18/02/2016
Science 30 Unit A: Biology – DNA
DNA Review - DNA:
Name: _______________
Date: _______________
- contains genetic code for making ______________ that make up organisms
- found in ______________
- specific parts are called ________________
- makes a double-____________ shape
DNA is made long chains of
____________________.
Each nucleotide is made up of three parts (two of
which never change)...
-
Deoxyribose (_____________)
____________________
____________________ base
Each and every nucleotide contains the sugar and
phosphate. But the nitrogen base can be one of four
molecules.
The Four Nitrogen base pairs are:
A - _________________
T - _________________
G - _________________
C – _________________
These four bases differ on each nucleotide.
Note that the bases only bond (through hydrogen bonds) with one other base:
Adenine always pairs with _____________________. (_______)
Guanine always pairs with ____________________ (_______)
From these four base pairs come all of the instructions for building the amino acids that make up
the proteins that make up life.
ex) Determine the complementary strand to ATTGCCGATGC.
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DNA Replication
Recall that in both ____________ and _____________, DNA makes an exact ___________ of
itself to start the cell division process.
This replication is possible because of the structure of DNA.
During DNA replication, the double helix _______________ (as the _____________ bonds
between the base pairs break).
The unzipped base pairs then pair up with ____________________ complementary base pairs,
making two ________________ daughter copies of DNA.
If you take any three of these base pairs, you get the instructions for the making a particular
_________________________ (the building blocks of proteins which are the building blocks of
pretty much everything else).
We get a code-book to determine what each DNA triplet
corresponds to:
This table on page 13 of your data booklet lets you figure out what
triplet codes for which amino acid.
Note that some triplets tell where a particular _______ and _____:
So that, when reading the gene, your body has a defined start and
endpoint for each set of amino acids produced.
Protein Mutations
Most of the time, this process of replication works perfectly. But there can be __________ in the
base pairs: this leads to mutations.
Just one change in the DNA sequence can have significant effect. Some disorders in humans
caused by genetic mutations include:
-
Hemophilia: inability to ______ blood
Sickle-cell _____________
Huntington`s Disease: ______________ condition leading to motor impairment
By knowing which parts of DNA code for which traits, scientists can sometimes cause
_________________ mutations as well. This creates _____________________ DNA.
This genetic engineering has led to genetically modified food:
Gene Therapy
- replacing a _______________ gene with a non-defective gene
- e.g. Cystic fibrosis, hemophilia
- Issues: How do we get the genes in the body and control them?
Practice: page 115 1-4
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