Molecular Genetics and Heredity Study Guide Answers

DNA monomer- nucleotide Base pairing- A—T and C—G Two strands are said to be complementary to each other. DNA polymerase- catalyzes the addition of nucleotides to form a complementary DNA strand Watson and Crick- credited with the discovery of the structure of DNA RNA Base pairing- A—U and C—G rRNA- makes up the ribosomal subunit mRNA- carries the DNA code from nucleus to ribosomes tRNA- transfers the correct amino acid

Transcription- RNA is produced from the DNA template Translation- RNA  protein Codon- a nucleotide triplet Sex chromosomes- X and Y (include genes that determine an individual’s sex Locus- a genes location along a chromosome Sexual life cycles- all go through meiosis, fertilization, and produce gametes Zygote- the result of fertilization of egg and sperm Prophase I- crossing over occurs

Meiosis steps: 1) chromosomes move to middle of cell in pairs 2) Alignment of tetrads (pairs) at metaphase plate 3) Separation of homologues 4) Separation of sister chromatids 5) Formation of 4 new daughter cells Gregor Mendel Conclusion from research- traits are inherited in discrete units, and are not the results of “blending” True breeding- homozygous for a trait (AA or aa) Homozygous- having two of the same alleles (AA or aa) Heterozygous- having two different alleles (Aa)

ABO blood groups- has multiple alleles (A, B, and O) example- AO= Type A; OO= Type O, etc. Polygenic inheritance- a trait controlled by more than one gene example- skin pigmentation in humans Gene linkage- genes located together on the same chromosome and are inherited together 2n=16 What does that mean- each cell has 8 homologous pairs DNA ligase- connects segments of DNA DNA replication- DNA bases unzip at the hydrogen bonds and new complementary bases pair up with original template Crossing over- homologous chromosomes cross over and exchange genetic information

Gene- a heritable unit that determines a character and can exist in different forms Allele- an alternative version of a gene Character- a heritable feature that varies among individuals Trait- a variant for a character Dominant allele- determines phenotype in a heterozygous (Aa) Recessive allele- has no effect on phenotype in a heterozygote Genotype- genetic makeup of an individual Phenotype- an organism’s appearance or observable traits Testcross- a cross between an individual with unknown genotype and homozygous recessive individual Monohybrid cross- a cross involving only one trait