Week 1&2- Cell Function Flashcards
state the cell theory.
- Cells are the basic structural and functional units of living organisms
- Cells activity, ind or collectively, dictates the activity of an organism
- Continuity of life has a cellular basis
3 main features of a cell?
plasma/ cell membrane: Allowing cells to be self-contained and forming a barrier, communication, selectively permeable
nucleus: The control centre of the cell, controlling activity and the life cycle
cytoplasm: Intracellular solution containing organelles and structures for functioning
functions of cell plasma/ membrane?
Allowing cells to be self-contained and forming a barrier, communication, selectively permeable, transport, receptors for signal transduction, enzymatic activity
tight junctions?
impermeable junction
formed by fusion of integral proteins in adjacent cells
interlocking junctional proteins
gap junctions?
communicating junctions that allow small ions to pass
formed by specialized integral proteins (connexons), which organize themselves into pores from one cell to another
eg, electrical signals
desmosomes?
anchoring junctions bind to adjacent cells together and help form internal tension reducing network
have cytoskeleton reinforcement
reduces cell damage that could occur from tearing
primary active transport?
uses the hydrolysis of ATP to directly provide energy for transportation
Na+/K+ Pump
secondary active transport?
uses energy which comes indirectly from energy stored in ionic gradients created by a primary transport pump → coupled systems, symporter
Na+ moving with the concentration gradient and glucose moving against the concentration gradient out of the cell
vesicular transport?
- Vesicular transport is required for large particles and macromolecules, which cannot be transported using protein channels or carrier.
- Instead transportation occurs within membranous sacs called vesicles
- This requires energy
phagocytosis?
endocytosis
(cell eating)- the cell engulfs a relatively large material and this is then usually digested in a lysosome
pinocytosis?
endocytosis
(cell drinking)- the cell takes in ECF and particles, this is routine process for most cells
compare cilia and flagella:
cilia- move fluid over cells surface
flagella- move entire cell
Rough ER?
synthesis of glycoproteins/ phospholipids that are transferred to organelles, inserted in plasma or secreted during exocytosis
smooth ER?
synthesis of FA, steroids, detoxifies drugs, stores and releases calcium ions in muscle cells
lysosomes?
vesicles formed from golgi complex and contains digestive enzymes
peroxisomes?
oxidize FA and amino acids, detoxifies harmful substances
vesicles contain oxidases
proteasome?
contains proteases, degrades unneeded/ damaged proteins by cutting them into small peptides
how is a chromosome made?
dan makes chromatin which is combined with histone proteins and RNA chains
chromatin is packaged into nucleosomes which forms a helical fiber which is looped into a chromosome
characteristic of a bacteria cell (prokaryotic)? (11)
- small (0.4-2um)
- cell wall is always present
- no nucleus
- one circular chromosome of double stranded DNA, sometimes plasmids
- no membrane bound organelles
- some are motile, use flagella
- plasma membrane is selectively permeable
- cytoplasm contains all enzymes and chemicals, no cytoskeleton
- no ER
- has ribosomes
- asexual reproduction
characteristics of a eukaryotic cells?
- larger (5-100um)
- bounded by cell wall on membrane
- has a nucleus that contains DNA
- double stranded DNA associated with histones to form pairs of chromosomes
- organelles are membrane bound
- some are motile, some are not
- plasma membrane is selectively permeable
- has cytoskeleton (moving of cytoplasmic fluid)
- has ER
- has ribosomes
- sexual or asexual reproduction
gram positive?
thick layer peptidoglycan surrounds plasma membrane and attached a polysaccharides (teichoic acids) which allows molecules in and out of the cell
- stains purple
gram negative?
have a thin layer of peptidoglycan which is sandwiched between plasma membrane and outer membrane
- stains red
antibiotics selective toxicity?
kill invading organisms without targeting the host
it does this by exploiting the differences in structure of the target cells and the host cells
what are the 4 main sites for antibacterial action?
- inhibition of synthesis of the bacterial cell wall
eg, penicillin - inhibition of nucleic acid synthesis
eg, sulphonamides - inhibition of protein synthesis
eg, tetracycline - disruption of bacterial cell membrane function
eg, polymyxins
principles of antimicrobial therapy:
mechanism of action?
bactericidal (lethal to bacteria)
bacteriostatic (slow microbial growth)
principles of antimicrobial therapy:
susceptible organisms?
narrow spectrum: active against a few organisms
broad spectrum: active against a wide variety of microorganisms (amoxicillin)
problems with antibiotic misuse?
- kill good bacteria
- create an environment for bacteria to become antibiotic resistant (fast replication of bacteria)
- viruses are not cells and don’t have targets that antibiotics work on
points on viruses?
- not cells
- consists of nucleic acid surrounded by protein coat
- parasitic dependancy on cells
- unable to produce or carry out metabolic functions
- use your cells to replicate and spread
what are stem cells?
Stem cells= produce other types of cells, allows for the adaptation of tissues
o Eg, epithelium cells replaced continuously
cell differentiation?
• Cells differentiate= have different functions, this happens after they reproduce
merocrine secretion?
secretions of that cell are excreted via exocytosis from secretory cells into an epithelial-walled duct and onto a bodily surface or into the lumen
eg, salivary glands, pancreas
halocrine secretion?
produced in the cytoplasm of the cell and released by the rupture of the plasma membrane, which destroys the cell and results in the secretion of the product into the lumen.
apocrine secretion?
accumulate at the apical surface of secreting cell, portion of the cell pinches off by exocytosis to release the secretion
endocrine secretion?
secretion is directly into blood
