The Cell as a Unit Flashcards
A study of peripheral blood smears shows that neutrophil nuclei of women have a Barr body, whereas those of men do not. The Barr body is an inactivated X chromosome. Which of the following forms of RNA is most likely to play a role in Barr body formation?
Long noncoding RNA (lncRNA).
There are forms of noncoding RNA that play a role in gene expression. Long noncoding RNA (lncRNA) segments greater than 200 nucleotides in length can bind to chroma- tin to restrict access of RNA polymerase to coding segments. The X chromosome transcribes XIST, a lncRNA that binds to and represses X chromosome expression.
What is the role of MicroRNAs?
miRNAs are noncoding sequences that inhibit the translation of mRNAs
Are small interfering RNAs (siRNAs) biologically made?
No, they are artificial! They have the same role as miRNAs in silencing gene expression.
What intracellular substance does drinking wine and restricting caloric intake increase?
Sirtuins.
They impact histone acetylation and deacetylation which may promote transcription of genes encoding for proteins that increase metabolic activity and inhibit effects of free radicals.
How do sirtuins promote longevity?
They promote increased insulin sensitivity and glucose utilisation
Which microfilament allows for cell movement?
Actin
What protein forms the scaffold for actin and myosin in muscle cells to contract?
Desmin
Which proteins transduce mitogenic signals from the cell membrane to the nucleus?
RAS proteins
Which molecule promotes angiogenesis?
Basic Fibroblast Growth Factor
What does Platelet-derived Growth Factor do?
Vascular Remodelling
What molecule connects epidermal basal cells to the basement membrane?
Fibronectin
Which cells are useful in creating knockout mice?
Embryonic Stem Cells
