Immune System and Protein Synthesis

HCB Final 2024

Innate Immunity

The body's first line of defense against pathogens, involving physical and chemical barriers.

Physical Barriers

Skin, mucous membranes, cilia.

Chemical Barriers

Stomach acid, enzymes, antimicrobial peptides.

Acquired/Adaptive Immunity

The immune response that develops over time, involving specific recognition of pathogens.

Cell-Mediated Immunity

T cells destroy infected or abnormal cells.

Humoral Immunity

B cells produce antibodies that neutralize pathogens.

Antigen

Molecule capable of inducing an immune response.

Epitope

Specific part of an antigen recognized by the immune system.

B Cells

Produce antibodies and present antigens to helper T cells.

T Cells

Mediate cell-based immunity.

Cytotoxic T Cells

Destroy infected/abnormal cells using perforins and granzymes.

Helper T Cells

Activate B cells and cytotoxic T cells; orchestrate immune response.

Class 1 MHC

Present on all nucleated cells; recognized by cytotoxic T cells.

Class 2 MHC

Present on antigen-presenting cells; recognized by helper T cells.

Natural Killer Cells (NKCs)

Kill virus-infected or cancerous cells without needing antigen presentation.

Leukocytes (WBCs)

White blood cells involved in immune responses.

Macrophages

Engulf pathogens and present antigens to T cells.

Neutrophils

First responders; phagocytose pathogens.

Eosinophils

Combat parasites; contribute to allergic responses.

Basophils

Release histamine during allergic reactions.

Dendritic Cells

Present antigens to T cells; initiate adaptive response.

Interferons

Antimicrobial proteins that inhibit pathogen replication.

Antibodies

Proteins produced by B cells that bind to antigens.

Variable Region

Binds to antigens.

Constant Region

Remains the same across the same type of antibodies.

IgA

Found in mucosal areas, saliva, tears; prevents pathogen colonization.

IgD

Functions mainly as a receptor on B cells.

IgE

Involved in allergic reactions.

IgG

Provides long-term immunity; crosses the placenta.

IgM

First antibody produced in response to infection.

Antibody Diversity

Achieved through random and permanent gene rearrangement to produce a wide array of antibodies.

Vaccines

Introduce harmless antigens to stimulate antibody production and memory cell formation.

Allergies

Hypersensitive immune responses to allergens.

mRNA

Transcribes DNA and carries information to ribosomes.

rRNA

Part of the ribosome, helps form peptide bonds during protein synthesis.

tRNA

Decodes mRNA to add amino acids during protein synthesis.

Ribosomes

Produce proteins by linking amino acids.

Transcription

RNA synthesis from a DNA template.

Translation

Ribosome reads mRNA to synthesize proteins using tRNA.

Primary Structure

Linear chain of amino acids linked by covalent peptide bonds.

Secondary Structure

α-helices and β-pleated sheets stabilized by hydrogen bonds.

Tertiary Structure

3D folding due to side-chain interactions.

Quaternary Structure

Multi-subunit complex; interactions between polypeptide chains.

Protein Electrophoresis

Separates proteins based on size and charge.

SDS-PAGE

Uses SDS to denature proteins and ensure migration depends only on size.

Size Exclusion Chromatography (SEC)

Separates molecules based on size using beads with holes.

Ion Exchange Chromatography

Separates proteins by charge.

Anion Exchange

Positive beads attract negative proteins.

Cation Exchange

Negative beads attract positive proteins.

Affinity Chromatography

Purifies specific proteins using binding antibodies or molecules.

Hydrophobic Interaction Chromatography (HiC)

Separates based on hydrophobicity.

Protein Denaturation

Caused by heat, pH changes, and environmental factors.