Genetics and Evolution
Molecular Basis of Inheritance
What are proteins?
====
- Proteins are complex macromolecules composed of amino acids.
- They play a crucial role in various biological processes.
- Proteins are involved in cell structure, growth and repair, signaling, enzyme function, and transport of molecules.
====
- Amino acids are the building blocks of proteins.
- There are 20 different types of amino acids that can be combined in various ways to form different proteins.
- The sequence and arrangement of amino acids determine the structure and function of a protein.
====
- Proteins are synthesized through a process called protein synthesis.
- The genetic information required for protein synthesis is stored in DNA.
- DNA is transcribed into mRNA, which is then translated into proteins.
====
- The synthesis of proteins involves several steps, including initiation, elongation, and termination.
- Initiation involves the assembly of the ribosome on the mRNA.
- Elongation is the addition of amino acids to the growing polypeptide chain.
- Termination occurs when a stop codon is reached, and the protein synthesis process is terminated.
====
- The structure of a protein is classified into four levels: primary, secondary, tertiary, and quaternary.
- The primary structure refers to the linear sequence of amino acids.
- The secondary structure includes alpha helices and beta sheets.
- The tertiary structure is the overall three-dimensional folding of the protein.
- The quaternary structure exists in proteins composed of multiple subunits.
====
- Proteins can fold into specific shapes due to various forces including hydrogen bonding, hydrophobic interactions, and disulfide bridges.
- The specific shape of a protein is essential for its function.
- Minor changes in protein structure can lead to loss of function or malfunctioning.
====
- Each protein has a specific function in the cell or organism.
- Some proteins act as enzymes, facilitating biochemical reactions.
- Others serve as structural components or transport molecules.
- Immunoglobulins are proteins involved in the immune response.
- Hemoglobin is a protein responsible for transporting oxygen in the blood.
====
Examples of protein functions:
- Collagen: Provides structural support to skin, bones, and ligaments.
- Insulin: Regulates blood glucose levels.
- Actin and myosin: Responsible for muscle contraction.
- Hemoglobin: Carries oxygen in red blood cells.
- Enzymes: Catalyze biochemical reactions in the body.
====
Proteins are responsible for the diversity of traits observed in organisms.
- Differences in protein structure and function contribute to the variation seen in individuals and populations.
- Genetic variations can result in altered proteins, leading to varied phenotypic traits.
Slide 11
Protein Synthesis
- Protein synthesis is the process by which cells build proteins.
- It involves two main steps: transcription and translation.
- Transcription occurs in the nucleus, where DNA is used as a template to produce mRNA.
- Translation takes place in the cytoplasm, where mRNA is used to assemble amino acids into a polypeptide chain.
- Ribosomes are the cellular machinery responsible for protein synthesis.
Slide 12
Transcription
- Transcription is the process of converting DNA into mRNA.
- It involves the following steps:
- Initiation: RNA polymerase binds to the promoter region of the DNA.
- Elongation: RNA polymerase moves along the DNA strand, synthesizing mRNA.
- Termination: RNA polymerase reaches a termination signal, and mRNA is released.
Slide 13
Genetic Code
- The genetic code is the set of rules by which the information in DNA is translated into protein.
- It is a triplet code, where each set of three nucleotides (codon) codes for a specific amino acid.
- There are 64 possible codons, but only 20 amino acids and three stop codons (UAA, UAG, UGA).
- The start codon (AUG) codes for methionine and initiates protein synthesis.
Slide 14
Translation
- Translation is the process of converting mRNA into a polypeptide chain.
- It involves three main steps: initiation, elongation, and termination.
- Initiation: The small ribosomal subunit binds to the mRNA, and the initiator tRNA carrying methionine binds to the start codon.
- Elongation: The ribosome moves along the mRNA, adding amino acids to the growing polypeptide chain with the help of tRNA molecules.
- Termination: The ribosome reaches a stop codon, and the polypeptide chain is released.
Slide 15
Regulation of Protein Synthesis
- Protein synthesis is tightly regulated in cells.
- Gene expression can be controlled at various levels, including transcription, mRNA processing, and translation.
- Regulatory proteins and transcription factors bind to DNA and affect the initiation of transcription.
- miRNAs and other RNA molecules can bind to mRNA and affect translation.
Slide 16
Mutations and Genetic Disorders
- Mutations are changes in the DNA sequence and can occur during DNA replication or as a result of mutagens.
- Mutations can be categorized as silent (no change in amino acid sequence), missense (change in amino acid), nonsense (premature stop codon), or frameshift (insertion or deletion).
- Mutations in protein-coding genes can lead to genetic disorders.
- Examples include cystic fibrosis, sickle cell anemia, and Huntington’s disease.
Slide 17
Protein Folding and Misfolding
- Protein folding is the process by which a protein assumes its three-dimensional structure.
- Chaperones assist in proper protein folding.
- Misfolding of proteins can lead to protein aggregation and the formation of amyloid plaques.
- Misfolded proteins are associated with neurodegenerative diseases like Alzheimer’s and Parkinson’s.
Slide 18
Proteins and Enzymes
- Enzymes are a type of protein that act as biological catalysts.
- They speed up chemical reactions by lowering the activation energy.
- Enzymes have an active site where substrates bind, and a specific shape is crucial for their function.
- Enzyme activity can be influenced by factors like temperature, pH, and substrate concentration.
Slide 19
Proteins in Signal Transduction
- Proteins play a critical role in signal transduction pathways.
- They receive signals from the environment or other cells and transmit them to the nucleus.
- Receptor proteins on the cell surface bind to signaling molecules and initiate a cascade of intracellular events.
- Examples include G-proteins, protein kinases, and transcription factors.
Slide 20
Protein Engineering and Biotechnology
- Protein engineering involves modifying proteins to improve their properties or create new functions.
- Techniques like site-directed mutagenesis and protein fusion are used.
- Biotechnology utilizes proteins in various applications, such as production of recombinant proteins, enzyme immobilization, and molecular diagnostics.
- Examples include insulin production using genetically modified bacteria and PCR (polymerase chain reaction) for DNA amplification.
Genetics and Evolution
Molecular Basis of Inheritance
What are proteins?
====
- Proteins are complex macromolecules composed of amino acids.
- They play a crucial role in various biological processes.
- Proteins are involved in cell structure, growth and repair, signaling, enzyme function, and transport of molecules.
====
- Amino acids are the building blocks of proteins.
- There are 20 different types of amino acids that can be combined in various ways to form different proteins.
- The sequence and arrangement of amino acids determine the structure and function of a protein.
====
- Proteins are synthesized through a process called protein synthesis.
- The genetic information required for protein synthesis is stored in DNA.
- DNA is transcribed into mRNA, which is then translated into proteins.
====
- The synthesis of proteins involves several steps, including initiation, elongation, and termination.
- Initiation involves the assembly of the ribosome on the mRNA.
- Elongation is the addition of amino acids to the growing polypeptide chain.
- Termination occurs when a stop codon is reached, and the protein synthesis process is terminated.
====
- The structure of a protein is classified into four levels: primary, secondary, tertiary, and quaternary.
- The primary structure refers to the linear sequence of amino acids.
- The secondary structure includes alpha helices and beta sheets.
- The tertiary structure is the overall three-dimensional folding of the protein.
- The quaternary structure exists in proteins composed of multiple subunits.
====
- Proteins can fold into specific shapes due to various forces including hydrogen bonding, hydrophobic interactions, and disulfide bridges.
- The specific shape of a protein is essential for its function.
- Minor changes in protein structure can lead to loss of function or malfunctioning.
====
- Each protein has a specific function in the cell or organism.
- Some proteins act as enzymes, facilitating biochemical reactions.
- Others serve as structural components or transport molecules.
- Immunoglobulins are proteins involved in the immune response.
- Hemoglobin is a protein responsible for transporting oxygen in the blood.
====
Examples of protein functions:
- Collagen: Provides structural support to skin, bones, and ligaments.
- Insulin: Regulates blood glucose levels.
- Actin and myosin: Responsible for muscle contraction.
- Hemoglobin: Carries oxygen in red blood cells.
- Enzymes: Catalyze biochemical reactions in the body.
====
Proteins are responsible for the diversity of traits observed in organisms.
- Differences in protein structure and function contribute to the variation seen in individuals and populations.
- Genetic variations can result in altered proteins, leading to varied phenotypic traits.
Slide 21
Protein Synthesis
- Protein synthesis is the process by which cells build proteins.
- It involves two main steps: transcription and translation.
- Transcription occurs in the nucleus, where DNA is used as a template to produce mRNA.
- Translation takes place in the cytoplasm, where mRNA is used to assemble amino acids into a polypeptide chain.
- Ribosomes are the cellular machinery responsible for protein synthesis.
Slide 22
Transcription
- Transcription is the process of converting DNA into mRNA.
- It involves the following steps:
- Initiation: RNA polymerase binds to the promoter region of the DNA.
- Elongation: RNA polymerase moves along the DNA strand, synthesizing mRNA.
- Termination: RNA polymerase reaches a termination signal, and mRNA is released.
Slide 23
Genetic Code
- The genetic code is the set of rules by which the information in DNA is translated into protein.
- It is a triplet code, where each set of three nucleotides (codon) codes for a specific amino acid.
- There are 64 possible codons, but only 20 amino acids and three stop codons (UAA, UAG, UGA).
- The start codon (AUG) codes for methionine and initiates protein synthesis.
Slide 24
Translation
- Translation is the process of converting mRNA into a polypeptide chain.
- It involves three main steps: initiation, elongation, and termination.
- Initiation: The small ribosomal subunit binds to the mRNA, and the initiator tRNA carrying methionine binds to the start codon.
- Elongation: The ribosome moves along the mRNA, adding amino acids to the growing polypeptide chain with the help of tRNA molecules.
- Termination: The ribosome reaches a stop codon, and the polypeptide chain is released.
Slide 25
Regulation of Protein Synthesis
- Protein synthesis is tightly regulated in cells.
- Gene expression can be controlled at various levels, including transcription, mRNA processing, and translation.
- Regulatory proteins and transcription factors bind to DNA and affect the initiation of transcription.
- miRNAs and other RNA molecules can bind to mRNA and affect translation.
Slide 26
Mutations and Genetic Disorders
- Mutations are changes in the DNA sequence and can occur during DNA replication or as a result of mutagens.
- Mutations can be categorized as silent (no change in amino acid sequence), missense (change in amino acid), nonsense (premature stop codon), or frameshift (insertion or deletion).
- Mutations in protein-coding genes can lead to genetic disorders.
- Examples include cystic fibrosis, sickle cell anemia, and Huntington’s disease.
Slide 27
Protein Folding and Misfolding
- Protein folding is the process by which a protein assumes its three-dimensional structure.
- Chaperones assist in proper protein folding.
- Misfolding of proteins can lead to protein aggregation and the formation of amyloid plaques.
- Misfolded proteins are associated with neurodegenerative diseases like Alzheimer’s and Parkinson’s.
Slide 28
Proteins and Enzymes
- Enzymes are a type of protein that act as biological catalysts.
- They speed up chemical reactions by lowering the activation energy.
- Enzymes have an active site where substrates bind, and a specific shape is crucial for their function.
- Enzyme activity can be influenced by factors like temperature, pH, and substrate concentration.
Slide 29
Proteins in Signal Transduction
- Proteins play a critical role in signal transduction pathways.
- They receive signals from the environment or other cells and transmit them to the nucleus.
- Receptor proteins on the cell surface bind to signaling molecules and initiate a cascade of intracellular events.
- Examples include G-proteins, protein kinases, and transcription factors.
Slide 30
Protein Engineering and Biotechnology
- Protein engineering involves modifying proteins to improve their properties or create new functions.
- Techniques like site-directed mutagenesis and protein fusion are used.
- Biotechnology utilizes proteins in various applications, such as production of recombinant proteins, enzyme immobilization, and molecular diagnostics.
- Examples include insulin production using genetically modified bacteria and PCR (polymerase chain reaction) for DNA amplification.