Biochemistry quiz

More questions about Biochemistry

These visible examples show the question style. LearnClash turns the full topic into ranked duels and spaced repetition.

1. 1 Easy

   Which vitamin is synthesized when human skin is exposed to sunlight?

   Answer: vitamin D

   Why: Skin makes it from a cholesterol relative when ultraviolet light lands, and above about forty degrees latitude winter sun is too weak for that step.

2. 2 Medium

   Which element serves as the central atom in a chlorophyll molecule?

   Answer: magnesium

   Why: It sits at the centre of a ring closely related to the one in blood pigment, which holds iron in that spot instead.

3. 3 Hard

   Which of the twenty standard amino acids has the highest isoelectric point?

   Answer: Arginine

   Why: Its basic guanidinium group has a pKa around 12.5, keeping it protonated and positively charged at physiological pH.

4. 4 Easy

   What cellular structures assemble amino acids into chains to make proteins?

   Answer: Ribosomes

   Why: A single growing mammalian cell can contain several million ribosomes, dedicating a huge portion of its energy budget purely to protein synthesis.

5. 5 Medium

   Which enzyme allows fireflies to produce light?

   Answer: Luciferase

   Why: A 2008 re-measurement found only about 41% of the reacting luciferin molecules emit a photon, well below the 88% reported in 1960.

6. 6 Hard

   What ratio of carbon, hydrogen, and oxygen defines basic carbohydrates?

   Answer: 1:2:1

   Why: The family name means watered carbon, coined when chemists noticed the formula looked like carbon with water attached.