Download Chapter 12 Reading Guide

Name __________________________________
Date___________ Period__________
CHAPTER 12 BOOK WORK
 Section 12.1
Complete the following table:
Scientists
Brief Description of Experiment
DUE: __________
Conclusion / Characteristics of
DNA Discovered
Griffith
Avery
Hershey-Chase
Watson & Crick
Franklin

Match the letter to the portion of the DNA structure
i. Hydrogen bonds: ____________
ii. Nucleotide: ______________
iii. Sugar-phosphate backbone: _____________
iv. Bases: ___________

A double helix looks like a twisted ladder. Which parts of a twisted
ladder would match the following parts of a DNA molecule:
i. Hydrogen bonds: _____________
ii. Sugar-phosphate backbone: ____________

Using Chargaff’s rules, if 28% of the nucleotides contain adenine, what percentage of the other
bases does the molecule contain?
i. Thymine: _______________
ii. Guanine: _______________
iii. Adenine: _______________
 Section 12.2
DUE: ___________
Synthesis of New DNA
Molecules
How can you investigate when and where cells
synthesize DNA? Scientists have done this by
briefly adding radioactively labeled thymine to
the medium in which a cell grows. A cell that is
synthesizing DNA will take the labeled thymine
nucleotide into its DNA. The graph shows the
total amount of radioactive label taken into DNA from thymine during an eight-hour period
between two cell divisions.

Using the information and graph above, answer the following questions
i. Contrast the amounts of radioactivity incorporated during the following times: (a) the first
four hours of the experiment, (b) the next two hours, and (c) the final two hours.
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
ii. Is DNA synthesized continually during the cell cycle (the period between cell divisions)? If
not, during what phase is it synthesized? How long is that phase?
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
iii. Which organelle or cell structure would you expect to contain the most radioactivity after
this experiment? Explain.
______________________________________________________________________
______________________________________________________________________

Briefly explain how DNA is replicated.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________

How are the long DNA molecules found in eukaryotes packed into short chromosomes?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
What is the role of DNA polymerase in DNA replication?
___________________________________________________________________________
___________________________________________________________________________

Complete the following table comparing the process of DNA Replication in prokaryotes and
eukaryotes.
Description
Prokaryotes
Eukaryotes
Location in Cell
Steps of Replication
End Products
 Section 12.3

DUE: ___________
What happens during transcription?
___________________________________________________________________________
___________________________________________________________________________

What happens during translation?
___________________________________________________________________________
___________________________________________________________________________

Describe three main differences between RNA & DNA.
i. _____________________________________________________________________
ii. _____________________________________________________________________
iii. _____________________________________________________________________

Using the genetic code (Figure 12-17), identify the amino acids that have the following messenger
RNA stand codes: UGGCAGUGC. ________________________________________________

Complete the following table:
RNA type
Location in Cell
Function
(inside nucleus only, outside nucleus
only, travels between inside & outside
of nucleus)
mRNA
rRNA
tRNA
 Section 12.4
DUE: __________
 What is a mutation?
___________________________________________________________________________
___________________________________________________________________________
 Explain how mutations can be neutral, beneficial or harmful.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________

Complete the following table:
Description
Gene Mutation
Chromosomal Mutation
Definition
Types
Effects

Complete the following table:
Gene Mutation
Type of Mutation
Point mutation
Frame-shift
mutation
Chromosomal Mutation
Deletion
Duplication
Inversion
Translocation
Definition
Drawing
 Section 12-5
Due _________
-
What is an operon? ________________________________________________
-
How are the lac genes turned on and off? _______________________________
_______________________________________________________________
-
What is the operator? ______________________________________________
-
Is the Ecoli bacteria an example of a prokaryote or eukaryote ________________
-
How are most eukaryotic genes controlled? ______________________________
_______________________________________________________________
-What is the “TATA box” ______________________________________________
-
How is gene regulation important during the development of a complex organism?
_______________________________________________________________
-
What do “hox” genes do? ____________________________________________