Just like the ABO alleles, each biological parent donates one of their two alleles to their child. A mother who is Rh- can only pass an Rh- allele to her son or daughter. A father who is Rh+ could pass either an Rh+ or Rh- allele to his son or daughter. This couple could have Rh+ children (Rh- from mother and Rh+ from father) or Rh- children (Rh- from mother and Rh- from father).
olecules can diffuse across membranes via transport proteins, or they can be aided in active transport by other proteins. Organelles such as the endoplasmic reticulum, Golgi apparatus, mitochondria and peroxisomes all play a role in membrane transport.
