metabolism
function of life; sum total of all chemical reactions in an organism
growth
function of life; ability to change or increase in size over time, may be limited in amount
reproduction
function of life; ability to produce new organisms of the same type
response
function of life; ability to demonstrate a specific response to a stimulus
homeostasis
function of life; ability to maintain a stable internal environment
nutrition
function of life; ability to convert materials from the external environment into usable forms
excretion
function of life; ability to remove waste products
gene
a segment of DNA on a chromosome which controls a particular structure or function in a cell
stem cells
cells that have the capacity to divide and to differentiate along different pathways
ribosomes
complexes of RNA and protein that are responsible for polypeptide synthesis
hydrophilic
attracted to water
hydrophobic
not attracted to water
osmosis
net movement of water molecules across a semi-permeable membrane from a region of low soluteconcentration to a region of high solute concentration (until equilibrium is reached)
endocytosis
process by which a cell takes material into the cell by infolding of the cell membrane
exocytosis
a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.
rER
organelle that synthesise proteins for secretion from the cell - acts as a transport system for newly formed proteins
golgi apparatus
stores, modifies, and packages proteins
mitochondria
the site of aerobic respiration (ATP production)
isotonic
a solution that has the same concentration of dissolved particles as the cell
hypertonic
solution has a higher concentration of solutes in water than the solute concentration inside (mass of potato decreases)
hypotonic
solution that has a lower concentration of dissolved particles compared with another solution (mass of potato increases)
mitosis
cell division in which the nucleus divides into two genetically identical nuclei containing the same number of chromosomes as the mother cell.
anabolism
the part of metabolism where larger molecules (macromolecules) are formed from smaller molecules (monomers) by reactions called condensation.
catabolism
type of metabolism in which larger compounds are broken down with the release of energy
hydrolysis
a chemical reaction in which a larger molecule is split into two smaller molecules
condensation reaction
the reaction that binds one monomer to another monomer
covalent bonds
bonds between atoms formed by the sharing of electrons between those two atoms
cohesion
term used when water molecules attract other water molecules.
adhesion
term used when water molecules attract another polar substance besides water.
monosaccharide
smallest (monomer) unit of carbohydrates
disaccharide
two monosaccharides bonded together by a condensation reaction
polysaccharide
many monosaccharides bonded together by many condensation reactions organized into a linear or branched shape
polypeptide
polymer of many amino acids joined by peptide bonds
proteome
the unique collection of proteins within a cell, tissue type, organ, or organism
active site
the area of an enzyme to which the substrate(s) attach(es)
polymers
large molecules composed of smaller units (monomers) connected by covalent bonds
ribose
the sugar of RNA
deoxyribose
the sugar of DNA
transcription
the process of creating RNA from DNA
translation
process of protein production which occurs at the ribosome in cells, DNA language is changed into the language of proteins
helicase
enzyme which opens the DNA double helix in the replication process
semi-conservative
type of replication in DNA in which each new DNA molecule has one original strand of the parent molecule
DNA polymerase
an enzyme which catalyses the linking of nucleotides in the new DNA strand
RNA polymerase
Enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during transcription
oxidation reaction
a chemical reaction in which electrons are lost (redox)
pyruvate
3-carbon compound formed by the breakdown of glucose in glycolysis, the first stage of cell respiration
glycolysis
first stage of cell respiration in which oxygen is not required and glucose is broken down into 2 pyruvate molecules
photosynthesis
process which converts light energy into chemical energy
chlorophyll
main pigment involved in the process of photosynthesis, absorbs light energy
photolysis
process in photosynthesis where water molecules are split using the energy from light
gene
a heritable factor that consists of a length of DNA and influences a specific characteristic.
locus
the specific place where a gene is found on a chromosome
allele
version of a gene, differing by one or more bases
nucleoid
region of a prokaryotic cell where the DNA exists
binary fission
a method of reproduction whereby a single- celled organism makes a copy of itself and splits in two
plasmid
small ring of DNA separate from the bacterial chromosome often used in genetic modification
histones
proteins associated with DNA in eukaryotic chromosomes
nucleosome
structure found in eukaryotic chromosomes consisting of a strand of DNA wrapped around eight histone molecules
homologous
chromosome pairs that occur at fertilization, one from the female parent and one from the male parent
centromere
region where sister chromatids attach
diploid
a cell which has chromosomes in homologous pairs
haploid
a cell that has only one chromosome of each homologous pair
meiosis
cell division where one diploid cell becomes four haploid cells
gamete
a sex cell, either a sperm cell or an egg cell
zygote
diploid fertilized egg
s phase
the stage in the cell cycle when DNA is replicated before division begins
sister chromatids
the two identical structures of a doubled chromosome
condensation
in DNA, the coiling of chromatin to form chromosomes; in chemical reactions, the joining of two organic molecules during which a water molecule is produced
meiosis 1
first part of meiosis during which homologous chromosomes separate to produce two diploid cells
meiosis 2
second part of meiosis during which sister chromatids separate to produce four haploid cells (gametes)
crossing over
a process during meiosis I involving the exchange of genetic material between non- sister chromatids
random orientation
a process during meiosis involving the lining up of chromosomes in an order determined by chance
co-dominance
alleles that have joint effects, both alleles are expressed in the organism's phenotype
genotypes
genes of an organism for a particular trait
sex linked
a trait that is controlled by alleles located on the sex chromosomes
non-disjunction
the process where two homologous chromosomes do not separate during anaphase I of meiosis, resulting in a daughter cell with one too many chromosomes and a daughter cell with one too few
autotrophic
organisms capable of producing their own food
species
a group of organisms which are structurally similar and able to pass their genetic traits on to their offspring
population
a group of interbreeding members of a species living at the same time in the same place
heterotroph
an organism not capable of producing its own food, requiring preformed organic compounds from other sources
decomposer
an organism that feeds on and breaks down waste organic material
saprotroph
an organism which uses detritus as its energy and nutrient source
ecosystem
the plants and animals in a region plus the non-living components of the environment
food chain
one possible set of feeding relationships starting with a producer