Eukaryotic Chromosome Flashcards
What are telomeres
Protective region at the end of each chromosomes
What do telomeres do
Prevent chromosomes from deteriorating at the ends
What does naked DNA mean
DNA molecules that aren’t associated with histone proteins or other molecules, in their free unbounded form
What are nucleosomes
Basic structural units of chromatin - consisting of DNA wrapped around histone proteins
What are Chromatosomes
Number of loosely associated nucleosomes
What is the shape nucleosome normally form
Solenoid shape
How can gene expression be regulated
Compaction of chromatin - more condense more transcription restrictions
What is the role of heterochromatin
Genome stability, chromosome organisation and gene regulation
Which type of chromatin is compact
Heterochromatin
What’s the role of euchromatin
Gene expression, transcriptional regulation and cellular function
Which type of chromatin is loosely compact
Euchromatin
What modification of gene activity can happen
Acetylation
Methylation
What does acetylation do
Neutralise the charge making DNA less tightly coiled and increase transcription
What does methylation
Maintains the positive charge, making DNA more coiled and reducing transcription
What modification reduced transcription
Methylation
What modification increases transcription
Acetylation
Definition of homologous chromosome
Pairs of chromosome one from each parent that have the same gene in the same order - different alleles
What makes a cell non-dividing in terms of chromosomes
They partially unravel and chromatin appear as a diffuse mass
What makes a cell dividing in terms of chromosomes
They condense and can be seen as chromosomes
