Histology: Anatomy of the Cell

Question 1

what is the composition of a cell (5)

Answer 1

• water
• protein
• lipid
• carbohydrate
• inorganic

Question 2

what type of cells have the most water

Answer 2

embryonic

Question 3

what does the cytoskeleton of a cell determine and what is it made of

Answer 3

• determines shape and fluidity

- made of thin, intermediate filaments and microtubules

Question 4

what are inclusions

Answer 4

other structures in the cytoplasm, may or may not be membrane-bound

Question 5

what kind of things are embedded in the phospholipid bilayer

Answer 5

cholesterol, integral and peripheral proteins

Question 6

what else is associated with a phospholipid (hydrophilic head, hydrophobic tail)

Answer 6

• glycerol (but this is interchangeable)

Question 7

function of mitochondria

Answer 7

energy production

Question 8

function of rough ER

Answer 8

protein synthesis

Question 9

function of smooth ER

Answer 9

cholesterol/lipid synthesis + detoxification

Question 10

function of golgi apparatus

Answer 10

modifications and packaging of secretions

Question 11

function of lysosomes

Answer 11

hydrolytic enzymes of intracellular digestion

Question 12

function of nuceus

Answer 12

contains genetic code

Question 13

are inclusions permenant /dispensable and are there for a long/short time

Answer 13

• dispensable

- short

Question 14

how might an inclusion appear in a cell

Answer 14

• synthesis by the cell

- taken in endocytotically

Question 15

what are examples of inclusions

Answer 15

glycogen, pigment, lipid droplets, presecretion product

Question 16

how do the different components of the cytoskeleton attach to the cell membrane and each other

Answer 16

anchoring and joining proteins

Question 17

describe the features of microfilaments

Answer 17

fine strands of actin that can associate and dissociate

Question 18

what do intermediate filaments do

Answer 18

bind intracellular elements together and to the cell membrane

Question 19

where are neurofilaments from

Answer 19

nerve cells

Question 20

where are glial fibrilliary acidic proteins from

Answer 20

glial cells of nervous systsem

Question 21

where are desmins from

Answer 21

muscle cells

Question 22

where are cytokeratins from

Answer 22

epithelial cells

Question 23

where are vimentins from

Answer 23

mesenchymal cells

Question 24

where are filasens from

Answer 24

lens of the eye

Question 25

where are lamins from

Answer 25

nucelus of all cells

Question 26

descibe the features of microtubules

Answer 26

hollow tubes of alternative alpha and beta tubulin subunits that can associate and dissociate

Question 27

where do microtubules originate

Answer 27

centrosome - MTOC

Question 28

what are MAPs and what is their function

Answer 28

microtubule associated proteins - stabilising

Question 29

what structures are microtubules important in

Answer 29

cilia, flagella and mitotic spindle

Question 30

what are kinesin and dyesin and their functions

Answer 30

motor ATPases that attach to and move microtubules but can also 'drag' organelles and vesicles whilst moving

Question 31

what way does kinesin move stuff

Answer 31

towards periphery of the cell

Question 32

what way does dyenin move stuff

Answer 32

towards centre of the cell

Question 33

what is at the core of the MTOC and what is the core made of

Answer 33

centrioles - made of specialised microtubule segments

Question 34

what is the nucleus enclosed by

Answer 34

an inner and outer nucleur membrane making a nuclear envelope

Question 35

what allows the nucelus to be continuous with the cytoplasm

Answer 35

nucleur pores

Question 36

what allows the nucleur membrane to be continuous with the rough ER

Answer 36

its studded with ribosomes

Question 37

what allows the nucleus to be continuous with the smooth ER

Answer 37

perinucleur cisterna - holes between the membranes to the ER/golgi

Question 38

where are mRNA and tRNA transcribed

Answer 38

nucleus

Question 39

where is rRNA transcribes

Answer 39

nucleolus

Question 40

what is the nucleolus

Answer 40

dense area in the nucleus

Question 41

what is the difference between euchromatin and heterochromatin

Answer 41

euchromatin is more dispersed and undergoing transcriptin whereas heterochromatin is more condensed and not undergoing transcription

Question 42

where are ribosomes formed and what are they made of

Answer 42

- nucleolus | - small subunit that binds DNA and a larger subunit that binds that catalyses peptide bond formation

Question 43

what is the ER

Answer 43

network of interconnecting membrane bound compartments

Question 44

what is a polysome

Answer 44

cluster of ribosoomes held together by a strand of mRNA undergoing translation by each ribosome

Question 45

describe the rough ER

Answer 45

studded with ribosomes and its amount in the cell varies with cell activity

Question 46

what is rough ER associated with

Answer 46

protein synthesis and glycoprotein formation initiation

Question 47

describe the process of protein synthesis

Answer 47

- free ribosome attaches to mRNA - ER signal peptide present, translation initiated and growing peptide inserted into a pore in rough ER - peptide forms in rough ER and signal sequence removes - ribosome detaches - most proteins go to smooth ER

Question 48

what occurs in the smooth ER

Answer 48

- continues proccessing proetins | - role in lipid synthesis

Question 49

what is the structure of the golgi complex

Answer 49

group of flattened membrane bound cisternae (discs) arranged into sub-compartments

Question 50

what are the functions of the golgi apparatus

Answer 50

- transports arriving vesicles from smooth and rough ER - modifies and packages macromolecules synthesis by ER - add sugars, cleave some proteins, sort into vesicles

Question 51

describe the layout of the mitochondria

Answer 51

- inner and outer membranes | - inner membrane is folded into christae to increase SA

Question 52

what are the fucntions of the mitochondria

Answer 52

- generates energy via oxidative phosphorylation | - synthesis some lipids and proteins

Question 53

describe mitochnodria DNA

Answer 53

circular and system for protein production

Question 54

what are the 3 types of intracellular junctions

Answer 54

- anchoring - communicating - occluding

Question 55

what do occluding junctions do and where are they found

Answer 55

- stop diffusion | - between adjacent cells

Question 56

what are the names for occluding junctions

Answer 56

zonula occludens/tight junctions

Question 57

what do zonula occludens do

Answer 57

join actin bundles of adjacent cells

Question 58

what do desmosomes do and what are they also known as

Answer 58

- join adjacent cells via submembrane intermediate filaments | - macula adherens

Question 59

where are macula adherens common and what do they do there

Answer 59

skin - mechanical stability

Question 60

what is a junctional complex and where are they found

Answer 60

close association of several types of junctions, found in certain epithelial tissues

Question 61

what do communicating junctions do and how do they do this

Answer 61

- allow selective diffusion between adjacent cells | - circular patch with pores allowing certain molecules through

Question 62

what are the pores in communicating junctions made from

Answer 62

connexon proteins

Question 63

what are communicating junctions also called and where are they found

Answer 63

- gap junctions | - epithelia, smooth and cardiac muscle

Question 64

what are the types of transport in/out a cell

Answer 64

- diffusion - transport proteins - vesicular transport (endocytosis/phagocytosis)

Question 65

how is endocytosis often mediated

Answer 65

receptors