Virology and Biotechnology Lecture Notes

Flashcards covering the fundamental concepts of virology, including viral structure and replication, as well as modern biotechnology techniques such as DNA sequencing, PCR, and genetic engineering.

Virus

An acellular infectious particle consisting of genes packaged in a protein coat.

Capsid

The protein shell built from subunits called capsomeres that encloses the viral nucleic acid.

Bacteriophages (Phages)

Viruses that infect bacteria, characterized by complex capsids and an elongated head that encloses DNA.

Viral Envelopes

Accessory structures surrounding the capsids of certain viruses, such as influenza, derived from host cell membranes.

Host Range

The spectrum of host cells that a specific virus is capable of infecting.

Lytic Cycle

A phage replicative cycle that results in the death of the host cell by lysing its cell wall to release new phages.

Virulent Phage

A type of phage that reproduces only through the lytic cycle.

Lysogenic Cycle

A replicative cycle where the phage genome is incorporated into the host cell's chromosome without destroying the host.

Prophage

The integrated viral DNA within a bacterial chromosome during the lysogenic cycle.

Temperate Phages

Phages that are capable of using both the lytic and lysogenic cycles.

Retroviruses

Viruses that use the enzyme reverse transcriptase to copy their RNA genome into DNA.

Reverse Transcriptase

An enzyme used by retroviruses to synthesize DNA from an RNA template.

Provirus

Viral DNA that is permanently integrated into the host genome, unlike a prophage which can exit.

Vaccines

Harmless derivatives of pathogenic microbes that stimulate the immune system to defend against the actual pathogen.

Epidemic

A viral disease outbreak that suddenly becomes apparent or widespread in a specific population.

Pandemic

A global epidemic resulting from viral strains that jump species or mutate.

Hemagglutinin (H)

A receptor on the influenza membrane that helps the virus stick to the host cell.

Neuraminidase (N)

An enzyme on the influenza membrane that helps the virus invade host cells.

Horizontal Transmission

The spread of viral disease in plants where the virus enters through damaged cell walls.

Vertical Transmission

The inheritance of a viral infection in plants from a parent plant.

Viroids

Small circular RNA molecules that infect plants and disrupt their growth.

Prions

Slow-acting, indestructible infectious proteins that cause brain diseases in mammals by converting normal proteins into the prion version.

DNA Sequencing

The process of exploiting complementary base pairing to determine the exact order of nucleotides in a DNA molecule.

Sanger Sequencing

Also known as dideoxy or chain termination sequencing, a technique developed by Sanger and colleagues to sequence DNA.

Bioinformatics

The use of computer and mathematical models to process and integrate large biological data sets.

Gene Cloning

A method to produce multiple identical copies of a specific gene of interest (GOI).

Plasmids

Small circular DNA molecules in bacteria that replicate separately from the bacterial chromosome.

Recombinant DNA

A DNA molecule produced by combining DNA from two different sources.

Cloning Vector

A plasmid or other DNA molecule used to carry foreign genetic material into a host cell for replication.

Restriction Enzymes

Bacterial enzymes that cut DNA molecules at specific sequences called restriction sites.

Sticky Ends

Staggered DNA fragments produced by restriction enzymes that can bond with complementary strands.

Gel Electrophoresis

A technique using a polymer gel to separate nucleic acids or proteins based on size, charge, or physical properties.

Polymerase Chain Reaction (PCR)

A three-step cycle consisting of denaturing, annealing, and extension used to exponentially amplify specific DNA segments.

Taq Polymerase

A heat-stable DNA polymerase used in PCR that remains active at temperatures up to $95\,^\circ\text{C}$.

Expression Vector

A cloning vector that contains a highly active bacterial promoter to ensure the expression of eukaryotic genes in bacterial cells.

Electroporation

The application of a brief electrical pulse to create temporary holes in plasma membranes, allowing recombinant DNA to enter cells.

Complementary DNA (cDNA)

DNA synthesized from an mRNA template using reverse transcriptase, representing the genes being expressed in a tissue.

Nucleic Acid Probes

Complementary DNA or RNA molecules labeled with dyes used to detect specific mRNA sequences.

DNA Microarray Assays

Technology used to compare and measure the expression patterns of thousands of genes simultaneously.

RNA Interference (RNAi)

A method to silence gene expression using synthetic double-stranded RNA molecules that match the target mRNA sequence.

CRISPR-Cas9 System

A gene-editing tool using a guide RNA and the Cas9 protein to target and cut or repair specific DNA sequences in living cells.

Genome-Wide-Association-Studies (GWAS)

Studies that test for genetic markers to identify sequences that vary among individuals and correlate with specific phenotypes.

Single Nucleotide Polymorphisms (SNPs)

Specific locations in the genome where a single nucleotide variant occurs among individuals.

Stem Cell

An unspecialized cell that can reproduce indefinitely and differentiate into specialized cell types.

Totipotent

A cell potency type where the cell can de-differentiate and give rise to all specialized cell types of an organism, common in plants.

Pluripotent

Cells, such as embryonic stem cells, that are capable of differentiating into many different cell types.

Induced Pluripotent Stem (iPS) Cells

Differentiated cells that have been reprogrammed using retroviruses to behave like embryonic stem cells.

Gene Therapy

The alteration of an individual's genes to treat diseases, often by using vectors to deliver functional genes into specific tissues.

Transgenic Animals

Animals produced by introducing genes from one species into the genome of another to produce substances for medical use.

Biotechnology

The manipulation of organisms or their components to produce useful products for medical, environmental, or agricultural use.