Week 2 - Tour of the cell Flashcards
centrioles
- two sets of microtubules arranged at right angles to eachother
- located in a region near centrosome → microtubule organising centre near nucleus
- organise microtubules into spindles used in cell division
cytoskeleton
- Provides SHAPE, SUPPORT & MOVEMENT of eg. macromolecules/ organelles
- fibres that extend through cytoplasm
- anchors organelles → microfilaments, microtubules, intermediate filaments
microfilaments
- two protein chains loosely twined together →contraction, crawling, ‘pinching’
microtubules
- largest of cytosketeal elements
- dimers of alpha- & beta- tubulin subunits
- facilitate movement of cells & materials
intermediate filaments
- between size of actin filaments & microtubules
- very stable, not usually broken down
peroxisomes
Similar to lysosomes
- membrane bound vescicles
- enclose enzymes
However
- enzymes in peoxisomes are synthesized by free ribosomes in the cytoplasm
- active in lipid metabolism
mitochondrion
- double membrane
- respiration
- carbohydrate metabolism
- ATP generation
- contain own DNA & ribosomes, divide by binary fission
golgi apparatus
Stack of 3-20 flattened, curved saccules
Modifies proteins & lipids
- receives vesicles form ER on cis (inner) face
- preps proteins for ‘shipment’ in vesicles
- packages proteins into vesicles at trans (outer face)
- vesicles have several destinations
→ within cell ( lysosomes & ER)
→ export from cell (secretions, exocytosis
lysosomes
membrane bound vesicles contain digestive enzymes involved in RECYCLING OF CELLULAR MATERIALS inc. lipids, proteins, nucleic acids, carbs, & whole organelles
destroy cells or foreign matter that the cell has engulfed by phagocytosis
rough endoplasmic reticulum
- studded w/ ribosomes
- involved in protein synthesis, modification & sorting
smooth endoplasmic reticulum
Lack of ribosomes Site of: - lipid synthesis - detoxification reactions - carbohydrate metabolism - calcium balance - synthesis (inc fat) & modification of lipids
endomembrane system
- network of membranes enclosing nucleus; ENDOPLASMIC RETICULUM, golgi apparatus, lysosomes & vacuoles
- includes plasma membrane
- may be directly connected to eachother or pass materials via vesicles
endoplasmic reticulum
- network of membranes that are form flattened, fluid-filled tubules or cisternae
- ER membrane encloses a single compartment called the ER lumen
nucleus
- Storage of GENETIC MATERIAL
- regulatio of DEVELOPMENT & METABOLISM
- transcription of DNA to RNA
- nucleolus contains RNA & PROTEIN
- nucleo pores provide PASSAGEWAYS FOR MOVEMENT OF MATERIALS
- dounle membrane - continuous w/ the ER
ribosomes
SITE OF PROTEIN SYNTHESIS
- consists of large & small subunits → each composed of rRNA & PROTEINS
- subunits assembled in the nucleus
- translate some mRNA produced from transcription of DNA to protein
- may be located on ER or free in cytosol
eukaryotic cells
PROTISTS, FUNGI, PLANTS, ANIMALS
- larger than prokaryotic cells
contain:
- membrane bound nucleus → house DNA
- specialised organelles
- plasma membrane
- some cells have a CELL WALL (plants)
plasma membrane
- boundary between cell and extracellular environment
functions:
- membrane transport in and out of cell →selectively permeable
- cell signalling using receptors
- cell adhesion
light microsxope
- uses light for illumination- maximum magnification 1000x
- resolution om2 micrometres
- 500x better than human eye
electron microscopy
TRANSMISSION ELECTRON MICROSCOPY (TEM)
- beam of electrons transmitted thorughsmp
- thin slices strained w/ heavy metals
- some electrons are scattered while other pass through to form an image
SCANNING ELECTRON MICROSCOPY (SEM)
- sample coated w/ heavy metal
- beam scans surface to make 3d image
prokaryotic cells
- lacks a membrane - bound nucleus →DNA in nucleoid
- cell wall outside of plasma membrane
- contains ribosomes
- ARCHAE & BACTERIA
CELL THEORY
- all living things are made up of cells
- cells are the basic unit of structure & function in living things
- cell structure is correlated to cellular function
- all cells arwe produced from other cells
- all cells are related by their decent from earier cells
