test 2 Flashcards
(23 cards)
What is multifactorial inheritance?
Inheriting a trait that is caused by more than one gene.
What is the difference between breeding experiments and pedigrees?
breeding experiments involve only descendants and no new individuals. Pedigree are best used for humans and other animals that have new individuals added to their family trees.
What is a monomorphic gene?
A gene with only one wild type allele
What causes sickle-cell anemia?
A single nucleotide substitution makes the incorrect amino acid and causes the protein to fold abnormally
Define syndrome
A group of expressed phenotypes that occur together and are caused by the same illness
What causes Huntington’s disease?
Too many repeats of glutamine (codon CAG). More than 40 repeats causes problems and the protein cannot fold correctly. The more repeats, the earlier the disease progresses.
What causes repeats in the HD gene’s coding region? Keyword: slips
C and G can pair with each other, so sometimes the DNA polymerase “slips” during replication and they pair with each other instead the template strand.
What are the characteristics of dominant autosomal inheritance?
- shows up in every generation
- at last one parent has to be affected
- males and females are affected equally and both transmit the gene
What are the characteristics of recessive autosomal inheritance?
- does not usually show up in every generation
- affected individuals usually have two unaffected parents
- two affected parents can only have affected offspring
- males and females are affected equally and both transit the gene
A mutation in ___________ causes decreased inhibition of muscle growth and is due to incomplete dominance in heterozygotes.
Myostatin
The Y chromosome only determines ___________
maleness
What are the characteristics of sex-linked dominant inheritance?
- affected individuals have at least one affected parent
- affected females usually pass the trait on to 50% of both male and female offspring
- affected males pass the trait on to all daughters
What are the characteristics of sex-linked recessive inheritance?
- males are much more affected than females because they are hemizygous
- parents of affected males are usually normal
mitosis only happens in _________
eukaryotes
What is chromatin?
the complex of protein and DNA in a cell’s nucleus
sister chromatids are joined at the ___________
centromere
Define metacentric and acrocentric chromosomes
metacentric chromosomes have their centromeres in the middle of the chromosomes. acrocentric chromosomes have their chromosomes toward one end of the chromosomes.
during G2 of the cell cycle, the cell _________ ____________ necessary for mitosis
synthesizes proteins
what is the kinetochore
the site at which chromosomes are attached to microtubules
In which stage of prophase I of meiosis does the synaptonemal complex form?
zygotene
another word for tetrad
bivalent
crossing over occurs in ___________ of prophase I of meiosis
pachytene
the name of the nodules that facilitate the exchange of DNA along the synaptonemal complex in prophase 1 of meiosis
recombination nodules
