Download Lesson 2 * Carbohydrates

Quiz – Page 38
1. Give 3 examples of a structural protein.
collagen, elastin, tubulin, keratin,a ctin
2. What class of protein in ferretin?
storage
3. What does kinesin do?
it interacts with microtubules to move organelles
4. What protein carries iron?
transferrin
5. What class of protein is rhodopsin.
receptor
Proteins
Homework due
today!
Lesson 6 – Nucleic Acids
Nucleic Acids
On your desks draw out the structure of a
nucleic acid as you remember it.
Nucleotide Structure
All nucleotides are made up of a pentose
sugar, a phosphate group and a variable
nitrogenous base.
Purines and Pyrimidines
There are 2 types of nitrogenous bases –
purines (double ring structures) and pyrimidines
(single ring structures).
Uracil
Uracil has one ring so it is a….
pyrimidine
In fact it is structurally VERY similar to
Thymine.
Nucleotide Structure Up Close
The Phosphodiester Bond
The nucleotide monomers are joined by a
dehyration synthesis reaction.
Phosphodiester
bond
A bond forms between the phosphate group
(C5) of one nucleotide and the hydroxyl group
(C3) on the sugar of another.
Base Pairing
On your desks write how the bases pair up. Indicate
which are purines and which are pyrimidines.
Purines always pair with pyrimidines. They are
held together by hydrogen bonds.
3 bonds between C andG and 2 bonds between T
and A (or U and A).
The Double Helix
The 2 strands of the double helix are in an anti-parallel
arrangement.
3’ and 5’
3’ is read “three prime” and refers to the third
carbon on the sugar. Five prime refers to the
5th.
Antiparallel Arrangement showing 3’ and 5’
Double Helix (again)
Features of the DNA double helix:
1. One complete turn has a length of
3.4 nm.
2. The diameter of the molecule is
2.0 nm.
3. There is a major groove and a
minor groove.
4. The helix is described as right
handed.
RNA vs DNA
List ways that DNA and RNA differ.
Polymerase Enzymes
DNA polymerase is an enzyme that catalyses the
formation of the phosphodiester bond between bases.
The formation of new strands of DNA occurs from 5’ to
3’ only. This presents a problem during DNA replication
as one strand (called the leading strand) can be
replicated as the molecule unzips but the other strand
(the 3’ to 5’ side, called the lagging strand) needs to be
replicated in sections then joined together later by an
enzyme called DNA ligase.
Your Task- Nucleic Acids
1. Past Paper Questions
You will need to access these in the department. Please
DO NOT TAKE past papers home – we have limited
numbers.
2004 MC Q8
2005 MC Q 11
2006 MC Q 4
2007 MC Q 7,9
2008 MC Q 6
2009 MC Q 3,4
2. Complete Scholar activities on nucleic acids.
3. Read and make notes on pages 39-42.
4. Make sure your glossary is up to date.
DUE Monday
(December 3rd)