genetic lesson dna and rna replication and its details

genetic lesson dna and rna replication and its details

1. Unit: GeneticsUnit: Genetics
Lesson: DNA and DNA Lesson: DNA and DNA
ReplicationReplication
Agricultural BiologyAgricultural Biology
Instructor: Instructor:

2. Student ObjectivesStudent Objectives
•Students will be able to identify and Students will be able to identify and
explain DNA structure.explain DNA structure.
•Students will understand how DNA Students will understand how DNA
pairs with specific bases and the pairs with specific bases and the
process of DNA replication.process of DNA replication.
•Students will comprehend the Students will comprehend the
importance of checking for errors importance of checking for errors

4. I. DNA StructureI. DNA Structure
•A) Double helix held together by A) Double helix held together by
weak hydrogen bondsweak hydrogen bonds
•B) NucleotidesB) Nucleotides
–1. Subunits that make up DNA1. Subunits that make up DNA
–2. Made of 3 components 2. Made of 3 components
•A) phosphate groupA) phosphate group
•B) deoxyribose = 5-carbon sugarB) deoxyribose = 5-carbon sugar
•C) nitrogen containing base C) nitrogen containing base

5. I. DNA StructureI. DNA Structure
•C) Four nitrogen basesC) Four nitrogen bases
–1. Purines 1. Purines
•A) Adenine A) Adenine
•B) Guanine B) Guanine
–2. Pyrimidines 2. Pyrimidines
•A) Thiamine A) Thiamine
•B) Cytosine B) Cytosine

6. I. DNA StructureI. DNA Structure

7. II. Pairing Between II. Pairing Between
BasesBases
•A) Purines on 1 strand A) Purines on 1 strand alwaysalways pair pair
with Pyrimidines on another strandwith Pyrimidines on another strand
–1. A pairs with T 1. A pairs with T alwaysalways
–2. G pairs with C 2. G pairs with C alwaysalways
•B) Complementary StrandsB) Complementary Strands
–1. Sequence of bases on one strand 1. Sequence of bases on one strand
determines the sequence on the other determines the sequence on the other
strand.strand.
–2. Make up the double helix and serve as 2. Make up the double helix and serve as
a template to build DNAa template to build DNA

8. II. Pairing Between II. Pairing Between
BasesBases

9. III. DNA ReplicationIII. DNA Replication
•A) Step 1 = double helix unwindsA) Step 1 = double helix unwinds
–1. DNA Helicase 1. DNA Helicase
•A) an enzyme that breaks apart the hydrogen bondsA) an enzyme that breaks apart the hydrogen bonds
–2. Hydrogen Bond2. Hydrogen Bond
•A) these bonds hold nucleotides togetherA) these bonds hold nucleotides together
–3. Proteins3. Proteins
•A) attach to the strands to keep the bonds from A) attach to the strands to keep the bonds from
reforming reforming
–4. Replication Forks4. Replication Forks
•A) two areas where the DNA opens up to A) two areas where the DNA opens up to allow allow
replication to occur replication to occur

10. III. DNA ReplicationIII. DNA Replication
•B) Step 2 = nucleotides are B) Step 2 = nucleotides are
addedadded
–1. DNA Polymerase1. DNA Polymerase
•A) enzyme that moves along each A) enzyme that moves along each
strand adding nucleotides strand adding nucleotides

11. III. DNA ReplicationIII. DNA Replication
•C) Step 3 = 2 strands of DNA are C) Step 3 = 2 strands of DNA are
formed formed
–1. Enzyme1. Enzyme
•A) DNA Polymerase remains attached until all A) DNA Polymerase remains attached until all
of the DNA is replicatedof the DNA is replicated
–2. New DNA2. New DNA
•A) once process is completed, 2 new strands A) once process is completed, 2 new strands
are completed are completed
–3. Nucleotide Sequence 3. Nucleotide Sequence
•A) identical sequences are present on both A) identical sequences are present on both
strands strands

12. IV. Checking for Errors IV. Checking for Errors
•A) Proofreading A) Proofreading
–1. The Polymerase can only add a 1. The Polymerase can only add a
nucleotide if the previous one was nucleotide if the previous one was
correctly placed correctly placed
•B) BacktrackingB) Backtracking
–1. DNA can go back and remove the 1. DNA can go back and remove the
incorrect nucleotide and replace it with incorrect nucleotide and replace it with
the correct one the correct one