Histology Quiz 1-Cytology

Front 1

unique feature of eukaryotic cells

Back 1

compartmentalized cytoplasm

Front 2

significance of membranes in eukaryotic cells (3)

Back 2

1. barrier between the cell and the external environment

2. subdivide cell into compartments

3. allow each type of organelle to maintain novel ionic and enzymatic interior environments

Front 3

three things membranes are composed of

Back 3

1. lipids
2. proteins
3. carbohydrates

Front 4

Can membranes be visualized in a light microscope? Why or why not?

Back 4

No.
1. Too thin (~7nm)
2. do not stain with H&E

Front 5

Can membranes be seen in an electron microscope?

Back 5

Yes, when stained with osmium tetroxide.

Front 6

Membrane lipids have _________ tails and __________ heads.

This makes them _________.

Back 6

uncharged, hydrophobic

polar, hydrophilic

amphipathic

Front 7

Because of their amphiphatic nature, membrane lipids form a lipid bilayer _____________.

Back 7

spontaneously

Front 8

The key to the organization of the membrane is the presence of the hydro______ center which acts as an ___________ to membrane proteins that can move within the lipid bilayer.

Back 8

phobic

anchor

Front 9

The membrane is highly permeable for ____________ that cross the membrane by simple diffusion.

Back 9

small, uncharged molecules

Front 10

2 different classifications of membrane protein structure

Back 10

integral and peripheral

Front 11

integral proteins

Back 11

Membrane proteins which have a hydrophobic region which is embedded into the hydrophobic core of the membrane

Front 12

transmembrane proteins

Back 12

integral membrane proteins that extend all the way through the membrane

Front 13

peripheral proteins

Back 13

not embedded within the lipid bilayer. (attach to integral proteins or hydrophilic heads of the membrane lipids)

Front 14

3 functional classifications of membrane proteins

Back 14

1. transport proteins
2. receptors
3. structural proteins

Front 15

transport proteins

Back 15

allow charged and polar molecules to enter cell and bypass impassible lipid bilayer

Front 16

3 types of transport proteins

Back 16

1. channel proteins
2. carrier proteins
3. pumps

Front 17

channel proteins

Back 17

form ores in the membrane which are either open or closed to certain molecules

Front 18

carrier proteins

Back 18

drag other molecules through the membrane by hiding them in cleft in the protein

Front 19

pumps

Back 19

use ATP energy to pump ions through the membrane

Front 20

receptor proteins

Back 20

bind to specific molecules in the extracellular matrix, resulting in conformational change that serves as a signal that allows the cell to adapt to its environment

Front 21

structural/anchoring proteins

Back 21

attach cell to its surroundings

use cytoplasmic domains to like to elements of the cytoskeleton

use extracellular domains to link to extracellular proteins

Front 22

carbohydrates

Back 22

oligosaccharides attached to extracellular domains of membrane proteins and lipids (glycoproteins & glycolipids)

Front 23

glycocalyx

Back 23

fuzzy coating visualized in electron microscope due to large amount of carbohydrates attached to proteins and lipids on the external surface of cells.

Front 24

ribosome

Back 24

RNA/protein particles

bring together mRNA and tRNA to synthesize a polypeptide

large and small subunit

Front 25

size of a ribosome

Back 25

15-25 nm

Front 26

3 types of ribosomes in eukaryotic cells

Back 26

1. free ribosomes
2. mitchondrial ribosomes
3. RER ribosomes

Front 27

free ribosomes

Back 27

majority of cellular proteins synthesized here

Front 28

RER ribosomes (4)

Back 28

proteins in
1. Golgi apparatus
2. lysosomes
3. secretory granules
4. plasma membrane

Front 29

mitochondrial ribosomes

Back 29

20% of mitochondrial proteins
(the rest synthesized on free ribosomes)

Front 30

polysomes

Back 30

string of ribosomes connected to single mRNA molecule

Front 31

glycogen

Back 31

storage form of polysaccharides

Front 32

endoplasmic reticulum

Back 32

series of membrane-formed anastomosin tubules and cisternae

Front 33

smooth ER

Back 33

no ribosomes, more tubular appearance

Front 34

functions of the smooth ER (4)

Back 34

1. lipid and steroid metabolism (membrane synthesis and recycling)
2. detoxification (well developed in liver cells, enzymes break down toxins)
3.glycogen metabolism
4.sarcoplasmic retculum (storage and transport of Ca 2+ in muscles, regulate contraction)

Front 35

rough ER

Back 35

ribosomes bound to surface, formed mostly of cisternae

Front 36

roles of the RER

Back 36

principle cite of synthesis of proteins destined for export out of the cell, into Golgi apparatus , lysosomes, and plasma membrane

Front 37

4 targets of RER protein synthesis

Back 37

1. out of the cell
2. Golgi apparatus
3. lysosomes
4. plasma membrane

Front 38

structure of Golgi apparatus

Back 38

series of stacked, flattened, membrane limited of POLARIZED cisternae and tubular extensions

Front 39

cis Golgi

Back 39

cisternae which receive vesicles from the RER

Front 40

medial Golgi

Back 40

middle cisternae

Front 41

trans Golgi

Back 41

cisternaefrom which the mature proteins are transported

Front 42

function of Golgi apparatus (3)

Back 42

postranslational
1. modification
2. sorting
3. packaging

of proteins

Front 43

modification of proteins in the Golgi

Back 43

adding/removing sugar residues, sulfate, phosphate groups

Front 44

location of protein modification in the Golgi

Back 44

early stages- cis Golgi
intermediate steps-medial Golgi
final modifications- trans Golgi

Front 45

location of sorting and packaging of proteins in the Golgi

Back 45

trans Golgi

Front 46

3 main destinations of proteins from Golgi

Back 46

1.secretory vesicles
2.lysosomes
3.constitutive pathway

Front 47

secretory vesicles

Back 47

vesicles which undergo maturartion process in which secretory proteins are retained within the vesicle.

mature secretory vesicles eventually fuse with the plasma membrane to release the secretory product into the extracellular space

Front 48

lysosomes

Back 48

spherical organelles of variable size produced by the Golgi, characterized by low pH and presnence of hydrolytic enzymes

digest senescent organelles and material take up from outside the cell

Front 49

hydrolytic enzymes found in lysosomes

Back 49

proteases, lipases, glucosidases

Front 50

mannose-6-phosphate

Back 50

principle sorting signal which direct proteins from the trans Golgi network to the lysosome

Front 51

I-cell disease

Back 51

mutation of enzymes that signal lysosome maturation causing lysosomal proteins to be secreted into the intercellular space

Front 52

3 types of lysosomes

Back 52

1.primary lysosomes
2.secondary lysosomes.phagosome
3.lupofuscin granules

Front 53

primary lysosome

Back 53

lysosomes which have not yet received substrates for digestion

Front 54

secondary lysosomes

Back 54

(phagosomes)
fusion of primary lysosome with target

Front 55

lupofuscin granules

Back 55

(residual bodies)
senescent, non-functioning lysosomes with indigestible material

Front 56

constitutive pathway

Back 56

small vesicles which are transported directly to the plasma membrane because they are not destined for lysosomes or secretory granules

Front 57

examples of proteins in consitutive pathway

Back 57

integral membrane proteins, continuosly secreted proteins

Front 58

peroxisomes

Back 58

0.5 µm, small membrane bound organelles containing catalase and other oxidative enzymes used to oxidize a wide range of organic substances such as very long fatty acids to convert ethanol to acetaldehyde.

Front 59

catalase

Back 59

oxidative enzyme, breaks down long chain FAs.

degrades toxic hydrogen peroxide, a byproduct of oxidation

Front 60

Lysosomes and peroxisomes have ________ precursors.

Back 60

different

Front 61

adrenoleukodystrophy

Back 61

inherited X-linked disorder
accumulation of lipid in brain/adrenals
progressivebrain damage, failure of adrenal glands, death

Front 62

Zellweger syndrome

Back 62

congential disease
mtations in proteins responsible for transport of peroxisomal enzymes from cytoplasm --> nonfunctioning peroxisomes

improper formation of myelin sheath, affect brain development, die before 6 mo age

Front 63

mitochondria

Back 63

produce ATP through oxidation of pyruvate and FAs
present in virtually all cells, esp. where large amounts of energy are used

Front 64

cells which do not contain mitochondria

Back 64

red blood cells and terminal keratinocytes

Front 65

evidence of symbiosis theory of mitochondria

Back 65

1. contain seperate genome
2. posses dual membrane
3.increase number by division

Front 66

mitochondrial matrix

Back 66

space enclosed within inner mitochondrial membrane

Front 67

Mitochondria are able to....

Back 67

migrate from one area of the cell to another to supply energy where needed.

Front 68

outer mitochondrial membrane

Back 68

contacts the cytoplasm on outer side
contacts intermembrane space on inner side
contains pores/anion channels which allow passage of small molecules, proteins, ions, etc

Front 69

inner mitochondrial membrane

Back 69

thinner than outer membrane
highly folded into cristae
contains many enzymes involved in energy production

Front 70

composition of intermembrane space

Back 70

pH and ionic composition similar to cytoplasm
protein composition is unique, enzumes that use ATP are generated here
cytochrome C located here

Front 71

cytochrome C

Back 71

initaites apoptosis

Front 72

mitochondrial matrix

Back 72

enclosed in inner mitochondrial membrane
contains soluble enzymes for Krebs cycle, DNA/RNA transcription/translation

mitochondrial DNA, ribosmes and RNAs

electron dense granules

Front 73

electron dense granules

Back 73

store Ca 2+, reflect role in metabolism of ions

Front 74

Approximately ______ of the proteins involved in oxidative phosphorylation are encoded by mitochondrial DNA.

Back 74

1/5

(Therefore mitochondrial myopathies [ex. lactic acidosis, cardiomyopathy] can have nuclear OR mitochondrial origin.)

Front 75

nucleus

Back 75

5-10 µm
large membrane bound
contains genome

Front 76

chromatin

Back 76

DNA bound to histones

Front 77

nuclear envelope

Back 77

consists of two membranes, perinuclear space between them, nuclear lamina and nuclear pores

Front 78

outer nuclear membrane

Back 78

closely resembles the membrane of the RER, continous with chambers of the RER
ribosomes attached to cityplasmic surface

Front 79

perinuclear space

Back 79

continous with lumen of RERE. can transport proteins fro RER to nucleus.

Front 80

inner nuclear membrane

Back 80

distinct ability to bind chromatin and lamins, supporetd by rigid network of intermediate filaments

Front 81

lamin

Back 81

provides stability, intermediate filaments, form dense meshwork beneath nucleus

***DISASSEMBLE during mitosis, reassemble after mitosis

Front 82

nuclear lamina

Back 82

thin, protein-dense layer, represents skeleon of nucleus formed by lamins

Front 83

nuclear pores

Back 83

70-80 nm openings through nuclear envelope, allow communication between cytoplasm and nucleus via <9nm particles

complex structure with protein spokes projecting into lumen of the more to the central plug

Front 84

nucleosomes

Back 84

smallest unit of chromatin, consists of 8 histones (2 each of H2A, H2B, H3, H4) and 166 DNA base pairs

Front 85

beads on a string

Back 85

nucleosomes joined by 48 bp DNA segment link

fiber = 11 nm = basic level of DNA packaging

Front 86

intermediate level of DNA packaging

Back 86

30 nm fiber

Front 87

euchromatin

Back 87

loosely packed, lightly stained, transcriptionally active DNA found in metabolically active cells such as neurons

Front 88

heterochromatin

Back 88

densely packed, dark staining, transcriptionally inactive DNA found in metabolically inactive cells

Front 89

3 main locations of heterochromatin

Back 89

1. periphery of nucleus, marginal heterochromatin is attached to the nuclear membrane
2.karyosomes
3. in association with nucleolus

Front 90

karyosome

Back 90

discrete body of chromatin irregular in shape and size, found throughout nucleus

Front 91

chromosomes

Back 91

condensed and organized chromatin found in dividing cells

Front 92

centromere

Back 92

place where two chromatids of a chromosomes are joined together

Front 93

kinetochore

Back 93

place where each chromosome becomes attached to the microtubles of the mitotic spindle

formed on the centromere

Front 94

nucleolus

Back 94

small area within nucleus in which ribosomal RNA is processed and assembled into ribosomal subunits

Front 95

3 morphologically distinct regions of nucleolus

Back 95

1.fibrillar centers
2. dense fibrillar component (pars fibrosa)
3. granular component (pars granulosa)

Front 96

fibrillar centers

Back 96

contain DNA loops with rRNA genes and transcription factors

Front 97

dense fibrillar component

Back 97

(pars fibrosa)
contains riboslmal genes thate rae being translated and large amounts of RNA

Front 98

granular component

Back 98

(pars granulosa)
site for ribosome assembly, made of densely packed custers of pre-ribsomal particles/partially assembled subunits

Front 99

3 functions of cytoskeleton

Back 99

1. determines shape of cells
2. provides structural support for organelles
3.plays a major role in cell motility (esp. in mitosis and cytokinesis)

Front 100

3 major types of cytoskeleton filaments

Back 100

1.actin filaments
2.microtubules
3. intermediate filaments

Front 101

actin filaments

Back 101

thin (6 nm), + and - ends, mostly found in periphery

Front 102

3 roles of actin filaments

Back 102

1.cell movement
2.cell shape
3. organelle transport

Front 103

2 forms of actin

Back 103

1. G-actin
2. F-actin

Front 104

G-actin

Back 104

soluble monomeric globular protein, can polymerize into F-actin, polymerization occurs head to tail

Front 105

F-actin

Back 105

double-stranded helical filament
has head to tail polarity
grows faster on one end
direction allows for motor protein to travel
spontaneous assembly at + end, dissassembly at - end gives effect of movement

Front 106

Actin filaments are also known as

Back 106

thin filaments

Front 107

2 functions of actin/thin filaments

Back 107

1. cortex formation
2. myosin interaction

Front 108

cytoplasmic cortex

Back 108

actin filaments form a thin sheath beneath the cytoplasm

Front 109

5 functions of the cytoplasmic cortex

Back 109

crosslined actin filaments
1. resist cell deformation
2.transmit forces
3. restrict movement of organelles
4. reinforce plasma membrane
3. restrict lateral motion of integral membrane proteins

Front 110

myosin

Back 110

interacts with actin to generate force and movement. (motor associated with thin filaments)

Front 111

microtubules

Back 111

cytoskeletal elements present in all cells (except erythrocytes)

Front 112

3 functions of microtubules

Back 112

1.organelle and vesicle movement (sometimes over long distances, ie. neuron)

more transport = more microtubules

2.mitotic spindle and chromosome movement
3.beating of cilia and flagella (proteins manipulate microtubules --> movement)

Front 113

structure of microtubules

Back 113

stiff, non-branching,cylindrical polymers, made of a-tubulin and ß-tubulin, polymerized side to side and head to tail ---> plus and minus end ---> can have transport

Front 114

Plus end of microtubules associated with

Back 114

cell periphery

Front 115

Minus end of microtubules associated with

Back 115

centriole/ microtubule-organizing center

Front 116

2 types of microtubule motor proteins

Back 116

1. dyneins
2. kinesins

Front 117

function of microtubule motor proteins

Back 117

use ATP energy to generate force that moves the motor and materials attached to it along the microtubule

Front 118

Dyneins (involved in beating of cilia and flagella) move toward the ______ end of the microtubule.

Back 118

minus

Front 119

Kinesins move toward the ______ end of the microtubule.

Back 119

plus

Front 120

4 higher order structures of microtubules

Back 120

1.cilia
2.flagella
3.centrioles
4.microtubule-organizing centers

Front 121

axoneme (structure)

Back 121

core of cilia and flagella, composed of 9 doublets and a central pair of microtubles

Front 122

axoneme (function)

Back 122

generates force for the movement of cilia and glagella (dynein arm grabs from one doublet to the other)

Front 123

centriole (basal body)

Back 123

found at the base of each cilium or glagellum, composed of microtubles arranged into 9 triplets WITHOUT THE CENTRAL PAIR

Front 124

microtubule-organizing center (MTOC)

Back 124

consists of two centrioles, virtually all cellular microtubules arise from the MTOC, most human cells contain MTOC
(not neurons and red blood cells which ar e incapable of division)

Front 125

function of intermediate filaments

Back 125

strong bu flexible polymers that provide mechanical support for cells

Front 126

Why don't intermediate filaments have motor proteins associated with them?

Back 126

They do not have polarity.

Front 127

Lamins

Back 127

(Nucleus)
form a meshwork of filamens on the inner side of the nuclear envelope, where they form the nuclear lamina and provide structural support for the nucleus

Front 128

keratins

Back 128

(epithelial cells)

Front 129

vimentin

Back 129

(connective tissue)

Front 130

desmin

Back 130

(muscle cells)

Front 131

glial fibrillary acidic protein (GFAP)

Back 131

(support cells of glial cells)

Front 132

4 functions of intermediate filaments:

Back 132

form bndles between the plasma membrane and nucleus to
1.spread tensile forces
2.maintain cell architecture
3.act as a cocoon when cell is damaged
4.anchor ion channel proteins