ESTAS 2 Flashcards
transpiration
loss of water vapour from plant leaves by evaporation of water at the surfaces of the mesophyll cells followed by diffusion of water vapour through the stomata
translocation
the movement of sucrose and amino acids in phloem:
– from regions of production (source)
– to regions of storage OR to regions where they are used in respiration or growth (sink)
pathogen
a disease-causing organism
transmissible
a disease in which the pathogen can be passed from one host to another
active immunity
defence against a pathogen by antibody production in the body
aerobic respiration
the chemical reactions in cells that use oxygen to break down nutrient molecules to release energy
anaerobic respiration
the chemical reactions in cells that break down nutrient molecules to release energy without using oxygen
deamination
the removal of the nitrogen-containing part of amino acids to form urea
synapse
a junction between two neurones
sense organs
groups of receptor cells responding to specific stimuli: light, sound, touch, temperature and chemicals
hormone
a chemical substance, produced by a gland and carried by the blood, which alters the activity of one or more specific target organs
homeostasis
the maintenance of a constant internal environment within set limits
gravitropism
a response in which parts of a plant grow towards or away from gravity
phototropism
a response in which parts of a plant grow towards or away from the direction from which light is coming
drug
any substance taken into the body that modifies or affects chemical reactions in the body
asexual reproduction
a process resulting in the production of genetically identical offspring from one parent
sexual reproduction
a process involving the fusion of the nuclei of two gametes (sex cells) to form a zygote and the production of offspring that are genetically different from each other
fertilisation
the fusion of gamete nuclei
pollination
the transfer of pollen grains from the anther to the stigma
self-pollination
the transfer of pollen grains from the anther of a flower to the stigma of the same flower or different flower on the same plant
cross-pollination
transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species
sexually transmitted infection
an infection that is transmitted via body fluids through sexual contact
inheritance
the transmission of genetic information from generation to generation
chromosome
a thread-like structure of DNA, carrying genetic information in the form of genes
gene
a length of DNA that codes for a protein
allele
a version of a gene
haploid nucleus
a nucleus containing a single set of unpaired chromosomes, e.g. in gametes
diploid nucleus
a nucleus containing two sets of chromosomes, e.g. in body cells
