Biology 1 Lab

Front 1

When restriction enzymes are used to cut a long strand of DNA, fragments of varying sizes may be produced, the fragments can be separated and visualized using a process known as

Back 1

Agarose Gel electrophoresis

Front 2

Electrophoresis separates DNA fragments according to

Back 2

their relative size.

Front 3

How are DNA fragments charged? How does this effect their behavior in electrophoresis

Back 3

DNA fragments are negatively charged, when placed in an electric field, they will be drawn toward the positive pole.

Front 4

In electrophoresis, how do the DNA fragments of varying sizes travel

Back 4

The smaller DNA fragments will travel farther, DNA fragments of the same size will stay together and appear to travel as a single band.

Front 5

In DNA, what is the five carbon SUGAR molecule known as

Back 5

deoxyribose

Front 6

In DNA, what is the phosphate group composed of:

Back 6

Molecule composed of a phosphorous bound to oxygen

Front 7

What are the DNA Nucleotide Bases:

Back 7

A=Adenine
C=Cytosine
G=Guanine
T=Thymine

Front 8

Is there a difference between the sugar-phosphate "backbone" of human, bacteria or plant DNA?

Back 8

No, the DNA backbone is the same

Front 9

Do plant, human or bacteria cells have the same bases? Are the bases paired the same? What is different

Back 9

Yes, they have the same bases and they are paired the same, A to T and G to C, the difference is in the linear base pair sequence.

Front 10

The specific site where an enzyme break (hydrolyze) the sugar-phosphate backbone is called:

Back 10

Recognition Site

Front 11

Enzymes that cause a break in the sugar-phosphate backbone at recognition sites are known as

Back 11

Restriction Endonucleases

Front 12

A restriction endonuclease used routinely in laboratories around the world is

Back 12

EcoRi

Front 13

The restriction enzyme generates fragments that are single stranded, these sites are known as:

Back 13

"overhangs" or sticky ends"

Front 14

In the DNA Isolation from Plant Nuclei and Human Cheek Cells, what was the EDTA used for

Back 14

to inhibit DNase activity. EDTA is a chelating agent that binds divalent cations Mg^2+ and Ca^2+ which are necessary for DNase activity

Front 15

What is a nucleotide composed of?

Back 15

1. Phosphate group
2. Sugar deoxyribose
3. 1 of the 4 Nitrogenous base: Adenine, Guanine, Thymine and Cytosine

Front 16

How are nucleotides bonded to each other and to the second strang

Back 16

They are covelantly bonded to each other and hydrogen bonded to the second strand.

Front 17

How can we break open the cell membrane to analyze the DNA in a Eukaryotic Cell?

Back 17

1. Through Osmotic Shock
2. By adding a detergent to disolve the plasma membrane
3. by mechanical action

Front 18

What is the homogenate? What is it composed of?

Back 18

After a detergent is used to dissolve the membrane plasma, the complex fluid containing cytoplasmic components, organelles and plasma membrane fragments

Front 19

DNA wrapped around this "protein" form the basic packing unit of DNA

Back 19

What are histones

Front 20

DNA wrapped around histones forming the basic packing unit of DNA is called the

Back 20

Nucleosome

Front 21

In the DNA Isolation from Plant Nuclei and Human Cheek Cells lab, what agent was used to unwrap the DNA from the histones

Back 21

SDS (Sodium Dodecyl Sulfate)

Front 22

What are the two types of cells?

Back 22

Eukaryotic and Prokaryotic

Front 23

What does DNA stand for?

Back 23

Deoxyribonucleic acid

Front 24

What is the difference between prokaryotic and eukaryotic cells

Back 24

Prokaryotic cells do not have a nucleui, instead, the DNA is contained in the nucleoid region of the cytoplasm.

Front 25

In the DNA Isolation from Plant Nuclei and Human Cheek Cells lab, what is added to the nuclear proteins to precipitate them after centrifugion?

Back 25

Sodium Chloride

Front 26

In the DNA Isolation from Plant Nuclei and Human Cheek Cells lab, how is the DNA isolated from the supernatant?

Back 26

With ethanol, which is an alcohol.

Front 27

What is the supernatant?

Back 27

Liquid lying above a solid.

Front 28

What is to decant?

Back 28

to gradually pour liquid from one container to the other without disturbing the sediment.

Front 29

In the DNA Isolation from Plant Nuclei and Human Cheek Cells lab, what is proteinase K used for?

Back 29

to break down proteins in the cheek cells.

Front 30

What does the three dimensional structur of restriction enzymes allow it to do?

Back 30

It allows it to attach to the double-stranded DNA molecule and slide along the helix until it reaches the recognition site that signals the enzyme to stop sliding.

Front 31

What does electrophoresis mean?

Back 31

to carry with electricity.

Front 32

Why do the shorter pieces of DNA travel farther than longer ones

Back 32

the matrix of the agarose gel acts as a molecular sieve though which smaller DNA fragments can move more easily.