Mendelian Genetics Flashcards
Define: chromosome
compact, transportable forms of dna
How many chromosomes and pairs of chromosomes do humans have?
46 chromosomes and 23 pairs
Which pairs are autosomes and which pairs are sex chromosomes? What are the sex chromosomes?
22 autosomes, 1 sex
Males: X and Y
Females: X and X
Describe the basic structure of chromosomes
Come in pairs;
Called sister chromatids on their own
Joined by a centromere
Define: Karyotype
a photograph of all chromosomes in the nucleus of a cell lined up in order of size and arranged in pairs
Define: genes
A segment of DNA which contains instructions for the construction and operation of an organism and determines its traits
Define: allele
different versions of the same genes
Define: genotype
genetic composition of the organism
Define: phenotype
physical expression of the genotype, which can be altered by environmental influences
Define: homozygous
genotype with two copies of the same allele
Define: heterozygous
genotype with two different alleles
Define: dominant
the characteristic that shows in the heterozygous individual
Define: recessive
The characteristic that is masked unless two copies of the same allele are expressed
Define: codominance
a condition in which both alleles of a gene pair in a heterozygote are fully expressed, with neither one being dominant or recessive to the other
Define: incomplete dominance
a form of intermediate inheritance in which heterozygous alleles are btoh expressed, resulting in a combined phenotype
