Biology Questions and Answers

Answer: A

Plants growing in saline water are halophytes, from the Greek halos, salt.

Mangroves are the familiar example. They exclude salt at the root, excrete it through leaf glands, or shed it in old leaves, and many have stilt roots and breathing roots for the waterlogged mud.

Answer: C

The embryo is found in the seed.

It is the young plant formed after fertilisation, consisting of the radicle, plumule and one or two cotyledons, packed with the stored food it will use until it can photosynthesise.

Answer: C

Cancer cells are damaged by radiation because they are undergoing rapid division.

DNA is most vulnerable while it is being replicated and the chromosomes separated, so dividing cells are far more radiosensitive than resting ones. It is also why radiotherapy affects hair follicles, bone marrow and gut lining - the body's other fast-dividing tissues.

Answer: A

Systemic lupus erythematosus is an autoimmune disease.

The immune system makes antibodies against the body's own nuclear material, and the resulting inflammation affects skin, joints, kidneys, heart and brain. Anaphylaxis and farmer's lung are allergic rather than autoimmune.

Answer: A

Blood is slightly alkaline, at pH 7.35 to 7.45.

It is held there by the bicarbonate buffer, by the lungs regulating carbon dioxide and by the kidneys excreting acid. Outside about 6.8 to 7.8 life cannot continue.

Answer: C

Hippocrates is called the father of medicine.

Working on Kos in the fifth century BC, he separated medicine from superstition, insisting that disease has natural causes. The Hippocratic Oath is named after him.

Answer: B

Prokaryotic and eukaryotic cells both contain DNA.

They also share ribosomes, a plasma membrane and cytoplasm. What the prokaryote lacks is a nuclear membrane and every membrane-bound organelle, so its DNA lies free in the cytoplasm as a single circular chromosome.

Answer: C

The oath taken by medical graduates comes from Hippocrates.

The Hippocratic Oath binds the physician to act for the patient's benefit, to do no harm and to keep confidence. Modern graduates usually take a revised version, such as the Declaration of Geneva.

Answer: A

Historia Animalium was written by Aristotle, in the fourth century BC.

It describes and classifies several hundred animals from his own observation and from what fishermen and hunters told him, and is the earliest systematic work of zoology. It is why he is called the father of biology.

Answer: D

Darwin concluded that populations fail to reach their reproductive potential because of selective pressures.

Every species could increase geometrically, yet numbers stay roughly stable. The difference is made up by deaths from competition, predation, disease and shortage - and which individuals die is not random.