by Nick Lane
reaction.
to offspring.
8-hydroxydeoxyguanosine (8-OHdG) oxidized DNA
lignin structural polymer, providing strong,
‘letter’ derived from attack of hydroxyl
flexible support for woody plants.
radicals on DNA, used as a surrogate measure
LUCA (Last Universal Common Ancestor) the last
of free radical damage.
ancestor common to all known life on Earth,
hydroxyl radical (●OH) violently reactive oxygen
including bacteria, archaea and eukaryotes.
free radical, which reacts in billiseconds with
malarial tolerance lack of response to malarial
almost all biological molecules.
parasite despite infection, leading to absence
hyperbaric oxygen oxygen under high pressure
or suppression of malarial symptoms.
(effectively increasing its concentration).
meiosis type of cell division that produces sex
IGF (insulin-like growth factors) group of closely
cells (gametes) with a single set of chromo-
related hormones, with important effects on
somes, rather than the two sets of their
sexual maturation, among many other effects.
diploid progenitors.
immunosuppression lowering of responsiveness of
messenger RNA a ribonucleic acid that encodes
the immune system to antigens.
genetic instructions to make a protein. Its
individual selection evolutionary selection of traits
sequence of ‘letters’ corresponds to the DNA
that benefit individuals rather than popu-
template on which it is made. It is used to
lations. It is by far the most important form of
convey genetic instructions from the DNA to
natural selection.
the protein-building apparatus (ribosomes).
GLOSSARY • 363
metabolic rate the oxygen consumption of an
bined with proteins, separated from the rest of
organism at rest (basal metabolic rate) or
the cell by a double membrane.
when active.
operon genetic unit in bacteria, comprising
metallothionein sulphur-rich stress protein, which
genes with related function that are all tran-
protects against physical stresses such as radi-
scribed and expressed together.
ation and oxygen poisoning.
organelle tiny specialized organ within a cell,
microglia inflammatory cells resident in the
such as a mitochondrion or chloroplast.
brain.
organic carbon carbon in biological molecules,
mitochondria (singular mitochondrion) the energy
such as carbohydrates, fats, and nucleic acids;
‘power-houses’ of eukaryotic cells, in which
also carbon in material of biological origin,
oxygen respiration takes place. They were
such as coal, oil and natural gas.
originally symbiotic purple bacteria, and still
oxidation loss of electrons to an oxidant such as
retain bacterial traits.
oxygen; the opposite of reduction.
mitochondrial DNA genetic material present inside
oxidative damage damage to biological molecules
mitochondria. It is comparable to bacterial
as a result of oxidation.
DNA in structure and genetic sequence.
oxidative stress distortion of chemical balance in
mitochondrial leakage escape of oxygen free rad-
cells towards the oxidized state, as a result of
icals from mitochondria during respiration.
an imbalance between the rate of formation of
mitochondrial SOD manganese superoxide dis-
oxygen free radicals, and their elimination by
mutase, found in mitochondria of eukaryotic
antioxidants.
cells (and in many bacteria).
oxygen poisoning toxic effects of breathing high
mitochondrial theory of ageing theory arguing that
levels of oxygen, caused by the formation of
damage to mitochondrial DNA by free radical
oxygen free radicals.
leakage from adjacent respiratory proteins is
oxygen-evolving complex enzyme used in photo-
the root cause of ageing.
synthesis to extract electrons and protons
mitosis type of cell division in eukaryotic cells in
from water, releasing oxygen gas as a waste
which the chromosomes are doubled and
product.
then separated to produce two daughter cells
oxygenic photosynthesis form of photosynthesis
genetically identical to the parent cell.
that uses the energy of light to split water,
molecular clock estimates of the timing of evo-
releasing oxygen as a waste product.
lutionary events based on rates of sequence
Permian geological period from about 286 to 245
divergence between equivalent genes in differ-
million years ago.
ent species.
peroxiredoxins group of sulphur-containing anti-
mutation an alteration in coding sequence of a
oxidant enzymes that break down hydrogen
gene that is passed on to the next generation.
peroxide to water using thioredoxin as an
myoglobin oxygen-binding protein containing
electron donor.
haem pigment, similar to haemoglobin and
Phanerozoic the ‘modern’ age of plants, animals
found in muscle cells of mammals.
and fungi, stretching from the Cambrian
neutrophil inflammatory cell that engulfs and
explosion, 543 million years ago, to the
digests bacteria and other ‘foreign’ particles.
present day.
Often called the ‘foot-soldiers’ of the immune
photon electromagnetic wave-particle with a
system because of their large numbers,
defined amount of energy.
unspecialized attributes and dispensability.
photorespiration complex series of biochemical
NFB (nuclear factor kappa B) important tran-
reactions that stunt plant growth in sun-light.
scription factor that stimulates expression of
The reactions parallel oxygen respiration by
inflammatory and antioxidant genes.
consuming oxygen and releasing carbon
nitric oxide (NO) gaseous signalling molecule with
dioxide, but do not generate energy, and are
profound physiological effects on blood
thought to protect plants against oxygen
vessels, immune system, nervous system and
toxicity.
sexual arousal.
photosynthesis synthesis of carbohydrates and
nitric oxide synthase umbrella term for several
other organic molecules from carbon dioxide
enzymes that generate nitric oxide gas.
and water, using the energy of sunlight.
Nrf-2 (nuclear factor erythroid-2-related factor 2)
plaque pathological conglomerate of proteins
important transcription factor that stimulates
and inflammatory cells. Senile plaques in
expression of antioxidant genes but sup-
Alzheimer’s disease are composed largely of
presses expression of inflammatory genes.
amyloid, microglial cells, and
damaged nerve
nucleic acid generic term for DNA (deoxyribo-
endings.
nucleic acid) and RNA (ribonucleic acid).
pleiotropy multiple effects or outcomes.
nucleus central ‘control centre’ of eukaryotic
polymorphic alleles different versions of the same
cells, containing genetic material (DNA) com-
gene found in a population.
364 • GLOSSARY
Precambrian geological period accounting for
singlet oxygen reactive form of molecular oxygen,
nine tenths of Earth’s history, from its for-
in which the spin of an electron is flipped so
mation about 4.6 billion years ago until the
that it enters a higher-energy orbital.
Cambrian period 543 million years ago.
snowball Earth global glaciation.
prokaryote cell without nucleus, such as a
SNP (single-nucleotide polymorphism) single letters
bacterium.
in the genetic code that vary between indi-
pro-oxidant opposite of an antioxidant, a mol-
viduals, giving many slightly different ver-
ecule that promotes the oxidation of other
sions of the same genes.
molecules.
SOD (superoxide dismutase) antioxidant enzyme
protein large molecule made of a long chain of
that converts superoxide radicals into oxygen
amino acids folded into a three-dimensional
and hydrogen peroxide.
shape that dictate’s its function. Cells make
soma the body, as opposed to the germ line (the
many different kinds of proteins, which make
sex cells).
up most of a cell’s structure and carry out all
somatic mutation theory theory arguing that
its functions. The amino acid sequences of
accumulation of mutations in DNA of somatic
proteins are encoded in the genes.
(body) cells during a lifetime is the root cause
proton positively charged particle within the
of ageing.
nucleus of an atom. The hydrogen nucleus is a
stem cell unspecialized progenitor cell, which
single proton.
divides by mitosis to replenish populations of
radiation poisoning toxic effects of radiation,
specialized (differentiated) cells.
many of which are caused by formation of
stomata pores in the surface of a leaf that allow
oxygen free radicals.
exchange of gases between the air and the
rate-of-living theory theory arguing that lifespan
plant’s tissues.
depends on metabolic rate.
stress protein protein produced in response to
recombination random swapping of different
physical stress (such as radiation, heat or
alleles of the same gene between chromo-
infection), which counters the stress.
somes, which generates new combinations of
stress response synchronized production of stress
alleles on a chromosome.
proteins, which coordinate resistance to
reduction addition of electrons to a molecule;
physical stress or its recurrence. The effect
opposite of oxidation.
persists for days, possibly much longer.
respiration generation of energy from bio-
sulphate-reducing bacteria anaerobic bacteria that
chemical reactions.
generate energy from organic matter using
respiratory chain chain of electron-transporting
sulphate instead of oxygen as the electron
proteins responsible for generating energy in
acceptor. Their waste product of respiration is
mitochondria and bacteria.
hydrogen sulphide gas (H2S) instead of water
ribosomal RNA ribonucleic acid constituent of
(H2O).
ribosomes. Comparisons of ribosomal RNA
superoxide radical (O ●–
2 ) mildly reactive oxygen
from different species have enabled the
free radical, which tends to behave as an
construction of an evolutionary tree of life.
electron donor, giving up a single electron to
ribosome protein-building machinery present in
revert to oxygen.
all cells.
symbiosis intimate relationship between two
RNA (ribonucleic acid) single-stranded thread of
organisms in which each partner gains a
nucleic acid, which resembles DNA in its
benefit from the other.
sequence of letters. There are various types of
tangle pathological feature of Alzheimer’s
RNA (messenger RNA, ribosomal RNA and
disease, in which neurons die off, leaving
transfer RNA), which are all essential to cells.
behind tangled fibrils of oxidized tau protein.
Rubisco (ribulose-1,5-bisphosphate carboxylase/
tau protein that maintains structure and
oxygenase) enzyme that binds carbon dioxide
function of microtubules in neurons. It
(CO2) in photosynthesis, incorporating it into
pathologically oxidized and phosphorylated
carbohydrate molecules. It can also bind
in Alzheimer’s disease.
oxygen, leading to photorespiration.
telomerase enzyme that renews telomere caps
saturated fat fat composed of fatty acids without
on chromosomes, preventing ‘fraying’ of
any double bonds between carbon atoms.
chromosome ends and loss of coding genes
selection pressure likelihood that a disadvan-
during DNA replication. When the telomerase
tageous trait will be eliminated from a
gene is permanently active, it conveys
population by natural selection. Traits that
‘immortality’ on cells in culture.
jeopardize reproduction are not passed on,
telomere non-coding DNA that caps ends of the
and so disappear from the population; mildly
chromosomes in eukaryotes, preventing loss
disadvantageous traits may be offset by
of gene-coding sequences during DNA
hidden benefits.
replication.
GLOSSARY • 365
thiol (–SH), the sulphur-containing group of translation conversion of RNA code into amino-the amino acid cysteine. It is an important
acid sequence as a protein is synthesized.
molecular switch in many transcription
tumour necrosis factor important protein in
factors, ‘reporting’ on the oxidation state of
inflammation, which attracts and activates
the cell.
inflammatory cells. It was originally identified
thioredoxin small sulphur-rich protein, which
and named for its toxic effect on tumours.
gives up electrons to regenerate antioxidant
ultraviolet radiation electromagnetic rays with
enzymes such as peroxiredoxins.
wavelength shorter than about 400 nano-
thrifty genotype particular genetic configuration
metres.
that encourages the ‘hoarding’ of energy
unsaturated fat fat composed of fatty acids with
during times of plenty.
one or more double bonds between carbon
tocopheryl radical poorly reactive free radical,
atoms.
&
nbsp; formed when vitamin E is partially oxidized.
Vendobionts first large animals (up to 1 metre in
transcription copying of the genetic code for a
diameter), which evolved during the Vendian
gene from DNA into messenger RNA, in
period, about 570 million years ago. They
readiness for protein synthesis.
were mostly radially symmetrical, quilted bags
transcription factor protein that binds to DNA,
of protoplasm, similar to jellyfish.
either stimulating or inhibiting the tran-
scription of one or more genes.
transgenic describes organisms that have had one
or more genes replaced or added through
genetic engineering.
Index
A
Anson, Lord 178
Baeuerle, Patrick 298, 298 n.
antioxidant 12, 170, 193, 306
Baikal, Lake 102
Acaryochloris marina 137
balance in cells 170
Balkan War syndrome 111
Adams, Douglas 131
in birds and mammals 256–7
Barja, Gustavo 255–7, 338
adenosine triphosphate see ATP
chain-breaking 186, 204–5, 207
basalt 66
AGE 311
definition of 195
bats 255
age
enzymes 195, 200–4
Baylor College of Medicine,
biological 292
extension of lifespan 12, 254
Houston 202
chronological 292
in evolution 16, 17, 18
BBC Reith lectures 173, 293
-related disease 242, 281–2,
failure of 294, 299, 317, 327, 342
Beck, Curt 88
288–94, 299–301, 326–7,
supplements 12, 75, 170,
Beckman, Kenneth 264–5
334–6, 341
180–1, 209–11, 294–5, 316,
Becquerel, Henri 107, 108,
age-1: 243–5
327
113
AIDS 328
AP-1: 208, 324
Beddoes, Thomas 6
Allen, Carol 337
apatite 35
Beerling, David 82, 91
Allen, John 265 n., 278–9, 281,
ApoE4 290–1, 303, 305–6, 309,
Berkeley, University of
337
310, 329
California at 124, 254, 264
alpha helix 174
apolipoprotein E4, 290 n., 303
Berner, Robert 24, 85–9, 90, 91,
alpha rays 113
Apollo astronauts
104
alpha-tocopheryl radical 186,
fire onboard Apollo 1: 8–9
Bert, Paul 9
192
rock samples from moon 22
beta-carotene see carotenoids