1. DNA Replication
SC.912.L.16.3 Describe the basic process of DNA replication and how it relates to the transmission and conservation of the genetic information.
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2. What do I need to know?
the basic process of DNA replication and how it relates to the transmission and conservation of genetic information
that mutations in the DNA sequence may or may not result in phenotypic change and how mutations in gametes may result in phenotypic changes in offspring
the basic processes of transcription and translation and how they result in gene expression
the basic processes of DNA are universal in organisms
that similarities in the genetic codes of organisms are due to common ancestry and the process of inheritance

3. Blame it on.. DNA Video - Key Vocabulary DNA RNA transcription
translation
amino acid
protein
cytoplasm
ribosome
nitrogen bases
mutation

4. Structure of DNA DNA is made of subunits called nucleotides
DNA nucleotides are composed of a phosphate, deoxyribose sugar, and a nitrogen-containing base
The 4 bases in DNA are: adenine (A), thymine (T), guanine (G), and cytosine (C)
Where does DNA replication occur?
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5. DNA Replication
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6. Think About This… DNA is only found in the nucleus
Who we are, how we look, and the mechanisms that make are body function are all determined by proteins
Proteins are only made in the ribosome.
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7. Why do we need both DNA and RNA?
DNA holds all the genetic information
DNA damage = mutation
Safer in the nucleus
RNA acts as messenger
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8. Protein Synthesis: The Central Dogma

9. DNA vs. RNA type of sugar bases # of strands
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10. Types of RNA 2 1 3 1 2 3 Type Function Messenger RNA (mRNA)
Carries copies of the instructions for assembling amino acids from DNA to the rest of the cell
Ribosomal RNA (rRNA)
Is a part of ribosomes
Transfer RNA (tRNA)
Transfers each amino acid to the ribosome to help assemble proteins 2 1 3 1 2 3
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11. Transcription
the making of messenger RNA (mRNA) from DNA in the nucleus
DNA unwinds and mRNA is made complementary to the DNA
A=U
G=C
3 nitrogen bases in mRNA is called a codon
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12. Translation
Involves 20 different amino acids in the sequence given by the three-base codons built from an alphabet of four bases
the process in the ribosome builds the polypeptide chains that will become proteins
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13. Genetic Code The Language of Proteins
each 3 nucleotide sequence in an mRNA strand is called a codon
codes for a 1 amino acid
codes for an amino acid using specific rules
there are 64 (43) possible codes, but only 20 amino acids
more than 1 triplet may code for the same amino acid
note that several codons can also act as start (AUG) or stop (UAA) signals
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14. Activity: Transcribe & Translate a Gene

15. Mutations Mutation: change in DNA
if a base is substituted or deleted, the triplet(s) are different
this sometimes leads to difference in the protein

16. Basic Process of DNA is Universal
Mutation: change in DNA
if a base is substituted or deleted, the triplet(s) are different
this sometimes leads to difference in the protein

17. Show What You Know
Genes for medically important proteins can be cloned and inserted into bacteria, as shown in the diagram below.
Why can bacteria recognize a human gene and then produce a human protein?
DNA replication in bacteria and humans is the same.
Bacterial cells contain the same organelles as human cells.
The basic components of DNA are the same in humans and bacteria.
Bacterial cells and human cells contain the same kind of chromosomes.

18. Show What You Know
A cell is replicating its DNA. Part of the DNA strand reads ACCGTAC. The new strand built off this segment reads TGGAATG. What effect might this have when the DNA replicates in the future?
Cells having the new DNA version will look or operate differently from cells with the original DNA.
Only the sections of DNA without mistakes will be used in the future so the DNA strand will shorten.
The DNA will be exactly like the original since only the original strand of DNA is used as a template.
When the new strand is used as a template the strand built from it will differ from the original DNA.

19. Show What You Know
Which of the following processes produces the nucleotide sequence UUA from the sequence AAT?
meiosis
replication
respiration
transpiration

20. Show What You Know
When an extra nitrogenous base is inserted into the DNA sequence of a gene, the protein product of the gene is usually nonfunctional. Which of the following statements best explains why?
The inserted base increases the rate of translation in the corresponding mRNA sequence.
The inserted base causes the DNA sequence to be transcribed into the RNA in the opposite direction.
The inserted base causes the codons in the mRNA sequence to be incorrect for the desired protein.
The inserted base signals enzymes to translate the DNA sequence rather than the RNA sequence into the protein.

21. Show What You Know
The diagram to the right represents a process that occurs in the nucleus of a eukaryotic cell.
Which of the following statements describes what is happening in this process?
Molecules of RNA are forming chromosomes.
A molecule of mRNA is directing the production of tRNA.
Molecules of DNA are being packaged for export to the ribosomes.
A molecule of DNA is being replicated to make two identical copies.