Cell Biology Chapter 5

Front 1

1. What were Meselson and Stahl studying?

Back 1

DNA replication.

Front 2

2. How many origins of replication are there in humans? Bacteria?

Back 2

Many are found in humans and usually only one is found in bacteria.

Front 3

3. What is the difference between homologous recombination and NHEJ?

Back 3

Non-homologous end joining repairs doublestrand breaks, however, it is error prone. May cause a loss or gain insequence. Not always precise

Homologous recombination is flawless/seamless repair of a double strand break.

Front 4

What’s a retrovirus?

Back 4

A virus that is composed of RNA.

Front 5

4. True or false homologous recombination is very precise in repair double strand breaks

Back 5

True

Front 6

5. What are mobile genetic elements? Are any of these genetic elements in the human genome?

Back 6

Genomes have mobile genetic elements called transposons.

Transposones encode enzyme that allow for movement ofthe DNA sequence (transposase) and encode for antibiotic resistance

Front 7

A. On the figure, indicate where the origin of replication was located (use O).

Back 7

Front 8

B. Label the leading-strand template and the lagging-strand template of the right-handfork [R] as X and Y, respectively.

Back 8

Front 9

C. Indicate by arrows the direction in which the newly made DNA strands (indicated bydark lines) were synthesized.

Back 9

5' -> 3'

Front 10

D. Number the Okazaki fragments on each strand 1, 2, and 3 in the order in which theywere synthesized

Back 10

Front 11

E. Indicate where the most recent DNA synthesis has occurred (use S).

Back 11

Front 12

F. Indicate the direction of movement of the replication forks with arrows.

Back 12