Biology Journal 8/27/2015
The DNA of a prokaryote is called
“naked.” Why is that? What’s different
about the DNA of a eukaryote and a
prokaryote?
Unit 1: Cell Biology
Review Questions
What kinds of cells make up…
1.
2.
3.
4.
5.
A human
A bacteria
An ant
E. coli
A bananna
Eukaryote
Prokaryote
Eukaryote
Prokaryote
Eukaryote
What kinds of cells would
have…
1. A chloroplast
2. 70s Ribosomes
3. A plasma
membrane
4. Mitochondria
5. Reproduce by
binary fission
6. Cell wall (any
kind)
Plant cell
Prokaryote (bacteria)
Every kind of cell!
Every eukaryote
Prokaryote (bacteria)
Prokaryote, Plant
cell, fungi cell
Make a drawing of a prokaryote cell and label the following
structures: cell wall, pili, flagella, and plasma membrane
enclosing cytoplasm that contains 70S ribosomes and a
nucleoid with naked DNA.
.
Nucleoid
Region where naked DNA can be
found; may have plasmids
(loops of “extra” DNA, which can
introduce new genes)
Cytoplasm
Jelly-like
substance
Flagella
Whip like; allows the cell
to move
Cell
Membrane
Made out of
phospholipids;
controls what
enters and
leaves cell
Cell Wall
Made out of
peptidoglycan
(mesh of amino
acids and
sugars)
Pili
Allows cells to connect
and exchange DNA
(sexual reproduction)
70S Ribosomes
make protein
Make a drawing of a eukaryotic plant cell and label the
following structures: plasma membrane enclosing cytoplasm
that contains 80S ribosomes and a nucleus, mitochondria,
chloroplasts, vacuole, and cell wall.
Plasma membrane
Mitochondria
Free 80S ribosomes
Lysosomes
Cytoplasm
Nucleus
Golgi apparatus
Rough Endoplasmic
Reticulum
Nucleus
DNA in a membrane
Mitochondria
Makes energy by
doing cellular
respiration
Vacuole
Large compartment
for storage of water
or other molecules
80S Ribosomes
They make protein;
sometimes attached
to ER
Cytoplasm
Jelly-like substance
Endoplasmic
Reticulum
Transports molecules; can
have ribosomes attached
(rough) or none (smooth)
Golgi Complex
Makes vesicles for molecules to
enter or leave the cell
Chloroplast
Makes glucose by doing
photosynthesis
Cell Wall
• In plant cells, it is made out of cellulose (a
carbohydrate)
• In fungi, it is made out of chitin (a carbohydrate)
• Animal cells don’t have one
Explain why there is a limit to
the size of a cell.
Cells are limited by a surface-tovolume ratio. This is because all
areas of the cell need to be close
enough to the surface area to
efficiently exchange nutrients and
wastes. Thus, cells must stay small
to survive.
What is a stem cell?
Describe how they might be useful in the
treatment of a particular disease.
A stem cell is a cell that has the ability to
differentiate, becoming other types of cells in the
body. They can replace any damaged tissues in
the body.
•
•
•
Replace retina tissue to cure failing sight
(Stargardt’s disease)
Replace damaged heart tissue from a heart attack
Replace killed bone marrow (leukemia)
A cell is 10 µm across. A student draws it as 250mm
wide. What is the magnification?
You don’t have to
draw it, but you can
if that helps!
Measured length
Actual size =
Magnification
250 mm
10 µm =
10 µm =
x
250,000 µm
Solve for x
x
25,000
times
X= 25000
magnified
Convert to the same
1000 µm
units before you divide! 250 mm
x
1 mm
= 250,000 µm
What 2 organelles are believed to have originated
as a result of the Endosymbiotic Theory?
Mitochondria and Chloroplasts!
Identify the structures in this false-colored microscopic image of a human liver cell
2
1
3
7
4
5
6
Identify the structures in this false-colored microscopic image of a human liver cell
1. Cytoplasm
2. Mitochondria
3. Ribosomes
(free)
7. Plasma
membrane
4. Nucleus
5. Endoplasmic Reticulum
(rough)
6. Lysosome
Identify the structures in these false-colored microscopic images
3
1
4
5
6
2
Identify the structures in these false-colored microscopic images
3. Cell membrane
1. Cell wall
4. Cytoplasm
(the darker spheres are ribosomes)
5. Pili
6. Flagella
2. Nucleoid region
(where DNA is located)
A microscope has the
objective lenses of 4x, 10x,
and 40x. The ocular eye
piece has a magnification of
10x. What is the maximum
magnification of this
microscope?
40 x 10 = 400 times magnification
Here is a human hair magnified 400 times.
What could be 3 pieces of
evidence that support the
endosymbiotic theory?
Mitochondria / chloroplasts have…
1. a double membrane
2. Their own DNA and ribosomes
3. Are the same size and bacteria
4. Reproduce via binary fission
when their cell divides
What kind of cell is this? What are 3
reasons you know that?
It’s a plant cell. (it’s also a eukaryote
because it has organelles)
It has a large
vacuole
It has
chloroplasts
It has a cell
wall
Compare and contrast eukaryotes and prokaryotes in a
Venn diagram.
Eukaryotes
Both
Prokaryotes
Compare and contrast eukaryotes and prokaryotes in a
Venn diagram.
Eukaryotes
Both
Prokaryotes
•Large and more complex
•Have a cell membrane
and cytoplasm
•Small and simple
•Has a nucleus and
organelles
•Reproduce through
asexual cell division
•Lacks a nucleus and lacks
organelles
•DNA is linear and in
many pieces
(chromosomes)
Have ribosomes (but they •DNA is circular and in
are different)
one piece (usually)
•Cells divide through
mitosis
•Cells divide through
binary fission
•Have 80s ribosomes
•Have 70s ribosomes
•Attaches and transfers DNA
through pili
Compare and contrast plant and animal cells in a
Venn diagram.
Plant
Both
Animal
Compare and contrast plant and animal cells in a
Venn diagram.
Plant
Both
Animal
•Often are high in
lysosomes
•Have chloroplasts
•Are eukaryotes
•Has a plant cell
wall
•Have other organelles in
•Can have great
common (mitochondria,
ability to move
ER, golgi bodies…)
•Has a large
vacuole
•Are similar in size
•No / very limited
ability to move
•Cells asexually
reproduce through
mitosis
A sperm cell has a tail that is 50µm long. A student
draws it as 75mm. What is the magnification?
You don’t have to
draw it, but you can
if that helps!
Measured length
Actual size =
Magnification
75 mm
50 µm =
50 µm =
x
Convert to the same
units before you divide!
75 mm
x
75000 µm
Solve for x
x
1500
x
X=
1500
magnified
1000 µm
1 mm
= 75000 µm
1. Which focus knob should you
use under the low magnification
objective lens?
Coarse focus knob (it changes
the focus a lot)
2. The image appears too dark.
What should you do?
The diaphragm controls how
much light passes through the
slide
3. The image appears too dark. What should you do?
The diaphragm controls how much light passes through
the slide. Also, make sure the light is on!