PH1123 - Inside the cell Flashcards
what are the simplest and oldest prokaryotes?
- bacteria
what is DNA in prokaryotes called?
- plasmids
what are the function of plasmids? (4)
- fertility; transfer of genetic material between bacteria
- resistance; antibiotics
- degradative; digestion of organic substances
- virulence; turn the bacteria into a pathogen
what is the cytoplasm? (3)
- area contained by the plasma membrane
- contains many membrane-bound compartments to facilitate distinct environment within organelles
- defined as everything excluding the nucleus
what is the cell cytosol? (3)
- largest compartment of the cell
- composed of densely packed molecules and aqueous gel
- site of many essential chemical reactions
we can infer that while cytosol is the fluid contained in the cell cytoplasm
what chemical reactions occur in the cytosol? (4)
- early steps in nutrient breakdown
- ATP generation (glycolysis)
- manufacture of protein
- signalling transduction
what is the mitochondria? (3)
- present in all eukaryotic cells
- function is cellular respiration (in cytosol; anaerobic glycolysis and in mitochondrion; pyruvate oxidation)
- distinctive structure
what is the relationship between the number of mitochondria and exercise?
- the more exercise the more mitochondria in muscle cells as cells adapt to a higher energy requirement
what are the four separate components of the mitochondria? (4)
- outer membrane
- intermembrane space
- inner membrane
- matrix
what are the functions of the outer membrane? (2)
- separation of internal and external environments
- role in cell death (disruption of outer membrane allows proteins from intermembrane space to leak into cytosol)
what is in intermembrane space?
- cytochrome c
what is cytochrome c important for? (2)
- essential component of the electron transport chain
- important in apoptosis
what does the inner membrane of mitochondria contain? (2)
- highly folded to form cristae
- mitochondria of cells with high ATP demand contain more cristae
- what does cristae enhance? (2)
- increase surface area of inner membrane
- enhance ability to produce ATP
what does the matrix of the mitochondria contain? (2)
- contains most of mitochondrial proteins/enzymes
- mitochondrial ribosomes, tRNA and mtDNA and several copies of the mitochondrial genome
what are the principal sites of intracellular digestion?
- lysosomes
where are lysosome produced?
- golgi
what do lysosomes contain and examples? (5)
- many hydrolytic enzymes
- lipases
- carbohydrates
- nucleases
- proteases
what are endosomes? (2)
- eukaryotic cells constantly taking up fluid and molecules via endocytosis
- membrane-bound organelles
how are endocytic vesicles formed? (3)
- plasma membrane buds inwards
- pinches off to form intracellular endycotic vesicle
- can fuse with lysosomes or be recycled to the surface
what are the functions of endosomes? (3)
- internalisation of nutrients
- regulation of cell surface protein expression
- uptake and digestion of extracellular debris
why do cells require endocytosis? (2)
- most molecules required for cellular function are large, polar molecules
- they cannot pass through the hydrophobic portion of the plasma cell membrane by passive means
what are the types of endocytosis? (3)
- pinocytosis
- receptor mediated endocytosis (clathrin/caveolin-mediated endocytosis)
- phagocytosis
what is pinocytosis? (4)
what is pinocytosis? (4)
- small particles are taken in by a cell by splitting off small vesicles from the cell surface
- nonspecific transport of substances
- cell takes in surrounding fluids
- active transport
what is receptor-mediated endocytosis? (3)
- receptor binds to ligand
- captured by clathrin coated pit
- mature pit bud off forming a coated vesicle
what is phagcytosis? (3)
- a cell engulfs a solid particle to form an internal compartment known as a phagosome
- pseudopodium
- eliminate debris or pathogens via lysosome
what do the professional phagocytes include? (6)
- white blood cells
- macrophages
- monocytes
- neutrophils
- mast cells
- dendritic cells
what is the sarcoplasmic reticulum?
- the endoplasmic reticulum in striated muscle cells in the heart and skeletal muscle
what are the two functional compartments of the endoplasmic reticulum? (2)
- rough endoplasmic reticulum
- smooth endoplasmic reticulum
what is the difference between the rough and smooth endoplasmic reticulum?
- the rough endoplasmic reticulum has ribosomes on its surface
what are ribosomes? (2)
- site of protein synthesis (translation)
- link amino acids together in the order specified by messenger RNA (mRNA) molecules
what are the two major components of ribosomes? (2)
- the small ribosomal unit
- the large ribosomal subunits
what is the function of the endoplasmic reticulum? (5)
- protein manufacture
- protein targeting
- steroid production
- drug detoxification
- Ca2+ storage/ release
what is the function of the smooth endoplasmic reticulum?
- lacks ribosomes and is involved in lipid manufacture
how does the amount of protein relate to the rough endoplasmic reticulum?
- cells that secrete large amounts of proteins have large amounts of rough endoplasmic reticulum
what is glycosylation and what is the purpose? (2)
- carbohydrates attached to proteins
- purpose is folding and stability
what part of the endoplasmic reticulum is steroid production, drug detoxification and Ca2+ storage associated with and what does it do? (2)
- smooth endoplasmic reticulum
- storage of proteins and sites of action of many enzymes
what are some examples of proteins and enzymes in the smooth endoplasmic reticulum? (3)
- membrane lipid synthesis
- cytochrome p450 enzymes (present in most tissue but especially liver)
- calsequesterin
what is calsequesterin?
- calcium binding protein of the sarcoplasmic reticulum
what is the function of the sarcoplasmic reticulum?
- forms extensive network surrounding muscle sacromeres and supplies them with Ca2+
what is the structure of the sarcoplasmic reticulum? (2)
- tubular network
- smooth muscle cells are spindle-shaped
what is the structure of the golgi apparatus? (4)
- flattened disc-shaped sacs (cisternae)
- located near nucleus
- cis (entry) and trans (exit) face
- proteins travel from the endoplasmic reticulum to golgi and within golgi via transport vesicles
what is cis and trans of the golgi apparatus? (2)
- incoming transport vesicles (cis)
- outgoing transport vesicles (trans)
what is the function of the golgi apparatus? (3)
- secretory pathway
- lysosome formation
- protein modification and sorting
