Nucleus, Chromatin Structure & Organelle Genomes - Nishimoto Flashcards
What is unique about mitochondria?
They have their own genome
What are two important reasons for chromatin?
Condensing DNA
Gene expression
What is chromatin?
The DNA-protein complex that makes up chromosomes
How can cytogeneticists take advantage of chromosome condensing? 2 examples
Can separate certain chromosomes by staining them or by using banding patterns
When you see abnormal chromosome, what should you be thinking?
Inherited genetic defects
Does replication & segregation occur at once?
No, in stages (think cell division)
3 DNA sequence elements needed to make a replicating chromosome
Telomere - end
Replication origin
Centromere - spindle attachment
What relative to chromosomes is present in a somatic cell?
Two homologous copies of chromosomes
What is a histone?
Protein that helps organize DNA in chromatin
Condensed chromatin
Decondensed chromatin
peripheral heterochromatin
euchromatin - form that is actively transcribed
Chromatin structure: interphase vs. mitotic
interphase - not condensed
mitotic - condensed, ready to split
Chromatin structure
DNA tightly wrapped around histone protein
protein:DNA :: 2:1
Highly conserved in eukaryotes
Reversibly packed
What is wrong with XX chromosomes?
What is X chromosome inactivation?
Not compatible with life
X chromosome is inactivated either in mom or pop chromosome, depending on cell
What is the instance at which a gene is expressed?
When chromosome regions puff to less condensed chromatin
Is chromatin rigid?
No, fluid and dynamic allowing for gene expression (whether they’re needed or not) and condensation
What are chromatin remodeling complexes?
Proteins that bind to nucelosomes and alter their structure
What dictates expression/silencing of genes? Name some examples
Post-translational modifications of histones
Acetylation
Phosphorylation
Glycosylation
Methylation
Describe what core histone tails can do
They can extend and interact with other nucleosome
MITOCHONDRIAL PROTEINS: Where are most of them encoded?
In the nucleus and must be transported to the mitochondria
How are mitochondrial genomes inherited in humans?
Maternally
Would all inherited traits from mitochondria come from mom?
No, most proteins are encoded in nucleus. Mitochondrial proteins are produced by 2 separate genetic systems
