2021 - JAMB Biology Past Questions and Answers - page 2

The alveoli are where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out.

Together with the spleen, the liver breaks down worn out red blood cells (erythrocytes)

The villi of the small intestine project into the intestinal cavity, greatly increasing the surface area for food absorption and adding digestive secretions.

In lab, we used Benedict's reagent to test for one particular reducing sugar: glucose. 

Benedict's reagent starts out aqua-blue. As it is heated in the presence of reducing sugars, it turns yellow to orange.

The portal vein or hepatic portal vein (HPV) is a blood vessel that carries blood from the gastrointestinal tract, gall bladder, pancreas, and spleen to the liver.

This blood contains nutrients and toxins extracted from digested contents. 

In Paramecium, Conjugation is a form of sexual reproduction. It is a temporary union of two individuals of same species for mutual exchange of genetic materials.

Through a process called conjugation, two paramecia line up side by side and then fuse together.

The two paramecium separate and go on their way in their watery environment.

They begin again to produce multiple copies of themselves through asexual fission.

During sexual reproduction, the micronuclei of each paramecium undergo meiosis, ultimately halving the genetic content to create a haploid nucleus.

These are exchanged between the two connected mates.

The haploid nuclei from each mate fuse to create a new, genetically varied, micronucleus.

It's discovered that tetraethyl lead (better known as lead) provided octane to gasoline, to fix knocking or pinging in engines that could damage them and waste gasoline.

Extremely high lead levels can lead to seizures, coma, and death.

Schistosomiasis, also known as bilharzia or 'snail fever', is a disease caused by parasites (worms called schistosomes) carried by freshwater snails.

Schistosomiasis control focuses on reducing disease through periodic, large-scale population treatment with medication;

a more comprehensive approach including potable water, adequate sanitation, and snail control would also reduce transmission.

The appendicular skeleton includes the bones of the shoulder girdle, the upper limbs, the pelvic girdle, and the lower limbs.

Aerenchyma is found in hydrophytes like  water lily.

This tissue encloses air and provides buoyancy to the plant parts