1. Bellwork What are the three parts of a DNA nucleotide?
What would the complementary strand of DNA look like (nitrogen bases)?
A T G C C G T T A A C G
What would the complementary mRNA strand look like?

2. DNA Structure Double Helix.
made up of millions of tiny subunits called Nucleotides.
Phosphate group
Pentose sugar
(deoxyribose)
Nitrogenous base
Phosphate
Nitrogenous
Base
Pentose
Sugar

3. Nucleotides Phosphate and sugar backbone
the nitrogen bases form the “rungs”.
There are four types of nitrogenous bases.

4. Nucleotides
Each base will only bond with one other specific base (Chargaff’s Rule, or Base-Pair Rule).
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Form a base pair.
Form a base pair.

5. Complementary base pairing:
the order of the bases in one strand determines the order of the bases in the other strand. C

6. Agenda 12/19- Protein Synthesis
Bellwork
Essential Question: How does DNA code for proteins? How does DNA determine the structure and function of an organism?
New information: Protein synthesis (transcription and translation)
Activity: Protein Synthesis practice worksheet in pairs

7. DNA
Gene
Trait
Protein

8. Protein Synthesis Overview
Cytoplasm
Nucleus
DNA
DNA is the genetic material
within the nucleus.
Transcription
Transcription creates an
mRNA using DNA information.
RNA
Translation
Translation creates a
protein using RNA information.
Protein

9. Protein Synthesis Overview
Cytoplasm
Nucleus
DNA
Sections of DNA that code for
proteins are called GENES.
A Gene
GENES determine what
proteins are made and
therefore what traits an
organism has.
Transcription
RNA
A gene does not build proteins directly. It sends instructions in the form of mRNA which directs protein synthesis.
Translation
Protein

10. Two Types of Nucleic Acids
RNA
DNA
Number of strands
Usually single-stranded
Usually double-stranded
Nitrogen Bases
URACIL (instead of T), A, C, and G
THYMINE (instead of U), A, C, and G
Pentose Sugar
Ribose
Deoxyribose
Codes for…
Codes for proteins
Codes for RNA

11. Two types of nucleic acids
# of strands
kind of sugar
TRANSCRIPTION DIFFERS FROM REPLICATION IN THAT ONLY 1 STRAND OF THE DNA MOLEUCLE IS TRANSCRIBED AND THAT MEANS THAT THE RESULTING RNA MOLECULE IS SS
ALSO MRNA IS SHORT COMPARED TO A LARGE CHROMOSOME
bases used

12. Types of RNA mRNA = messenger RNA Made during transcription
Carries a complementary copy of the DNA code out of the nucleus for protein synthesis on a ribosome

13. Types of RNA mRNA = messenger RNA tRNA = transfer RNA
Transfers amino acids to the ribosome for protein synthesis
Found in the cytoplasm
rRNA = ribosomal RNA

14. Transcription First the DNA is “unzipped”.
Complementary RNA nucleotides are added to the template strand, forming the new RNA molecule.
DNA
DNA coding strand 5’ G T C A T T C G G 3’ G
RNA 5’ U C A 3’ 3’
CALLED TRANSCRIPTION BECAUSE THE NUCLEIC ACID LANGUAGE OF DNA HAS TO BE REWRITTEN AS A SEQUENCE OF BASES ON RNA
ACTIVATED GENES DO NOT LEAVE THE NUCLEUS BECAUSE THE CYTOPLASM IS TOO HOSTIL
INSTEAD A MESSAGE IS CARRIED ON A STRAND OF MRNA
THE PROCESS OF MRNA FORMATION IS CALLED TRANSCRIPTION BECAUSE IN THE NUCLEUS THE MRNA IS TRANSCRIBED FROM THE DNA TEMPLATE C A G T A A G C C 5’
DNA template strand

15. TRANSCRIPTION RNA polymerase attaches
mRNA nucleotides to the DNA template:
Guanine to Cytosine
Cytosine to Guanine
Adenine to Thymine
Uracil to Adenine
RNA polymerase cannot attach Thymine G
RNA 5’ U C A 3’ C A G T A A G C C

16. What happens after transcription?
The new mRNA molecule (and DNA) has more information than is required for making the protein.
The parts that aren’t directly needed for making the protein are called INTRONS- they stay IN the nucleus.

17. What happens after transcription?
The new mRNA molecule (and DNA) has more information than is required for making the protein.
The parts that are needed for making the protein are called EXONS- they EXit the nucleus after being spliced together.

18. Translation
The process of reading the RNA sequence of an mRNA and creating the amino acid sequence of a protein.
DNA T C A G
template
strand
Transcription
mRNA A G U C
Messenger
RNA
Codon
Translation
THE GENETIC INSTRUCTIONS FOR THE AA SEQUENCE OF A POLYPEPTIDE CHAIN ARE WRITTEN IN DNA
AND TRANSCRIBED TO RNA AS A SERIES OF 3 BASE WORDS CALLED CODONS
TRIPLETS IN THE DNA ARE TRANSCRIBED INTO COMPLEMENTARY 3 BASE CODONS IN THE MRNA
AND THEN THE MRNA CODONS ARE TRANSLATED INTO AA THAT WILL MAKE UP A POPYPEPTIDE
Protein
Lysine
Serine
Valine
Polypeptide
(amino acid
sequence)

19. Transcription Translation CUC IS WHAT IS ON MRNA GAG GLUTAMIC ACID
THE TRNA MOLECULE BINDS TO THE MRNA MATCHING UP ITS COMPLEMENTARY ANTICODON TO THE MRNA CODON
GO OVER THIS OVERHEAD
Transcription
Translation

20. Protein Synthesis Overview
Cytoplasm
Nucleus
DNA
Transcription
Transcription creates mRNA
from DNA information- happens
in nucleus.
RNA
Translation
Translation creates protein
using RNA information; happens
at a ribosome (in cytoplasm or
on rough ER).
Protein

21. 5 Minute Writing AAG GCT TAT GCC CAT
If one DNA strand has the nitrogen base sequence below, what will the complementary strand look like?
What will the mRNA produced during transcription look like?
What happens during the process of translation?
AAG GCT TAT GCC CAT

22. Protein Synthesis Overview
Cytoplasm
Nucleus
DNA
DNA is the genetic material
within the nucleus.
Transcription
Transcription creates an
mRNA using DNA information.
RNA
Translation
Translation creates a
protein using RNA information.
Protein

23. mRNA codons and the Amino Acids for which they code

24. Gene Mutations Point mutations: a single nucleotide is changed
Ex. Of a triplet sequence: the fat cat sat
Point mutations: a single nucleotide is changed
Substitution: Ex. F in “fat” is changed to an “e”:
the eat cat sat

25. Gene Mutations Point mutations: a single nucleotide is changed
Ex. Of a triplet sequence: the fat cat sat
Point mutations: a single nucleotide is changed
Deletion: Ex. F in fat is deleted:
the atc ats at
Frameshift mutation: caused by insertion or deletion of fewer (or more) than 3 nucleotides; usually results in all codons after that point being altered.

26. Gene Mutations
When the code is changed due to a mutation, the amino acid sequence may be altered, resulting in changes in the protein (or no protein at all).
Ex. Of a triplet sequence: the fat cat sat
Substitution: Ex. F in “fat” is changed to an “e”:
the eat cat sat
Deletion: Ex. F in fat is deleted:
the atc ats at (frameshift mutation) 26