Lecture 2

Question 1

plasma membrane

Answer 1

trilaminar, low res on lM, therefore, EM better. Trilaminar appearance is 1 layer of external membrane, 2nd layer is intermembranous tails and 3rd is internal membrane. Had lipid rafts (integral proteins) and non-lipid rafts. Diffusion, channels, carrier proteins and endo/exocytosis

Question 2

Cytoplasm

Answer 2

aqueous solution with some structure. where physiological processes take place

Question 3

nucleus

Answer 3

nuclear membrane, has pores contining DNA in the form of chromatins, nucleolus which contains rRNA

Question 4

Nucleoulus

Answer 4

non-membraneous region of nucleus, has rRNA, ribosome production and assembly. Can have multiple in one cell of different sizes

Question 5

chromatin

Answer 5

In nucleus. Nucleoprotein complex, basophollic (purple stain), DNA and proteins (histones). Usually see heterochromatins appear darker and indicate that the DNA is inactive. Euchromatins are less tightly wound and so, appear lighter and is easily transcribed. More euchromatin = more active

Question 6

Rough Endo R

Answer 6

basophillic staining, interconeccted, membrane-limited flattened sacs (cisternae). robosomes on membrane

Question 7

Ribosomes

Answer 7

Free or on RER (12-20nm), protein synthesis

Question 8

Smooth Endo R

Answer 8

Eosinophillic staining (pink), no associated ribosomes, tubular NOT sheet like (RER), lipid and steroid synthesis, membrane formation and recycling

Question 9

golgi apparatus

Answer 9

post-translation modification, stacked, flattened cisternae, vesicles, polarised. Need lots to be unstained as it shows up pale. Comes in cis face and out trans face packaged

Question 10

mitochondria

Answer 10

ATP production, moves around cell. Outer mitochondrial membrane, intermembrane membrane, inner mitochondral membrane (increases SA, folds produce cristae), matrox. Independednt from nucleus (has mDNA)

Question 11

microtubules

Answer 11

assemble and disassemble quickly. transport of vesicles, movement, cell division and migration

Question 12

centrioles

Answer 12

‘cell centre’, made up of 9 microtubule triplets. Occur in pairs

Question 13

microfilaments

Answer 13

Myosin and actin (thinner, shorter, more flexible than microtubules, assemble and disassemble quickly)

Question 14

intermediate filaments

Answer 14

structural role in cells (associated with cell-cell juntions), cytokeratines and vimetin stable therefore, doesn’t really assemble/disassemble