LGS Mixed Practice Test #18

Question 1

Calvin cycle:‌​‍

Accepted Answer

Dark reaction of photosynthesis — CO2 fixation in photosynthesis stroma.‌​‍

Answer

DNA replication

Answer

Glycolysis

Answer

Krebs cycle

Question 2

Compounds with the same molecular formula but different structures are called:‌​‍

Accepted Answer

Isomers — Isomerism: same formula, different arrangement (structural or stereo).‌​‍

Answer

Isotopes

Answer

Isobars

Answer

Allotropes

Question 3

The atomic number of an atom is equal to the number of:‌​‍

Accepted Answer

Protons — Z = number of protons; uniquely identifies an element.‌​‍

Answer

Protons + Neutrons

Answer

Electrons in outer shell

Answer

Neutrons

Question 4

Which of the following best describes the 'Engage' phase of the 5E learning model in a constructivist classroom?

Accepted Answer

A. Students explore concepts through hands-on activities and inquiry to generate new questions. — The 'Engage' phase in the 5E model is designed to capture students' interest and stimulate curiosity by activating prior knowledge and posing questions. Option A aligns with this purpose, while B refers to the 'Explain' phase, C to 'Elaborate,' and D to 'Evaluate.'

Answer

B. The teacher provides direct instruction to clarify misconceptions and reinforce learning.

Answer

C. Students apply their understanding to new contexts through collaborative problem-solving.

Answer

D. The teacher assesses prior knowledge to identify gaps before introducing new content.

Question 5

tan 0° =

Accepted Answer

0 — tan 0° = sin 0°/cos 0° = 0/1 = 0.

Answer

1

Answer

∞

Answer

−1

Question 6

The 'Normal Lapse Rate' — gradual decrease in atmospheric temperature with altitude — is:‌​‍

Accepted Answer

6.4°C per km — Temperature falls ~6.4°C per km of altitude increase.‌​‍

Answer

1°C per km

Answer

10°C per km

Answer

3.2°C per km

Question 7

Most local anesthetics contain a tertiary amine group. This specific functional group is critical for which aspect of their mechanism of action?

Accepted Answer

B. Allowing the drug to exist in an ionized form that can bind to intracellular sodium channels. — The tertiary amine group in local anesthetics allows them to be protonated (ionized) at physiological pH. While the uncharged form crosses the neuronal membrane, the intracellular charged form is essential for binding to the voltage-gated sodium channels from the inside, thereby blocking nerve impulse transmission. The amide linkage, not the tertiary amine, is responsible for resistance to esterase metabolism, and the overall structure is designed for membrane penetration.

Answer

A. Increasing the overall lipophilicity of the drug molecule.

Answer

C. Preventing their metabolism by plasma esterases or hepatic enzymes.

Answer

D. Enhancing the drug's ability to remain in the extracellular space.

Question 8

The Kerala State Government confers the 'Guru Shreshta Award' annually to outstanding teachers. Which of the following would be the most distinguishing quality of a recipient of this award?

Accepted Answer

B. Their innovative pedagogical approaches that foster critical thinking and overall personality development among students. — The Guru Shreshta Award recognizes excellence in teaching. While other options are valuable contributions or indicators of a good teacher, the most distinguishing quality for this specific award is the implementation of innovative teaching methods that go beyond rote learning to cultivate critical thinking and holistic development in students. It emphasizes the quality and impact of teaching over mere longevity or administrative contributions.

Answer

A. Their consistent efforts in improving the school's physical infrastructure and facilities.

Answer

C. Their long tenure of service (e.g., 25+ years) without any disciplinary actions.

Answer

D. Their success in securing 100% pass rates in public examinations for multiple consecutive years.

Question 9

In the context of environmental biotechnology, what is the most significant advantage of employing genetically engineered microorganisms (GEMs) compared to naturally occurring microbial strains for the bioremediation of complex industrial waste containing recalcitrant organic compounds?

Accepted Answer

C. GEMs can be specifically designed to possess novel metabolic pathways or enhanced expression of existing enzymes, leading to more efficient and targeted degradation of specific recalcitrant pollutants. — The primary advantage of genetically engineered microorganisms (GEMs) in bioremediation is their ability to be specifically designed. This engineering allows them to acquire novel metabolic pathways or enhance existing enzymatic activities, enabling more efficient and targeted breakdown of recalcitrant organic pollutants that natural microbes struggle to degrade. While other options present potential outcomes or features, they are either overstatements, not universally true, or secondary to the fundamental engineered capability.

Answer

A. GEMs can naturally adapt to a broader spectrum of extreme pH and temperature conditions, making them universally applicable without prior site assessment.

Answer

B. GEMs are capable of completely mineralizing pollutants into inert inorganic compounds, thereby eliminating all secondary environmental impacts.

Answer

D. GEMs require significantly less incubation time and nutrient supplementation in situ, making them a more cost-effective solution for large-scale environmental clean-up projects.

Question 10

When a science teacher uses a working model of a volcano to demonstrate an eruption, what primary educational objective is being addressed through this teaching aid?

Accepted Answer

B. To provide a safe and concrete simulation of a complex natural phenomenon. — Working models are excellent for simulating complex or dangerous real-world phenomena in a controlled environment. This allows students to visualize and understand processes that would otherwise be abstract or inaccessible, providing a concrete learning experience without risk.

Answer

A. To enhance students' memorization of geological terms.

Answer

C. To reduce the need for textbook reading and note-taking.

Answer

D. To assess students' prior knowledge about volcanoes.

LGS Mixed Practice Test #18