How Proteins are Made

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• How Proteins are Made

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How RNA differs from DNA

• 1st- RNA consists of a single strand of
  nucleotides instead of the 2 strands found in DNA

RNA
DNA
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How RNA differs from DNA

• 2nd- RNA nucleotides contain the five-carbon
  sugar ribose rather than the sugar deoxyribose
  found in DNA

One less Oxygen
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How RNA differs from DNA

• 3rd- RNA has
• A, C, G, and U- Uracil (U bonds with A because
  no T in RNA)

Example DNA ATGCATCG RNA UACGUAGC
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Transcription and Translation

• The instruction for making a protein are
  transferred from a gene to an RNA molecule in a
  process called transcription.

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Transcription and Translation

• Cells then use 2 different types of RNA to read
  the instructions on the RNA molecule and put
  together the amino acids that make up the protein
  in a process called translation.

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Transcription Making RNA

• Step 1 Transcription begins when RNA
  polymerases bind to the genes promoter (a
  specific sequence of DNA that acts as a start
  signal for transcription.

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Transcription Making RNA

• Step 2 RNA polymerases then unwind and separate
  the 2 strands of the double helix, exposing the
  DNA nucleotides on each strand.

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Transcription Making RNA

• Step 3 RNA polymerase adds and then links
  complementary RNA nucleotides as it reads the
  gene.

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Transcription

• Messenger RNA (mRNA) is a form of RNA that
  carries the instructions for making a protein
  from a gene and delivers it to the site of
  translation.

http//10.11.3.62/videos/The20Language20of20Lif
e20Understanding20the20Genetic20Code/sec7268_3
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Gene Regulation and Structure

• In eukaryotes, many genes are interrupted by
  introns (long segments of nucleotides that have
  no coding information.

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Gene Regulation and Structure

• Exons are the portions of a gene that are
  translated (expressed) into proteins.

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Gene Regulation and Structure

• The exons that remain are stitched back
  together by the spliceosomes to form a smaller
  mRNA molecule that is then translated.

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Transcripton Codons

• The RNA instructions are written as a series of
  three-nucleotide sequences on the mRNA called
  codons.
• Example UAU UGU AGG
• Codes for Tyrosine Cysteine Arginine

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mRNA Codon Chart
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EOC QUESTIONS

• A short chain of DNA has the nucleotide sequence
  ATA CCG. Its complementary mRNA nucleotide
  sequence is

B. UAU GCC
A. TAT GCC
C. TUT GCC
D. UAU GGC
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EOC QUESTIONS

• What is the maximum number of amino acids that
  could be coded for by a section of mRNA with the
  sequence GUCCAGAACUGU?

A. 3
B. 4
C. 6
D. 12
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EOC QUESTIONS

• If a codon reads UGU, what is its anticodon?

A. TCT
B. AGA
D. ACA
C. UGU
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EOC QUESTIONS

• What is the name of the amino acid coded by AGU?
• ___________________

Serine
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Translation Assembling Proteins

• Transfer RNA (tRNA) molecules are single strands
  of RNA that temporarily carry a specific amino
  acid on one end.

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Translation Assembling Proteins

• An anticodon is a three-nucleotide sequence on a
  tRNA that is complementary to an mRNA codon.

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Translation Assembling Proteins

• Ribosomal RNA (rRNA) molecules are RNA molecules
  that are part of the structure of ribosomes.

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Steps of Translation

• Step 1 The ribosomal subunits, the mRNA, and
  the tRNA carrying methionine bind together.
• Step 2 The tRNA carrying the amino acid
  specified by the codon in the A site arrives.

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Steps of Translation

• Step 3 A peptide bond forms between adjacent
  amino acids.
• Step 4 The tRNA in the P site detaches and
  leaves its amino acid behind.

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Steps of Translation

• Step 5 The tRNA in the A site moves to the P
  site, the tRNA carrying the amino acid specified
  by the codon in the A site arrives.
• Step 6 A peptide bond is formed. The tRNA in
  the P site detaches and leaves its amino acid
  behind.

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Steps of Translation

• Step 7 The process is repeated until a stop
  codon is reached. The ribosomes complex falls
  apart. The newly made protein is released.

http//10.11.3.62/videos/The20Language20of20Lif
e20Understanding20the20Genetic20Code/sec7269_3
00k.asf
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EOC Test Prep
1. Which cellular function does this model
represent?
A. Transcription
B. Translation
C. Transformation
D. DNA replication
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EOC Test Prep
2. Which part of the model represents a codon?
F. A
G. B
Codons are associated with mRNA
H. C
J. D
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EOC Test Prep
3.What does the part labeled E represent?
A. Ribosome
The circles represent amino acids which are what
proteins are made up of.
B. Growing protein chain
C. Messenger RNA
D. Transfer RNA
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Practice

• DNA- A C C T G T A A C G A G C C A G T T
• mRNA- U G G
• tRNA- A C C
• Codon - _____
• Amino Acid- Tryp

A C A U U G C U C G G U C A A
U G U A A C G A G C C A G U U
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Thre Leu Leu Glyc Glu