A2.3 HL only Flashcards
AIDS
a disease caused by the human immunodeficiency virus (HIV) that occurs when the immune system is severely damaged
HIV
a virus that attacks cells that help the body fight infection, making a person more vulnerable to other infections and diseases
COVID-19
an infectious disease caused by the SARS-CoV-2 virus. Most people infected with the virus will experience mild to moderate respiratory illness and recover without requiring special treatment
Virus
an infectious agent of small size and simple compositionthat can multiply only in living cells of animals, plants, or bacteria
Outbreak
more cases of a disease than expected in a specific location over a specific time period
Epidemic
the rapid spread of disease to a large number of hosts in a given populationwithin a short period of time
Pandemic
an infectious disease that has a sudden increase in casesand spreads across a large region, for instance multiple continents
single stranded
a nucleic acid structure made up of a single chain of nucleotides, as opposed to the double-stranded structure of DNA.Single-stranded DNA (ssDNA) is more flexible and dynamic than double-stranded DNA (dsDNA)
double stranded
consists of two polynucleotide chains whosenitrogenous basesare connected by hydrogen bonds
capsid
the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers
Envelope
a surrounding structure or membrane that can refer to a cell envelope, viral envelope, or nuclear envelope
Spherical
capsidshave a spherical shape. Although the virus looks spherical, when examined closely it reveals that they are icosahedral in shape. The triangles of the icosahedral capsid are fused to form a spherical shape. Some of the spherical viruses have an envelope made of lipid membranes.
Helical
a virus with a helical structure, meaning its genetic material is coiled up inside a hollow protein cylinder, or capsid, that resembles a spring or helix
Polyhedral
a virus with a many-sided capsid, or shell, that surrounds its nucleic acid.The capsid is often shaped like an icosahedron, which is a geometric shape with 20 triangular sides and 12 corners
Complex
often in a combination of helical and icosahedral shapes. The head-tail morphology of these complex viruses is unique and is used for infecting bacteria. These types of viruses are also called bacteriophages.
Bacteriophage lambda
a temperate phage, which, upon infection of Escherichia coli, enters either thelyticor lysogenic replication pathway
Coronavirus
a group of related RNA viruses that cause diseases in mammals and birds. In humans and birds, they cause respiratory tract infections
Spike proteins
a protein that forms a large structure known as a spike or peplomer projectingfrom the surface of an enveloped virus
reverse transcriptase
an enzyme that converts RNA into DNA, commonly found in retroviruses like HIV. It is used in molecular biology research to create complementary DNA strands from RNA templates, allowing for the amplification of RNA sequences similar to DNA
retrovirus
A type of virus that has RNA instead of DNA as its genetic material. It uses an enzyme called reverse transcriptase to become part of the host cells’ DNA. This allows many copies of the virus to be made in the host cells.
CD4 Helper T-cell
one type of lymphocyte that helps coordinate the immune response against infection and disease. They interact and activate other cells in the immune system
Lytic Cycle
one of two cycles that a virus can use to reproduce inside a host cell. The lytic cycle is a series of stages in which a virus hijacks a host cell, uses its components to manufacture more of the virus, destroys and exits the cell, and then goes on to infect other cells.
Biosynthesis
the process by which living organisms create complex products from simpler components through chemical reactions
virions
a complete, infectious virus particle that contains a virus’s genome and a protein coat
lysis
the process of breaking down a cell’s plasma membrane, or outer membrane, which releases the cell’s contents
Proviruses
a viral genome that is integrated into the DNA of a host cell.It is an inactive form of a virus that can be passed on from one cell generation to the next without causing lysis
prophages
a bacteriophage (phage) genome that is integrated into a bacterial cell’s genome or exists as a plasmid.Prophages are latent bacterial viruses that are harmless to the host and reproduce when the host does
genome
the complete set of DNA (genetic material) in an organism, and it contains all the information needed for that organism to develop and function
mitosis
a process in which a cell divides to produce two identical daughter cells
Lysogenic cycle
a viral reproductive stage where a virus’s DNA is replicated using the host cell’s DNA.This process occurs during host cell division, and the viral DNA is replicated along with the host’s DNA without harming the host cell
Integration
incorporation of the genetic material of a virus in to the host genome. A term used to confirm the successful binding of foreign dna into an organisms own genome
recombination
a biological process that involves breaking and exchanging DNA strands to create new combinations of alleles
Replication
the process of copying a DNA molecule to create two identical copies
binary fission
a type of asexual reproduction in which a cell divides into two identical daughter cells
convergent evolution
a biological process that occurs when unrelated organisms evolve similar traits or behaviors in response to similar environmental pressures
virologist
a scientist who studies viruses and how they affect humans, animals, plants, and bacteria.They may also be medical doctors who diagnose, treat, and manage viral infections
Virus First Hypothesis
a theory that viruses existed before cells and were responsible for the development of cellular life
Repressive Hypothesis
Viruses may have once been small cells thatparasitisedlarger cells. Over time, genes not required by their parasitism were lost. The bacteriarickettsiaandchlamydiaare living cells that, like viruses, can reproduce only inside host cells
Escape Hypothesis
Some viruses may have evolved from bits of DNA or RNA that “escaped” from the genes of a larger organism.
Retroviruses
unique class of virusesthat challenge the central dogma of biology, such that their RNA genomes are first reverse transcribed into DNA
molecular clock
a figurative term used to estimate when two or more species diverged from each other by analyzing the rate of genetic mutations in their DNA or protein sequences
Antigenic drift
genetic variation in viruses, arising from the accumulation ofmutationsin thevirus genesthat code for virus-surface proteins that hostantibodiesrecognize. This results in a new strain of virus particles that is not effectively inhibited by the antibodies that prevented infection by previous strains.
Antigenic shift
a sudden, major change in a virus’s surface antigens that creates a new variant of the virus.It occurs when two or more different strains of a virus combine, or when a virus from an animal population gains the ability to infect humans.Antigenic shift is a rare event that can lead to worldwide pandemics
