Explanation

• The two strands of DNA run in opposite directions (5' to 3' on one strand and 3' to 5' on the other).
• This orientation is known as antiparallel.
• It is crucial for proper DNA replication and function.

Last verified on 01-10-2026

Explanation

• The nucleus contains the cell’s genetic material (DNA).
• DNA carries hereditary information.
• The nucleus controls many cell activities.
• In prokaryotic cells (like bacteria), DNA is not enclosed in a nucleus; it is found in the nucleoid region.
• Genetic material = DNA.

Explanation

• Total bones in adult human body = 206
• At birth = 270–300 bones (fuse to become 206)

The total bones of our body can be divided into:

• Axial skeleton = 80 bones
• Appendicular skeleton = 126 bones

Additional information:

• Newborn baby has 300 bones
• Longest bone = Femur
• Shortest bone = Stapes
• Bones in human skull = 22

Last verified on 30-03-2026

Explanation

• Antarctic Notothenioids live in extremely cold waters.
• Includes Antarctic icefish and Antarctic cod.
• Can live in seawater as cold as −2°C.

Explanation

• Amylase breaks down starch.
• Starch → Maltose + smaller sugars.
• Found in saliva and pancreatic juice.
• Salivary amylase starts starch digestion in the mouth

Explanation

• O⁻ (O Negative) is the universal donor blood group.
• It can be transfused to A, B, AB, and O blood groups.
• O⁻ blood lacks A, B, and Rh (D) antigens.

Additional information:

• Universal Recipient: AB⁺ (AB Positive)
• ABO Blood Groups: A, B, AB, O
• Rh Types: Positive (+) and Negative (−)
• Total Common Blood Groups: 8 (A⁺, A⁻, B⁺, B⁻, AB⁺, AB⁻, O⁺, O⁻)

Last verified on 14-07-2026

Explanation

• Vitamin C deficiency causes scurvy.
• It can cause bleeding/loose gums, easy bruising, and poor wound healing.
• Other signs include rough skin, corkscrew hair, and red spots around hair follicles.
• Rickets is mainly caused by Vitamin D deficiency.

Last verified on 13-09-2026

Explanation

• Carbon dioxide (CO₂) — the main greenhouse gas causing global warming.

Additional information:

• Methane (CH₄) — potent, from livestock and fossil fuels.
• Nitrous oxide (N₂O) — from fertilizers and industry.
• Water vapor — natural, amplifies warming.
• Fluorinated gases — synthetic, very strong effect.

Explanation

• Heinrich Wilhelm Waldeyer coined the word "neuron" in 1891.
• He based it on the ancient Greek word for sinew or cord.
  
• Neuron theory/doctrine emerged at the end of the 19th century.
• Core claim — Nerve tissue = individual cells; each is a genetic, anatomic, functional, and trophic unit.
  
  Last updated by NA on 09-09-2026

Explanation

• ECG stands for Electrocardiogram.
• It is a test that records the electrical activity of the heart.
• It is commonly used to check heart rate and rhythm.

Last verified on 09-09-2026