Practice Test - NEET MCQ

At any θ,
T - mgcosθ =

⇒ T = mg cosθ + 
Since v is constant,
⇒ T will be minimum when cos θ is minimum.
⇒ θ = 180° corresponds to Tminimum.

Young's Modulus of elasticity =stress/strain
Y= [F/a/△l/l] ​ or Y= [Fl​/a△l]
or △l= [Fl/aY] ​= Fl​/ πr²Y
In the given problem, △l∝ l​/ r²
When both l and r are doubled, △l is halved.

We know that magnitude of bulk modulus
K=[P/(dV/V)]
Now, percentage change in volume is. 10^-3 %
Therefore, (dV/V)x100=10^-3
So, dV/V=10^-5
Hence, k is,
K=40atm/10^-5=40x1.01x10⁵ /10^-5 =4.04x10¹¹ N/m² 

Force applied on the base is equal to the weight of the liquid, since in both cases the same liquid has been poured in the container, it will exert the same force on the base of the container.
F¹​=F²​

Given:
a=g/2​ 
Pressure at A
P_A​=P_o​+ρgh+(2ρ)g(h−x)=P_o​+3ρgh−2ρgx
Pressure at B
P_B​=P_o​+ρgx
Using
P_A​−P_B​=[2ρ(h+x)+ρ(h−x)]a
∴ (P_o​+3ρgh−2ρgx)−(P_o​+ρgx)=[3ρh+ρx]×g/2​
OR 3ρgh−3ρgx=3​ρgh/2+1​ρgx/2
OR 3​ρgh/2=7​ρgx/2  ⟹x=3​h/7
∴ Difference in the heights between two columns ΔH=(2h−x)−x=2h−2x 
⟹ ΔH=2h−6h/7​=8h/7

 

Since,1st transition series belongs to 3d orbital and 2nd transition series belongs to 4d-orbital. According to the given option, atomic number 39 to 48 (5s²4d^1-10) belongs to second transition series.

Ford-block elements, group number is equal to the number of electrons in (n - 1)d subshell + number of electrons in valence shell (nth shell).

[Kr]4d¹⁰5s⁰

Sc (3d¹ 4s²)has 631 kJ mol^-1 and Zn (3d¹⁰ 4s²) has 906 kJ mol^-1 

Lanthanides, Ce(Z = 58) ñ Lu(Z = 71) and Actinoids comprises of f block elements.

Elements characterized by the filling of 4f orbitals are lanthanides.

group is 15 so total valence electrons will be 5 while period is 3rd so n value of valence shell will be 3.

This is the correct option as statement 'b' is false. Biosynthetic phase reactions occur in stroma or matrix of chloroplasts and do not require light.

ATP is synthesized by cells (in mitochondria and chloroplasts) is named phosphorylation.

• In the photorespiratory pathway, there is no synthesis of ATP or NADPH. Therefore, photorespiration is a wasteful process.
• In C₄ plants photorespiration does not occur. This is because they have a mechanism that increases the concentration of CO₂ at the enzyme site.

Jan Ingenhousz's experiments with an aquatic plant showed that in bright sunlight, small bubbles containing oxygen were formed around the green parts of the plant, while in the dark, they did not. This demonstrated that sunlight is essential for the process by which plants release oxygen.

• Electrons from excited chlorphyll molecule of photosystem II are accepted first by Quinone.
• Photosystem II is a photosynthetic pigment system along with some electron carriers that is located in the appressed part of the grana thylakoids.
• Photosystem II has chlorophyll a, b and carotenoids. Other components of PS II are phaeophytin, plastoquinone (PQ), cytochrome complex and blue coloured copper-containing plastocyanin.

In C₄ plants, Carbon dioxide is fixed in malic acid with the help of enzyme phosphoenel pyruvate (PEP). Malic acid is a four-carbon compound that later changes into oxaloacetic acid.

Dark reaction of Carbon dioxide fixation in CAM plants is called as ossification because it produces Malic acid. These plants open their stomata during night to prevent transpiration.

The organism that depends on dead and decaying organic matter is called a saprophyte. Saprophytes are a type of decomposer that obtain their nutrients and energy by breaking down dead plant or animal material. They play a vital role in the ecosystem by recycling nutrients and returning them to the environment for other organisms to use. 

Example: Moulds, Mushroom etc. 

• Autotrophs, on the other hand, are organisms that can produce their own food using inorganic substances and an external energy source, such as sunlight. They convert carbon dioxide and water into organic compounds through the process of photosynthesis (in plants) or chemosynthesis (in some bacteria). Autotrophs do not rely on dead organic matter for their nutrition.
• Carnivores are organisms that primarily consume the flesh of other animals. They obtain their energy and nutrients by hunting and feeding on other living organisms, rather than on dead organic matter.
• Herbivores are organisms that primarily consume plant material. They obtain their energy and nutrients by feeding on plants or plant parts. Herbivores generally do not depend directly on dead and decaying organic matter as their main source of nutrition.

Energy is a fundamental requirement for all living organisms to carry out their various biological processes. Within cells, energy is stored and transferred in different molecules. The molecule that primarily stores and transfers energy in living systems is called adenosine triphosphate, or ATP.

A: FAD (Flavin adenine dinucleotide) is another molecule involved in energy transfer within cells, but it is not the primary molecule for energy storage.

B: NADH (Nicotinamide adenine dinucleotide) is an important molecule in cellular respiration, which is involved in the transfer of electrons and hydrogen ions during energy production. While it plays a role in energy transfer, it is not the primary molecule for energy storage.

D: ADP (Adenosine diphosphate) is the molecule that forms when one phosphate group is removed from ATP. It is the "lower energy" form of ATP and can be converted back into ATP by adding a phosphate group. However, it is not the primary molecule for energy storage.

The TCA cycle begins with a condensation reaction. In this step, an acetyl group, derived from the breakdown of glucose or fatty acids, combines with oxaloacetic acid (OAA), a four-carbon molecule, in the presence of water. This condensation reaction forms a six-carbon compound called citric acid or citrate.

The complete reaction is as follows:
Acetyl-CoA + OAA + H₂O → Citric Acid (Citrate)

The condensation step is significant because it marks the entry of the acetyl group into the TCA cycle and the beginning of a series of enzymatic reactions that ultimately lead to the release of energy and the regeneration of OAA.

During anaerobic respiration, less energy is produced compared to aerobic respiration because incomplete oxidation of glucose occurs. Anaerobic respiration occurs in the absence of oxygen, typically in situations where oxygen is not readily available or during strenuous exercise when oxygen demand exceeds supply.

The two molecules of pyruvic acid (produced from one glucose molecule during glycolysis). The acetyl CoA then enters a cyclic pathway, tricarboxylic acid cycle, more commonly called as Krebs’ cycle. Thus, acetyl-CoA interconnecting between two cyclic pathways.

Plants unlike animals have no special systems for breathing or gaseous exchange. Stomata and lenticels allow gaseous exchange by diffusion.

(a) Stomata: Stomata are tiny openings present on the surface of leaves, primarily on the underside. These openings are surrounded by specialized cells called guard cells. Stomata regulate the exchange of gases, including the intake of carbon dioxide (CO₂) for photosynthesis and the release of oxygen (O₂) and water vapor (H₂O) during transpiration. Stomata play a crucial role in the gas exchange process in plants.

(d) Lenticels: Lenticels are small openings or pores in the bark of woody plant stems. They allow for gaseous exchange between the internal tissues of the stem and the external environment. Lenticels facilitate the exchange of gases, such as oxygen (O₂) and carbon dioxide (CO₂), in stems and other woody parts of plants.

Acetyl CoA is a 2-carbon compound and 3-phosphoglycerate molecule enter into cyclic reactions during Calvin cycle.

Aerobic respiration is the process that leads to a complete oxidation of organic substances in the presence of oxygen, and releases carbon dioxide, water and a large amount of energy present in the substrate. This type of respiration is most common in higher organisms.

Aerobic Respiration:

Fermentation is a kind of anaerobic respiration in absence of oxygen to produce ethanol and carbon dioxide gas. Dough kept overnight in warm place becomes soft and spongy due to carbon dioxide gas released during fermentation.

Phosphofructokinase is a kinase enzyme that phosphorylates fructose-6-phosphate in glycolysis. The enzyme catalysed transfer of a phosphoryl group from ATP is an important reaction in a wide variety of biological processes.