Chapter 17.1-17.3 - E3 Flashcards
What is it called when cytoplasmic organelles are contributed to the zygote by both parents? And what organism does this occur in?
Biparental
Yeast
What is it called when cytoplasmic organelles are contributed to the zygote by one parent? And what organism does this occur in?
Uniparental
Transmitted by the maternal lineage
Occurs in Eukaryotes
What the role of the mitochondrial RNA polymerase?
To transcribe mitochondrial DNA
What is it called when multiple protein-coding genes, typically of related function, clustered together and expressed as a single mRNA?
Operon (polycistronic)
Why are mitochondrial mutations especially bad?
They are pleiotropic (complex) due to reduced ATP production.
What is Leber’s hereditary optic neuropathy (LHON)?
Causes blindness in late adolescence/early adulthood
All affected children have an affected mother, but all affected mothers don’t have affected children
What are the three most common contributors for this incomplete disease penetrance of LHON?
Maternal heteroplasmy
Influence of specific nuclear genes
Effect of environmental factors
What is variability in mitochondrial DNA sequence (multiple alleles) present among the mitochondrial DNAs present in a single oocyte called?
Heteroplasmy
What is a single mitochondrial DNA sequence (single allele for each gene) for all copies of mitochondrial DNA in a cell called?
Homoplasmy
Mitochondrial mutations have ________ penetrance and do not show ________ _________.
Mitochondrial mutations have variable penetrance and do not show Mendelian Inheritance.
LHON is a mitochondrial disorder. Of the children of a father who is heteroplasmic for this disorder and a mother without the disease gene:
A. None will have the disorder
B. 25% will have the disorder
C. 50% will have the disorder
D. A variable number of children will have this disorder
E. All will have the disorder
A. None will have the disorder
- Mitochondria come from mom and none from dad
The rules of the third-base wobble are also more flexible in the ________ than for ________ ________.
The rules of the third-base wobble are also more flexible in the mitochondria than for cytoplasmic ribosomes.
How many different codons are there?
64
How many different codons bind tRNAs?
61
3 codons are stop codons
What is the wobble rule?
Increased flexibility in the base pairing at the third position in a codon, this happens because some tRNAs can bind more than one codon
