The document describes an experiment with urchin embryos, indicating that at the 8-cell stage, some cells are more determined than others, affecting their ability to develop into adults. It also discusses the role of the casparian strip in plant roots, which prevents water and minerals from entering the stele through the apoplast. Additionally, it highlights the functionality of mitochondria in cellular respiration and compares water potential in plants.

1. B. You do an experiment in which you divide 8 cell stage urchin embryos. In half the embryos,
you use a dn needle to embryo in the horizontal plane while the other half you divide in the
opposite adult each experiment, you get two balls of with cells each. you find that in only group
both sets of cells go on to form a complete adult urchin, In the other group, only half the form
cells urchins. What can you conclude based only on this experiment? VERSION B a. At the 8
cell stage, some of the cells have become more determined than other cells. b. At the 8 cell stage,
some of the cells are mare differentiated than other cells. c There is an inducer molecule that is
causing some cells to develop into an adult. d. None of these are valid conclusions from this 9. In
the process that is depicted in the figure to the right, the role played by the notochord provides a
good example of a. Cytoplasmic segregation b. Induction c, Cleavage 10. In the figure to the
right, the cells that will form the peripheral nervous system are represented by 11. The function
of the Casparian stripls) is to a, prevent water and minerals from entering the stele through the
apoplast, forcing the fluid to cross a cell membrane. b. provide additional ion channels for the
regulation of mineral uptake.
Solution
Answer:
11). A. Prevent wate and minerals from entering the stele through the apoplast, forcing the fluid
to cross cells membrane.
Casparian strip A band of waterproof, corky tissue that is found on the side and walls of the
endodermis of roots. The strip prevents water from entering the pericycle except through the
cytoplasm of endodermal cells; this may be importantin producing root pressure. "Casparian
strip."
12). D. Collenchyma, support
Collenchyma tissue strengthened by the thickening of cell walls, as in young shoots and it gives
mechanical support to plant body.
13). B. Mitochondria
Mitochondria found in both plants and animal. It helps in cellular respiration and release energy.
14). A. Plant 1 has less water.
The water potential increases as the purity of the water increases. If the water has less water
potential means less water and its purity is low. The highest water potential is zero.