17.1 — monohybrid inheritance Flashcards
covers: essential genetics vocabulary; monohybrid crosses in genetic diagrams and Punnet squares.
what is genetics?
genetics is the study of genes and how characteristic are inherited
what is a gene?
a sequence of bases on a DNA molecule that codes for a protein (polypeptide) which results in a characteristic,
e.g. a gene for eye colour
what is an allele?
different versions of the same gene that codes for variants of a characteristic. alleles are represented by letters.
e.g. B= brown eyes, b= blue eyes.
what is a genotype?
an organisms genetic makeup - its alleles.
e.g. BB, Bb or bb
what is a phenotype?
an organism’s physical characteristics as determines d by its genotype and environment
what is a dominant allele?
an allele that is always expressed in the phenotype, even when only one copy is present in the genotype.
shown with an uppercase letter
what are recessive alleles?
an allele that is only expressed in the phenotype when it is homozygous, and will be masked by a dominant allele.
shown with a lowercase letter
what is a locus?
the specific position of a gene on a chromosome.
what is a homozygous organism?
an organism with two identical alleles for a trait.
what is a heterozygous organism?
an organism with two different alleles for a trait.
humans are (1) _______ organisms, meaning they have (2) ___ copies of each gene. this means they have (3) ___ alleles for every characteristic.
- diploid
- two
- two
what typos of cells are gametes, and what does this mean?
haploid, meaning that they have one allele per gene.
what does monohybrid inheritance involve?
the transmission of one gene from parents to their offspring
what do monohybrid crosses track?
the inheritance pattern of the alleles for a single characteristic, controlled by one gene with two possible alleles.
what is the F1 generation?
the offspring from a cross between individuals with homozygous dominant and homozygous recessive genotypes
