CSIR NET Life Sciences Mock Test - 8 - UGC NET MCQ

Calculation:

The area of the rectangle is 144 cm² and the sides are in the ratio 4:9.
Let the length be 4x and the breadth be 9x. 
Area of a rectangle = length × breadth gth

Therefore, the length cm and the breadth =18 cm
Perimeter of a rectangle =2 (Length Breadth)

Perimeter 

Perimeter  Perimeter cm

The formula for Arithmetic Sequence:
a_n = a₁ + (n – 1)d
According to the question
q = p + (3 - 1)d
⇒ q = p + 2d    ----(1)
And 3 = p + (5 - 1)d
⇒ 3 = p + 4d    ----(2)
Solving (1) and (2), we get
q = 3 - 2d
and p = 3 - 4d      [from (2)]
According to the question pq is minimum
= (3 - 4d) (3 - 2d) is minimum
= (9 - 18d + 8d²) is minimum
Differentiation the above equation with respect to d is 0
⇒ -18 + 16d = 0
⇒ d = 9/8
∴ The value of d is 9/8.

In 200 mixture, milk  = liter

Water in the mixture=200-160 = 40 liter

Let the quantity of mixture is taken out = 5x

Then,  

480 - 12x = 350 - 7x 

5x = 130

x = 26 

Quantity of mixture taken out = 130 liter

Given,

Aristotle was a Greek philosopher, who first classified organisms as either plant or animals. Modern biological classification has given five kingdoms.

A few plants exhibits unusual flowering phenomenon. Bamboo species is one of them, which produces flower once in their life time, generally after 50-100 years. They produce large number of fruits and die

If the cells containing plasmids are infected with helper phage, then single stranded DNA can be produced, packaged and secreted into the medium. DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person's body has the same DNA.

Pulmonary respiration is the exchange of gases between the alveoli of the lungs and the blood in the capillaries. The exchange of gases between blood and tissue cell occurs in internal respiration.

In Bacteria, when many flagella present only at one pole, are known as Lophotrichoous.

Flagella: It is a slender threadlike structure, especially a microscopic part that enables many protozoa, bacteria, spermatozoa, etc. to swim.

Parts of flagella: Bacterial flagellum is composed of three parts – filament, hook and the basal body.

Based on the number and placement of flagella on the cell, there are four types of flagellar arrangements. They are:

Enzymes are proteins or non-proteins that act as bio-catalysts. Holoenzymes comprise a prosthetic group and an apoenzyme. The prosthetic group can be either co-factors or co-enzymes. Cutting a potato is a physical change and doesn’t lead to the breakage of bonds in the enzymes present in it.

In angiosperms, the egg is devoid of wall.

In female gemetophyte, the egg apparatus is attached to the wall of embryo sac only at the micropylar end and it is surrounded by the central cell. The egg apparatus is comprised of an egg cell and two synergids. Cells of the egg apparatus and the antipodal cells are uninucleate and haploid whereas the central cell is binucleate or diploid.

Asexual Reproduction: It is the process in which a new individual is formed by the involvement of a single parent with or without the involvement of the gamete formation. The individuals produced are genetically and morphologically similar. It occurs in unicellular organisms where cells divide by mitotic division and no fertilization takes place. The division occurs very rapidly.

Types Of Asexual Reproduction

Binary Fission: It is seen in amoeba and euglena. The parent cell undergoes mitosis and increases in size. The nucleus also divides. Two identical daughter cells are obtained, each containing a nucleus. Prokaryotes like bacteria majorly reproduce by binary fission.

Budding: In this, the offspring grows out of the body of the parent. It remains attached to the parent until it matures. After maturation, it detached itself from the parent and lived as an individual organism. This form of reproduction is most common in Hydras.

Fragmentation: In some organisms like Planarians, when the body of an organism breaks into several pieces each piece grows into an individual offspring. This is known as fragmentation. It can occur through accidental damage by predators or otherwise, or as a natural form of reproduction. In a few animals such as seastar, a broken arm grows into a complete organism.

Regeneration: It is a modified form of fragmentation and occurs mostly in Echinoderms. When a part of an organism, like an arm, detaches from the parent body, it grows into a completely new individual. 

Parthenogenesis: This is a form of asexual reproduction where the egg develops without fertilization. This process occurs in bees, wasps, ants, aphids, rotifers, etc. Ants, wasps, and bees produce haploid males. Parthenogenesis has been observed in a few vertebrates such as hammerhead sharks, Komodo dragons, and blacktop sharks when the females were isolated from the males.

DNA replication is the process by which the DNA duplicates itself. At the start of the DNA replication, the hydrogen bonds between the nucleotides of two strands break by the action of enzyme helicase. RNA primer attaches on the template strand which provides a 3' end for DNA polymerase to work on. The DNA is synthesized by DNA polymerase in the 5'-3' direction on leading strand by DNA polymerase. When the DNA polymerase works in the opposite direction on lagging strand it synthesizes discontinuous short DNA segments known as Okazaki in 3'-5' direction. DNA ligase is the enzyme which helps in joining the Okazaki segments and forms the continuous complimentary strand of the daughter DNA.

Proteins are made up of hundreds or thousands of smaller units known as amino acids that are linked in lengthy chains. A protein is made up of 20 different types of amino acids that can be combined in various ways.

Schwann cells secrete a myelin sheath.

The myelinated nerve fibres are enveloped with Schwann cells, which form a myelin sheath around the axon. The gaps between the two adjacent myelin sheaths are called Nodes of Ranvier. 

The compound that contains ionic, coordinate, and covalent bonds is ammonium chloride (NH₄Cl). Here’s how these bonds are present:

• Ionic bond: Formed between the ammonium ion (NH₄⁺) and the chloride ion (Cl^-).
• Coordinate bond: Present in the ammonium ion where one nitrogen atom shares its pair of electrons with hydrogen atoms.
• Covalent bond: Found within the ammonium ion where nitrogen and hydrogen atoms are bonded by sharing electrons.

Other compounds listed do not exhibit all three types of bonds:

• Sodium chloride (NaCl) contains only ionic bonds.
• Methane (CH₄) has only covalent bonds.
• Water (H₂O) consists of covalent bonds only.

Hence , the Correct Answer is Option A

The inner cell mass (ICM) forms within the blastocyst, prior to its implantation within the uterus. The ICM is the only pluripotent cell lineage in the blastocyst. The ICM forms the epiblast and hypoblast layers, which develop into the embryonic tissues and extraembryonic tissues, respectively.

The tiny molecules of naked circular RNA that infect plants are called viroids.

• Viroids are much smaller than viruses and do not have a protein coat.
• They cause diseases in plants by disrupting normal cell processes.
• Unlike viruses, viroids contain only RNA and no other components.

Therefore, Correct Answer is Option B.

'Palade particles' is another name for ribosomes.

• Ribosomes are non-membrane bound organelles and granular structures that was discovered by George Palade in 1953.
• They are composed of ribonucleic acid (RNA) and proteins.
• Ribosomes are protein synthesizers of a cell and they are found in both Prokaryotic and Eukaryotic cells.

Genotype-Phenotype concept was first produced by Johannsen.

The external physical characters of a trait that are expressed is called phenotype. Wilhelm Johannsen first studied heredity and proposed the difference between genotype and phenotype. According to Johannsen, the genotype of an organism is responsible for its phenotype through development and environmental effect.

The -COOH group of cellular amino acids can form Ester and amide bonds inside the cell.

The reaction of amines with esters to form amides is of fundamental importance in organic synthesis. In noncatalytic reactions, this can occur when a highly reactive ester is used, or the nucleophile is activated by harsh stoichiometric base.

Microtubules of a dividing cell form the mitotic spindle required for chromosome segregation. Microtubules in the nerve and epithelial cells play a role in organelle transport.

The internal framework of a cell (the cytoskeleton) is responsible for positioning the various organelles. This is particularly evident in polarized epithelial cells where organelles are specifically ordered from the apical to the basal end of the cell.

So, both I and II statements are correct.

Following are the properties which a biosensor should possess:

If the biosensor used in invasive, the probe must be tiny and biocompatible, having no toxic or antigenic effects.

The biosensor should be cheap, small, portable, and capable of being used by semi-skilled operators.

If the traditional methods used are encouraged and the decentralization of laboratory testing is discouraged, then there is no use of producing more biosensors. Thus, there should be a market for biosensors.

“The specificity of substrate binding is mediated by the spatial arrangement of atoms in an enzyme’s substrate binding site as well as the substrate.” This is a property of the active site of the enzyme.

In ecology, edge effects are changes in population or community structures that occur at the boundary of two or more habitats. Areas with small habitat fragments exhibit especially pronounced edge effects that may extend throughout the range. As the edge effects increase, the boundary habitat allows for greater biodiversity.

Seed germination is mediated by phytochromes while inhibition of stem elongation, stimulation of leaf expansion, and regulation of floral initiation is the function of cryptochrome.

In the female reproductive cycle, the germ cell divides mitotically and produces millions of oogonia. Most of the oogonia will undergo degeneration by the process known as atresia.

All of the above statements given in the question, are correct.
For recombination to occur, the R2 segment of the Trp DNA molecule must recombine with R3 segment of the bottom DNA molecule. R1 segment of the top molecule must recombine with R4 segment of the bottom DNA molecule.

A selectable marker is a gene that helps in identifying successful transformants. They eliminate the growth of non-transformants and favor the growth of the desired organism. It is one of the features which facilitate cloning in a vector.