BIOLOGY- exam revision

plant tissue culturing (micropropagation)

Growth of plant cells on nutrient agar in sterile conditions which are closely regulated e.g. temperature, light.

plant cuttings

production of new plants from fragments such as the stem or roots from the original plant

plant graftings

the attachment of the stem of one plant (the scion) to the stem of another plant with an already developed root system (the root stack)

binary fission

cells divide via mitosis and cytoplasm is plit into 2 e.g. bacteria

budding

the development of a new organism from an outgrowth of a parent organism e.g. hydra

vegetative propagation

growing a new plant from a fragment of a parent plant e.g. plant roots

spore formation

they detach from the parent organism and develop into new individuals e.g. fungi.

fragmentation

Organism detaches into separate fragments, which are then capable of developing into new separate organisms e.g. sea stars.

parthenogenesis

When an embryo can develop from a female gamete alone without the need for a male to fertilise it e.g. grasshopper

incomplete dominance

Phenotype is partially expressed in the heterozygote as phenotypes are blended.

co-dominance

both alleles in the genotype are fully expressed in the heterozygote

noncoding DNA and coding DNA

coding DNA- produces proteins.

non-coding DNA- carries out other regulatory functions in the cell

• signals for DNA replication