Eukaryotes & Prokaryotes Flashcards
Function of the nucleus
- site of dna replication + transcription (making mrna)
- contains the genetic code for each cell
- site of ribosome synthesis
Nucleus structure
Nuclear envelope = double membrane
Nuclear pores - holes to let mRNA etc out
Nucleolus - smaller sphere inside which = site of rna production + makes ribosomes
- nucleoplasm = site of granular, jelly like material
What’s the flagella
A whip like structure for mobility & sometimes as a sensory organelle for chemical stimuli
What are cilia + features
Hairlike projections that come out of cells
- they can be mobile or stationary
Mobile = help move substances in a sweep motion e.g. mucus in trachea
Stationary - key in sensory organs e.g. nose
What are centrioles
- made up of microtubules
- occur in pairs to form a centrosome
What are centrioles involved in
Production of spindle fibres, flagella, undulipodia
Organise chromosomes in cell division
What is the cytoskeleton
A network of protein fibres running through the cytoplasm: consisting of,
Microtubules
Microfilamnets
& intermediate filaments
What are microtubules
(Found on cytoskeleton interior)
Maintain cell shape by resisting compressive forces and acts as tracks for movement of organelles
What are microfilaments
(Thickening the cortex) they resist tension & are responsible for cell movements & contraction
What are intermediate filaments/fibres
Found throughout cell
Hold organelles & provide mechanical strength
Function of the cytoskeleton
ALL REQUIRE ATP
- move chromosomes
- move organelles
- change cell shape in processes like cytokineses & endocytosis
- move cilia & flagella
- support the cell and maintain its shape
Rough endoplasmic reticulum and smooth endoplasic reticulum differences & similarities
- sim: both have folded membranes called cisternae
- diff: RER = ribosomes on the CISTERNAE too + PROTEIN synthesis
SER = no ribosomes & synthesis & storage of LIPIDS & CARBOHYDRATES
What’s the Golgi apparatus & vesicles
Where protein are modified & packaged off into
Vesicles (folded membranes making cisternae, tho secretary ones pinch off from the cisternae)
Function of the Golgi apparatus & the vesicles
Add carbohydrates to proteins to form glycoproteins
Produce secretory enzymes
Form lysosomes
Transport modify & store lipids
Finished products are transported to cell surface in Golgi vesicles where they fuse with the membrane and the contents are released
What are lysosomes
Bags of hydrolytic digestive enzymes (50 diff types)
What do lysosomes do
- hydrolyse phagocytic cells
- completely break down dead cells (autolysis)
- exocytosis (release enzymes to outside the cell to destroy material)
- digest worn out organelles for reuse of materials + break down pathogens
Mitochondria structure
- double membrane (Cristae inner membrane)
- mitochondrial matrix (fluid centre)
- loop of mitochondrial dna
Function of mitrochindra
Site of atp production & aerobic respiration
Dna there to code for enzymes needed in respiration
Ribosome function
Site of protein synthesis
Ribosome structure details
80s = large ribosomes in Eukaryotic cells
70s in prokaryotic cells / mitochondria / chloroplasts
They’re small and made up of 2 subunits of protein & rRNA
Chloroplast function
Site of photosynthesis
Chloroplast structure
Surrounded by double membrane
Found in plants
Fluid filled stroma contains enzymes for photosynthesis
Contains thylakoids (folded membranes with pigment)
Cell wall function
Provide structural strength to cells (plant & fungi)
Cell wall structure (plants vs fungi)
Plant cells = made up of microfibrils of the cellulose polymer
Fungi = made of chitin (nitrogen containing polysaccharide)
Cytoplasm function
Where metabolic reactions occur
Cell surface plasma membrane function and structure (short)
Phospholipid bilayer
Controls what exits & enters cell
Found in all cells
Production & secretion of proteins steps
- Polypeptide chains are synthesised on the RER
- These chains move to the cisternae in the RER and are packaged into vesicles to be sent to the Golgi apparatus via the cytoskeleton
- In the Golgi apparatus, proteins modified & packaged into the vesicles
- Secretory vesicles carry the proteins to the cell surface membrane where it fuses & releases the protein by exocytosis
What ribosomes make want proteins (e.g. intracellular vs extracellular proteins)
Free ribosomes = intracellular
Ribosomes in the RER = extracellular (2 be secreted by cell!)
Vacuole function
Maintains the turgidity of the cell
Contains selectively permeable tonoplast containing cell sap
How do prokaryotic cells differ from eukaryotic cells
- no nucleus or nuclear envelope
- 70s ribosomes
- no RER, vesicles, Golgi apparatus
- peptidoglycan cell wall
- reproduce via binary fission
- DNA not in nucleus / wound around histone proteins
How eukaryotic and prokaryotic cells are similar
Both have ribosomes and cytoplasms
Before protein synthesis what happens flow chart
Nucleus contains gene for protein
Protein transcribed in nucleus
MRNA produced
MRNA leaves nucleus through nuclear pores
Protein syntehssi (translation occurs at the RER)
