Nucleotides
Starter
What is DNA ?
Where will you find DNA in a cell?
Nucleotides
Aims:
•What are the components of DNA?
•How are these components arranged
within the DNA double helix?
•What is the function of DNA?
Watch the video.
Answer the questions on your worksheet.
https://www.youtube.com/watch?v=54n8DLreEe4
DNA (and RNA) is a nucleic acid
It is made from lots of nucleotide
monomers joined together by condensation
reactions to form a polynucleotide.
Its function is to act as an information
carrying molecule that determines the
structure of proteins, including enzymes.
Nucleotide
Three parts
Four
Adenine
types
Look at all
Guanine
this
Cytosine
Nitrogen!
Thymine
Nucleotide
Three parts
Purines
have two
rings
Four
Adenine
types
Guanine
Cytosine
Thymine
Nucleotide
Three parts
Pyrimidines
have one
ring
Four
Adenine
types
Guanine
Cytosine
Thymine
Nucleotide
Three parts
Deoxyribose
sugar
Phosphate
Group
Three parts
Nucleotide
Rungs are bases
Sides are
phosphates and
sugars
(deoxyribose)
Rungs are bases
The rungs (bases)
are held together
by hydrogen bonds
Sides are
phosphates and
sugars
(deoxyribose)
The rungs (bases)
are held together
by hydrogen bonds
This means that
when DNA needs
to be copied, the
two strands can be
easily split apart
The rungs (bases)
are held together
by hydrogen bonds
This means that
when DNA needs
to be copied, the
two strands can be
easily split apart
When the
molecules twist
into a helix, they
are held in a stable
structure, by the
formation of
hydrogen bonds
between each coil
of the helix.
10 bases for each
complete turn (3.4nm)
What is the relationship
between the quantities adenine
and thymine in DNA?
What is the relationship
between the quantities of
guanine and cytosine in DNA?
What about the ratio in
different species?
Nucleotides
TASK:
Complete the questions on your sheet. The
notes in your Unit 2 booklet are up to you
to do in your own time.
All questions to be completed for
homework.
THE END