Introduction lecture Flashcards
Define the term “molecular medicine”
interdisciplinary life science: to understand
- normal/pathological cellular processes
- more precise diagnostics
- targeted therapies
define the term “translational medicine”
highly interdisciplinary field of molecular medicine: molecular basic research (bench) to clinical research (bedside)
describe the main stages in development of new drugs
- TARGET (identification, characterization, validation)
- COMPOUND/POTENTIAL DRUG (high-throughput screening, efficiency & toxicology, in vitro & animal models
clinical trials - APPROVAL by authorities
describe the three phases in clinical trials
Phase I: Safety (toxic?), 20-100 individuals
Phase II: Safety/efficacy, 100-300 individuals
Phase III: more individuals, 300-3000
what are the major classes of biological molecules, what are the building blocks?
nucleic acids (nucleotides), proteins (amino acids), polysaccharides (monosaccharides), lipids/triacylglycerids (fatty acids)
Describe the structure of an eukaryotic cell (what do they have that prokaryotes do not have?)
- nucleus, nucleolus (rRNA)
- mitochondria
- ER & golgi
- peroxisome & lysosome
describe the nucleus
chromatin, surrounded by nuclear envelope with pores (diffusion of small molecules, active transport of proteins & RNA)
What happens in ER and golgi?
glykosylation, sorting of proteins
what happens in peroxisome and lysosome?
degradation of lipids and proteins
describe the interphase of the cell cycle and how long the different stages take!
G1: protein synthesis, organelle production, cell growth (10h)
G0: arrested or terminally differentiated cells (muscle cells, neurons)
S: synthesis, replication (2-4h)
G2: preparation for mitosis (1h)
what are the 5 stages of mitosis?
Pro-meta-prometa-meta-ana-telo
What happens in prophase?
condensation of chromosomes, spindel formation
What happens in Prometaphase?
Nuclear envelope breaks apart
What happens in Metaphase?
chromosomes line up between spindle poles
What happens in Anaphase?
Separation of sister chromatids, movement to opposite sites
What happens in Telophase?
formation of nuclear envelope, decondensation of chromosomes, cell division (cytokinesis)
how is the cell cycle regulated?
cell-cycle specifc cyclins that activate CDKs (cyclin-dependent kinases), inhibited by CDK inhibitors
CDKs activate nuclear target proteins that drive cell cycle
when does the cell cycle normally arrest?
- contact with other cells
- DNA damage
- terminal cell differentiation
- senescence
describe the extrinsic apoptosis pathway
external signal - ligand to death receptor (Fas) - initatior caspase8 - executioner: effector caspases cleave substrate proteins - apoptosis
describe the intrinsic apoptosis pathway
internal signal - mitochondria release cyt. c - Cyt C and Apaf.1 (apoptic protease activating factor) and ATP form apoptosome - caspase9 - … (same way)
what are caspases?
cystein-dependent aspartate-directed proteases (cleave proteins)
how is DNA-replication initiated?
DNA-polalpha complex with 7-10 nt RNA-primer, extended by poly alpha
what polymerase makes the leading strand?
pol e
what polymerase makes the lagging strand?
pol delta
what does helicase do?
separates the two strands
what does topoisomerase to?
twists up supercoiling (releases topological stress)
what is PCNA?
clamploader (coordinates replication), proliferating nuclear cell antigen, binds polymerases etc. (more than 100 proteins for repair, chomatin remodeling, signalling..)
why does the chromosome become shorter with every replication?
no obvious way to copy 3’ end (lagging strand) - no RNA-primer beyond end to initiate replication and maintain the telomere
what does telomerase do?
reverse transcriptase that provides RNA-template so that DNA-polymerase can complete lagging strand
where is telomerase active?
embryonic stem cells, sperm cells, activated lymphocytes, cancer cells (often)
job of RNA-polymerase I
rRNA precursors (nucleolus)
job of RNA-polymerase II
mRNA precursors, miRNA, lncRNA (nucleoplasm)
job of RNA-polymerase III
5S rRNA, tRNA, some miRNAS (nucleoplasm)
what is RNA-maturation?
preRNA to mRNA, 7mG-cap, polyA-tail, removal of introns (splicing)
how many codons are there?
4^3 = 64 (1-6 per aa, stop)
what are the three stages in the ribosome?
aminoacyl, peptidyl, exit
what are the two main ways of protein degradation?
- lysosomal: acidic pH, hydrolytic enzymes, non-selective
2. targeted: marked with ubiquitin by ATP-dependent proteasome
difference between southern, northern and western blot?
southern (DNA), northern (RNA), western (proteins)
how does CRISPR/Cas9 work?
RNA-guided DNAse (Cas9) that induces a double strand break at the site matching the RNA sequence (CRISPR), repaired by non-homologous end joining or homolog recombination with donor DNA
describe the stages of mRNA
transcribed pre-mRNA is modified at 5’ end during transcription (5’ cap) and shortly after transcription (3’ polyadenylation), splicing, export via nuclear pores, transport to ribosomes for translation, excess mRNA is degraded by nucleases
