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Science 9 Review Worksheet 5.2 With Answers
1. How does binary fission in bacteria differ from binary fission in eukaryotic cells?
Bacteria in binary fission just duplicate their single chromosome and split apart. They do not go through
the stages of mitosis like cells with nuclei (eukaryotic cells).
2. How does budding in yeast cells differ from binary fission in amoebas?
When yeast cells bud, one cell is larger than the other, getting most of the cytoplasm.
3. What is fragmentation?
Fragmentation is when parts of an organism break off and then develop into new, complete organisms.
4. What is plant grafting?
Plant grafting is when one plant part is attached to another plant. The attached plant part then grows on
the plant and becomes part of the other plant.
5. What is therapeutic cloning?
Therapeutic cloning is using stem cells to correct health problems by growing them into healthy tissues or
organs that can replace defective ones.
6. Use the following KEY to answer the questions a-e below. KEY: A. binary fission B. budding
C. fragmentation D. vegetative reproduction E. spore formation
a. This reproduction begins as an outgrowth of the parent, then separates to become an
independent organism.
budding
b. This reproduction happens in bacteria.
Binary fission
c. This is a common reproduction method in the hydra.
budding
d. In this kind of reproduction, an animal grows from a piece that has separated from the
parent.
fragmentation
e. This form of reproduction is often used to survive extreme conditions.
Spore formation
7. Compare similarities (if there are any) and differences between budding and binary fission.
In many-celled organisms, budding involves mitosis making a cell mass that forms into a new organism
growing on the parent. Binary fission is happening only in bacteria and involves just the duplication of a
single chromosomes and then splitting the cell into two equal parts. In yeast budding, the chromosomes
are duplicated and separated into two cells which then unevenly divide their cytoplasm leaving one which
is larger and the other smaller.
8. List two multicellular organisms that reproduce by budding.
Sponges and hydras
9. List three ways that plants can reproduce asexually.
Plants can reproduce by fragmentation (Eurasian milfoil), by sprouts (potatoes), by making new bulbs, by
making runners, or by growing new, “baby plants” on stems or leaves.
10. Explain why organisms that reproduce asexually often produce large numbers of offspring.
Often these organisms are food for others so to survive they reproduce in large numbers. They may also
reproduce in large numbers because the chances of getting an offspring to a suitable environment are low.
Science 9 Review Worksheet 5.2 With Answers
11. How do some spores survive unfavourable conditions?
Some spores have tough outer coats that protect them from unfavourable conditions.
12. There is a bacterium on the laboratory bench beside you. What do you think limits the number of
times the bacterium will divide?
If there is food, moisture, low radiation (darker conditions), and the right temperature
13. Why are most multicellular organisms unable to reproduce by budding?
Budding occurs mostly in organisms that move little and most animals move which makes budding a less
practical way to reproduce asexually. Cells of most multicellular organisms become specialized and can
not turn themselves into other kinds of cells again which is needed if an organism is to make a complete
organism from buds.
14. Explain why bacteria do not undergo mitosis.
Bacteria have just one chromosome so it just needs to be replicated and then the cell can divide.
15. How are embryonic human stem cells like plant cells?
Human stem cells can change themselves into any kind of cell like plant cells which reproduce asexually
do (Like growing roots on a stem cut off from a plant.).
16. Sea stars are able to attach to oysters, pry open their shells, and eat the insides. Oyster farmers
once tried to destroy sea stars by cutting them into pieces and throwing them back into the ocean.
Predict what happened and why.
Each piece of starfish became a new complete starfish and there were now more starfish than ever – all
eating the oysters.
17. Why do you think boaters are asked to clean weeds off their motors before entering, and after
exiting a water body?
Pieces of water weed may stay attached to the boat motor and survive long enough so that when the boat
is put into another lake these pieces break off and become entire new water weeds contaminating a new
lake.
18. What are the advantages of asexual reproduction?
Asexual reproduction is fast and can quickly provide large numbers of new offspring. Only a single
parent is needed to make many offspring.
19. What are the disadvantages of asexual reproduction?
Asexual reproduction makes identical clone copies of the parent so if the parent has a health weakness, all
the offspring have the same weakness. Also, many times asexually produced offspring are formed near
their parents and end up competing with their parents for food and space.
20. Compare and contrast reproductive and therapeutic cloning.
In reproductive cloning, an egg cell has its nucleus removed and then a nucleus from some other body cell
from another individual is put into the egg cell which is stimulated to divide into a complete new
individual that is a copy of the one that the nucleus was taken from.
In therapeutic cloning, a stem cell (a general cell from an early embryo stage which can become any kind
of specialized cell) has its nucleus removed and then a nucleus from another individual’s body cell is put
Science 9 Review Worksheet 5.2 With Answers
in it and it is stimulated to become some new tissue or organ to replace some defective tissues or organ in
the individual.