T2 Storage and Use of Genetic Information Flashcards
What is the diameter of packed chromatin fibres?
30nm
Which protein carries others into the nuclear envelope?
Importin
What initiates transcription in prokaryotes?
Sigma factor binding to Pribnow box and then RNA polymerase to bind, mRNA detachment from DNA occurs due to a repeated mRNA sequence of V
When are inclusion bodies created?
When enzymes cannot be targeted to lysosomes
What is initiator tRNA in prokaryotes and eukaryotes respectively?
fmet-tRNA and met-tRNA
How many triplet codons are there?
64
How many rings does a purine have?
2
How is the destination of a protein determined?
By the signal sequence of the protein
What causes aneuploidies?
Nondisjunction during oogenesis
What is the diameter of an entire mitotic chromosome?
1.4 um
Which amino acids are polar?
Arginine, asparagine, aspartate, glutamate, glutamine, lysine, serine, thereonine, tyrosine, histadine
Where is the restriction point?
Between M and G1
What is Ras?
The gene that regulates actin and microtubules skeletons causing transformation of cell type
How many chromosomes are in a normal human karyotype?
46
What is the point mutation leading to sickle cell anaemia?
GAG = GTG so glutamate becomes valine
How will a protein destined for the interior of the endoplasmic reticulum get there?
Binds to signal recognition particle (SRP) which binds to receptor on ER membrane
When does the nuceolous disappear
Prophase
What is a metacentric chromosome?
Has the centromere in the middle
What catalyses entry into S phase?
Cdk1
What are LINES and SINES?
Retrotransposable elements (moderately repetitive) Viral are LINES (long interspersed elements) Non viral are SINES (short interspersed elements)
Which enzyme repairs DNA in eukaryotes?
DNA polymerase beta and epsilon
How may gene mutations will lead to cancer?
5-7
How long does G1 last?
6-9 hours
How many genes are in the human genome?
23,000