GCSE Biology - How do Pregnancy Tests Work? #41

The video explains how pregnancy tests work by detecting the hormone HCG in urine. It describes the role of monoclonal antibodies in the test strip, which bind to HCG if present. The test strip has fixed antibodies and free-moving blue beads with antibodies. If HCG is present, it binds to the beads, causing them to stick to the strip and turn it blue, indicating a positive result. The video also notes that most tests have two lines, with one acting as a control, and emphasizes reading instructions for different tests.

What hormone is detected by pregnancy tests to determine if a woman is pregnant?

• Estrogen

• Progesterone

• HCG

• Testosterone

What is the role of monoclonal antibodies on the right side of the test strip?

• They change color when in contact with urine.

• They are fixed and specifically bind to HCG.

• They are free to move and bind with any hormone.

• They dissolve in the presence of HCG.

What happens to the blue beads if the urine does not contain HCG?

• They dissolve in the urine.

• They flow over the fixed antibodies without binding.

• They change color regardless of HCG presence.

• They bind to the fixed antibodies and change color.

How is a positive pregnancy test result visually indicated?

• The entire strip turns red.

• A single line appears.

• The strip remains unchanged.

• The entire strip turns blue.

Why is it important to read the instructions before using a pregnancy test?

• The instructions contain a warranty.

• All tests have the same design.

• Different tests may have different indicators for results.

• Instructions are only for first-time users.