Download Chapter 11 A - Iowa State University

Chap 11:
Nucleic Acids
Supplemental Instruction
Iowa State University
Leader: ADAM
Course: BIO 212 (3)
Instructor: Kemdirim
Date:
Exam will cover chapters 5,6,7,8 and11.
Resources to utilize:
 Lecture notes
 Book chapters also end of chapter summaries and questions.
 Learn Smart Mcgraw connect questions
Nucleic Acids
I. Describe the characteristics of DNA that allow it to fulfill its genetic role
i. Informative- DNA has information to make an entire organism
ii. Replication- Genetic material must be accurately copied
iii. Transmission- Genetic material must be able to be passed from parent to
offspring.
iv. Variation- Differences in genetic materials must account for variations
within a species.
II. _________ are the building blocks of DNA and RNA. (if you don’t know this I dis-own
you as my SI students : ) nucleotides
III. What are the 3 components of the answer above? Phosphate, pentose sugar, nitrogenous
base
IV. How does two strands of DNA (remember they are in opposite directions) bind to each
other to form a double helix? Hydrogen bonding
V. DNA associates with proteins (histones) to form __________. The complete compliment
of organism’s genetic material is known as its ____________. Chromosomes,
genome.
VI. 5 different bases are divided into two groups. Name the two groups and the bases that are
in each group. Purine: A G (double ring) Pyrimidine’s GUT (single ring)
VII.
Numbering
a. In sugar, carbon atoms are numbered (clockwise/ counterclockwise).
b. Numbering starts where on the sugar? Carbon atoms on the right of oxygen
c. The base is attached to which carbon atom? 1
d. The phosphate is attached to which carbon atom? Which carbon atom
does an attaching phosphate link to?
e. What is the directionality of DNA?
f. What forms the backbone of DNA? Sugar and phosphate
Supplemental Instruction
1060 Hixson-Lied Student Success Center  294-6624  www.si.iastate.edu
Structure of DNA/RNA Strand
I. Nucleotides are __________ attached to each other in linear form. Covalently
II. Linkage is by what type of bond? Phosphoester (covalent bond between phosphate and
oxygen
III. ______________ bond- phosphate group links 2 sugars
phosphodiester
IV. The backbone has (positive,negative) charge because of the (positive,negative) charge of
phosphate. Both neg
V. In DNA (5’ or 3’) end is the phosphate and (5’ or 3’) is hydroxyl.
Who solved the structure of DNA?
Francis Crick and James Watson
Who used X-ray diffractions to suggest DNA was a helical structure? Rosalind Franklin
What did Erwin Chargaff accomplish? Analyzed base composition and found A=T and G=C
Complete the complementary strand of this example (noting directionality):
5’ATCGTCGATCGGGTA 3’
3’ TAGCAGCTAGCCCAT 5’
DNA REPLICATION
I. What are the three possible models that were suggested?
i. Semi Conservative (new double stranded DNA contain one parental strand
and one daughter strand)
ii. Conservative Mechanism (both parental strands in the DNA remain
together)
iii. Dispersive Mechanism (segments of parental DNA and new DNA are
interspersed in both strands)
II. Meselson and Stahl experiment
a. Used an isotope of which element? N
b. What are the two isotopes and which is heavy
and which it light? N14 L N15 H
c. E. Coli were cultured on a medium with
Which isotope? N 15
d. The cells were then switched to medium with
Isotope _______. N14
This allowed new DNA to be labeled by _____ and orginal
DNA labeled by ______ N 14, N15
e. After centrifuge, describe where DNA with
heavy nitrogen, light nitrogen would be and where DNA with
both would be.
III. Results:
After round one of replication, all DNA were? Half heavy
These results were consistent with which theories? C/SC
After the second round of DNA replication, what was observed?
Both light and heavy
Consistent with which theory?