Weeks 1-5 Flashcards
Formative 1 (114 cards)
What is the difference between prokaryotic, eukaryotic cells and viruses?
What is the role of surface projections?
Prokaryotic = few membrane bound organelles and smaller ribosomes Eukaryotic = have DNA and histones and larger ribosomes Viruses = lack all cell characteristics
Surface projections = Binds eukaryotic cells via cell junctions
What are all the cell properties?
Irritable - react to unnatural things Conductive - pick up, react, pass on things Contractile - can move Absorb and assimilate Excrete and secrete Respire Grow Reproduce
What is a tissue definition and how is it formed?
What part of a cell is compound tissue?
Cellular and extracellular elements assembled to form basis of bodily functional systems, when 1 or more cell types usually predominate.
Formed via histogenesis
Cell epithelium
What are the 3 primary germ layers (examples)?
Ectoderm (nervous tissue), mesoderm (muscle), endoderm (epithelium)
What are the 4 tissue types?
Epithelia: closely packed cells that line organ surface, derived form 1/3 germ layers
Connective tissue: cells from mesoderm which produce extracellular fibre matrix
Muscular tissue: mesoderm cells with filaments and of contractile proteins in cytoplasm
Nervous tissue: from neuroectoderm, cells with neurites that conduct impulses upon stimulation
What proteins allow endocytosis?
Related pathologies?
Fusogenic proteins
Anaemia, lysosomal storage disorders, Zellweger’s syndrome
The protein synthesis pathway?
Related pathologies to exocytosis?
Recognition of peptide signal sequence Peptide orientated by docking protein Translation and insertion of protein into endoplasmic reticulum Protein modification and processing Protein stored Exocytosis
I-cell disease, Lewy bodies, pro-insulin diabetes
Properties of lysosome and proteasome?
Lysosome = works in acidic conditions, peroxisome is type containing catalase Proteasome = digests protein with ubiquitation
Purpose of microscopes in medicine?
To distinguish between normal and abnormal tissue
What are the different types of stain?
H and E: Haematoxylin - stains components purple / blue
Eosin - stains basic components pink
Periodic acid Schiff: stains aldehydes, from oxidised sugars, bright pink / purple
Trichome: shows different components, such as muscle
Weigert’s elastin: stains elastic
What is the size of most cells, RBCs and mitochondria?
7-20 micrometers
- 2 micrometers
- 0 X 0.2 micrometers
What are chromosomes, chromatin and nucleosomes?
Chromosomes = condensed chromatin Chromatin = DNA and RNA proteins combined ( proteins are both acidic and basic (histones)) Nucleosomes = 2 DNA double helix wrapped around 8 histones
What is the difference between heterochromatin and euchromatin?
Hetero = + condensed, is near nuclear envelope, represents SWITCHED OFF genes Eu = - condensed, is centrally located, represents SWITCHED ON genes
Properties of histones?
- Rich in basic amino acids
- Core histones = H2A, H2B, H3, H4
- Linker histones = H1, H5
- Use for DNA compacting and chromatin regulation
What are the 3 tissue groups based on cell proliferation?
- Epidermis = Continually renewing
- Liver / kidney = Conditionally renewing
- Nerve cells / cardiac cells = static / non-proliferative
What are the 5 cell cycle stages and when does DNA synthesis occur?
Prophase, prometaphase, metaphase, anaphase, telophase
S phase
What is the role of cyclins and why are they clinically important?
- Determine cell progress through cell cycle
- Coordinate cell entry into next phase
- Cyclin-dependent kinases = activated when they bind to cyclin
- Target proteins are then activated or inactivated
Clinical importance = may be anti-cancer agents as they arrest cell cycle - tumour suppressors
What are the properties of bases and what is polymerisation direction?
What is the difference between DNA and RNA structure?
What is an insertion mutation?
Aromatic, planar, hydrophobic
2’ DNA = hydrogen
2’ RNA = hydroxyl
Chemical inserted between DNA bases
What are the stages of DNA replication?
- Helicase unravels DNA
- Leading strand = 3’ end
- Lagging strand = 5’ end
- Lagging strand = ozaki fragments so 5-3’ direction
- RNA primer required for replication
What are the properties of mRNA?
What shifts start codons?
- 5’ cap added post-transcription for translation
- Has ribosome binding site
- Has start / stop codons
- 5’ and 3’ UTRs which have info for mRNA stability and translation
- Poly(A) tail and signal added post-transcription to regulate mRNA stability and translation
Mutations
What are the impacts of UTR mutation?
Causes disease as proteins can’t bind
What determines protein 3D structure and what bonds do primary proteins and cystine have?
What are the properties of peptide bonds?
What do all proteins start with?
Genes
Disulphide
Double bond characteristics, no free electron rotation, bond is planar
Methionine
What are the properties of alpha helix and beta sheets?
What are the main polypeptide forces?
Alpha = COOH and NH2 form hydrogen bonds Beta = 5-10 amino acids with hydrogen bonds - parallel and anti-parallel
Hydrophobic, electrostatic (hydrogen, Van der Waal, ionic), covalent
What are the types of protein mutations?
- Dysfunctional or absent protein
- Cut metabolic pathway
- Dysfunctional regulatory protein or receptor
- Protein aggregation
- Loss / impairment of infection defence