Answers and
Explanations
1) The correct answer is 3. Monera
(prokaryotes) lack a membrane-bound nucleus and are almost all
unicellular.
2) The correct answer is 3. Only
chloroplasts and mitochondria are capable of reproducing
themselves and have their own genomes.
3) The correct answer is 1.
Centrioles function in cell division of animals, but are rarely
found in plants; chloroplasts are lacking in animals and the
endoplasmic reticulum and Golgi apparatus are present in both
animals and plants.
4) The correct answer is 2. All of
the other answers relate to factors that affect the rate of
enzyme action. Enzymes function better at or near a particular pH
(pH optimum). A greater concentration of substrate or enzyme will
also increase the rate of enzyme activity. Nearby Golgi
complexes, on the other hand, will exert no special effect on
nearby enzymes.
5) The correct answer is 2.
Lysosomes are membrane bound, eukaryotic organelles which contain
enzymes. These enzymes are used to hydrolyze (digest) cells such
as bacteria or other materials taken in by the white blood
cell.
6) The correct answer is 4. Most
human enzymes break down at temperature above body temperature,
which is 37° Celsius; cooler temperatures slow enzymes down but
do not denature them.
7) The correct answer is 3. The word
arthropod means "jointed foot." Of the animals listed,
only arthropods have exoskeletons.
8) The correct answer is 2. Salt is
the only answer that specifies an inorganic compound. Glucose,
maltase (an enzyme that hydrolyzes maltose), and cellulose are
all organic, carbon-based compounds.
9) The correct answer is 1. The ions
which make up the various salts usually require active transport
to move across cell membranes, and active transport is always
required to move ions against a concentration gradient (that is,
from a region of lower concentration to a region of higher
concentration). This is an unusual use of the word "transport"
which elsewhere refers to the circulatory system.
10) The correct answer is 1. Cell
theory was developed during the 1830s and 1840s, at a time when
light microscopes first began to reveal details of tissues and
cells. Improved optics and microscopical techniques made this
possible. The five-kingdom classification system and
gene-chromosome theory are twentieth century ideas. Bacteria and
viruses were discovered in the latter part of the nineteenth
century.
Other practice
questions:
