anatomy of cell

Question 1

common features of the cell

Answer 1

outer membrane, inner cytosol, cytoskeleton, organelles, inclusions

Question 2

plasma membrane

Answer 2

phospholipids. contains integral proteins. gives cell ability to exocytose and endocytos materials out of membrane

Question 3

inclusions

Answer 3

dispensable, may only be present as transients. represents components synthesised in cell itself or taken from extracellular environment

Question 4

what are cytoskeletons made of

Answer 4

set of filamentous cytosolic proteins

Question 5

3 classes of cytosolic proteins

Answer 5

microfilaments, intermediate, microtubules

Question 6

what are microfilaments

Answer 6

made of protein actin. actin molecules can assemble into filaments that can later dissociate. very dynamic

Question 7

intermediate filament

Answer 7

made of 6 proteins that vary in cell types. bind intracellular elements together and to membrane. more than 50 types

Question 8

what are microtubules

Answer 8

made of 2 tubulin proteins. hollow, originate from centrosome, include stabilising proteins (MAPs), can assemble and disassemble

Question 9

nucleus

Answer 9

contains chromosomes, mRNA and tRNA transcribed in nucleus, rRNA transcribed in nucleolus. contains euchromatin and heterochromatin

Question 10

euchromatin

Answer 10

DNA dispersed and actively undergoing transcription

Question 11

heterochromatin

Answer 11

DNA highly condensed and not active

Question 12

ribosomes

Answer 12

formed in nucleolus, important role in protein synthesis, each ribosome made of subunit that binds RNA. and a large unit that catalyses formation of peptide bonds

Question 13

ER

Answer 13

forms network of membrane bound compartments in cell. 2 types SER and RER

Question 14

RER

Answer 14

Studded w ribosomes, vital in protein synthesis, amount of RER varies in cell types

Question 15

SER

Answer 15

continues processing proteins, site of lipid synthesis, most cells contain little SER

Question 16

golgi

Answer 16

golgi manages modification and packaging of macromolecules synthesised in ER. Adds sugars, cleaves proteins

Question 17

mitochondria

Answer 17

composed of inner and outer membrane, inner folded to increase surface area. power generators of the cell. generate ATP, contain own DNA

Question 18

intercellular junctions

Answer 18

specialised membrane structures which link individual cells together into a functional unit, prominent in epithelia

Question 19

occluding junctions

Answer 19

link cells to form a diffusion barrier. known as tight junctions

Question 20

anchoring junctions

Answer 20

provide strength, link submembrane actin bundles of adjacent cells together. common in skin

Question 21

communicating junctions

Answer 21

selective diffusion of molecules between cells. pores are produced by connexon proteins. found in epithelia and some smooth muscle. known as gap junctions

Question 22

junctional complex

Answer 22

several types of junctions found in certain epithelial tissues

Question 23

transport in and out of cell

Answer 23

diffusion, transport proteins, incorporation into vesicles (vesicular transport)

Question 24

vesicular transport : endocytosis

Answer 24

material from outside can come in. cell membrane invaginates, fuses and newly made endosomes bud into cell. process is receptor mediated. exocytosis is opposite