Biochemistry Protein Synthesis and Enzymology

Biochemistry Study Notes

Protein Synthesis

Definition: Process by which cells generate proteins from amino acids.
Key Steps:
1. Transcription: DNA is transcribed to messenger RNA (mRNA) in the nucleus.
  - RNA polymerase binds to DNA, synthesizing mRNA.
2. Translation: mRNA is translated to a protein at the ribosome.
  - tRNA brings amino acids to the ribosome based on the codon sequence of mRNA.
  - Peptide bonds form between amino acids, creating polypeptides.
Post-Translational Modifications: Proteins may undergo modifications (e.g., phosphorylation, glycosylation) after synthesis that affect their function.

Enzymology

Definition: Study of enzymes, their kinetics, mechanisms, and regulation.
Enzyme Structure:
- Active site: Region where substrate binds and reaction occurs.
- Enzymes are often proteins that lower activation energy of reactions.
Kinetics:
- Michaelis-Menten equation describes the rate of enzymatic reactions.
- Key parameters: Km (Michaelis constant) and Vmax (maximum velocity).
Inhibition:
- Competitive inhibition: Inhibitor competes with substrate for active site.
- Non-competitive inhibition: Inhibitor binds elsewhere, reducing enzyme activity.

Molecular Biology

Definition: Study of the molecular basis of biological activity.
Key Concepts:
- DNA Replication: Process of copying DNA prior to cell division.
- Gene Expression:
  - Involves transcription and translation of genes into proteins.
  - Regulated by factors such as enhancers and repressors.
Techniques:
- PCR (Polymerase Chain Reaction): Amplifies DNA sequences.
- Gel electrophoresis: Separates nucleic acids based on size.

Nucleic Acids

Types: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Structure:
- DNA: Double helix, composed of nucleotides (adenine, thymine, cytosine, guanine).
- RNA: Single strand, composed of nucleotides (adenine, uracil, cytosine, guanine).
Functions:
- DNA: Stores genetic information.
- RNA: Involved in protein synthesis and gene regulation.

Lipids

Definition: Diverse group of hydrophobic molecules, including fats, oils, and phospholipids.
Functions:
- Energy storage: Fats provide long-term energy.
- Structural components: Phospholipids compose cell membranes.
- Signaling molecules: Steroids and other lipids act as hormones.

Carbohydrates

Definition: Organic compounds made of carbon, hydrogen, and oxygen.
Types:
- Monosaccharides: Simple sugars (e.g., glucose, fructose).
- Disaccharides: Two monosaccharides (e.g., sucrose, lactose).
- Polysaccharides: Long chains of monosaccharides (e.g., starch, glycogen, cellulose).
Functions:
- Energy source: Carbohydrates provide quick energy.
- Structural roles: Cellulose in plant cell walls; chitin in fungal cell walls.

These notes provide a summary of key aspects of biochemistry, focusing on important concepts in protein synthesis, enzymology, molecular biology, nucleic acids, lipids, and carbohydrates.

Protein Synthesis

Process by which cells create proteins from amino acids.
Two main steps: transcription and translation.
Transcription happens in the nucleus, DNA is copied into mRNA.
RNA polymerase binds to DNA and synthesizes mRNA.
Translation occurs at the ribosome, mRNA is translated into a protein.
tRNA brings amino acids to the ribosome based on the codon sequence of mRNA.
Peptide bonds form between amino acids, building polypeptides.
Proteins can be modified after synthesis (e.g., phosphorylation, glycosylation) to affect functionality.

Enzymology

Study of enzymes, their kinetics, mechanisms, and regulation.
Enzymes are often proteins that lower activation energy of reactions.
The active site is the region where the substrate binds and the reaction occurs.
Michaelis-Menten equation describes the rate of enzymatic reactions.
Km (Michaelis constant): substrate concentration at half the maximum velocity.
Vmax (maximum velocity): maximum rate of reaction.
Competitive inhibition occurs when an inhibitor competes with the substrate for the active site.
Non-competitive inhibition happens when an inhibitor binds to a different site, reducing enzyme activity.

Molecular Biology

Study of the molecular basis of biological activity.
DNA Replication: Process of copying DNA before cell division.
Gene Expression: Involves the transcription and translation of genes to produce proteins.
Gene expression is regulated by factors such as enhancers and repressors.
Common techniques:
- PCR (Polymerase Chain Reaction): Amplifies DNA sequences.
- Gel Electrophoresis: Separates nucleic acids based on size.

Nucleic Acids

Two main types: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
DNA: Double helix structure made up of nucleotides (adenine, thymine, cytosine, guanine).
RNA: Single-stranded structure made up of nucleotides (adenine, uracil, cytosine, guanine).
Functions:
- DNA: Stores genetic information.
- RNA: Involved in protein synthesis and gene regulation.

Lipids

Diverse group of hydrophobic molecules such as fats, oils, and phospholipids.
Key functions:
- Energy storage: Fats provide long-term energy.
- Structural components: Phospholipids compose cell membranes.
- Signaling molecules: Steroids and other lipids act as hormones.

Carbohydrates

Organic compounds made of carbon, hydrogen, and oxygen.
Types:
- Monosaccharides: Simple sugars (e.g., glucose, fructose).
- Disaccharides: Two monosaccharides (e.g., sucrose, lactose).
- Polysaccharides: Long chains of monosaccharides (e.g., starch, glycogen, cellulose).
Functions:
- Energy source: Carbohydrates provide quick energy.
- Structural roles: Cellulose in plant cell walls; chitin in fungal cell walls.