multicellular Organismd Flashcards
Gene
Section of DNA that codes for a particular protein
Allele
Different forms of the same gene
Phenotype
Version of a characteristic seen in an individual
Genotype
A statement of the alleles an individual has for a characteristic
Dominant
Always present in offspring Represented by capital letters
Recessive
Only displayed when two recessive alleles are present e.g. tt
Homozygous
Both alleles of gene present are the same e,g. tt or TT
Heterozygous
Both alleles of gene present are different e.g. Tt
What is continuous variation
The majority of characteristics show continuous variation which is caused by polygenic inheritance. this means that the characteristics are influenced by more than one gene
what is fertilisation
Fertilisation is the fusion of the nuclei of the two haploid gametes to produce a diploid zygote which divides to form an embryo
What is the male gamete in plants
Pollen
What is the female gamete in plants
Ovule
what is the 1st stage of mitosis
Chromosomes replicate and condense and are visible as pairs of identical chromatids attatched at a centromere
what is the 2nd stage of mitosis
Nuclear membrane breaks down
What is the 3rd stage of mitosis
Chromosomes assemble at the equator of the cell and spindle fibres attatch at the centromeres
what is the 4th stage of mitosis
Spindle fibres contract separating the sister chromatids to opposite poles of the cell
what is the 5th and final stage of mitosis
Sister chromatids are now called Chromosomes. A new nuclear membrane forms and the cytoplasm divides. Two identical daughter cells are produced
what does Haploid mean
Having a single set of unpaired chromosomes
what does diploid mean
having 2 sets of complete chromosomes one from each parent
