Download dna-structure-ppt1 - Mrs Smith`s Biology

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DNA
Reproductive (sex) cell that fuses with
another of the same type of cell during
fertilisation
Gamete
A homozygous organism with two recessive
alleles
Higher Human Biology
Unit 1 – Human Cells
DNA
Learning Outcomes
Content
• Explain the term genotype.
• Describe what the DNA molecule is made up
from and how it is bonded.
Process
• Model making!
Benefit
• Understand how inheritance is carried out.
• Explain how CSI DNA works!
New Information
• The genotype (genetic makeup
of an organism) of a cell is
determined by the sequence of
bases in its DNA.
• DNA is the molecule of
inheritance and can direct its
own replication.
• Made up of nucleotides.
DNA Nucleotide
Structure of a DNA nucleotide (deoxyribose
sugar, phosphate and base).
Phosphate
Group
O
O=P-O
O
5
CH2
O
N
C1
C4
Sugar
(deoxyribose)
C3
Pentose
C2
Nitrogenous base
(A, G, C, or T)
DNA Nucleotide
Structure of a DNA nucleotide (deoxyribose
sugar, phosphate and base).
Phosphate
Group
O
O=P-O
O
My house (sugar), a garage
(base) and a satellite dish
5
(phosphate group)
CH2
O
N
C1
C4
Sugar
(deoxyribose)
C3
Pentose
C2
Nitrogenous base
(A, G, C, or T)
DNA Backbone
• Nucleotides bond to form a sugar–phosphate
backbone.
• Base pairs (adenine, thymine and guanine,
cytosine,) held by weak hydrogen bonds forming a
double helix.
• Double stranded antiparallel structure with
deoxyribose and phosphate at 3' and 5' ends of
each strand.
Sugar-phosphate backbone
• Nucleotides bond to form a sugar–phosphate
backbone.
• Covalently bonded (strong bond)at position 3 and
5 carbon.
DNA 4 Bases .....
• 2 purines (double
garage; double
ringed structure)
• 2 pyrimidines
(single garage;
single ringed
structure)
• Complementary
base pairing due to
hydrogen bonding
• A + T have 2 bonds
• C + G have 3
bonds
New Information
• The genotype of a cell is determined by the
sequence of bases in its DNA.
• DNA is the molecule of inheritance and can
direct its own replication.
• Structure of a DNA nucleotide (deoxyribose
sugar, phosphate and base). Nucleotides bond
to form a sugar–phosphate backbone. Base
pairs (adenine, thymine and guanine, cytosine,)
held by weak hydrogen bonds forming a
double helix. Double stranded antiparallel
structure with deoxyribose and phosphate at 3'
and 5' ends of each strand.
DNA Double Helix
5
O
3
3
O
P
5
O
C
G
1
P
5
3
2
4
4
2
3
1
P
T
5
A
P
3
O
O
P
5
O
3
5
P
Activity
• Research one of these AMAZING scientists
• Make your own model of DNA!
Review
Comment on each others DNA model;
• Positives comments
• Improvements that could be made