The Cytoplasm Flashcards
What is the name of the cells produced after first zygotic cellular division following fertilisation and what do they do?
Blastomeres - give rise to all tissue types of the foetus
What cellular activity are muscle / other contractile cells specialised for?
Movement
What cellular activity are epithelial cells specialised for?
Form adhesive and tight junctions between cells
What cellular activity are fibroblasts, cells of bone and cartilage specialised for?
synthesise and secrete components of the extracellular matrix
What cellular activity are neurons and sensory cells specialised for?
Convert physical and chemical stimuli into action potentials
What cellular activity are cells of digestive glands specialised for?
synthesis and secretion of degradative enzymes
What cellular activity are cells of mucous glands specialised for?
synthesis and secrete glycoproteins
What cellular activity are certain cells of the adrenal gland, testis and ovary specialised for?
synthesis and secretion of steroids
What cellular activity are cells of the kidney and salivary gland ducts specialised for?
ion transport
What cellular activity are macrophages and neutrophils specialised for?
intracellular digestion
What cellular activity are fat cells specialised for?
lipid storage
What cellular activity are cells lining the intestine specialised for?
metabolite absorption
What is the function of the plasmalemma and what does it consist of?
Acts as a selective barrier regulating the passage of materials into and out of the cell and facilitating transport of specific molecules
- needs to maintain constant ion content in the cytoplasm
- also important in signalling and recognition
consist of phospholipids, cholesterol, proteins, with oligosaccharide chains linked to many phospholipid and protein molecules
What is the structure and function of the golgi apparatus?
Structure: several elongated flattened saclike membrane structures
Function:
- modifies, packages and sorts materials that arrive from the ER in transport vesicles
- forms secretory vesicles and lysosomes
What is the structure and function of vesicles?
Structure: spherical shaped membrane bound sac containing various types of material to be transported through the cell
Function: transport cellular material
What is the structure and function of lysosomes?
Structure: spherical shaped membrane bound organelles formed from golgi apparatus which contain digestive enzymes
Function: digest microbes or materials
What is the structure and function of peroxisomes?
Structure: smaller spherical shaped membrane bound organelles formed from the ER or through fission and contain oxidative enzymes
Function: detoxify specific harmful substances either produced by cell or taken into the cells
Engage in beta oxidation of fatty acids to acetyl coA
What is the structure and function of mitochondria?
Structure: Double membrane bound organelles containing a circular strand of DNA
Function: synthesis most ATP during aerobic respiration using fuel (glucose) and in the presence of oxygen
What is the structure and function of ribosomes?
Structure: formed of both protein and ribosomal RNA organised in both large and small subunits
Can be bound to a membrane (rer) or free
Function: Synthesise proteins
Bound ribosomes- produce proteins that are secreted /incorpotated into plasma membrane and within lysosomes
free ribosomes: produce proteins for use in the cell
What is the structure and function of cytoskeleton?
Structure: network of proteins filaments and tubes (microtubules, intermediate filaments and microfilaments)
Function: intracellular support and organisation of cell, important in movement and cell division
What is the structure and function of microfilaments?
Structure: actin protein monomers - 2 thin intertwined filaments
Function: maintain cell shape, separate cells in cytokinesis, support microvilli, muscle contraction, changing shape of cell
What is the structure and function of intermediate filaments?
Structure: numerous protein components
Function: support and stabilise junctions between cells
What is the structure and function of microtubules?
Structure: hollow tubes of tubulin protein
Function: maintain cell shape (rigidity), organise and move organelles, support flagella and cilia, vesicular transport and separate chromosomes in cell division
What is the structure and function of centrosome?
Structure: amorphous region next to nucleus
Function: organise microtubules and participate in mitotic spindle formation
What is the structure and function of proteosomes?
Structure: barrel shaped protein complexes in both cytosol and nucleus
Function: degrade and digest damaged/uneeded proteins
What is the structure and function of inclusions?
Structure: aggregates of specific types of molecules
Function: temporary storage for the molecules (melanin)
What is the structure and function of the cilia?
Structure: short membrane extensions supported by microtubules
Function: move substances over surfaces
What is the structure and function of flagellum?
Structure: long singular membrane extension supported by microtubules
Function: propels sperm
What is the structure and function of microvilli?
Structure: thin membrane fold projecting from the surface and supported by microfilaments
Function: increase SA for greater absorption
What is the structure and function of the nucleus?
Structure: large structure with a double membrane containing nucleolus, chromatin and nucleoplasm
Function: houses DNA that serves as genetic material to produce proteins
What is the structure and function of nuclear envelope?
Structure: double membrane barrier between cytoplasm dab nuclear contents - continuous with RER
Function: separate nucleus from cytoplasm
What is the structure and function of nuclear pores?
Structure: openings in nuclear membrane
Function: allow passage of materials from cytoplasm and nucleoplasm (RNA, proteins, ions and water soluble molecules)
What is the structure and function of nucleolus?
Structure: large prominent structure in nucleus
Function: synthesis of ribosomes
What is the structure and function of cytoplasm,?
Structure: contents of cells between plasma membrane and nuclear envelope
(cytosol + organelles)
Function: responsible for many cellular processes
What is the structure and function of cytosol?
Structure: viscous fluid containing dissolved ions, proteins, carbohydrates and lipids)
Function:support for organelles, viscous fluid medium for diffusion to occur
What is the structure and function of organelles?
Structure: membrane bound and non-membrane bound structures
Function: specific metabolic activities of the cell
What is the structure and function of RER?
Structure: membrane network with ribosomes attached to cytoplasmic surface
Function: modifies, transports and stores protein produced by attached ribosomes- these are secreted, become part of plasma membrane or serves as enzymes for lysosomes
What is the structure and function of SER?
Structure: interconnected membrane network
Function: synthesises, transports and stores lipids. Metabolizes carbs, detoxifies drugs, alcohol and poisons, forms vesicles and peroxisomes
What are the different mechanisms of passive diffusion?
1) Simple diffusion: net movement of small non polar substances down conc gradient across selectively permeable membrane
2) Facilitated diffusion: movement of ions and small polar substances down conc gradient across selectively permeable membrane with assistance of transport proteins
- channel mediated =ion through protein channel
- carrier mediated= small polar molecule by carrier protein
3) Osmosis: diffusion of water across selectively permeable membrane- direction determined by relative solute conc
What are the different mechanisms of active transport?
1) Primary: movement of substances up its conc gradient using ATP
2) Secondary: movement of substance up its conc gradient using energy from movement of another substance down its conc gradient
3) symport: movement of substance up conc gradient in the same direction as NA+
4) antiport: movement of substance up conc gradient in opposite direction as Na+
What are the different mechanisms of vesicular transport?
1) Exocytosis: bulk movement of substance OUT of cell by fusion of secretory vesicle with membrane
2) Endocytosis: bulk movement of substances INTO cell by fusion of secretary vesicle at plasma membrane
3) Phagocytosis: form of endocytosis where pseudopodia engulf particulate materials external to the cell
4) Pinocytosis: form of endocytosis in which vesicles forms as interstitial fluid is taken up by the cell
5) receptor mediated endocytosis: plasmam membrane receptors bind specific substance and this receptor and bound substance are taken up by the cell
What happens if you have non-functioning parathyroid receptors?
Pseudohypoparathyroidism - parathyroid hormone is produced but the respective target receptor is absent - causes low calcium levels
What happens if you have non-functioning growth hormone receptors?
Dwarfism - Growth hormone is produced by anterior pituitary gland buts its respective target receptor is absent
Why is quality control during protein production in the RER so important?
Proper functioning in the RER and of ERAD to dispose of defective proteins is very important as it can cause many inherited diseases
What is osteogenesis imperfecta?
In some forms of this disease bone cells synthesise and secrete defective pro collagen molecules which produces weak bones
What is jaundice?
Yellowish discolouration of the skin causing by accumulation of bilirubin in the extracellular fluid, alongside other pigmented compounds
The SER enzymes in livers cells are supposed to metabolise bilirubin to bile for excretion but often in newborn infants the SER is underdeveloped causing failure to convert bilirubin
