DNA Notes
How was the DNA Model Formed?
1) In the 1950’s a biochemist named Erwin __________ found that the amount of adenine (A) in DNA
always equaled thymine (T), as is the same for cytosine (C) and guanine (G). Soon after this discovery
was known as __________________:
_______ = _______
_______= _______
2) Soon after a young chemist named ____________ ______________ created images of DNA using
a technique known as ________________. Franklin used X rays to create images on film and found
that the general shape of DNA is a ____________ ______________
3) In 1953 _____________ _____________, an American biochemist, and ____________
_____________, an English physicist, worked together in Cambridge, England to develop a model for
DNA. Watson and Crick were the first scientist to discover the __________________.
*DNA stands for ___________________ ______.
Shape of DNA:
It is the blueprint of life.
DNA has a very distinct shape. It is arranged in a form of a helix. A helix is a
shape of a _____ ____. However, a DNA molecule is a _______ ______
What is DNA made up of?
DNA is made up of subunits called _____________.
Each nucleotide is composed of 3 parts:
a. _____________________________
b. _____________________________
c. _____________________________
Nitrogen Bases:
Adenine – Thymine
Cytosine – Guanine
*All living things have the
Same 4 bases, but the order matters!
Nucleotide:
What does the letters in your DNA code for?
Your DNA sequence is a message for your cells to make specific
_________. It is essentially like a recipe so your cells know
what ingredients to put into your proteins. The proteins that
are made allow you to express the ______________________
________________
A gene is a piece of DNA that codes for a particular protein.
How DNA makes a copy of itself
One of the unique characteristics of DNA is that it can _____
_______using one of the strands as a _____. DNA can
replicate and match base pairs to make complementary
strands
EX:
Strand 1: A T C C G T A G C
Strand 2
____________________
Strand 1:
T T G A T C T C C
Strand 2
____________________
Changes in Genes
-
Sometimes mistakes happen when DNA is copied, similar to how we might make a typo.
-
___________ - change in DNA sequence. Sometimes they are random, and sometimes they are
caused by external factors called mutagens.
-
___________ - cause mutations. Examples include x-rays, UV light, chemicals in cigarettes
-
Types of Mutations
o
Substitution – a base is ___________ in the sequence
o
Deletion – a base is _____________ from the sequence
o
Insertion – a base is _____________ to the sequence