JAMB Biology Past Questions & Answers - Page 21

Arteries carry blood away from the heart and veins carry blood back to the heart.

Arteries transport blood away from the heart and branch into smaller vessels, forming arterioles. Arterioles distribute blood to capillary beds, the sites of exchange with the body tissues. Capillaries lead back to small vessels known as venules that flow into the larger veins and eventually back to the heart.

If a woman is colorblind, that means she has the nonworking gene on both X chromosomes.

Since sons almost always get their only X chromosome from their mom, chances are they will be colorblind too.

Centromeres are chromosomal regions that mediate kinetochore assembly and spindle attachment during cell division.

In simple organisms, such as cnidarians and flatworms, every cell in the body is close to the external environment.

Their cells are kept moist and gases diffuse quickly via direct diffusion. Flatworms are small, literally flat worms, which “breathe” through diffusion across the outer membrane.

Annelids have a closed circulatory system; the blood is entirely contained in vessels. 

Annelids have no lungs, although many species have simple gills.

Translocation is the movement of materials in plants from the leaves to other parts of the plant.

Nutrients, mainly sugars, are created in the leaves during photosynthesis. These are then transported throughout the plant through phloem, which are a long series of connected cells.