AS Definitions Flashcards
Abiotic factors.
Non-living conditions in a habitat.
Activation energy.
The energy required to initiate a reaction.
Active site
Area of an enzyme with a shape complimentary to a specific substrate, allowing the enzyme to bind a substrate with specificity.
Adenosine diphosphate (ADP)
A nucleotide composed of a nitrogenous base (adenine), a pentode sugar and two phosphate groups. Formed by the hydrolysis of ATP, releasing a phosphate ion and energy.
Adenosine triphosphate (ATP)
A nucleotide composed of a nitrogenous base (adenine), a pentose sugar and three phosphate groups. The universal energy currency for cells.
Agglutinins
Chemicals (antibodies) that cause pathogens to clump together so they are easier for phagocytes to engulf and digest.
Alleles.
Different versions of the same gene.
Amino acids.
Monomer used to build polypeptides and thus proteins.
Anabolism (anabolic)
Reactions of metabolism that construct molecules from smaller units. These reactions require energy from the hydrolysis of ATP.
Analogous structures.
Structures that have adapted to perform the same function but have a different origin.
Anaphase.
Third stage of mitosis when chromatids are separated to opposite poles of the cell.
Antibiotic-resistant bacteria
Bacteria that undergo mutation to become resistant to an antibiotic and then survive to increase in number
Antibiotics
A chemical or compound that kills or inhibits the growth of bacteria.
Antibodies
Y-shaped glycoproteins made by B cells of the immune system in response to the presence of an antigen.
Antigen
Identifying chemical on the surface of a cell that triggers an immune response.
Antigen-antibody complex.
The complex formed when an antibody binds to an antigen.
Antigen-presenting cell.
A cell that displays foreign antigens complexed with major histocompatibility complexes on their surfaces.
Antisense strand.
The strand of DNA that runs 3’ to 5’ and is complementary to the sense strand. It acts as a template strand during transcription.
Antibiotic-resistant bacteria
Bacteria that undergo mutation to become resistant to an antibiotic and then survive to increase in number
Antibiotics
A chemical or compound that kills or inhibits the growth of bacteria.
Antibodies
Y-shaped glycoproteins made by B cells of the immune system in response to the presence of an antigen.
Antigen
Identifying chemical on the surface of a cell that triggers an immune response.
Antigen-antibody complex.
The complex formed when an antibody binds to an antigen.
Antigen-presenting cell.
A cell that displays foreign antigens complexed with major histocompatibility complexes on their surfaces.
Antisense strand.
The strand of DNA that runs 3’ to 5’ and is complementary to the sense strand. It acts as a template strand during transcription.
Anti-toxins
Chemicals (antibodies) that bind to toxins produced by pathogens so they no longer have an effect.