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 BiologyReview Questions

What kinds of cells make up…

EukaryoteProkaryoteEukaryoteProkaryoteEukaryote

1. A human2. A bacteria3. An ant4. E. coli5. A bananna

What kinds of cells would have…

Plant cellProkaryote (bacteria)

Every kind of cell!

Every eukaryoteProkaryote (bacteria)

Prokaryote, Plant cell, fungi cell

1. A chloroplast2. 70s Ribosomes3. A plasma

membrane4. Mitochondria5. Reproduce by

binary fission6. Cell wall (any

kind)

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.

.

NucleoidRegion where naked DNA can be found; may have plasmids (loops of “extra” DNA, which can introduce new genes)

FlagellaWhip like; allows the cell to move

PiliAllows cells to connect and exchange DNA (sexual reproduction)

70S Ribosomesmake protein

CytoplasmJelly-like substance Cell Wall

Made out of peptidoglycan (mesh of amino acids and sugars)

Cell MembraneMade out of phospholipids; controls what enters and leaves cell

Plasma membrane

Mitochondria

Free 80S ribosomes

Lysosomes

Cytoplasm

Golgi apparatus Rough Endoplasmic Reticulum

Nucleus

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.

NucleusDNA in a membrane

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

Golgi ComplexMakes vesicles for molecules to enter or leave the cell

80S RibosomesThey make protein; sometimes attached to ER Cytoplasm

Jelly-like substance

VacuoleLarge compartment for storage of water or other molecules

MitochondriaMakes energy by doing cellular respiration

Endoplasmic Reticulum

Transports molecules; can have ribosomes attached (rough) or none (smooth)

ChloroplastMakes glucose by doing photosynthesis

Explain why there is a limit to the size of a cell.

Cells are limited by a surface-to-volume 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!

Actual size =Measured length

Magnification

10 µm =250 mm

x X= 25000

Solve for x

Convert to the same units before you divide!

25,000 times magnified

250 mm1000 µm

1 mmx = 250,000 µm

10 µm =250,000 µm

x

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

1 2 3

4 5 6

7

Identify the structures in this false-colored microscopic image of a human liver cell

1. Cytoplasm 2. Mitochondria 3. Ribosomes(free)

4. Nucleus 5. Endoplasmic Reticulum(rough)

6. Lysosome

7. Plasmamembrane

1

2

3 4

5

6

Identify the structures in these false-colored microscopic images

1. Cell wall

2. Nucleoid region(where DNA is located)

3. Cell membrane4. Cytoplasm

(the darker spheres are ribosomes)

5. Pili

6. Flagella

Identify the structures in these false-colored microscopic images

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 membrane2. Their own DNA and ribosomes3. Are the same size and bacteria4. Reproduce via binary fission

when their cell divides

What kind of cell is this? What are 3 reasons you know that?

It has chloroplasts It has a cell

wall

It has a large vacuole

It’s a plant cell. (it’s also a eukaryote because it has organelles)

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 are different)

•DNA is circular and in 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 eukaryotes and prokaryotes in a Venn diagram.

Plant Both Animal

Compare and contrast plant and animal cells in a Venn diagram.

Plant Both Animal

•Have chloroplasts •Are eukaryotes •Often are high in lysosomes

•Has a plant cell wall

•Have other organelles in common (mitochondria, ER, golgi bodies…)

•Can have great ability to move

•Has a large vacuole •Are similar in size

•No / very limited ability to move

•Cells asexually reproduce through mitosis

Compare and contrast plant and animal cells in a Venn diagram.

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!

Actual size =Measured length

Magnification

50 µm =75 mm

x X= 1500

Solve for x

Convert to the same units before you divide!

1500 x magnified

75 mm1000 µm

1 mmx = 75000 µm

50 µm =75000 µm

x

1. Which focus knob should you use under the low magnification objective lens?

The diaphragm controls how much light passes through the slide

2. The image appears too dark. What should you do?

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!

Coarse focus knob (it changes the focus a lot)