Repetitive DNA

Question 1

Which centrifugation method would be used to help determine if a newly discovered organism from thermal ocean vents had ribosomes smaller than human ribosomes?

Answer 1

Sedimentation velocity centrifugation

Question 2

Which centrifugation method would be used to help determine if a newly discovered organism from thermal ocean vents contained satellite DNA?

Answer 2

Equilibrium centrifugation

Question 3

Which mechanism do DNA transposons move by?

Answer 3

Cut and paste

Question 4

Which mechanism do Retrotransposons move by?

Answer 4

Copy and paste

Question 5

Genes that are transcribed but not translated into protein are classified as:

Answer 5

RNA-coding genes

Question 6

What is the final product of multiple copy RNA-coding genes?

Answer 6

RNA

Question 7

What is an array?

Answer 7

A collection of tandem repeats

Question 8

What is one common application of minisatellites?

Answer 8

Forensics

Question 9

How do you calculate the total bp added to the genome?

Answer 9

number of repeats x bp/repeat

Question 10

What is the difference between analytical and preparative?

Answer 10

Analytical is used to study the properties of molecules and Preparative is used to purify molecules

Question 11

What is CsCl used for?

Answer 11

DNA purification and analysis

Question 12

What is sucrose used for?

Answer 12

Purification of proteins and cellular oganelles

Question 13

Describe the process of Equilibrium Density Centrifugation

Answer 13

1. ) High molecular weight DNA is mixed with CsCl and spun really fast
2. ) The CsCl forms a gradient from highest density at the bottom to lowest density at the top
3. ) DNA migrates to a position in the gradient where its density matches the density of the CsCl

Question 14

What determines density in Equilibrium Density Centrifugation?

Answer 14

GC-content, not size; higher GC = higher density

Question 15

Why is DNA sheared in Equilibrium Density Centrifugation?

Answer 15

Shearing gives a broad band instead of a tight band

Question 16

What would happen if satellite DNA has a GC-content that is nearly the same as the main band GC-content?

Answer 16

The satellite would not be visible

Question 17

Sedimentation velocity is a function of:

Answer 17

Density, size, and shape

Question 18

What is the standard unit for sedimentation velocity?

Answer 18

Svedberg Unit (S)

Question 19

What happens to trinucleotide repeats during replication?

Answer 19

They get expanded; add string of amino acids to the protein

Question 20

How is interspersed repetitive DNA produced?

Answer 20

By the movement of transposons

Question 21

What is transposition?

Answer 21

The movement of genetic elements between nonhomologous sites in the genome

Question 22

What are 2 examples of nonhomologous sites in the genome?

Answer 22

1. ) Different places within one chromosome

2. ) Between 2 chromosomes

Question 23

Which type of elements are responsible for evolutionary change within a genome?

Answer 23

Mobile elements

Question 24

What are 2 things contained within a mobile element?

Answer 24

1. ) An enzyme that mediates its own movement

2. ) Special sites upon which the enzyme acts

Question 25

What are 2 functions of transposase?

Answer 25

1. ) Disconnects transposon from flanking DNA

2. ) Inserts it into a new target DNA site

Question 26

What are the 3 classes of transposons?

Answer 26

1. ) DNA transposons
2. ) LTR-containing retrotransposons
3. ) Non-LTR retrotransposons

Question 27

What are transposons?

Answer 27

Mobile genetic elements, sometimes referred to as “selfish DNA” or “jumping genes”

Question 28

What did Barbara McClintock discover?

Answer 28

Transposable elements in maize; Ac and Ds elements