Q 01/05

Which gas do plants release as a by-product of photosynthesis?

A) Carbon dioxide

B) Oxygen

C) Nitrogen

D) Hydrogen

Answer · why

B) Oxygen

Oxygen: the plant splits water molecules and releases their oxygen, so the gas comes from water rather than from the carbon dioxide it takes in.

Q 02/05

Which part of the cell is nicknamed the 'powerhouse of the cell'?

A) Nucleus

B) Mitochondrion

C) Ribosome

D) Chloroplast

Answer · why

B) Mitochondrion

Mitochondrion: it even carries its own DNA, inherited from the mother, and that DNA resembles a bacterium's, a clue to where mitochondria came from.

Q 03/05

Which chemical element has the symbol Na?

A) Nickel

B) Sodium

C) Neodymium

D) Potassium

Answer · why

B) Sodium

Sodium: Na comes from natrium, a name taken from natron, the salt ancient Egyptians used to dry out mummies.

Q 04/05

Who discovered cells in 1665 by looking at a slice of cork under a microscope?

A) Robert Hooke

B) Isaac Newton

C) Galileo Galilei

D) Louis Pasteur

Answer · why

A) Robert Hooke

Robert Hooke: what he actually saw were only the walls of the cork's cells, which he likened to the pores of a honeycomb.

Q 05/05

DNA is made of four bases: adenine, guanine, cytosine and which other?

A) Thymine

B) Uracil

C) Glycine

D) Lysine

Answer · why

A) Thymine

Thymine: it always pairs with adenine across the double helix, and it was named after the calf thymus glands it was first isolated from.