Punjab Biology 2018 Paper 1 — Solved MCQs

Question 1

Archaebacteria can tolerate temperature

Accepted Answer

D. 120°C — Archaebacteria can tolerate temperatures up to 120°C due to their unique membrane lipids and enzymes that remain stable under extreme heat conditions. This adaptation allows them to thrive in environments such as hot springs and deep-sea hydrothermal vents.

Question 2

Biome is a large

Accepted Answer

D. Climax community — Biomes are considered climax communities because they have reached a state of ecological equilibrium, where the dominant plant and animal species are well-adapted to the prevailing environmental conditions and remain relatively stable over time. This stability reflects the balance achieved between biotic and abiotic factors within the biome.

Question 3

The desert ecosystem of Mianwali and Bhakkar is called

Accepted Answer

A. Thal — In Pakistan you can ind the desert ecosystem in western Punjab (Mianwali and Bukhar) where it is known as “Thal”

Question 4

The bone which provides attachment site for muscles

Accepted Answer

A. Compact bone — The correct answer is A) compact bone.A) Compact bone: Compact bone provides strength and support to bones and serves as the primary attachment site for muscles and tendons. It forms the dense outer layer of bones, protecting internal structures and providing a rigid framework for movement.

Question 5

Treasure of all types of resources is

Accepted Answer

D. Water — The correct answer is C) environment.C) Environment: The environment encompasses all living and non-living components of Earth, including air, water, soil, plants, animals, and humans. It encompasses the interactions between these components and influences resource availability and sustainability.

Question 6

A dilute solution compared to cell concentration is termed as

Accepted Answer

B. Hypotonic — Explanation will be added soon.

Question 7

The number of NH3 molecules required to produce one molecule of urea is

Accepted Answer

B. 2 — Explanation will be added soon.

Question 8

Which one is not a joint disease?

Accepted Answer

B. Sciatica — The correct answer is B) sciatica.A) Arthritis: Arthritis refers to inflammation and pain in the joints. It encompasses various conditions affecting the joints, such as osteoarthritis and rheumatoid arthritis.B) Sciatica: Sciatica is not a joint disease; instead, it is a symptom of an underlying condition, such as a herniated disc or spinal stenosis. It involves pain, numbness, or tingling that radiates along the sciatic nerve, which runs from the lower back down the back of each leg.C) Disc slip: Disc slip, commonly known as a herniated or slipped disc, involves the displacement or rupture of the intervertebral discs in the spine. While it can cause pain and discomfort, it primarily affects the spinal discs rather than the joints.D) Spondylolysis: Spondylolysis is a defect or stress fracture in the vertebrae, typically occurring in the lower back (lumbar spine). While it involves the bones of the spine, it is not primarily considered a joint disease.

Question 9

A vehicle for the transport of male gamete in a land plant is

Accepted Answer

B. Pollen tube — The pollen tube acts as a vehicle for the transport of male gametes in land plants because it provides a direct pathway for the sperm cells to travel from the pollen grain to the ovule, facilitating fertilization.

Question 10

Reproduction is necessary for the survival of

Accepted Answer

B. Specie — Reproduction ensures the continuation of species by producing offspring that inherit genetic traits, allowing for adaptation to changing environments and the maintenance of biodiversity. Without reproduction, species would fail to replace aging individuals and face extinction over time.

Question 11

Apoptosis is

Accepted Answer

C. Suicide of cells — Apoptosis is often termed "suicide of the cell" because it is a programmed cell death mechanism initiated by the cell itself in response to various signals or conditions. This self-destructive process helps maintain tissue homeostasis by eliminating damaged, infected, or unwanted cells, ultimately contributing to overall organism health.

Question 12

Cell cycle involves

Accepted Answer

D. Growth of cell, replication of DNA and cell division — 1. Growth: During the cell cycle, the cell undergoes a period of growth where it accumulates nutrients and synthesizes necessary biomolecules to increase its size and prepare for division.2. Replication: The cell replicates its DNA during the S phase of the cell cycle, ensuring that each daughter cell receives a complete set of genetic information. This step is crucial for maintaining genetic integrity and providing the necessary material for division.3. Division: The cell divides into two daughter cells during the M phase (mitosis or meiosis), ensuring the distribution of replicated DNA and cellular components to each new cell. Division is essential for growth, repair, and reproduction in multicellular organisms, enabling the expansion and renewal of tissues and the propagation of genetic material.

Question 13

Resting membrane potential of a neuron is

Accepted Answer

C. -70mV — The resting membrane potential of a neuron is approximately -70mV due to the unequal distribution of ions across the cell membrane, with more negatively charged ions inside the cell than outside. This potential difference is maintained by the sodium-potassium pump and ion channels, contributing to the neuron's readiness to generate and transmit electrical signals.

Question 14

Optimum temperature for the growth of plants is

Accepted Answer

B. 25-30°C — The optimum temperature range for plant growth, typically between 25°C to 30°C, facilitates optimal enzyme activity, photosynthesis, and nutrient uptake. Within this range, metabolic processes are maximized, promoting efficient growth, development, and yield production in most plant species. However, extremes outside this range can inhibit enzyme function, disrupt cellular processes, and lead to reduced growth and productivity.

Question 15

A particular array of chromosomes that an individual possesses is called

Accepted Answer

B. Karyotype — A karyotype is a visual representation of an individual's complete set of chromosomes, arranged and photographed during metaphase of cell division. It provides insight into chromosomal abnormalities, genetic disorders, and sex determination, aiding in clinical diagnosis and genetic research.

Question 16

All the genes found in a breeding population constitute

Accepted Answer

D. Gene pool — The gene pool of a breeding population comprises all the genetic variation present within that population, including alleles for specific traits. This diversity is essential for adaptation, evolution, and maintaining species viability over time.

Question 17

Primer for PCR contains about

Accepted Answer

B. 10-20 bases — Primers for PCR typically contain around 20nucleotide bases, which are short, single-stranded DNA sequences that anneal to complementary regions on the target DNA strands. These primers serve as starting points for DNA polymerase to initiate DNA replication during the PCR process.

Punjab Biology 2018 Paper 1 — Solved Past Paper with Answers

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