HW 4
1. 1 meter = _____ centimeters.
1,000
1,000,000
1,000,000,000
100
1,000,000,000,000
2. Which of the following choices correctly matches a tool and its proper application?
View Available Hint(s)
scanning electron microscopy (SEM) to study the detailed movements of living cells
light microscopy to study the internal structure of cilia
transmission electron microscopy (TEM) to study the movement of organelles within a living cell
cell fractionation to study the function of specific organelles
transmission electron microscopy (TEM) to study the surfaces of preserved cells
3. _____ are surface appendages that allow a bacterium to stick to a surface.
Flagella
Fimbriae
Mitochondria
Ribosomes
Cell walls
What is a function of a bacterium's capsule?
DNA storage
propulsion
protein synthesis
protection
The DNA-containing region of this bacterial cell is indicated by the letter _____.
Where is a bacterial cell's DNA found?
ribosomes
nucleus
peroxisome
nucleoid region
capsule
In a bacterium, where are proteins synthesized?
ribosomes
nucleus
peroxisome
nucleoid region
capsule
What name is given to the rigid structure, found outside the plasma membrane, that surrounds and supports the bacterial
cell?
capsule
pili
cell wall
flagella
nucleoid region
The _____ is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave
the cell.
plasma membrane
nucleoid region
ribosome
pili
cell wall
The structure that regulates the passage of material into and out of this bacterial cell is indicated by the letter _____.
4. Beginning within the nucleus, the first step leading to the synthesis of a polypeptide is _____.
translation of an RNA nucleotide sequence into a sequence of amino acids
linking of nucleotides to form a polypeptide
removal of introns from RNA and the stitching together of exons
transferring of information from DNA to messenger RNA
translation of a DNA nucleotide sequence into a sequence of amino acids
5. Which organelle plays a role in intracellular digestion?
plasmodesma
ribosome
Golgi apparatus
lysosome
chloroplast
6. Mitochondria are found in _____.
View Available Hint(s)
plant cells only
animal cells only
plant and animal cells
all cells
animal cells and prokaryotic cells, but not plant cells
7. Plant cells and animal cells share many of the same structures, but each type of cell also has unique structures. In
this activity, you will indicate which cell structures are found only in plant cells, only in animal cells, or in both plant and
animal cells.
Drag each cell structure to the appropriate bin. If a structure is found in both plant cells and animal cells,
drag it to the "both" bin.
Nucleus | chloroplast | mitochondrion | golgi apparatus | central vacuole | centriole | cytoskeleton | plasma
membrane | cellulose cell wall | endoplasmic reticulum
Plant cell only:
Animal cell only:
Both:
Drag the correct description under each cell structure to identify the role it plays in the plant cell.
Makes sugar by converting light energy into chemical energy
A)
B)
C)
D)
E)
Regulates cytoplasm composition, creates internal pressure, and stores cell compounds
Modifies and packages proteins
Strong, protective structure made from cellulose fibrils
Houses the genetic information of the cell
Produces chemical energy (ATP) that can power the cell
___ plant cell wall
___ central vacuole
___ chloroplast
___ mitochondrion
___ golgi apparatus
The structure of a chloroplast is closely tied to its function as the site of photosynthesis.
Some of the following statements are true for chloroplasts; others are true for mitochondria.
Which statements are true for chloroplasts? Select the three that apply.
They are the sites of reactions that convert chemical energy from food molecules to ATP.
Their inner membrane has infoldings called cristae.
They are the sites of reactions that convert solar energy into chemical energy.
Their matrix contains enzymes that function in cellular respiration.
They contain the green pigment chlorophyll.
They have membranous sacs called thylakoids that are surrounded by a fluid called stroma.
8. Part A – diagram skip
Part B – comparing eukaryotic and prokaryotic cells
Lysosome | nucleoid | flagella | mitochondria | plasma membrane | ribosomes | nucleolus
Prokaryotic only:
Eukaryotic only:
Both:
Part C – diagram skip

1. In eukaryotic flagella, the fibers that slide past one another due to the activity of dynein proteins are microtubules .

2. Many cell organelles, most notably the nucleus, are anchored by intermediate filaments which are assembled
from a diverse class of proteins.

3. Centrosomes are sites where protein dimers assemble into microtubules .

4. The extension of pseudopodia in amoeba is due to the regulated assembly and destruction of microfilaments .

5. The only cytoskeletal fibers not associated with intracellular movement or whole cell locomotion are
the intermediate filaments .

6. During muscle contractions, myosin motor proteins move across tracks of microfilaments .
9.
Structure: desmosomes | cellulose | plasmodesmata | gap junctions | collagen | tight junctions
Pick one: Plant or animal
1) Membrane protein complexes that strengthen the adhesion between adjacent cells, like rivets, to
protect against pulling forces
2) Small channels that form across the plasma membranes of adjacent cells; especially important in
intercellular communication
3) Membrane proteins that create a watertight seal between cells
4) Small channels between cells that are otherwise surrounded by walls; enable movement of water and
solutes between cells
5) A polysaccharide that is used to synthesize cell walls, which protect cells and help maintain their shape
6) Long fibers of protein found in the extracellular matrix that provide structural support for cells
ANSWER KEY:
1. 100 cm
2. cell fractionation to study the function of specific organelles
3.
a. a. Fimbriae
b. b.protection
c. c. D
d. d. nucleoid region
e. e. ribosomes
f. f. cell wall
g. g. plasma membrane
h. h. C
4. transferring of information from DNA to messenger RNA
5. lysosome
6. plant and animal cells
7.
a. plant cell only: chloroplast, cellulose cell wall, central vacuole
animal cell only: centriole
both: mitochondrion, ER, cytoskeleton, golgi, nucleus, plasma membrane
b. plant cell wall: strong, protective structure made from cellulose fibrils
central vacuole: regulates cytoplasm composition, creates internal pressure, and stores cell compounds
chloroplast: makes sugar by converting light energy into chemical energy
mitochondrion: produces chemical energy (ATP) that can power the cell
golgi apparatus: modifies and packages proteins
c.
They are the sites of reactions that convert solar energy into chemical energy.
They contain the green pigment chlorophyll.
They have membranous sacs called thylakoids that are surrounded by a fluid called stroma
8. PART A
a.
b.
c.
d.
e.
f.
g.
Synthesizes lipids
Assembles ribosome
Defines cell shape
Produces secretory proteins
Modifies and sorts proteins
Digests proteins
Generates ATP
PART B
Prokaryotic only: nucleoid
Eukaryotic only: mitochondria, lysosome, nucleolus
Both: ribosomes, flagella, plasma membrane
PART C
1.
2.
3.
4.
5.
6.
Microtubules
Intermediate filaments
Microtubules
Microfilaments
Intermediate filaments
Microfilaments
9.
a.
b.
c.
d.
e.
f.
1. Desmosomes – animal
2. Gap junctions – animal
3. Tight junctions – animal
4. Plasmodesmata – plant
5. Cellulose – plant
6. Collagen - animal