week 2

• A benign cancer does not spread to the other parts of the body
• malignant cancer spreads to the other parts of the body
• metastasis is the formation of tumors
• cancer cells are different from normal cells by having multiple nuclei, distorted shape, smaller cytoplasm, ignoring cell signals, the inability to enter the G0 phase, lasting up to 25 years, ignoring programmed cell death, abnormal DNA, and higher activity of tyrosine kinases.
• Density-dependent inhibition: cells stopping division after a layer is completed
• Cancer cells are unaffected by density-dependent inhibition
• Angiogenesis: formation of new blood vessels
• Cancer cells send chemical messengers to redirect blood vessel growth to provide the growing tumor with oxygen and nutrients
• Mutations can trigger proto-oncogenes to create oncogenes
• Oncogene: mutated gene that has the potential to create cancer cells
• Oncogenes have a higher tendency to develop with age as mutations accumulate (>50)
• Proto-oncogene: gene that has the potential of being mutated and becoming an oncogene and generate cancer cells
• Surgery: removes tumours
• Chemotherapy: nonspecific destruction of rapidly dividing cells
• Radiation: damages DNA of both cancer and normal cells
• Vaccines: used for cervical cancer
• Targeted therapies: reduction of the redirection of blood vessels towards tumors, reduction of kinase activity levels, through drugs
• Immunotherapy: utilize immune therapy to fight off cancer cells with recognition of antigens on the surface of cancer cells
• Active immunotherapy: addition of interferon and interleukin to enhance the immune system
• Radioimmunotherapy: attach radioactive isotopes to specific antibodies and to deliver them directly to the cancer cell, or attach a drug to kill the cells
• the hallmark of cancer is uncontrolled growth
• Cancers can be caused by viruses or environmental factors such as tobacco smoke, radiation, and chemicals
• The first step towards cancer is mutations that cause changes in genes that regulate cell division
• Cancer can be caused by mutations that affect genes involved in controlling cell division (e.g., p53)
• Cell cycle checkpoints are mechanisms that ensure DNA replication occurs correctly and prevent damaged cells from dividing.
• signal receptor: protein that changes shape and activity after binding to a signalling molecule
• signals are recognized by the cells through receptors in the cell membrane or in the cytoplasm of the cell
• after binding to a signalling molecules, receptors send messenger proteins to elicit an intracellular recponse
• Induction of a signal cascade requires ATP. This can be seen in the epinephrine pathway.

  
• Signalling molecules can interact with protein kinases in the cytoplasm to induce cell division

  
• A signal cascade is a chain reaction involving many different proteins
• Many signal molecules are hormones and growth factors, including estrogen, adrenaline, and insulin.
• testosterone is recognized by a receptor protein in the cytoplasm. A hormone-receptor complex is formed, which interacts with the DNA in the nucleus, leading to the production of a new protein in the cytoplasm.
• A signal that binds to a receptor protein may induce a signal transduction pathway that involves many different proteins eg. kinases, before a cellular response occur.
• Signals eg. testosterone, may bind to a receptor which then triggers genes to be expressed in the cytoplasm
• Some signals eg. epinephrine, may interact with signal transduction kinases as well as activation of enzymes before a cellular response occurs
• Insulin, which activates kinases, in turn activate other signal molecules, which then trigger different metabolic pathways in the body
• steps of cellular signalling

  A) plasma membrane

  B) cytoplasm

  C) reception

  D) receptor

  E) signalling molecule

  F) transduction

  G) signal transduction

  H) response

  I) activation

  J) response

  
• Types of phospholipid structures

  A) liposome

  B) micelle

  C) bilayer sheet

  
• Types of proteins found on cell membrane

  A) peripheral

  B) integral