Download 3.5.3 - OpenStudy

3.5.3 Test (TS): Teacher-Scored Unit Test
Test
Biology Sem 1 (S3549303)
Chycora Jenkins
Points possible: 50
Date: ____________
In this test you will apply what you have learned in the unit. Please answer the questions below.
Submit this to your teacher when you are done.
1. Below are the results of an experiment similar to Louis Pasteur’s experiment.
Trials
Observations
Flask 1: Sealed flask of boiled meat broth
Clear; no microorganisms present
Flask 2: Open flask of boiled meat broth
Very cloudy; many microorganisms present
Flask 3: Flask of boiled meat broth with an Sshaped tube
Clear; no microorganisms present
a) How do the results of flask 3 disprove spontaneous generation? (4 points)
It showed that if that when removed of all microorganisms and they did not generate its self again
spontaneously. It was not left out to the air as a contaminate. So it disproved spontaneous generation of
bacteria, proving bacteria only comes from other bacteria.
b) Which part of cell theory do these results most support? (2 points)
The theory says that new cells are formed from other existing cells and the cell is a fundamental unit of
structure, physiology, and organization in all living organisms.
2. Eukaryotic cells have many different specialized structures that are involved in making, organizing, and
delivering a protein molecule. Describe the four organelles that are involved and the sequence of events
of this process. Describe the role of each organelle. (Start with the protein production in the ribosomes.)
(8 points)
3. Cells are usually very small. Why is it an advantage to have many small cells instead of one very large
cell? (3 points)
4. a) What is cell differentiation? Give one example. (4 points)
4. b) Why is it dangerous to a fetus for the pregnant mother to drink alcohol? (3 points)
5. a) Why are embryonic stem cells especially useful in medical research? (2 points)
b) Why is the use of embryonic stem cells controversial? (3 points)
c) Why is it important for science and society to communicate about stem cell research? (3 points)
6. a) Explain the difference between passive transport and active transport. (2 points)
b) Give one example of a molecule using passive transport and one example of a molecule using active
transport. (4 points)
7. A cell sample was placed in saltwater. The researchers wanted to observe the effect of the saltwater
on the cell over a 90-second period.
a) Based on the information in the graph, explain what physical process causes the cell to change size. (3
points)
Osmosis causes the cells to change in size according to the time spent in the salt water.
b) What does this graph tell you about the concentration of salt inside the cell? (3 points)
The concentration of salt inside the cell is low, so then there salt outside the cell pulls the water from
inside the cell outside causing it to shrink in size.
8. Dutch elm disease affects the function of vascular tissue in trees. A tree with the disease reacts by
plugging the vascular tissue with gum. These plugs prevent the disease from traveling up the trunk of the
tree.
a) If xylem tissue is plugged by gum, what other substances are prevented from traveling up the stem? (3
points)
Water and ions, using water contacting cells which are narrow tracheid’s and wider vessel members.
b) Describe how phloem is affected if the leaves start to die off. (3 points)
The phloem is effected by the deprivation of water from the disease of the tree, as a result the
metabolism of the plant will shift down ward causing the phloem to decrease due to the dying of the
leaves.
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