Biology A-Level Exam
With answers
abiotic factors - answer-non-living conditions in a habitat
activation energy - answer-the energy required to initiate a reaction.
active site - answer-area of an enzyme with a shape complementary to a specific substrate,
allowing the enzyme to bind a substrate with specificity.
active transport - answer-movement of particles across a plasma membrane against a
concentration gradient. Energy is required. (ATP)
adenosine diphosphate (ADP) - answer-a nucleotide composed of a nitrogenous base
(adenine), a
pentose sugar and two phosphate groups. Formed by the hydrolysis of ATP, releasing a
phosphate ion and energy.
adenosine triphosphate (ATP) - answer-a nucleotide composed of a nitrogenous base
(adenine), a
pentose sugar and three phosphate groups. The universal energy currency for cells.
agglutinins - answer-chemicals (antibodies) that cause pathogens to clump together so they are
easier for phagocytes to engulf and digest.(caused by cross linking by antibodies that have a
number of binding sites)
alleles - answer-different versions of the same gene.
amino acids - answer-monomer used to build polypeptides and thus proteins
anabolism (anabolic) - answer-reactions of metabolism that construct molecules from smaller
units. These reactions require energy from the hydrolysis of ATP.
analogous structures - answer-structures that have adapted to perform the same function but
have a different origin.
anaphase - answer-third stage of mitosis when chromatids are separated to opposite poles of
the cell.
antibiotic-resistant bacteria - answer-bacteria that undergo mutation to become resistant to an
antibiotic and then survive to increase in number.
antibiotics - answer-a chemical or compound that kills or inhibits the growth of bacteria
antibodies - answer-Y-shaped glycoproteins made by B cells of the immune system in response
to the
presence of an antigen.
,antigen - answer-identifying chemical on the surface of a cell that triggers an immune response
antigen−antibody complex - answer-the complex formed when an antibody binds to
an antigen.
antigen-presenting cell (APC) - answer-a cell that displays foreign antigens complexed with
major histocompatibility complexes on their surface plasma membranes, so it can be recognised
by other cells
antisense strand 'lagging strand' - answer-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 - answer-chemicals (antibodies) that bind to toxins produced by pathogens so they
no longer have an effect.
apoplast - answer-the cell walls and intercellular spaces of plant cells.
apoplast route - answer-movement of substances through the cell walls and cell spaces by
diffusion and into cytoplasm by active transport.
arrhythmia - answer-an abnormal rhythm of the heart.
artefacts - answer-objects or structures seen through a microscope that have been created
during the processing of the specimen.
artificial active immunity - answer-immunity which results from exposure to a safe form of a
pathogen, for example, by vaccination.
artificial passive immunity - answer-immunity which results from the administration of antibodies
from
another animal against a dangerous pathogen.
asexual reproduction - answer-the production of genetically identical offspring from a single
parent.
assimilates - answer-the products of photosynthesis that are transported around a plant, e.g.,
sucrose
atrial fibrillation - answer-an abnormal rhythm of the heart when the atria beat very fast and
incompletely.
atrio-ventricular node (AVN) - answer-stimulates the ventricles to contract after imposing a slight
delay to ensure atrial contraction is complete.
,autoimmune disease - answer-a condition or illness resulting from an autoimmune response.
autoimmune response - answer-response when the immune system acts against its own cells
and destroys healthy tissue in the body.
autotrophic - answer-organisms that acquire nutrients by photosynthesis.
B effector cells - answer-B lymphocytes that divide to form plasma cell clones
B lymphocytes (B cells) - answer-lymphocytes which mature in the bone marrow and that are
involved in the production of antibodies
B memory cells - answer-B lymphocytes that live a long time and provide immunological
memory of the
antibody needed against a specific antigen.
belt transect - answer-two parallel lines are marked along the ground and samples are taken of
the area
at specified points.
Benedict's reagent - answer-an alkaline solution of copper(II)sulfate used in the chemical tests
for reducing sugars and non-reducing sugars. A brick-red precipitate indicates a positive result.
beta pleated sheet - answer-sheet-like secondary structure of proteins
binomial nomenclature - answer-the scientific naming of a species with a Latin
name made of two parts − the first indicating the genus and the second the
species.
biodiversity - answer-the variety of living organisms present in an area
biuret test - answer-the chemical test for proteins; peptide bonds form violet coloured complexes
with
copper ions in alkaline solutions.
Bohr effect - answer-the effect of carbon dioxide concentration on the uptake and release of
oxygen by
haemoglobin
bradycardia - answer-a slow heart rhythm of below 60 beats per minute
breathing rate - answer-the number of breaths (inhalation and exhalation) taken per minute.
, bulk transport - answer-a form of active transport where large molecules or whole bacterial cells
are
moved into or out of a cell by endocytosis or exocytosis
bundle of his - answer-conducting tissue composed of purkyne fibres that passes through the
septum of
the heart
alpha-glucose - answer-glucose in which the hydrogen atom on carbon no.1 projects above the
plane of the ring
ab initio protein modelling - answer-a model is built based on the physical and electrical
properties of the atoms in each amino acid in the sequence
accuracy - answer-how close a measured or calculated value is to the true value
active immunity - answer-where the immune system is activated and manufactures its own
antibodies
adaption - answer-a characteristic that enhances survival in the habitat
adhesion - answer-the attraction between water molecules and the walls of the xylem vessels
affinity - answer-a strong attraction
alveoli - answer-tiny folds of the lung epithelium to increase the surface area
amphiphilic - answer-attracted to both water and fat - containing hydrophobic and hydrophilic
parts
amylopectin molecule - answer-a molecule of polysaccharide with glycosidic bonds between
carbon 1 and 4, and branches formed by glycosidic bonds between 1 and 6. It is a constituent of
starch
amylose molecule - answer-a molecule of polysaccharide with long straight chains of between
100 and 1000 alpha glucose molecules. It is a constituent of starch. Like maltose, it has
glycosidic bonds between carbon 1 and 4
anatomical adaptations - answer-structural features
anatomy - answer-a branch of science that concerns the studying of the structure of living
organisms
With answers
abiotic factors - answer-non-living conditions in a habitat
activation energy - answer-the energy required to initiate a reaction.
active site - answer-area of an enzyme with a shape complementary to a specific substrate,
allowing the enzyme to bind a substrate with specificity.
active transport - answer-movement of particles across a plasma membrane against a
concentration gradient. Energy is required. (ATP)
adenosine diphosphate (ADP) - answer-a nucleotide composed of a nitrogenous base
(adenine), a
pentose sugar and two phosphate groups. Formed by the hydrolysis of ATP, releasing a
phosphate ion and energy.
adenosine triphosphate (ATP) - answer-a nucleotide composed of a nitrogenous base
(adenine), a
pentose sugar and three phosphate groups. The universal energy currency for cells.
agglutinins - answer-chemicals (antibodies) that cause pathogens to clump together so they are
easier for phagocytes to engulf and digest.(caused by cross linking by antibodies that have a
number of binding sites)
alleles - answer-different versions of the same gene.
amino acids - answer-monomer used to build polypeptides and thus proteins
anabolism (anabolic) - answer-reactions of metabolism that construct molecules from smaller
units. These reactions require energy from the hydrolysis of ATP.
analogous structures - answer-structures that have adapted to perform the same function but
have a different origin.
anaphase - answer-third stage of mitosis when chromatids are separated to opposite poles of
the cell.
antibiotic-resistant bacteria - answer-bacteria that undergo mutation to become resistant to an
antibiotic and then survive to increase in number.
antibiotics - answer-a chemical or compound that kills or inhibits the growth of bacteria
antibodies - answer-Y-shaped glycoproteins made by B cells of the immune system in response
to the
presence of an antigen.
,antigen - answer-identifying chemical on the surface of a cell that triggers an immune response
antigen−antibody complex - answer-the complex formed when an antibody binds to
an antigen.
antigen-presenting cell (APC) - answer-a cell that displays foreign antigens complexed with
major histocompatibility complexes on their surface plasma membranes, so it can be recognised
by other cells
antisense strand 'lagging strand' - answer-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 - answer-chemicals (antibodies) that bind to toxins produced by pathogens so they
no longer have an effect.
apoplast - answer-the cell walls and intercellular spaces of plant cells.
apoplast route - answer-movement of substances through the cell walls and cell spaces by
diffusion and into cytoplasm by active transport.
arrhythmia - answer-an abnormal rhythm of the heart.
artefacts - answer-objects or structures seen through a microscope that have been created
during the processing of the specimen.
artificial active immunity - answer-immunity which results from exposure to a safe form of a
pathogen, for example, by vaccination.
artificial passive immunity - answer-immunity which results from the administration of antibodies
from
another animal against a dangerous pathogen.
asexual reproduction - answer-the production of genetically identical offspring from a single
parent.
assimilates - answer-the products of photosynthesis that are transported around a plant, e.g.,
sucrose
atrial fibrillation - answer-an abnormal rhythm of the heart when the atria beat very fast and
incompletely.
atrio-ventricular node (AVN) - answer-stimulates the ventricles to contract after imposing a slight
delay to ensure atrial contraction is complete.
,autoimmune disease - answer-a condition or illness resulting from an autoimmune response.
autoimmune response - answer-response when the immune system acts against its own cells
and destroys healthy tissue in the body.
autotrophic - answer-organisms that acquire nutrients by photosynthesis.
B effector cells - answer-B lymphocytes that divide to form plasma cell clones
B lymphocytes (B cells) - answer-lymphocytes which mature in the bone marrow and that are
involved in the production of antibodies
B memory cells - answer-B lymphocytes that live a long time and provide immunological
memory of the
antibody needed against a specific antigen.
belt transect - answer-two parallel lines are marked along the ground and samples are taken of
the area
at specified points.
Benedict's reagent - answer-an alkaline solution of copper(II)sulfate used in the chemical tests
for reducing sugars and non-reducing sugars. A brick-red precipitate indicates a positive result.
beta pleated sheet - answer-sheet-like secondary structure of proteins
binomial nomenclature - answer-the scientific naming of a species with a Latin
name made of two parts − the first indicating the genus and the second the
species.
biodiversity - answer-the variety of living organisms present in an area
biuret test - answer-the chemical test for proteins; peptide bonds form violet coloured complexes
with
copper ions in alkaline solutions.
Bohr effect - answer-the effect of carbon dioxide concentration on the uptake and release of
oxygen by
haemoglobin
bradycardia - answer-a slow heart rhythm of below 60 beats per minute
breathing rate - answer-the number of breaths (inhalation and exhalation) taken per minute.
, bulk transport - answer-a form of active transport where large molecules or whole bacterial cells
are
moved into or out of a cell by endocytosis or exocytosis
bundle of his - answer-conducting tissue composed of purkyne fibres that passes through the
septum of
the heart
alpha-glucose - answer-glucose in which the hydrogen atom on carbon no.1 projects above the
plane of the ring
ab initio protein modelling - answer-a model is built based on the physical and electrical
properties of the atoms in each amino acid in the sequence
accuracy - answer-how close a measured or calculated value is to the true value
active immunity - answer-where the immune system is activated and manufactures its own
antibodies
adaption - answer-a characteristic that enhances survival in the habitat
adhesion - answer-the attraction between water molecules and the walls of the xylem vessels
affinity - answer-a strong attraction
alveoli - answer-tiny folds of the lung epithelium to increase the surface area
amphiphilic - answer-attracted to both water and fat - containing hydrophobic and hydrophilic
parts
amylopectin molecule - answer-a molecule of polysaccharide with glycosidic bonds between
carbon 1 and 4, and branches formed by glycosidic bonds between 1 and 6. It is a constituent of
starch
amylose molecule - answer-a molecule of polysaccharide with long straight chains of between
100 and 1000 alpha glucose molecules. It is a constituent of starch. Like maltose, it has
glycosidic bonds between carbon 1 and 4
anatomical adaptations - answer-structural features
anatomy - answer-a branch of science that concerns the studying of the structure of living
organisms
