NEET Unit Test - 4 - NEET MCQ

Given - φ = 3.3 × 10⁻¹⁹ J and h = 6.6 × 10⁻³⁴ J·s

We know that, Φ = hν₀ = hc / λ₀
Where ν₀ = threshold frequency, λ₀ = threshold wavelength, and c = speed of light

The work function is written as –
ν₀ = φ / h
⇒ ν₀ = (3.3 × 10⁻¹⁹) / (6.6 × 10⁻³⁴) = 0.5 × 10¹⁵ = 5 × 10¹⁴ Hz

Substance left undecayed, N₀​−(3/4)​N₀​=(1/4)​N₀​
N/N0​ ​=1/4​=(1/2​)ⁿ
 
∴ Number of atoms left undecided, n=2 i.e, in two half-lives
∴ t=nT=2×4=8 months

To determine the resistance of a carbon resistor based on the color bands, we need to refer to the standard resistor color code. The colors represent digits and multipliers as follows:

• Green: 5
• Red: 2
• Orange: Multiplier of 10^3 (1,000)

Given the color bands: Green, Red, Orange

The resistance value is calculated as follows:

1. First digit: Green = 5
2. Second digit: Red = 2
3. Multiplier: Orange = 10^3 (1,000)

So the resistance is:

Resistance=(52)×10^3 ohms=52,000 ohms=52 kilo-ohms

Answer: The approximate resistance of the resistor is 52 kΩ.

The correct IUPAC name of the given compound is 3-ethyl-4,4-dimethylheptane.

The general formula C_nH_2nO₂ could be for open chain carboxylic acids. For example, ethanoic acid: C₂H₄O₂.

The three CH₃ radicals attached to the positively charged carbon are electron repelling group. Therefore, these CH₃ radicals exhibit +I effect (Inductive effect) and repel electrons towards the positively charged Carbon. This decreases the positive charge and makes the compound more stable.

Cyclopentadienyl anion is more stable than allyl anion as the former is aromatic and is stabilised by resonance.

The compounds containing nitrogen but no carbon atom do not give positive Lassaigne's test as no NaCN is formed.

(1) Reaction (i) is stereospecific. In this reaction, inversion of configuration occurs due to S_N² mechanism.

(2) Reaction (ii) is non-stereospecific. There is change in configuration due to racemisation.

(3) Reaction (iii) is stereospecific. There is no change in configuration as this reaction takes place through S_N2 mechanism.

The assertion that trans 2-butene reacts with Br2 to produce meso 2, 3-dibromo butane is correct but it does not involve syn–addition.
Halogenation of alkenes takes place by ante-addition.

The IUPAC name of the given compound is 3-ethyl-5-methylheptane.

Lines in NCERT: 1. Restriction enzymes belong to a larger class of enzymes called nucleases.
2. The cutting of DNA at specific locations became possible with the discovery of the so-called  ‘molecular scissors’– restriction enzymes.
3. Downstream processing is the last process in recombinant DNA technology(6th). After completion of the biosynthetic stage, the product has to be subjected through a series of processes before it is ready for marketing as a finished product.
4. And the last method uses ‘disarmed pathogen’ vectors, which when allowed to infect the cell, transfer the recombinant DNA into the host.

RNAi or RNA interference takes place in all eukaryotic organisms as a method of cellular defense. This method involves silencing of a specific mRNA. Using Agrobacterium vectors, nematode specific genes are introduced into the host plant (tobacco plant). The introduction of DNA was such that it produced both sense and anti-sense RNA in the host cells. These two RNAs being complementary to each other formed a dsRNA (double stranded RNA) that initiated RNAi.

- The Assertion is correct because competitive inhibitors indeed bind to the active site of an enzyme, which prevents the substrate from binding.

- The Reason is also correct as increasing the substrate concentration can outcompete the inhibitor for the active site, thereby restoring enzyme activity.

- Additionally, the Reason effectively explains the Assertion as it describes how competitive inhibition can be mitigated, confirming that both statements are true and that the Reason is the correct explanation for the Assertion.

This is the correct answer. Leucoplasts are colourless plastids that generally occur near the nucleus of non-green cells and possess internal lamellae.

The function of GLUT-4 is to enable glucose transport into the cells. GLUT-4 is an insulin-regulated glucose transporter that is responsible for insulin-regulated glucose uptake into fat and muscle cells.

Useful biological products are obtained from transgenic animals to treat disease like Emphysema, Cystic fibrosis and Phenylketonuria.

Topic in NCERT: Biological products

Line in NCERT: "transgenic animals that produce useful biological products can be created by the introduction of the portion of dna (or genes) which codes for a particular product such as human protein (α-1-antitrypsin) used to treat emphysema. similar attempts are being made for treatment of phenylketonuria (pku) and cystic fibrosis."

During G₁ phase, DNA content is 2C.S phase is marked by replication of DNA and the amount of DNA per cell is doubled. During G₂ phase, synthesis of RNA and proteins takes place. During mitosis, DNA content gets equally distributed among two daughter cells.

Line in NCERT: "The interphase is divided into three further phases: G1 phase (Gap 1), S phase (Synthesis), G2 phase (Gap 2)."

In Diploid cells, each homologous chromosome consists of one paternal and one maternal chromosomethat fuse together during fertilization of gametes.

These are membrane bound vesicular structures formed by the process of packaging in the Golgi apparatus.

In 1997, an American company got patent rights on Basmati rice through the US patent and trademark office. This allowed the company to sell a new variety of Basmati in the US and abroad.

Topic in NCERT: Basmati, in the us and abroad

Line in NCERT: "in 1997, an american company got patent rights on basmati rice through the us patent and trademark office."

Microorganisms such as Lactobacillus and others commonly called Lactic Acid Bacteria (LAB) grow it milk and convert into curd. During growth, the LAB produce acids that coagulate and partially digest the milk proteins. A small amount of curd added to the fresh milk as inoculums or starter contain millions of LAB, which at suitable temperature multiply, thus, converting milk to curd, which also improves its nutritional quality by increasing vitamin-B12 Note In our stomach, the LAB play other options are not related with LAB bacteria beneficial role in checking disease causing microbes. 

NCERT Topic: Microbes in human welfare

NCERT Line: "which also improves its nutritional quality by increasing vitamin B,"

The right granted to the company or organization of which others cannot use it is called biopatent. This right is given as intellectual right to the company.

Topic in NCERT: Biotechnology and its applications

Line in NCERT: "the patent extends to functional equivalents, implying that other people selling basmati rice could be restricted by the patent."

Zinc is a cofactor for the proteolytic enzyme carboxypeptidase.

Methanogens are bacteria which grow on cellulosic material and produce a large amount of methane along with CO₂ and H_2.For example: Methanobacterium
Methanogens are the bacteria found in cattle dung (gobar) and in anaerobic sludge during sewage treatment. They grow anaerobically on cellulosic material and produce a large amount of methane (the main constituent of biogas) along with CO₂ and H₂. These methanogens are grown on slurry which comprises of cattle dung where they act upon the dung and lead to its breakdown and release of gases like methane and carbon-dioxide. Thus, methanogens are used in biogas production.

NCERT Topic: Microbes in production of biogas

NCERT Line: "certain bacteria, which grow anaerobically on cellulosic material, produce large amount of methane along with CO2 and H2."

First gene therapy was done in 1990 to a 4 year old girl with a ADA deficiency. ADA enzyme is essential for proper functioning of immune system.