STEM Quiz: MCQs for YSC Preparation

Which structure is common to both prokaryotic and eukaryotic cells?

• Nucleus

• Mitochondria

• Ribosomes

• Golgi apparatus

Answer explanation

Ribosomes are essential for protein synthesis and are found in both prokaryotic and eukaryotic cells. In contrast, structures like the nucleus, mitochondria, and Golgi apparatus are specific to eukaryotic cells.

Which of the following is the most abundant protein in the human body?

• Keratin

• Collagen

• Haemoglobin

• Myosin

Answer explanation

Collagen is the most abundant protein in the human body, making up about 30% of total protein content. It provides structure and strength to skin, bones, and connective tissues, surpassing other proteins like keratin and myosin.

In the Hardy-Weinberg equation $p^2 + 2pq + q^2 = 1$, what does $q^2$ represent?

• Homozygous dominant genotype

• Heterozygous genotype

• Homozygous recessive genotype

• Frequency of recessive alleles

Answer explanation

In the Hardy-Weinberg equation, $q^2$ represents the frequency of the homozygous recessive genotype in a population. This means individuals with two recessive alleles.

Which kingdom includes organisms that are autotrophic and eukaryotic?

• Fungi

• Plantae

• Protista

• Animalia

Answer explanation

The kingdom Plantae includes organisms that are autotrophic, meaning they produce their own food through photosynthesis, and eukaryotic, as they have complex cells with a nucleus. Other options do not fit these criteria.

What term describes the symbiotic relationship between fungi and plant roots?

• Commensalism

• Mutualism

• Parasitism

• Competition

Answer explanation

The term 'mutualism' describes the symbiotic relationship between fungi and plant roots, where both organisms benefit. Fungi enhance nutrient absorption for plants, while plants provide carbohydrates to fungi.

The SI unit for the moment of force is:

• Joule

• Newton-meter

• Pascal

• Watt

Answer explanation

The moment of force, also known as torque, is measured in Newton-meters (Nm). This unit represents the rotational effect of a force applied at a distance, making Newton-meter the correct choice among the options.

A ball is thrown vertically upward. At the highest point, its:

• Velocity is maximum, acceleration is zero.

• Velocity is zero, acceleration is maximum.

• Both velocity and acceleration are zero.

• Velocity and acceleration are equal.

Answer explanation

At the highest point of its trajectory, the ball's velocity is zero because it has stopped moving upward. However, the acceleration due to gravity is still acting on it, making the acceleration maximum.

Which wave property determines the pitch of sound?

• Amplitude

• Frequency

• Speed

• Wavelength

Answer explanation

The pitch of sound is determined by its frequency. Higher frequencies correspond to higher pitches, while lower frequencies result in lower pitches. Amplitude affects loudness, not pitch.

What happens to the frequency of light when it enters a medium with a higher refractive index?

• Increases

• Decreases

• Remains the same

• Doubles

Answer explanation

The frequency of light remains the same when it enters a medium with a higher refractive index. While the speed and wavelength change, frequency is determined by the source and does not vary with the medium.

The Doppler Effect applies to which type of waves?

• Only sound waves

• Only electromagnetic waves

• Both sound and electromagnetic waves

• Only transverse waves

Answer explanation

The Doppler Effect occurs when there is a change in frequency or wavelength of waves due to the relative motion between the source and observer. It applies to both sound waves and electromagnetic waves, making 'Both sound and electromagnetic waves' the correct choice.