Anatomy of the Cell Flashcards
Which of these is essential to life: organelles or inclusions?
Organelles
What are the three main classes of filaments?
Microfilaments, intermediate filaments and microtubules (thick filaments)
What are microfilaments composed of?
Actin
What are microtubules composed of and are they polar or non polar?
Tubulin, polar
Which 2 proteins attach to and move along microtubules?
Kinesin and dynein
What class of enzymes are kinesin and dynein?
ATPases
What are kinesin and dynein important in?
Movement of cell components with long processes
What is the nucleus enclosed by?
Nuclear envelope
What is the nuclear envelope composed of?
Inner and outer membrane with nuclear pores
Is the outer or inner nuclear membrane studded with ribosomes?
Outer
What lies between the outer and inner nuclear membranes?
Perinuclear cistern
Where is mRNA transcribed?
Nucleus
Where is rRNA transcribed?
Nucleolus
Where is tRNA transcribed?
Nucleus
Give the names of 2 DNA which are contained in the nucleus and name the one with is undergoing transcription.
Euchromatin (undergoing transcription), neterochromatin
What is the RER studded with?
Ribosomes
Where are ribosomes formed?
Nucleolus
What are ribosomes made of and what do its parts do?
Small subunit (binds RNA) and large subunit (catalyses formation of peptide bonds)
Is the nucleus surrounded by a single or double membrane?
Double
What colour do ribosomes stain in H and E stained light microscope preparation?
Blue
What is the site of lipid synthesis?
Smooth ER
What does this describe? “Group of flattened, membrane bound cisternae in sub-compartments with transport vesicles arriving from the SER.”
Golgi Apparatus
Where are proteins which are to remain unpackaged in the cytosol synthesised?
Polysones
“Folded inner membrane in mitochondrion” - what does this describe?
Cristae
Do mitochondrion contain their own DNA for protein production?
Yes
Are lipid droplets surrounded by a membrane?
No
Are lipid droplets inclusions or organelles?
Inclusions
What are the three types of intracellular junctions and what do they do?
There are 3 types of junctions:
Occluding junctions: link cells to form a diffusion barrier.
Anchoring junctions: provide mechanical strength.
Communicating junctions: allow movement of molecules between cells.
What are occluding junctions also known as?
Tight junctions or zonula occludens
What do transmembrane cadherin molecules bind to?
Each other in the extracellular space, and, through link molecules, to actin of the cytoskeleton.
What do desmosomes do?
Link submembrane intermediate filaments of adjacent cells.
Where are desmosomes very common, and what time of intracellular junction are they?
Skin, anchoring
Link submembrane intermediate filaments of a cell to the extracellular matrix through transmembrane proteins - this describes what?
Hemidesmosomes
What are communicating junctions also termed?
Gap junctions
What produces the pores in communicating junctions?
connexon proteins
Where are gap junctions found?
epithelium, cardiac and smooth muscle,
