Chapter 11
What are Mendel’s two main principles of inheritance?
Segregation (alleles separate during gamete formation) and independent assortment (genes for different traits assort independently).
How can the environment influence gene expression?
External factors like temperature or nutrition can affect how genes are expressed, leading to phenotypic variations.
Which experiments established DNA as the genetic material?
Griffith (transforming principle), Avery (DNA as transforming material), HersheyChase (DNA in phages).
What is the function of DNA polymerase?
Adds nucleotides to synthesize a new DNA strand complementary to the template.
What are the main types of RNA and their functions?
mRNA (messenger RNA) carries genetic info; tRNA (transfer RNA) brings amino acids; rRNA (ribosomal RNA) makes up ribosomes.
How do Punnett squares predict genetic outcomes?
They show possible genotype combinations and predict the ratios of genotypes and phenotypes in offspring.
What are the stages of meiosis?
Prophase I, Metaphase I, Anaphase I, Telophase I, followed by meiosis II stages similar to mitosis.
Describe the structure of DNA.
A double helix with sugar phosphate backbone and nitrogenous bases paired via hydrogen bonds.
What is transcription?
The process where RNA polymerase synthesizes mRNA from a DNA template.
What is a dihybrid cross?
A cross that examines two traits simultaneously, typically represented in a 4x4 Punnett square.
How does meiosis differ from mitosis?
Meiosis reduces chromosome number by half and creates genetic diversity; mitosis produces identical diploid cells.
What are Chargaff’s rules?
In DNA, A = T and C = G in equal amounts.
What is translation?
The process where ribosomes read mRNA codons and assemble amino acids into a protein.
How do you determine the phenotype and genotype ratios in a dihybrid cross?
By setting up a 4x4 Punnett square with parental genotypes and analyzing the outcomes.
How does DNA replicate?
Enzymes like DNA polymerase add complementary nucleotides at the replication fork during semiconservative replication.
What are codons and anticodons?
Codons are three nucleotide sequences on mRNA; anticodons are complementary sequences on tRNA.
What are examples of inheritance patterns other than Mendelian dominance?
Incomplete dominance, codominance, and multiple alleles.
What is the role of helicase?
Unwinds the DNA double helix at the replication fork.
What are mutations?
Changes in DNA sequence; point mutations alter one nucleotide, frameshift mutations insert or delete nucleotides, potentially affecting protein structure.