Cell types and specialization Flashcards
What are the three key structural features of any cell?
1) Plasma membrane
2) Nuclear region (DNA)
3) Cytoplasm
What are some key features of prokaryotic cells?
No nucleus, little defined internal structures, unicellular and usually very small (between 0.5 and 2 micrometres in diameter)
What are some key features of eukaryotic cells?
Nucleus, more complex and specialized organelles, unicellular (yeasts/protozoa) or multicellular (animals/plants/fungi) with variable size (between 2 and 20 micrometres)
EUBACTERIA: Prokaryotic essential features
Plasma membrane, peptidoglycan cell wall and the genomic DNA is not separated from the cytoplasm.
What are the structural differences between Gram negative and Gram positive bacteria?
Gram positive only have an outer cell wall, whilst Gram negative have an extra outer lipopolysaccharide external membrane.
Gram negative bacteria have short fimbriae for attachment.
How do some bacterial cells show diversity?
1) Differences in cell shape
2) Appendages (flagella/pili/fimbriae)
3) Infoldings of he plasma membrane for photosynthesis (cyanobacteria)
ARCHAEA: Prokaryotic essential features
Similar to bacterial cells in size, shape, appendages and DNA
Unique cell shapes (branched/flat/square), distinct cell biochemistry, lack a peptidoglycan cell wall and mostly found as extremophiles
Essential features of eukaryotic cells
Plasma membranes, DNA found in the nucleus and present as chromosomes, compartmentalized cytoplasm with organelles and a complex cytoskeleton of microtubules and actin filaments for integrity.
What are some essential features of animal cells?
Nucleus, mitochondria, Golgi apparatus, endoplasmic reticulum, small vacuoles, 80s ribosomes, centrioles and a cytoskeleton
What are some essential features of plant cells?
Nucleus, mitochondria, Golgi apparatus, peroxisomes, endoplasmic reticulum, 80s ribosomes, a single large vacuole, chloroplasts, cytoskeleton and cellulose cell wall
What are protists?
Mainly unicellular eukaryotes with a flexible cell surface with a supportive pellicle and some contractive vacuoles.
What are fungi?
Unicellular yeasts or filamentous hyphae with multiple nuclei per compartment with a rigid chitin cell wall.
What are the common features shared by prokaryotic and eukaryotic cells?
Similar plasma membrane, genetic information encoded in DNA, similar mechanisms for transcription/translation, shared metabolic pathways, conserve energy in ATP, similar mechanism for photosynthesis and for the synthesis and inserting of membrane proteins and proteasomes of similar construction
What are the features only found in eukaryotes?
Nucleus (envelope/pores)
Chromosomes (histones)
Complex organelles (ER/Golgi /Lysosomes/Endosomes/Peroxisomes/Glyoxisomes)
Organelles for aerobic respiration and photosynthesis
Cytoskeleton, flagella and cilia
Mechanism for phagocytosis
Diploid genes/RNA polymerases/meiosis
How can cells differentiate and specialize?
Movement - external projections which undulate to cause movement = mostly in unicellular organisms
Signalling - nerve cells have a central body with terminal dendrites for long axon
Transport - RBC specialized for gas transport (lack of nucleus and organelles)
Reproduction - sperm cells have a flagellum to move towards the egg cell
