Cell Basics Flashcards
Describe the properties of protoplasm and the tenets of the cell doctrine.
cell doctrine - all living organisms are made from cells and they are the basic/structural units of all organisms.
protoplasm - the cytoplasm in eukaryotes, contains ions, proteins, and nucleic acids.
Describe the relationship between cells, tissues, organs and systems of the body.
cells - basic unit of living organism
simple tissue - a collection of similar cells
compund tissue - a mix of cells and extracellular matrix
organ - a distinct group of several tissues
system - a group of organs with a distinct role
List the four basic tissue types.
epithelia: sheets of closely-packed cells derived from one of the 3 germ layers (ectoderm, mesoderm, endoderm) and which cover or line a surface of an organ.
connective tissues - cells derived from mesoderm and produce extracellular matrix of fibers and ground substance
muscular tissues: derived from mesoderm and composed of cells (or multinucleated syncytia) whose cytoplasm contains filaments made of contractile proteins (actin, myosin, etc)
Nervous tissues: develop from neurectoderm and consist of cells of which the main type possesses processes called neurites (axons and dendrites) which conduct impulses when stimulated
List the main membrane bounded organelles of the cell and state their functions.
mitochondria - responsible for respirationa and ATP production
nucleus - contains DNA which controls protein synthesis
endoplasmic reticulum - RER has ribosomes which are used for protein synthesis, SER is used for lipid synthesis
golgi - packs and sorts proteins from the ER
lysosome - membrane bound and contains digestive enzymes
Describe how the cell is divided into compartments.
the cell is divided into compartments via compartmentalisation. this is done via the phospholipid bilayer creating unique environments with specific conditions for organelles.
Discuss the process of secretion.
the secretion of materials from the cell is known as exocytosis, and it expels secretory vesicles which are produced by secretory cells. the secretory vesicle moves towards the cell surface membrane, and then fuses with it. the contents are then released. it is an active process.
Discuss the process of uptake of material by cells.
the uptake of materials in endocytosis. material from outside of the cell fuses with the cell surface membrane. the membrane then pinches off to form a vesicle which then travels inside of the cell. it is also an active process.
Be aware of the aims and purpose of personal and professional development.
to give the necessary knowledge, skills and
attitudes to enable you to assess patients and interact with colleagues in a professional manner at a level appropriate to your training and to stimulate and maintain enthusiasm for clinical medicine
early in the course
Understand how early clinical and professional development is assessed.
information governance training, mfqs, gp tutor sign off
Explain briefly how a microscope works.
a light microcope works by shinign light through a sample so that it can be seen in a microscope. the sample must be extremely thin for this to work.
a transmission electron microscope works by passing a beam of electrons through a specimen to produce an image
Describe how tissues are prepared for examination in the light microscope and become familiar with the appearance of the commonly used stains
in order to cut a thin section of a sample, it must first be impregnated with wax. the water in the cell is removed and replaced with something miscible between alcohol and wax. xylene is used to dewax.
the tissue is floated out in water bath to reverse compression. the tissue is transparent so stains are used. most common is haematoxylin and eosin. H stains acid components blue, E stains basic components pink
Give examples of other methods of tissue preparation e.g. cryostat sections, use of the electron microscope
a smaple can be freezed, and then dewaxing is not needed. tissue is mounted in OCT and sectioned with a cryostat.
preparation of a sample to use in a TEM is the same except different chemicals are used and a copper grid replaces the glass slide.
Consider the ways to interpret a 2D section of a 3D structure (plane of section)
sections of a sample will not always be cut perpendicularly, so care has to be taken when viewing slides and interpreting the 2D section of the structure
Understand the role and importance of epidemiology in medicine and public health
epidemiology is important as it shows the distribution of disease in a population. this allows chnages to be made to healthcare capactity
in medicine it allows doctors to consider how to prevent and treat disease, make sure best treatment is used, to work out amount of illness
Be able to explain what is meant by evidence-based medicine
using the best knowledge and treatments available for a patient. the volume of evidence can be unmanagable, statistically significant benefits may be marginal clinically
Understand the role of public health in improving health and preventing disease
public health is to reduce inequality and protecting and imporving population wellbeing. understanding health trends can help to understand the most effective way of preventing disease. improvement can be done through education, addressing soci-economic factors and through population interventions.
Explain the hierarchy of protein structure.
primary - the order of amino acids
secondary - chain of amino acids organised into alpha helix and beta pleats
teritary - the 3D packing of secondary structure elements
quaternary - number and position of polypeptide subunits.
Explain what is meant by the primary structure of proteins.
the primary structure is the sequence of the amino acids
Describe the nature of the peptide bond.
the bond is a resonance hybrid, and there is a delocalisation of electrons across the whole bond. it has a double bond character. a molecule of water is released when it is formed.
Explain what is meant by secondary and tertiary structure of proteins.
the alpha helix and beta pleat maximise hydrogen bonding and minimise steric repulsion. it is the localised organisation of the polypeptide backbone. beta side chains point alternatively up and down. they can be arranged in parallel and antiparallel strands.
polypeptides greater than 200 amino acids often have multiple teritary domains. the tertiary structure is a protein’s exact 3D structure.
Have a basic grasp of the relationship between genes and their expressed protein products.
genes determine the sequence of amino acids, which then determine the protein that is made.
Describe the key features of the basic building components of nucleic acids i.e. bases, sugar(s) and phosphate.
the bases are adenine, guanine (purines), cytosine, thymine and uracil (pyrimidines). the sugars are beta D deoxyribose and beta D ribose. the phosphate groups contain inorganic phosphate.
Understand and be able to explain the nature of a phosphodiester bond.
the phosphodiester bond is polar and asymmetric. it is the linkage between 3’ carbon and 5’ carbon.
Highlight the differences between DNA and RNA.
DNA contains deoxyribose whereas RNA contains only ribose. RNA contains uracil, not thymine. RNA is a single strand.
Describe what is meant when a nucleic acid is described as having polarity and explain why this is the case.
All the phosphodiester linkages in DNA and RNA strands have the same orientation along the chain, giving each linear nucleic acid strand a specific polarity and distinct 5’ and 3’ ends.
Give a brief overview of the DNA double-helix structure and how it is stabilised.
the DNA helix is two polynucleotide chains coiled around an axis. the chains are antiparallel and run 5’ to 3’ in oppositie directions. the bases are inside and the phophate is on the outside. hydrogen bonding between pairs and hydrophobic stacking forces.
Describe the Watson-Crick base-pairs.
A + T form a pair using two hydrogen bonds, C + G form a pair with 3 hydrogen bonds. T is replaced by U.
Understand what is meant by ‘genetic code’ and the relationship between genotype and phenotype.
genetic code - 3 nucleotides in a row (triplet) code for an amino acid.
genotype - individual’s collection of genes
phenotype - expression of geneotype, an organism’s observable characteristics.
