cells or tissue to take over the function of defective gene.

Ecosystem services include all activities performed by nature to benefits human beings.

The most important ecological service includes soil formation. Soil is essential for the growth of plants that provide food to all living forms.

• In a dihybrid cross, two new kinds of plants with new traits are formed. This is possible only when all traits assort independently and recombine to form a new combination.
• Mendel found that each pair of alleles segregates independently of the other pairs of alleles during gamete formation. 
• This is known as the Law of independent assortment and hence it can be proved by the dihybrid cross.

Hence, the correct option is C

Topic in NCERT: Law of Independent Assortment

Line in NCERT: "Based upon such observations on dihybrid crosses (crosses between plants differing in two traits) Mendel proposed a second set of generalisations that we call Mendel's Law of Independent Assortment."

The strand of DNA that forms mRNA is called the template strand or the antisense strand. During transcription, the DNA molecule unwinds, and one of the strands (the template strand) is used as a template to synthesize a complementary RNA molecule, which is called messenger RNA (mRNA). The other strand of DNA, which is not used as a template during transcription, is called the coding strand or the sense strand because it has the same sequence as the mRNA molecule (except for the presence of thymine instead of uracil).

When a graph is drawn to compare the relationship between species richness and area for wide variety of texa, the graph appears to be a rectangular hyperbola.

Autosomal domionant trait can express its effect in homozygpous as well as heterzygous condition.

Protein molecules get denatured due to high temperature, very high or low pH and high energy radiation but there is no effect due to high pressure.

To match the items correctly:

- α-1-antitrypsin - Emphysema: α-1-antitrypsin deficiency can lead to emphysema.
- Transposon - Mobile genetic element: Transposons are DNA sequences that can move around the genome.
- ELISA - AIDS: ELISA is a technique used to detect HIV antibodies in AIDS diagnosis.
- Retroviral vector - Gene therapy: Retroviruses are used as vectors in gene therapy.

Therefore, the correct match is:
B: A-(iii), B-(iv), C-(i), D-(ii)

• Proteins are polymers of amino acids undergo dehydration to form a peptide linkage.
• Dipeptides are formed by a single peptide bond and a tripeptide through two peptide bonds and so on.

In plants, cytokinesis or division of cytoplasm occurs due to the formation of the cell plate.

In animals, cytokinesis occurs due to the formation of constriction in the middle cell membrane.

Line in NCERT: "The formation of the new cell wall begins with the formation of a simple precursor, called the cell-plate that represents the middle lamella between the walls of two adjacent cells."

The Convention on Biological Diversity aimed to address the urgent need for global action to conserve biodiversity and promote its sustainable use.

Synthesis of DNA by DNA polymerases occurs only in 5'→3' direction. One strand called leading strand , is copied in the same direction as the unwinding helix. The other strand is known as lagging strand. Replication of lagging strand is in a dicontinuous way , and in the direction of growth of lagging stand is 3'→5' though in short segments of DNA which are always in the 5'→3' direction. These short segments are called Okazaki fragments joined together by the action od DNA ligase.

• More than 70 per cent of all the species recorded are animals, while plants (including algae, fungi, bryophytes, gymnosperms and angiosperms) comprise no more than 22 per cent of the total.
• Among animals, insects are the most species rich taxonomic group, making up more than 70 per cent of the total.

In the given food web, organisms I (phytoplanktons) act as producers, organisms II, V and VII act as primary consumers as they feed on producers, organisms III and VI act as secondary consumers as they upon primary consumers, and organism IV acts as a tertiary consumer.

• The physical appearance of a character or organism's observable characteristics or traits is called as phenotype.
• The genetic makeup of an individual is called genotype. Tallness, round, wrinkled, yellow etc. are due to their genetic makeup.

Phenotype Example:

Hence, the correct option is A
NCERT Reference: Topic " MENDEL’S LAWS OF INHERITANCE” of chapter "Principles of Inheritance and Variation" of NCERT

Line in NCERT: "TT and tt are called the genotype of the plant while the descriptive terms tall and dwarf are the phenotype."

Adenosine deaminase enzymes is crucial for the immune system to function and its absence is caused by the deletion of a gene. It is cured by the gene therapy.
Insulin consists of chain A and chain B that are linked together by disulphide bridges.
Transgenic mice are being used to test the safety of the polio vaccine.
RNAi involves silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA.

Origin of universe is explained by big bang theory. According to this theory, whole universe was concentrated into single sphere. Due to same unknown region, there was explosion in it that forms different galaxies still moving away from each other.

Darwin judged the fitness of an individual by number of offspring the individual produce in particular niche. More the viable offspring formed the more fit the organism in that surrounding.

In monohybrid and dihybrid cross F₂ generation is obtained by selfing of F₁ hybrids as male and female.

Fig: Monohybrid cross showing F₁ and F₂ generation

Hence, the correct option is B

Topic in NCERT: Gametes

Line in NCERT: "The F1 plant of the genotype Tt when self-pollinated, produces gametes of the genotype T and t in equal proportion."

Lysosomes are single membrane structures containing enzymes for digestion of all types of macromolecules.