protein synthesis + inheritance (mocks) Flashcards
define the genome
the entire DNA of an organism
define a gene
a section of a molecule of DNA that codes for a specific protein.
what nitrogenous base does uracil replace in RNA?
thymine
describe transcription
- A section of the DNA helix is untwisted and unzipped.
- The template strand of DNA is copied into a new molecule of messenger RNA. The bases on the mRNA nucleotide match with their complementary base pair on the template DNA strand (give eg).
- The new mRNA molecule leaves the nucleus through the nuclear pores into the cytoplasm and onto the ribosome.
describe translation
- At the ribosome, the bases on the mRNA are read in threes to code for a single specific amino acid.
- This amino acid is brought to the ribosome by a tRNA molecule.
- The codons on the mRNA connect to the anticodons on the tRNA.
- The amino acids join together to form a polypeptide chain which then folds to reveal a unique 3D structure (a protein).
define an allele
Alleles are different versions of the same gene
define the dominant allele
an allele that will always be expressed in the phenotype when they are present.
define the recessive allele.
alleles that can be masked by a dominant one so they will only be expressed in the phenotype in the absence of a dominant allele.
define homozygous alleles
both alleles are the same
define heterozygous alleles
the alleles are different
define the phenotype
the physical appearance of an individual regarding a particular characteristic
define the genotype
the genetic makeup of an individual regarding a particular characteristic.
define codominance.
when both alleles are expressed in the same phenotype because neither allele is dominant over the other.
