Download 1.1 Check and Reflect Answers

1.1 Check and Reflect answers
Key Concept Review
1. The life processes that cells perform are: intake of nutrients,
movement, growth, respond to stimuli, exchange of gases, waste
removal, and reproduction.
2. The five organelles and their functions that are common to plant
and animal cells are the nucleus (control centre of cell), Golgi
apparatus (modifies, sorts, and packages proteins for delivery
throughout cell or out of cell), endoplasmic reticulum (carries
materials through the cell), cytoskeleton (maintains the cell’s
shape), and mitochondrion (supplies energy to the cell).
3. Three differences between plant and animal cells are:
• that plant cells have cell walls while animal cells have cell
membranes only
• that plant cells have chloroplasts (animal cells do not have
chloroplasts)
• that animal cells have centrioles that are involved in cell
division while plant cells do not
4. Granum and thylakoid structures can be described as solar
collectors because they collect the light energy from the Sun,
which is used in photosynthesis.
5. TABLE 1.1 Structures and Organelles in Cells
Cell Structure or
Organelle Animal or Plant Cell
cell membrane animal and plant cells
cytoplasm animal and plant cells
nucleus animal and plant cells
cell wall plant cells
chloroplast plant cells
vacuole animal and plant cells
vesicle animal and plant cells
rough endoplasmic
reticulum
animal and plant cells
ribosome animal and plant cells
smooth endoplasmic
reticulum
animal and plant cells
lysosome animal and plant cells
Golgi apparatus animal and plant cells
mitochondrion animal and plant cells
cytoskeleton animal and plant cells
6. Fluorescence microscopy works using a special fluorescent
substance that is added to the cells. When the stained cell is placed
in ultraviolet light, the fluorescent substance glows.
7. Students’ answers may vary but could include the transmission
electron microscope and scanning electron microscope.
8. An electron micrograph is created by an electron microscope.
9. The cell is the building block of life because all living things are
made of cells, which perform all the basic functions of life (take in
nutrients, exchange gases, reproduce, grow, move, and remove
wastes).
10. Sometimes it is difficult to see the cell parts because both the cell
and the background may be transparent or blend into each other.
Contrast makes it possible to differentiate the cell parts from the
background.
11. Students’ answers may vary but could include adding a stain, such
as methylene blue or iodine, changing the light levels, or adding a
fluorescent substance and using ultraviolet light.
Connect Your Understanding
12. Students’ answers may vary but could include the following: A cell
biologist may use an electron microscope to get a greater
magnification (300 000 to 1 500 000× magnification) or to create a
three-dimensional image of the cells. A light microscope would be
better for looking at living samples.
13. To determine the total magnification, you need to know the
magnification of the ocular lens and the magnification of the
objective lens.
14. You would expect the cells of a desert plant to have thick cell walls
to reduce the amount of water the plant loses. Plants that live in the
desert need to conserve water.
15. Students’ answers may vary but could include the following: We
would expect to see more mitochondria in the cells taken from the
athlete’s leg muscle because those cells would need more energy
due to active use (muscles need a great deal of energy during
activity). The cells from the skin of an elderly person would have
fewer mitochondria because skin cells do not need as much energy.
16. Students’ answers may vary but could include the following: A
microscope can be used to check the health of the cells, to check
the number of different cells (e.g., red and white blood cells), and
the appearance of the cells.
17. Students’ answers may vary but could include the following:
• plant cells have cell walls while animal cells have cell
membranes only
• plant cells have chloroplasts (animal cells do not have
chloroplasts)
36 Unit A: Tissues, Organs, and Systems of Living Things
• plant cells have a large central vacuole
• animal cells have centrioles, which function in cell division
• plant cells store energy in the form of starch or oils
• animal cells store energy in the form of glycogen or in the form
of fats
• some animal cells have specialized compounds; for example,
red blood cells contain hemoglobin
18. Students’ answers may vary but could include the fact that
microscope technology has allowed scientists to see cells and their
internal structures. These observations have helped scientists
understand how cells work.
Reflection
19. Students’ answers may vary but could include the differences
between plant and animal cells, the different