Unit 7 Biology Content

Question 1

3 big differences between Nuclear DNA (nDNA) and Mitochondrial DNA (mtDNA).

T1

Answer 1

1. You 100% of your mtDNA from your mom, but roughly 50% of nDNA from both parents.
2. mtDNA is located in the mitochondria of cells, while nDNA is located in the nucleus of cells.
3. mtDNA codes for things related to energy production, like the synthesis of ATP, while nDNA codes for every thing else; a vast array of things, from metabolism, to growth, to development etc.

Question 2

How is mtDNA useful in identifying individuals?

T1

Answer 2

If regular DNA isn’t present, or if there is a case regarding how a female is related to someone, mtDNA is useful, since mtDNA is always from your mother and it doesn’t change (unless genetic mutation).

Question 3

How is normal DNA useful in identifying individuals?

T1

Answer 3

You get 50% of your DNA from each parent, so seeing how similar one person’s DNA is to another may give hints if they’re related.

Question 4

What are some differences between DNA in Prokaryotic Cells and Eukaryotic Cells?

T1

Answer 4

1. DNA is in the nucleus for Eukaryotes, while for Prokaryotes it is in the cytoplasm
2. There is more DNA in Eukaryotes than Prokaryotes
3. Prokaryotes always only have 1 chromosome (often circular) while Eukaryotes have many linear chromosomes

Question 5

Define and describe “plasmid” briefly.

T1

Answer 5

In addition to chromosomes, some bacteria (and organisms like yeast and fungi ) have Plasmids, which are small circular DNA molecules.

Question 6

Basic 4 steps for how plasmids are used in genetic engineering:

T1

Answer 6

1. A restriction enzyme is used to cut a fragment out of the bacteria’s plasmid
2. That same restriction enzyme cuts a DNA fragment out of the DNA from another organism
3. Because the same restriction enzyme was used, that organism’s DNA fragment can be placed into the bacteria’s plasmid
4. The plasmid is inserted into the bacteria, which “transforms” the bacteria. The bacteria will now express the traits of the DNA fragment that was cut out of the other organism

Question 7

Where do restriction enzymes cut DNA?

T2

Answer 7

At a specific base pair sequence. They cut in what looks like a zigzag, leaving sticky ends, which means that one side of the DNA stretches a few base pairs farther than the other side.

Question 8

How does Gel Electrophoresis separate DNA fragments by length?

T2

Answer 8

1. The DNA fragments (cut by restriction enzymes) are placed together in the gel.
2. An electrical current runs through the gel. DNA is negatively charged, and the positively charged side of the gel is on the other side farthest away from the DNA
3. The DNA will slowly move in the gel, towards the positive side
4. Larger fragments wont move as far in the gel, since they are heavier, and smaller fragments will move farther to the positive side of the gel, as smaller fragments are lighter

Question 9

What does loading dye do in Gel Electrophoresis?

T2

Answer 9

It weights the DNA fragments down into the wells, and it dyes the DNA fragments so you can see it.

Question 10

For the P20 micropipette, from top to bottom for each square, what unit does each square represent?

T2

Answer 10

(Top to bottom)
Top square=tens place
Middle square=ones place
Bottom square=tenths place

Question 11

For any pipette, how do you know what is the maximum amount it can hold?

T2

Answer 11

The number in the name of the pipette is the maximum amount of liquid it can hold.

Question 12

For the P200 pipette, from top to bottom for each square, what unit does each square represent?

T2

Answer 12

(Top to bottom)
Top square=100s place
Middle square=10s place
Bottom square=1s place

Question 13

For the P1000 pipette, from top to bottom for each square, what unit does each square represent?

T2

Answer 13

(Top to bottom)
Top square=1000s place
Middle square=100s place
Bottom square=10s place

Question 14

When using the plunger on a pipette, what does the first stop do?

T2

Answer 14

It takes in/collects the liquid.

Question 15

When using a plunger on a pipette, what does the second stop do?

T2

Answer 15

It ejects/dispenses the liquid.

Question 16

How can DNA Fingerprints from Gel Electrophoresis include or exclude suspects?

T3

Answer 16

If the DNA bands from a crimescene match the DNA bands of a suspect, then it would include that person. If a suspect’s DNA bands are different from the crimescene DNA, then that person is excluded.

Question 17

If given the DNA bands of one parent, and the DNA bands of a child, how do you determine what the other child’s parent is?

T3

Answer 17

Match all the bands between the child and the known parent. Then for the remaining bands of the child, whichever other parent has DNA bands that match those remaining bands, is the other parent.

Question 18

In Gel Electrophoresis, do smaller DNA fragments move more or less. Are they farther or not as far from the well?

T3

Answer 18

Smaller fragments travel farther. Larger fragments do not travel as far. Smaller fragments are lighter than larger fragments.

Question 19

Define genetic engineering.

T4

Answer 19

Genetic engineering is the intention modification of the characteristics of an organism by changing its genetic material.

Question 20

Define Recombinant DNA:

T4

Answer 20

DNA that resulted from combining 2 or more difference DNA sources together

Question 21

List the steps in making Recombinant DNA:

T4

Answer 21

1. A restriction enzyme is used to cut out a segment of DNA from one organism, lets say a bear.
2. That same restriction enzyme cuts a segment of DNA from another organism, lets say a bird.
3. DNA Ligase is used to insert the bear’s DNA fragment into the empty space in the bird’s DNA (made from DNA fragment taken out of the bird’s DNA)

Using the same restriction enzyme on two different organisms’ DNA will guarantee that either DNA fragment will fit into the other organism’s DNA

Question 22

Define the role of restriction enzymes in genetic engineering:

T4

Answer 22

The role of restriction enzymes is to cut DNA into specific shapes- either to remove an undesirable gene, or to create special DNA fragments that can fit into the DNA of other organism’s.

Question 23

If there is a gene of interest on a DNA strand, how do you determine which restriction enzyme to use, to isolate that gene of interest?

T4

Answer 23

You look for the restriction enzyme that has the sequence that it cuts at, on both sides of the gene of interest.

The restriction enzyme will cut on both sides, cutting the gene out of the DNA.

Question 24

Define an operon simply:

T4

Answer 24

It is a group of genes that works together to regulate things like gene expression (transcription and translation) and protein synthesis. All this teamwork is controlled by a promoter and operator region.

Question 25

How does an operon work to “turn on” or “turn off” genes?

T4

Answer 25

Certain proteins will bind to or leave the operator region, which either tells the genes to do their job or to stop doing what they’re doing.

Question 26

What are 2 ways we sterilize the lab?

T5

Answer 26

With disinfectants, and high heat.

Question 27

What is a negative control?

T5

Answer 27

A group in an experiment that doesn’t receive the treatment, and therefore doesn’t change at all during the experiment. Used so we know what happens when no stimulus is applied.

Question 28

What is a positive control?

T5

Answer 28

A group in an experiment that does receive the treatment. Used so we know what should happen if the stimulus is applied.

Question 29

Define transformation:

T5

Answer 29

It is the process of an organism taking up foreign genetic material.

Question 30

What is an example of transformation that we did?

T5

Answer 30

When some E Coli bacteria take up the pGLO plasmid, that is transformation because the pGLO plasmid is a recombinant plasmid, which means it contains DNA from another organism

Question 31

List the steps in the Transformation of bacteria, describe why each step is needed:

T5

Answer 31

1. Bacterial cells treated with Calcium Chloride
   a. This makes the bacteria’s cell membrane more permeable to the plasmid
2. (At the same time as step
   #1) Bacterial cells treated with the plasmid
   a. We want to get the plasmid into the bacteria
3. Bacteria is treated on ice
   a. Makes cell membrane even better for experiment
4. Cells put on heat shock at 42 degrees celsius
   a. Makes cell membrane more permeable, as this is the stage when the plasmid is taken into the bacteria
5. Bacteria put back on ice
   a. Cell will shrink and keep the plasmids inside. Also gives bacteria time to heal from wounds caused by transformation

Question 32

What organism’s DNA was taken to make the pGLO plasmid?

T5

Answer 32

A bioluminescent jellyfish called Aequorea Victoria.

GFP Protein was isolated from this jellyfish and put in the pGLO plasmid.

Question 33

What is the role of Arabinose sugar in pGLO plasmid?

T5

Answer 33

To remove the araC repressor that binds to pBAD operator, so RNA Polymerase can cause GFP Protein to be made

Question 34

Why did we feed our bacteria Arabinose?

T5

Answer 34

So the bacteria would be able to synthesize GFP Protein, which would cause them to glow under UV light.

Question 35

Briefly explain the operon operating in the pGLO plasmid:

T5

Answer 35

1. GFP Protein production is normally turned off, as araC makes a regulatory protein called araC repressor, which binds to pBAD operator, preventing RNA Polymerase from synthesizing GFP Protein, as RNA Polymerase binds to pBAD to synthesize GFP.
2. When Arabinose is present, it binds to the araC repressor which removes it, therefore letting RNA Polymerase binds to the pBAD operator, therefore allowing the production of GFP Protein.

Question 36

Why was it necessary to grown transformed bacteria in the presence of an antibiotic (like ampicillin)?

T5

Answer 36

Because that way we know which bacteria was transformed, as the non-transformed bacteria would be killed by the antibiotics, but transformed bacteria has the Bla gene which codes for resistance against antibiotics. Without antibiotics, all the bacteria would live and there would be no way of knowing which bacteria had the plasmid and which didn’t.

Question 37

When bacteria grows in the presence of ampicillin, does the bacteria grow in a lawn or in colonies. Why?

T5

Answer 37

The bacteria grows in the presence of ampicillin, it grows in little colonies.

This is because the beta-lactamase secreted by bacteria covers a certain space making that space ampicillin-free, so bacteria can only grow in that space.

Question 38

When bacteria grows normally, does it grow in colonies or a lawn. Why?

T5

Answer 38

Bacteria normally grows in a lawn. The bacteria is free to grow anywhere it wants.

Question 39

What does the ori region do in pGLO plasmid?

T5

Answer 39

It tells the plasmid to replicate itself. It is the start of plasmid replication.

Question 40

What does Bla gene do in pGLO plasmid?

T5

Answer 40

it codes for the beta-lactamase enzyme, which provides resistance to the ampicillin antibiotic

Question 41

What does ara C gene do in pGLO plasmid?

T5

Answer 41

It codes for the regulatory protein called araC repressor, which prevents GFP Protein from being made, by binding to the PBAD region so RNA Polymerase cant bind there.