1. Modern Molecular Genetics University of Maryland College Park LFSC 620
Protein Synthesis
Modern Molecular Genetics
University of Maryland College Park
LFSC 620

2. Lesson Objectives DNA structure Proteins and Cell structure
Nucleotide
Nitrogen bases
Proteins and Cell structure
mRNA
tRNA
The DNA-Protein connection

3. DNA (Deoxyribonucleic acid)
Structure
Made up of subunits called nucleotides
2 strands of nucleotides
Nucleotides contain
Deoxyribose sugar
Phosphate group
Nitrogen bases
Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)

4. The Double Helix Bases are bonded together by a hydrogen bond
Base are complimentary to each other
A-T
C-G

5. RNA (Ribonucleic acid)
There are several types of RNA
Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)
There are several differences between RNA and DNA
1 strand
Ribose sugar
Thymine (T) is replaced by Uracil (U)

6. Proteins and Cell Functioning
The work of the cell is carried out by many types of molecules called proteins.
Proteins are made up of subunits called Amino Acids.
There are 20 different amino acids that are arranged in specific sequences to form many different proteins.

7. Amino Acids and proteins
The sequence of amino acids determines the shape of the protein
The peptide bond that forms between them causes it to fold and bend in a particular shape.
The shape of the protein enables it to carry out its function.
Enzymes- regulate chemical reactions
Hormones-cell communication
Proteins are found in the cell membrane
Channels
Receptors
markers

8. The DNA-Protein connection
Proteins are made at the ribosomes according to the directions stored in the cell’s DNA code
Offspring inherit genetic information from their parents which make these proteins
Making many of the same proteins causes both parent and offspring to form same structures that give them similar features.
If the parent’s DNA carries a code for a protein that does not function properly, the children may also make the defective protein

9. Protein synthesis Begins in the nucleus (animation)
DNA code of a particular protein is read and used to produce mRNA.
This process is called transcription
The nucleotides are organized in groups of three.
The sequence of bases found in mRNA is called a codon
Each codon codes for a particular amino acid.
Code is determined from the DNA code.

10. Transcription

11. mRNA codon-amino acid table

12. tRNA Every three bases are called anticodons
tRNAs job is to pick up and transfer amino acids to the ribosome.

13. Translation
tRNA molecules carry the amino acids to the ribosome to make the protein. The process of the mRNA codon matching its bases with the tRNA anticodon is called translation.
This process verifies the genetic code for the appropriate protein.

14. Animated protein synthesis websites