NEET Unit Test - 4 - NEET MCQ

• Structure (I): This structure has complete octets for all atoms and does not involve any formal charges, making it the most stable.
• Structure (II): This structure has a negative charge on the oxygen atom, which is highly electronegative, and a positive charge on the carbon atom. While it is less stable than (I), the placement of charges is still reasonable due to oxygen's electronegativity.
• Structure (III): This structure is the least stable because it places a positive charge on the less electronegative carbon atom and a negative charge on another carbon atom, leading to less favorable charge distribution.

Thus, the stability order is (I) > (II) > (III).

The efficiency of a heat engine is defined as the ratio of work done to the heat supplied, i.e.,

where T₂ is temperature of sink,
and T₁ is temperature of hot reservoir.

F = YA (∆l/l)
F = Mg, Y = Sy, A = A using this we get
So, Mg ≤ Sy x A => A ≥ Mg/Sy

We know that dq = dU + dW
And as dU =  60 and dq = 140J
We get dW = 140 - 60 = 80J

Displacement is the shortest distance between initial and final positions. When final position of a body coincides with its initial position, the displacement is zero, but the distance travelled is non-zero.

In the given graph temperature remains constant with variation in volume. So the process is isothermal and PV = constant.

Using E = mc²

Comparing both quantities,

for the first particle , we have

for the second particle, we have

Phase difference between the velocity of the first and second partcile

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

Acetic acid salt on heating with soda lime gives methane.

The correct answer is Option B.
 
5 isomers are possible. C₅H₁₀(C_nH_2n). Molecules having the CnH2n formulas are most likely to be cyclic alkanes. The five isomers are:

(1)   Cyclopentane 
(2) 1-Methylcyclobutane  
(3) 1-Ethylcyclopropane 
(4) 1,1-Dimethylcyclopropane 
(5) 1,2-Dimethylcyclopropane
 

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

Since the solubilities of A and B are quite different, the technique of recrystallisation can be used to separate A and B from their mixture.

(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 reactions is called Kolbe's electrolysis.

Dendrites  are short fibres which branch repeatedly and protrude out of the cell body. One of the fibres arising from the cell body is very long with a branched distal end and it is called Axon. 

Zinc is a cofactor for the proteolytic enzyme carboxypeptidase.

This is the correct option. Leeuwenhoek was the first to observe, describe and sketch a free living cell.

Egg yolk contains lampbrush chromosome where two homologous chromosomes with several chiasmata with several loop in chromatic region is found.

Two equatorial plates are formed by centromeres in metaphase 1 of meiosis.

Second messengers are molecules that relay signals received at receptors on the cell surface to trigger physiological changes. Nitrogen oxide (NO) acts as second messenger

This is the correct option. Food vacuoles occur in the cells of protozoan protists, several lower animals and phagocytes of higher animals.

The plasma membrane is composed of lipids that are arranged in a bilayer. Also, the lipids are arranged within the membrane with the polar head towards the outer sides and the hydrophobic tails towards the inner part. The membrane proteins can be classified as integral or peripheral. Peripheral proteins lie on the surface

pituitary thyroid hormone is also called as collip’s hormone. Cortisol is called as glucocorticoid hormone. Aldosterone is called as mineralocorticoid andsomatostatin is called as inhibiting hormone.

The shape of Spirillum bacteria is coiled like a cork-screw. Many spirilla are rigid and capable of movement. A special group of spirilla known as spirochetes are long, slender, and flexible.

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.

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

Centrosome is an organelle usually containing two cylindrical structures called centrioles. They are surrounded by amorphous pericentriolar materials. Both the centrioles in a centrosome lie perpendicular to each other in which each has an organisation like the cartwheel. They are made up of nine evenly spaced peripheral fibrils of tubulin protein. Each of the peripheral fibrils is a triplet. The adjacent triplets are also linked.

Prophase is the most elaborate stage of cell division.

• In early prophase, chromatin condenses.
• In mid prophase, chromosomes shorten and become distinct with each having two chromatids attached to a narrow point called centromere.
• In late prophase, centrosomes reach the poles, form asters and begin to develop spindle fibres. Cells, when viewed under microscope at the end of prophase, do not show Golgi complex, endoplasmic reticulum, nucleolus and nuclear envelope.

Pineal secretes a hormone called melatonin.