Karteikarten
Th1L01 Cells and organelles
Karten in diesem Stapel (56)
- 1Nothing less than _______ can be called living.A cell
- 2An organised assembly of cells and their extracellular products which carry out similar and coordinated activities within the bodyTissue
- 3An assembly of tissues coordinated to perform specific functions within the bodyOrgan
- 4An assembly of organs with specific, related activities, sharing regulatory influencesSystem
- 5A diffuse functional network of cells situated in many parts of the body, sharing specific activitiesSystem
- 6The three main characteristics of a prokaryote (3)1. single-celled
2. circular, free-lying chromosome
3. no membrane-bound organelles - 7Eukaryotic DNA islinear and serial
- 8Main components of a virusnucleic acid (DNA or RNA) and proteins
- 9Viruses subvert _________ machinery to make more virusesprotein synthesis
- 10Viruses are not cells or organisms in the strict sense because.... (2)1. They lack a
plasma membrane
2. Only operate chemically within
host cells - 11Extra-chromosomal DNA is found inplasmids (pro and eu) and mitochondria (eu only)
- 12Ribosome of prokaryotes70S
- 13Ribosome of eukaryotes80s (70s in mitochondria)
- 14Transmission Electron Microscope (TEM)to look inside a
cell (electrons go through the specimen) - 15Scanning Electron Microscope (SEM)to see the cell
surface(electrons scattered off cell surface by heavy metal
coating e.g. Au) - 16Both types of EM involve elaborate preparation and can only evaluate ___ cellsdead
- 17Life span of enterocytes5-6 days
- 18Life span of erythrocytes115 days
- 19Life span of neuronslifespan
- 20Limits of the maximum size of a celldiffusion distance
- 21Diffusion efficiency at a distance above _____ is reduced50μm
- 22Surface Area (SA) :Volume (V)
- 23Sphere: SA =4Πr^2
- 24Sphere V=4/3Πr^3
- 25How to specialised cells overcome this problem of diffusion distance? (3)Thin processes, "giant" multinucleated cells and gap junctions
- 26Thin processesDirect transport of substances around cell via cytoskeleton
e.g. neurones and oligodendrocytes - 27Giant” multinucleate cellsGene expression can occur in more than one place e.g. skeletal muscle cells
- 28Types of protein filament that make up cytoskeletonactin, IF and MT
- 29Cytosol1. The aqueous environment within the plasma membrane
2. Together with organelles make up the cytoplasm - 30The only organelle visible by light microscopynucleus, as it is the largest organelle in the cell (diam. 3-10μm)
- 31Chromatincomplex of DNA/histone and non-histone
proteins - 32DNA winds around histones into _______nucleosomes
- 33Length of naked DNA1.8m
- 34Length of DNA packaged into nucleosomes95 mm
- 35DNA length post mitosis120μm
- 36Non-dividing chromatin is ____decondensed
- 37Nucleolus (3)1. Where rDNA is transcribed and ribosome subunits assembled
2. Contains a nuclear envelope surrounded by two layers of membrane
3. Nuclear pores allows transport in and out - 38Smooth endoplasmic reticulum (SER) (2)1. Biosynthesis of lipids, steroids
2. Metabolise carbohydrates/steroids - 39Rough endoplasmic reticulum (RER) (3)Coated with ribosomes
1. Ribosomes are involved in the translation, proteins for
secretion or insertion into cell membrane
2. Proteins are folded
3. Vesicles are budded from RER and transported to the Golgi
body for further transport and modification - 40Golgi body composition4-8 closely-stacked, membrane-bound channels (many
stacks/mammalian cell) - 41Golgi1. Modifies proteins delivered from RER e.g. by adding sugar
(carbohydrate) or lipid (fat) side-chains
2. Synthesise/package materials to be secreted
3. Direct new proteins to their correct compartments
4. Transport lipids around cell
5. Create lysosomes
6. Vesicles bud off bud off from the Golgi - 42Golgi vesiclesfuse with the inner surface of the plasma membrane
and release their contents (exocytosis)
e.g. hormones and neurotransmitters - 43SER concentrations are high in theliver and kidneys as well as endocrine glands that produce hormones
- 44RER concentrations are high innuclear membrane; many found in pancreatic secretory cells because they require a lot of enzymes
- 45Mitochondria composition (3)1. Two layers of membrane, 0.5-2μm long
2. Contain mDNA that encode some of their proteins
3. Inner membrane in folds - cristae – increase surface area - 46Mitochondria1. Sugars oxidised to generate ATP (Krebs cycle enzymes located in different parts of the membrane)
- 47Number of _______ per cell reflects metabolic activitymitochondria
- 48Functional vesicleslysosomes, peroxisomes
- 49Lysosomes composition (2)1. Electron-dense spheres with diameter 80-800nm
2. Lysosomal proteins are tagged with mannose -6- phosphate - 50Lysosomes1. Involved in protein, RNA and DNA
degradation/recycle/excrete
2. Contain powerful enzymes that require low pH - 51Peroxisomes compositionLarge (0.5-1.5μm), not very electron-dense
- 52Peroxisomes1. Involved in detoxification and phospholipid synthesis
2. Enzymes which generate (and degrade) H2O2 - 53Zellweger syndromeInherited absence of peroxisomes
- 54Myoclonic Epilepsy with Ragged Red Fibers (MERRF syndrome) (2)1. Mutation of mitochondrial gene for tRNA-lys
2. Disrupts synthesis of oxidative phosphorylation enzymes - 55Hutchinson-Gilford Progeria (3)1. Mutation in lamin A part of the nuclear envelope
2. Distorted shape of nucleus (blebbed)
3. Production of unique progerin protein - 56Tay Sachs Disease1. Mutation of the lysosomal hexosaminidase-A enzyme
2. Causes accumulation of ganglioside that is neurotoxic