Inheritance Flashcards
Genome
The entire DNA of an organism
Gene
A section of DNA which codes for a particular protein
What does the nucleus of a cell contain?
Chromosomes on which genes are located
DNA molecule
Two strands coiled to form a double helix, the strands being linked by a series of bases: Adenine with Thymine, and Cytosine with Guanine
RNA molecule
Single stranded and contains Uracil instead of Thymine
Transcription
When two strands of DNA double helix are separated. One strand is used as a template and the RNA bases are lined up in correct order using complementary base pairing.
Translation
Involves assembling amino acids in correct order following the sequence of bases on mRNA. It takes place at one of many small structures in the cell cytoplasm called ribosomes. The mRNA travels out of the nucleus and attaches to a ribosome.
Protein synthesis
The code for making the protein is read such that every three bases on the mRNA codes for one amino acid. This triplet of bases is know as a codon. Amino acids are carried to the ribosome by another molecule called tRNA which also has a triplet of bases called an anticodon and this can match up with the complementary bases on the mRNA. The ribosome then forms peptide bonds between the amino acids and a polypeptide chain is formed. This can then fold and join up with other polypeptides to form a protein.
Alleles
Alternate forms of a gene which give rise to differences in inherited characteristics
Dominant
Allele of a gene that is expressed in the heterozygote
Recessive
Allele that is not expressed in the phenotype when a dominant allele is present (i.e. the heterozygote)
Homozygous
Genotype with the same allele of a gene e.g. AA or aa
Heterozygous
Genotype with different alleles of a gene e.g. Aa
Phenotype
How a gene is expressed. The “appearance” of an organism resulting from its genotype
Genotype
Alleles an organism has for a certain characteristic
Codominance
Pattern of inheritance where neither allele of a gene is dominant over the other so that both alleles are expressed in the phenotype