Class Notes (836,213)
Canada (509,690)
Biology (6,817)
Biology 1002B (1,346)
Tom Haffie (863)
Lecture 17

Biology Lecture 17/18

3 Pages
Unlock Document

Biology 1002B
Tom Haffie

Lecture 17 Methylation can also occur in histones Chromatin that is loose and available to polymerase will be more likely transcribed. XiST (x inactive specific transcript)  RNA transcript made from inactive x  Not translated  Functions as RNA and shuts down most genes in that X  The top four…  Colon  Prostate  Lung  Breast Cancer is genetic?  You inherit the predisposition to get cancer  Mutations in particular genes cause cancer, some correlations between cancer and mutation in certain genes  Some environmental agents that cause cancer seem to be mutagens  Genetic make up puts the body in an environment that makes you more likely to get cancer Cell cycle control  CDK(inase)- regulators (enzymes) of protein expression by phosphorylation are constitutive  However inactive unless bound to respective cyclin protein  Both combine and phosphorylate a whole range of proteins down stream to drive cell cycle  Ex. CDK2 and Cyclin E combine to drive cell thru G0 checkpoin  Under the influence of external and internal controls, cell may actively cycle, sit in G0 or undergo apoptosis Expression of proto-oncogenes promotes cell cycling: eg EGFR (epidermal growth factor)  Also expressed during embryonic growth (are same as those that are expressed in tumour)  They are just normal genes that are doing their jobs of making embryos  EGFR is a membrane bound protein that has an external receptor part, internal domain and then an internal signalling domain  The protein binds to the membrane, it detects EGF hormone in environment and it signals the nucleus to turn on dividing genes  If EGFR is defective, then it will send signals without EGF being present  Oncogenes: in charge of embryonic development, if deregulated= oncogenes EGF Pathways  Once during embryonic development you have enough cells, you need to shut down embryonic genes  If we lose activity of suppressor genes we might get a tumour  They are called tumour suppressors- they evolved to supress embryonic genes  TP53 is important cell division reduction gene ensures genes are ok to move into S phase  TP53 is the master tumour suppressor gene, coding a transcription factor whose activity can result in o Increased DNA repair o Cell cycle arrest by blocking cyclin/ CDK, until DNA is repaired o Apoptosis Inappropriate expression of miRNA can promote cycling e.g. oncomirs  Oncomeres= miRNAs  Are micro RNAs that are important in cancer development 
More Less

Related notes for Biology 1002B

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.