Punjab Biology 2017 Paper 3 — Solved MCQs

Question 1

The incidence of stones of calcium phosphate is

Accepted Answer

B. 15% — The incidence of calcium oxalate type stones are 70% of all the kidney stones. The incidence of other types of stones of calcium phosphate and of uric acid is 15% and 10% respectively.

Question 2

Lizards bask in the sun to gain:

Accepted Answer

A. Heat — Lizards bask in the sun primarily to gain heat. They are ectothermic animals, meaning they rely on external sources of heat to regulate their body temperature. By basking in the sun, lizards absorb warmth to raise their body temperature, which helps with their metabolism, digestion, and overall activity levels.

Question 3

Cardiac muscles are the muscles of:

Accepted Answer

A. Heart — Cardiac muscles are primarily found in the heart. These muscles are specialized for continuous, rhythmic contraction to pump blood throughout the body. They have unique properties that enable them to contract and relax in a coordinated manner, ensuring the heart's proper functioning as a vital organ in the circulatory system.

Question 4

Which is not unguligrade:

Accepted Answer

D. Bear — Bears are not unguligrade. They are plantigrade, meaning they walk with their entire foot (heel to toe) touching the ground. Bears have flexible feet with five toes that are adapted for walking, climbing, and digging.

Question 5

2,4 D kills broad leaved species:

Accepted Answer

B. Dicots — Dicots, which include many broad-leaved plants like most weeds, flowers, and trees, are highly susceptible to 2,4-D. The herbicide disrupts their growth processes, leading to wilting, yellowing, and eventual death.

Question 6

Luteinizing hormone induces:

Accepted Answer

A. Ovulation — In females, LH surge triggers ovulation, which is the release of a mature egg from the ovary. This surge typically occurs around the middle of the menstrual cycle and is essential for fertility.

Question 7

Plant hormone florigen is produced in:

Accepted Answer

C. Leaf — The leaf is proposed site for the production of florigen. Leaves are known to be involved in various physiological processes, including photosynthesis and hormone synthesis. Some studies suggest that leaves produce florigen in response to environmental cues.

Question 8

In microcephaly, the individuals are born with small:

Accepted Answer

A. Skull — K is the chemical symbol for potassium.

Question 9

The number of chromosomes in sugarcane is:

Accepted Answer

C. 80 — Sugarcane has 80 chromosomes.

Question 10

The most critical phase of mitosis:

Accepted Answer

B. Anaphase — The critical phase of mitosis is typically considered to be anaphase. Anaphase is crucial because it ensures the accurate distribution of genetic material to the daughter cells. During anaphase, sister chromatids, which contain identical copies of the DNA, are pulled apart by the shortening of spindle fibers. This process ensures that each daughter cell receives one complete set of chromosomes, with the correct number and type, necessary for maintaining genetic stability and integrity. Any errors during anaphase, such as unequal distribution of chromosomes, can lead to genetic abnormalities in the daughter cells, making it a critical phase in the process of cell division.

Question 11

The cell death due to tissue damage is called:

Accepted Answer

B. Necrosis — Necrosis is cell death that occurs as a result of external factors such as injury, infection, or toxins. It's typically characterized by swelling, inflammation, and damage to surrounding tissues. Necrosis is considered an uncontrolled and often pathological form of cell death. This type of cell death is characterized by inflammation and damage to surrounding tissues, unlike apoptosis, which is a programmed and controlled process.

Question 12

When a single gene has multiple phenotypic effects, the phenomenon is called:

Accepted Answer

C. Pleiotropy — “PLEIOTROPY” refers to the phenomenon in which a single locus affects two or more apparently unrelated phenotypic traits and is often identified as a single mutation that affects two or more wild-type traits.

Question 13

A commonly used restriction enzyme is:

Accepted Answer

D. Eco R1 — This is the correct and commonly used restriction enzyme. EcoRI recognizes the DNA sequence GAATTC and cuts it between the G and the A, resulting in sticky ends. It's widely used in molecular biology and genetic engineering for cutting DNA molecules at specific sites.

Question 14

Archeobacteria tolerate temperature upto:

Accepted Answer

C. 120°C — A group of bacteria, called archeabacteria can tolerate temperatures up to 120°C.

Question 15

Overgrazing may lead to the transformation of grassland into a:

Accepted Answer

D. Desert — Overgrazing can contribute to the transformation of grasslands into desert ecosystems. Excessive grazing pressure can remove vegetation cover, exposing the soil to erosion and reducing its ability to retain moisture. This can lead to desertification, where the land becomes barren and unable to support significant plant or animal life, resulting in the conversion of grassland into desert.

Question 16

In Sindh, the desert ecosystem is called:

Accepted Answer

A. Thar — In Sindh, this desert ecosystem is called “Thar”.

Question 17

The commercial waste from industry comprises substances called:

Accepted Answer

A. Sewage — It refers to wastewater or liquid waste discharged from domestic, commercial, and industrial sources, including toilets, sinks, showers, and industrial processes.

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