Revisione Anno III

Insulin is one of many human proteins that are made by genetically engineered bacteria.

Some people cannot produce insulin because their immune system has destroyed the cells that make insulin.

State the name of the disease caused by the destruction of these cells.

Eye lashes and eye lids are mechanical barriers that help to prevent particles and pathogens entering

the eye. State the name of the white blood cells that digest pathogens.

• phagocytes

• monocytes

• red blood cells

• lymphocyte

Which are both chemical barriers to the transmission of pathogens?

• A mucus and stomach acid

• B mucus and white blood cells

• C skin and hairs in the nose

• D skin and stomach acid

Which body defence is a chemical barrier?

• A antibody production

• B hairs in the nose

• C mucus lining the airways

• D skin

What is a pathogen?

• A a bacterium

• B a disease-causing organism

• C a disease that is transmissible

• D a white blood cell that engulfs bacteria

Carbon dioxide is one of the components of inspired and expired air.

State the name of the chemical used to test for the presence of carbon dioxide

What helps oxygen to be absorbed rapidly into the blood in the lungs?

• A Air breathed in has less oxygen than air breathed out.

• B Alveoli have thick walls and a large surface area.

• C Alveoli have thin walls and a large surface area.

• D The concentration of oxygen in the blood is higher than in the alveoli.

A girl holds her breath for 30 seconds, breathes out, and then breathes in.

Compared with the air she breathes out, the air she breathes in contains less

• A carbon dioxide and water vapour.

• B nitrogen and water vapour.

• C oxygen and carbon dioxide.

• D oxygen and nitrogen.

What makes alveoli suitable as a gas exchange surface?

• A

• B

• C

• D

Respiration occurs in all living organisms.