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Section 1.1
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Opening Activity: What do you biologically inherit from your parents?
Latin Root Word:
Review of Old Information: Recall that the DNA is the hereditary information for all living things. In
this molecule is the code for all of our traits. However, one important question remains… how do we get
from the genetic code from DNA in the nucleus, to the production of our phenotypes (or what we actually
look like)? The answer to this lies in the proteins your cell’s produce. The bulk of what we look like and
our ability to survive come from the enzymes and tissues in our bodies being made of proteins. Proteins
are made in a process called “protein synthesis.”
The genes directing protein production are in the _______________, and the enzymes and amino
acid building blocks for protein production are in the __________________. A problem with this process
is getting the information from the DNA (genes), which cannot leave the nucleus, to the cytoplasm, where
the protein building blocks await. The key to solving this problem lies in a nucleic acid called
_______________, which carries the genetic information from DNA into the cytosol, and then assists in
producing proteins.
New Information: Structure of DNA and DNA Replication.
DNA Structure:
DNA consists of two molecules that are arranged into a ladder-like structure called a ___________ Helix.
A molecule of DNA is made up of millions of tiny subunits called _______________.
Each nucleotide consists of:
1.
2.
3.
Each base will only bond with one other specific base.
_________ (A)
_________ (T)
_________ (C)
_________ (G)
Because of this complementary base pairing, the order of the bases in one strand determines the order of
the bases in the other strand.
To crack the genetic code found in DNA we need to look at the _____________ of _____________.
The bases are arranged in triplets called _____________.
AGG-CTC-AAG-TCC-TAG
TCC-GAG-TTC-AGG-ATC
A gene is a section of ___________ that codes for a ______________.
Each unique _______________ has a unique sequence of _______________.
This unique sequence of bases will code for the production of a unique ________________.
It is these proteins and combination of proteins that give us a unique physical appearance.
See pages 185-187
1. DNA is made up of repeating subunits called ____________________.
2. What are the three parts of a DNA nucleotide? _______________________________________.
3. What are the four nitrogen-bases found in DNA nucleotides? _____________________________.
4. The shape of DNA is the _______________ _______________.
Label the molecule of DNA: P = phosphate group, S = pentose sugar, A/T/C/G Bases
DNA Replication
What is the purpose of DNA replication?
o To make an ____________ of DNA
o Occurs before _______________
o So the ________ daughter cells have the exact same DNA as the ____________ parent cell
Where does DNA replication take place? In the ____________
Each strand is a _____________ (parent) for the ____________ strand (daughter)
3 Steps of DNA Replication
The parent DNA __________ and unzips – weak hydrogen bonds are broken by enzyme –
______________
________________ base pairing – free floating nucleotides in the nucleus fit into place – A to T and
C to G
The nucleotides (along the phosphate-sugar backbone) join up by the enzyme _________________
DNA is considered Semiconservative
o each helix of DNA is made up of one parent (__________) and one daughter
(__________________)
Activity:
See pages 185-187
The process of copying DNA in a cell is called ____________________. In the first step, the twonucleotide chains separate. The point at which the two chains separate is called the _____________
_____________, and are separated by enzymes called ____________________. In the next step,
enzymes called _______________ _____________ bind to the separated chains and place the
complementary nucleotides across from the original chains. When replication is completed, two exact copies
of the original DNA molecule are produced and the cell is ready to undergo cell division. Typically there is
an error in about 1 of every 10,000 _______________ pairs, and these errors are called
______________. However, enzymes can proofread the DNA and repair it so that the rate of error is
about 1 per _______________ _______________ nucleotides.