1. What we already know: The nucleus contains DNA
Eukaryotes have linear DNA
Prokaryotes have circular DNA
DNA is copied during Interphase of the Cell Cycle

2. What we already know:
Traits are distinguishing features or characteristics
Traits are passed from parent to offspring
Traits are passed on through genes
Genes are specific sections of DNA
In sexual reproduction, offspring get half of their genes from each parent

3. DNA is INFORMATION DNA= deoxyribose nucleic acid
A molecule that stores information
Contains the instructions for making proteins
Like a cookbook contains the instructions for making a cake

4. Proteins and Amino Acids
Proteins are large molecules made up of chains of amino acids
There are 20 different amino acids that combine into thousands of different proteins
Folding of the string of amino acids is critical for protein function

5. Proteins and Amino Acids
Proteins can vary in size from just 20 amino acids, like this one found in Gila Monster saliva…
To this protein nicknamed “Titan” with 34,350 amino acids, found in human muscle tissue

6. Check for Understanding:
What is the relationship between proteins and amino acids?
What is a trait?
When is DNA copied?
What is a gene?

7. Check for Understanding:
What is the relationship between proteins and amino acids?
20 amino acids come together in various combinations to make proteins
What is a trait?
Distinguishing features or characteristics
When is DNA copied?
During Interphase of the Cell Cycle
What is a gene?
A specific section of DNA that contains the code for a protein

8. DNA & The Genetic Code DNA molecule is shaped like a twisted ladder
The molecule is formed from nucleotide subunits that consist of:
Phosphate
Sugar (Deoxyribose)
Nitrogen Base

9. DNA & The Genetic Code All Tigers Can Growl
The side rails of the ladder are formed by the sugar-phophates
The rungs of the ladder are formed by two bases coming together
There are four different bases in DNA
Adenine
Thymine
Cytosine
Guanine
All Tigers Can Growl

10. Some comic relief…

11. DNA Structure Video

12. DNA & The Genetic Code
The sequence (order) of bases in a strand of DNA makes the code for building proteins
The genetic code is a “triplet” code meaning that every three bases codes for one amino acid
A gene is the entire sequence of bases that codes for a specific protein
Like a recipe for a specific dish

13. Replication of the DNA Replication is the copying of DNA
Two strands separate
Free-floating nucleotides match up with the nucleotides on each strand
Two identical molecules of DNA are made

14. Watch Replication in Action
This movie shows a computer animation of how DNA is replicated
Another video on YouTube

15. Check for Understanding
What three components make up the nucleotide subunit?
What are the four bases and what is the rule about how they pair together?
Describe what is meant by a “triplet code.”
What are the steps of DNA replication?

16. Check for Understanding
What three components make up the nucleotide subunit?
Phosphate, Sugar, Nitrogen Base
What are the four bases and what is the rule about how they pair together?
Adenine pairs with Thymine
Cytosine pairs with Guanine
Describe what is meant by a “triplet code.”
Three bases code for one amino acid
What are the steps of DNA replication?
Strands separate
Nucleotides pair up
Two identical strands are made

17. RNA is needed to make proteins:
RNA is ribonucleic acid and is very similar to DNA except:
RNA has ribose sugar instead of deoxyribose sugar
RNA has Uracil instead of Thymine
RNA is a single strand

18. RNA is needed to make proteins:
EUKARYOTES: RNA copies the information from the DNA inside the nucleus then travels outside to the cytoplasm
PROKARYOTES: RNA and proteins are made in the cytoplasm

19. RNA is needed to make proteins:
Three different types of RNA are involved in making protein:
messanger RNA (mRNA)
ribosomal RNA (rRNA)
transfer RNA (tRNA)
mRNA carries the message or code outside the nucleus
rRNA makes up part of the ribosome
tRNA brings the correct amino acids to the ribosome for protein construction

20. Check for Understanding
How is RNA different from DNA?
What are the three types of RNA involved in making proteins?

21. Check for Understanding
How is RNA different from DNA?
RNA has ribose sugar instead of deoxyribose sugar
RNA has Uracil instead of Thymine
RNA is a single strand
What are the three types of RNA involved in making proteins?
messanger RNA (mRNA)
ribosomal RNA (rRNA)
transfer RNA (tRNA)

22. Transcription Transcription produces a single-stranded molecule of RNA
One strand of DNA is the template or pattern
The steps of transcription are:
The DNA molecule opens up along a gene
RNA nucleotides (A,U,C,G) match up and join the open DNA strand
The complete RNA strand is released and moves to the cytoplasm
Transcription

23. Transcription is different than replication:
Only one strand of DNA is transcribed so only one strand of mRNA is produced
The mRNA is released, it does not stay attached to the DNA
Many copies of mRNA can be made from a single gene in a short period of time
Transcription on YouTube
Transcription

24. Check for understanding
What are the steps of transcription?
How is transcription different than replication?

25. Check for understanding
What are the steps of transcription?
The DNA molecule opens up along a gene
RNA nucleotides (A,U,C,G) match up and join the open DNA strand
The complete RNA strand is released and moves to the cytoplasm
How is transcription different than replication?
Only one strand of DNA is transcribed so only one strand of mRNA is produced
The mRNA is released, it does not stay attached to the DNA
Many copies of mRNA can be made from a single gene in a short period of time

26. Translation
Translation is how cells TRANSLATE the language or code of nucleotide bases into the language of amino acids
Translation occurs in the cytoplasm at the ribosome
If DNA is the cookbook, and mRNA is the recipe, then the ribosome is the kitchen and tRNA is the chef!

27. Translation rRNA is part of the ribosome that attaches to the mRNA
tRNA has a triplet of bases on one end and can attach to a single amino acid on the other end
tRNA does the translation of bases to amino acids when it matches up with mRNA

29. Brain Break! Link to Translation Video
Another video that reviews Translation and Transcription

30. Translation
Translation begins when a ribosome attaches to the beginning of an mRNA molecule
A tRNA molecule carrying an amino acid matches up to a complementary triplet on mRNA on the ribosome
The ribosome attaches one amino acid to another as it moves along the mRNA molecule
The tRNA molecules are released after the amino acids they carry are attached to the growing chain of amino acids
The ribosome completes the translation when it reaches the end of the mRNA strand and the newly made protein molecule is released

31. The Central Dogma DNA RNA Protein
The process of making proteins is the same in all cells
This is the foundation of molecular biology, biochemistry, and genetics
Translation
Transcription
DNA
RNA
Protein
Another YouTube video!

32. Check for understanding
Where does translation occur?
Which RNA makes up the ribosome?
Which RNA is the “recipe?”
Which RNA does the actual translation of bases into amino acids?
What is the “central dogma” of molecular biology?

33. Check for understanding
Where does translation occur?
In the cytoplasm
Which RNA makes up the ribosome?
rRNA
Which RNA is the “recipe?”
mRNA
Which RNA does the actual translation of bases into amino acids?
tRNA
What is the “central dogma” of molecular biology?
Transcription
Translation
DNA
RNA
Protein

34. Replication, Transcription, Translation Challenge!
Copy this DNA sequence:
A - T - G - A - C - G
Write the base pairs of the complimentary strand of DNA (replication)
Write the complimentary mRNA strand to your new strand (transcription)
Use the chart to find the correct amino acids that the tRNA would attach to the protein (translation)

35. The Universal Genetic Code

36. The Universal Genetic Code

37. Check your answers: Replication: T - A - C - T - G - C Transcription
A - U - G - A - C - G
Translation
Met (Methionine) and Thr (Threonine)

38. A HISTORY OF DNA (1928) Frederick Griffith
Discovers that a “transforming factor” changes harmless bacteria into deadly bacteria
(1952) Rosalind Franklin
Takes x-ray photographs of DNA
(1953) James Watson and Francis Crick
Use Franklin’s images to describe the structure of DNA
(1962) Watson, Crick, and Wilkins win the Nobel Prize, Franklin has already died from cancer (1958) so she does not get recognition 38