JAMB Biology Past Questions & Answers - Page 36

176.

The body of a snail is divided into head...

A.

thorax and abdomen

B.

visceral mass and abdomen

C.

thorax and foot

D.

visceral mass and foot

Correct answer is D

A snail's body consists of these main parts – the head, the visceral hump, and the foot

177.

Which of the following is a characteristics of a bacteria except _______?

A.

they can be seen under microscope

B.

they range from 0.5 ยต m in diameter

C.

They are grouped accordingly to their cell shape

D.

they do not cause disease

Correct answer is D

Bacteria is a disease- causing organism, hence all other options hold true except this one.

178.

What organelle is the site of photosynthesis in plants?

A.

Chloroplasts

B.

Ribosomes

C.

Cytoplasm

D.

Mitochondria

Correct answer is A

Chloroplast is the combination of two biological terms, plastid (an organelle in a plant cell), and chloros, which means green. chlorophyll which is an important pigments for photosynthesis.

A ribosome is a complex cellular mechanism used to translate genetic code into chains of amino acids. Long chains of amino acids fold and function as proteins .

The jellylike material that makes up much of a cell inside the cell membrane, and, in eukaryotic cells, surrounds the nucleus.

Mitochondrial is a spherical or elongated organelle in the cytoplasm of nearly all eukaryotic cells, containing genetic material and many enzymes important for cell metabolism, including those responsible for the conversion of food to usable energy.

179.

Agglutination is the _______ of the ________

A.

coagulation, white bloodcell

B.

coagulation, water

C.

white blood cells, red blood cell

D.

coagulation, red blood cell

Correct answer is D

The clumping of cells such as bacteria or red blood cells in the presence of an antibody or complement.

During blood transfusions, the antibodies react with the transfused blood group(if its of different blood group), the erythrocytes clump up and stick together causing them to agglutinate.

180.

Ability to taste PTC in some individuals is a character that is

A.

acquired

B.

heritable

C.

sex-linked

D.

morphological

Correct answer is B

PTC(phenylthiocarbamide) has the unusual property that it either tastes very bitter or is virtually tasteless, depending on the genetic makeup of the taster. The ability to taste PTC is often treated as a dominant genetic trait, although inheritance and expression of this trait are somewhat more complex.

To some people, small amounts of the compounds phenylthiocarbamide (PTC) taste very bitter; other people do not taste these compounds. The myth is that there are only two kinds of people, tasters and non-tasters, and that the trait is controlled by a single gene, with the allele for tasting dominant over the allele for non-tasting.
∴ ability to taste PTC in some individuals is a character that is heritable.