ch. 3 cellular form and function Flashcards

1
Q

inclusions

two kinds of inclusions

A

stored cellular products
* glycogen granules, pigments, fat droplets
foreign bodies
* viruses, intracellular bodies, dust particles, and other debris phagocytized by a cell

never enclosed in a unit membrane
NOT ESSENTIAL FOR CELL SURVIVAL

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2
Q

development of the cell theory 2

cell theory

A

all organisms composed of cells and cell products

cell is the simplest structural and functional unit of life

an organism’s structure and functions are due to activities of cells

cells come only from preexisiting cells

cells of all species exhibit biochemical similarites

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3
Q

cell shapes and sizes 1

about how many types of cells in human body with varied shapes

A

200

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4
Q

cell shapes and sizes 1

squamous

A

thin, flat, scaly

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5
Q

cell shapes and sizes 1

cuboidal

A

squarish looking

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6
Q

cell shapes and sizes 1

cuboidal

A

taller than wide

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7
Q

cell shapes and sizes 1

polygonal

A

irregulary angular shapes, multiple sides

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8
Q

cell shapes and sizes 1

stellate

A

star like

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9
Q

cell shapes and sizes 1

spheroid to ovoid

A

round to oval

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10
Q

cell shapes and sizes 1

discoid

A

disc shaped

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11
Q

cell shapes and sizes 1

fusiform

A

thick in middle tampered towards the ends

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12
Q

cell shapes and sizes 1

fibrous

A

thread-like

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13
Q

cell shapes and sizes 2

human cell size

A

most cells about 10-15 micrometers

ex. egg cells (very large) 100 micrometer diameter

some nerve cells over 1 meter long

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14
Q

cell shapes and sizes 2

human cell size limit on cell size

A

an overly large cell cannot support itself may rupture

for a given increase in diamete, volume increases more than surface area

volume proportional to cube of diameter
surface area proportional to square of diameter

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15
Q

basic components of a cell 2

plasma (cell) membrane

A

surrounds cell
defines boundaries

made of proteins and lipids

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16
Q

basic components of a cell 2

cytoplasm

A

organelles
cytoskeleton
inclusions (stored or foreign particles)
cytosol (ICF, intracellular fluid)

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17
Q

basic components of a cell 2

extracellular fluid (ECF)

A

fluid outside of cells includes tissue (interstitial) fluid

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18
Q

the plasma mebrane 1

plasma membrane

A

border of the cell

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19
Q

the plasma mebrane 1

plasma membrane appears as pair of

A

dark parallel lines when viewed with electron microscope

has intracellular and extracellular faces

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20
Q

the plasma mebrane 1

plasma membrane functions

A

defines cell boundaries

governs interactions with other cells

controls passage of materials in and out of cell

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21
Q

membrane lipids 1

98% of membrane molecules are

A

lipids

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22
Q

membrane lipids 1

phospholipids

A
  • 75% of membrane lipids are phospholipids
  • amphipatic molecules arranged ina bilayer
  • hydrophilic phosphate heads face water on each side of membrane
  • hydrophobic tails-are directed toward the center, avoiding water
  • drift laterally, keeping membrane fluid
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23
Q

membrane lipids 2

cholesterol

A
  • 20% of the membrane lipids
  • holds phospholipids still and can stiffen membrane
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24
Q

membrane lipids 2

glycolipids

A
  • 5% of the membrane lipids
  • phospholipids with short carb chains on extracellular face
  • contributes to glycocalyx-carb coating on cell surface
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25
Q

membrane proteins 1

membrane proteins

A

2% of the molcules but 50% of the weight of membrane

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26
Q

membrane proteins 1

integral proteins-penetrate membrane

A
  • transmembrane proteins pass completelt through
  • hydrophilic regions contact cytoplasm, ECF
  • hydrophobic regions pass through lipid of the membrane
  • some drift in membrane, others are anchored to cytoskeleton
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27
Q

membrane proteins 1

peripheral proteins

A
  • adhere to one face of the membrane (do not penetrate it)
  • usually tethered to the cytoskeleton
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28
Q

membrane proteins 2

functions of membrane proteins include

A
  • receptors
  • second messenger systems
  • enzymes
  • channels
  • carriers
  • cell-identity markers
  • cell-adhesion molecules
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29
Q

membrane proteins 3

receptors

A

bind chemical signals

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30
Q

membrane proteins 3

second messenger systems

A

communicate within cell receiveing chemical message

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31
Q

membrane proteins 3

enzymes

A

catalyze reactions including digestion of molecules production of second messagers

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32
Q

membrane proteins 3

channel proteins

A

allow hydrophilic solutes and water to pass through membrane

some are always open, some are gated
* ligand-gated channels-respond to chemical messengers
* voltage-gated channels-respond to charge changes
* mechanically-gated channels-respond to physical stress on cell

CRUCIAL TO NERVE AND MUSCLE FUNCTION

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33
Q

membrane proteins 4

carriers

A

bind solutes and transfer them across membrane
* pumps-carriers that consume ATP

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34
Q

membrane proteins 4

cell identity markers

A

glycoproteins acting as identification tags

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35
Q

membrane proteins 4

cell-adhesion molcules

A

mechanically link cell to extracellular material

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36
Q

second messengers

chemical first messenger (epinephrine) binds to a

A

surface receptor

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37
Q

second messengers

receptor activates G protein

A

an intracellular peripheral protein that gets energy from guanosine triphosphate (GTP)

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38
Q

second messengers

G protein relays signal to

A

adenylate cyclase which converts ATM to cAMP (second messenger)

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39
Q

second messengers

cAMP activates

A

cytoplasmic kinases

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40
Q

second messengers

kinases add phosphate groups to

A

other enzymes turning some on and others off

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41
Q

second messengers

up to 60% of drugs work through

A

G proteins and second messengers

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42
Q

the glycocalyx

fuzzy coat external to

A

plasma membrane
* carbohydrate moieties of glycoproteins and glycolipids
* unique in everyone but identical twins

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43
Q

the glycocalyx

functions

A
  • protection
  • immunity to infection
  • defense against cancer devlopment
  • transplant compatibility
  • cell adhesion
  • fertilization
  • embryonic
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44
Q

microvilli 1

extensions of membrane (1-2 micrometers)

A
  • gives 15-40 times more surface area
  • best developed in cells specialized in absorption
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45
Q

microvilli 1

on some absorptive cells they are very dense and appear as a fringe

A

“brush border”
some microvilli contain actin filaments that are tugges toward the center of cell to milk absorbed content into cell

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46
Q

cilia 1

cilia

A

hairlike processes 7-10 micrometers

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47
Q

cilia 1

single, nonmotile primary cilium found on nearly

A

every cell
* “anntenna” for monitoring nearby conditions
* helps with balance in inner ear: light detection in retina

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48
Q

cilia 1

multiple nonmotile cilia

A

found on sensory cells of nose

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49
Q

cilia 1

ciliopathies

A

defects in structure and function of cilia

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50
Q

cilia 1

motile cilia

A

respiratory tract
uterine tubes
ventricles of brain
ducts of testes

50-200 micrometers
beat in waves sweeping material across a surface in one diretion
power strokes followed by recovery strokes

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51
Q

cilia 2

axonene-core of motile cilium

A
  • has 9+2 structure of microtubules
  • two central microtubules surrounded by ring of nine pairs
  • ring of nine pairs anchors cilium to cell as part of basal body
  • dynein arms “crawl” up adjacent microtubule, bending the cilium
    uses energy from ATP
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52
Q

cilia 4

cilia beat freely within a saline layer at cell surface

A

chloride pumps pump into ECF
and follow
mucus floats on top of saline layer

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53
Q

cystic fibrosis

cystic fibrosis

A

hereditary disease in which cells make chloride pumps but fail to install them in the plasma membrane

chloride pumps fail to create adequate saline layer on cell surface

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54
Q

cystic fibrosis

thick mucus plugs

A

pancreatic ducts and respiratory tract

  • inadequate digestion of nutrients and absorption of oxygen
  • chronic respiratory infections
  • life expectanct of 30
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55
Q

flagella

tail of a sperm

A

only functional flagellum in humans

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56
Q

flagella

whip-like structure with axoneme identical to cilium’s

A
  • much longer than cilium
  • stiffened by coarse fibers that support the tail
57
Q

flagella

movement is undulating, snake like, corkscrew

A

no power stroke and recovery strokes

58
Q

pseudopods 1

pseduopods

A

continually changing extension of the cells that vary in shape and size

can be used for cellular locomotion, capturing foreign particles

59
Q

membrane transport

plamsa membrane is selectively permeable

A

allowing some things through but preventing others from passing

60
Q

membrane transport

passive mechanisms require no ATP

A
  • random molecular motion of particles provides necessary energy
  • filtration, diffusion, osmosis
61
Q

membrane transport

active mechanisms consume ATP

A

active transport and vesicular treatment

62
Q

membrane transport

carrier-mediated mechanisms uses a

A

membrane protein to transport substances across membrane

63
Q

Filtration

Filtration

A

Particles are driven through membrane by physical pressure

64
Q

Filtration

Filtration Ex

A

Filtration of water and small solutes through gaps in capillary walls

  • allows delivery of water and nutrients to tissues
  • allows removal of waste from capillaries in kidneys
65
Q

Simple Diffusion

Simple diffusion

A

Net movement of particles from a place of HIGH concentration to place of a LOWER concentration

  • due to constant, spontaneous molecular motion
  • molecules collide and bounce off each other
66
Q

simple diffusion

Substances diffuse ____ their concentration gradient

A

Down

  • does NOT require a membrane
  • substance can diffuse through a membrane if the membrane is permeable to the substance
67
Q

simple diffusion

factors affecting diffusion rate through a membrane

A
  • temp: temp increases, motion of particles increases
  • molecular weight: larger molecules move slower
  • steepness of concentrated gradient: difference increased rate increased
  • membrane surface area: increased area increased rate
  • membrane permeability: permiabilty increased rate increased
68
Q

osmosis

osmosis

A

net flow of water through a selectively permeable membrane
* water moved from the side where it (water) is MORE concentrated to the side where it is LESS concentrated
* solute particles that CANNOT pass through the membrane “draw” water from the other side

69
Q

osmosis

crucial consideration for

A

IV fluids

70
Q

osmosis

osmotic imbalances underlie

A
  • diarrhea
  • constipation
  • edema
71
Q

osmosis

water CAN diffuse through
________
but osmosis is enhanced by
________

A

phospholipid bilayers
aquaporins
* channel proteins in membrane specialized for water passage

cells can speed osmosid by installing more aquaporins

72
Q

osmosis

osmotic pressure

A

hydrostatic pressure required to stop osmosis
* increases as amount of nonpermeating solute rises

73
Q

osmosis

reverse osmosis

A

process of applying mechanical pressure to override osmotic pressure
* allows purification of water

74
Q

osmolarity and tonicity

one osmole (osm)

A

takes into account whether solute ionizes in water
* 1 M glucose is 1 osm/L
* 1 M NaCl is 2 osm/L

75
Q

osmolarity and tonicity

osmolarity

A

number of osmoles per liter of solution
* body fluids contain a mix of many chemicals and osmolarity is the TOTAL osmotic concentration of ALL solutes
* blood plasma, tissue fluis, and intracellular fluid are 300 miliiomoles per liter (MOsm/L

76
Q

osmolarity and tonicity

tonicity

A

ability of a surrounding solution (bath) to affect fluid volume and pressure in a cell
* depends on concentration of nonpermeating solutes

77
Q

osmolarity and tonicity

hypotonic solution

A

causes cell to absorb water and swell
* has a LOWER concentration of nonpermeating solutes than intracellular fluid (ICF)

78
Q

osmolarity and tonicity

hypertonic solution

A

causes cell to lose water and shrivel (crenate)
* has a HIGHER concentration of nonpermeating solutes than ICF

79
Q

osmolarity and tonicity

isotonic solution

A

causes NO change in cell volume
* concentration of nonpermeating solutes in bath and ICF are the SAME
* ex. normal saline (0.9% NaCl)

80
Q

effects of tonicity on RBCs

hypotonic, isotonic, and hypertonic solutions affect the

A

fluid volume of a RBS
* causes cell to shrivel and get swollen

81
Q

carrier-mediated transport

transport proteins in membrane carry solutes

A

into and out of cell (or organelle)

82
Q

carrier-mediated transport

specificity

A
  • transport proteins are specific for PARTICULAR solutes
  • solute (ligand) binds to receptor site on carrier protein
  • solute is released unchanges on other side of membrane
83
Q

carrier-mediated transport

saturation

A
  • as solute concentration rises the rate of transport RISES but only to a point (transport maximum (Tm)
    *

transport maximum- transport rate at which all carries are occupied

84
Q

carried-mediated transport

3 kinds of carriers

A

uniport
symport
antiport

85
Q

carrier-mediated transport

uniport

A

carries ONE type of solute
ex. calcium pump

86
Q

carrier-mediated transport

symport

A

carries TWO or MORE solutes simultaneously in same direction (cotransport)

ex. sodium-glucose transporters

87
Q

carrier-mediated transport

antiport

A

carries TWO OR MORE solutes in opposite direction (countertransport)

ex. sodium-potassium pump removes, brings in

88
Q

carrier-mediated transport

3 mechanisms of carrier-mediated transport

A

facilitated diffusion
primary active transport
secondary active transport

89
Q

carrier mediated transport

facilitated diffusion

A

carrier moves solute DOWN its concentration gradient
* does NOT consume ATP
* solute attaches to binding site on carrier, carrier changes conformation, then releases solute on other side of membrane

90
Q

carrier-mediated transport

primary active transport

A

carrier moves solute through a membrane up its concentration gradient
* the carrier protein uses ATP for energy
* ex. calcium pump (uniport) uses ATP whil expelling calcium from cell to where it is already more concentrated
* sodium-potassium pump (antiport) uses ATP while expelling sodium and importing potassium into cell

91
Q

carrier-mediated transport

the sodium-potassium pump
(-pump)

A
  • each pump cycyle consumes 1 ATP and exchanges 3 for 2
  • keeps concentration higher and concentration lower within the cell than in ECF
  • necessary because and constantly leak through membrane
    half of daily calories utilized for - pump
92
Q

carrier-mediated transport

  • pump functions
A
  • maintains steep concentration gradient allowing for secondary active transport
  • regulates solute concentration and thus osmosis and thus cell volume
  • maintains negatively charged resting membrane potential
  • PRODUCES HEAT
93
Q

carrier-mediated transport

secondary active transport

A

carrier moves solute through membrane but only uses ATP indirectly
* ex. sodium-glucose transporter (SGLT) (symport)
moves glucose into cell while simultansoult carrying sodium down its gradient
depends on the primary transport performed by - pump
does not itself use ATP

SGLTs work in kidney cells that have - pump at other end of cell
* prevents loss of glucose to urine

94
Q

vesicular transport

vesicular transport

A

moves large particles, fluid droplets, or numerous molecules at once through the membrane in vesicles- bubble-like enclosures of membrane

95
Q

vesicular transport

endocytosis

A

vesicular processes that bring material into cell

96
Q

vesicular transport

types of endocytosis

A

phagocytosis
pinocytosis
receptor-mediated endocytosis

97
Q

vesicular transport

phagocytosis

A

“cell eating” engulfing large particles
* psuedopods, phagosomes, macrophages

98
Q

vesicular transport

pinocytosis

A

“cell drinking” taking in droplets of ECF containing molecules useful in the cell
* membrane caves in then pinches off pinocytic vesicle

99
Q

vesicular transport

receptor-mediated endocytosis

A

particles bind to specific receptors on plasma membrane
* clathrin-coated vesicle

100
Q

vesicular transport

exocytosis

A

discharging material from the cell

101
Q

vesicular transport

utilizes motor proteins energized by

A

ATP

102
Q

vesicular transport

receptor-mediated endocytosis

A
  • more selective endocytosis
  • enables cells to take in speciffic molecules that bind to extracellular receptors
103
Q

vesicular transport

clathrin-coated vesicle in cytoplasm

A

uptake of LDL from blood stream

104
Q

vesicular transport

transcytosis

A
  • transport of material across the cell by capturing it one one side and releasing it on the other
  • receptor-mediated endocytosis moves it into the cell and exocytosis moves it out the other side
105
Q

vesicular transport

exocytosis

A
  • secreting material
  • replacement of plasma membrane removed by endocytosis
106
Q

cytoskeleton

cytoskeleton

A

network of protein filaments and cylinders
* determines cell shape, supports structure, organizes cell contents, directs movement of materials within cell, contributes to movements of the cell as a whole

composed of: microfilaments, intermediate fibers, microtubules

107
Q

cytoskeleton

microfilaments

A
  • 6 nm thick
  • made of actin protein
  • forms terminal web
108
Q

cytoskeleton

intermediate filaments

A
  • 8-10 nm thick
  • within skin cells made of protein keratin
  • give cell shape, resist stress
109
Q

cytoskeleton

microtubules

A
  • 25 nm thick
  • consist of protofilaments made of protein tubulin
  • radiate from centrocome; can come and go
  • maintain cell shape, hold organelles, act a railroad tracks for walkin motor proteins, makde axonemes of ciliar and flagells, form mitotic spindle
110
Q

Organelles

Internal structures of a cell, carry out

A

specialized
metabolic tasks

111
Q

organelles

Membranous organelles

A

Nucleus, mitochondria, lysosomes, peroxisomes,
endoplasmic reticulum, and Golgi complex

112
Q

organelles

Nonmembranous organelles

A

Ribosomes, centrosomes, centrioles, basal bodies

113
Q

the nucleus

nucleus

A

largest organells
* most cells have one nucleus
* a few cell types are anucler or multinucleate

114
Q

nucleus

nuclear envelope

A

double membrane around nucleus
* perforated by nucler pores formed by prings of proteins
regulate molecular traffic through envelope
hold the two membrane layers together

115
Q

nucleus

nuclear envelope is supported by

A

nuclear lamina
* web of protein filaments
* provides points of attachment for chromatin
* helps regualte cell life cycle

116
Q

nucleus

nucleoplasm

A

material in nucleus
* chromatin (thread-like) composed of DNA and protein
* nucleoli– masses where ribocomes are produced

117
Q

Endoplasmic Reticulum

endoplasmic reticulum

A

system of channels (cisterane) enclosed by membrane

118
Q

Endoplasmic Reticulum

rough endoplasmic reticulum

A

parallel, flattened sacs covered with ribosomes
* continuous with outer membrane of nuclear envelope
* produces phospholipids and proteins of the plasma membrane
* synthesizes proteins that are packaged in other organelles or secreted from cell

119
Q

Endoplasmic Reticulum

smooth endoplasmic reticulum

A
  • lack ribosomes
  • cisternar more tubular and branching
  • cisternar thought to be continous with rough ER
  • synthesizes steroids and other lipids
  • detoxifies alchol and other drugs
  • calcium storage
120
Q

Endoplasmic Reticulum

rough and smooth ER are functionally different parts of the same

A

network

121
Q

ribosomes

ribosomes

A

small granules of protein and RNA
* found in nucleoli, in cytocol and on outer surfaces of rough ER and nuclear envelope

they “read” coded genetic messgaes (messenger RNA) and assemble amino acids into proteins specified by the code

122
Q

golgi complex

golgi complex

A

a system of cisternae that synthesizes carbs and put finishing touches on protein synthesis
* receives newly synthesizes protein from rough ER
* sorts proteins, splices come, adds carbs moieties to some, and packages them into membrane-bound golgi vesicles

  • some vesicles become lysosomes
  • some vesicles migrate to plasma membrane and fuse to is
  • some become secretory vesicles that store a proteins product for later release
123
Q

lysosomes

lysosomes

A

package of enzymes bound by a membrane
* generally round but variable in shape

124
Q
A
125
Q

lysosomes

functions

A
  • intracellular hydrolytic digestion of proteins, nucleic acids, complex carbs, phospholipids, and other substances
  • autophagy: digestion of cell’s surplus organelles
  • autolysis: “cell suicide” digestion of a surplus cell by itself
126
Q

peroxisomes

peroxisomes

A

resemble lysosomes but contain different enzymes and are produced by endoplasmic reticulum

127
Q

peroxisomes

function is to use molecular oxygent to oxidize

A

organic molecules
* reaction produce hydrogen peroxide
* catalase breaks down excess peroxide to
* neutralize free radicals, detoxify alchol, other drugs, and a variety of blood-borne toxins
* break down fatty acids into acetyl groups for mitochondrial use in ATP synthesis

in all cells but abundant in liver and kidney

128
Q
A
129
Q

proteasomes

proteasomes

A

hollow, cylindrical organells that disposes of surplus proteins
* contain enzymes that break down tagged, targeted proteins into short peptides and amino acids

130
Q

mitochondria

mitochondria

A

organelles specialized for synthesizing ATP

continually change shape from spheroidal to thread-like

131
Q

mitochondria

surrounded by a double membrane

A
  • inner membrane has folds called cristae
  • spaces between cristae called matrix
    matrix contains ribosomes, enzymes uses for ATP synthesis, small circular DNA molecule
    mitochondrial DNA (mtDNA)
132
Q

mitochondria

“powerhouses” of the cell

A

energy is extracted from organic molecules and transferred to ATP

133
Q

evolution of mitochondrion

Mitochondria evolved from bacteria that invaded another primitive cell, survived in its cytoplasm, and became permanent residents.

A

– The bacterium provided inner membrane; host cell’s
phagosome provided outer membrane
– Mitochondrial ribosomes resemble bacterial ribosomes
– mtDNA resembles circular DNA of bacteria
– mtDNA is inherited through the mother
– mtDNA mutates more rapidly than nuclear DNA
* Responsible for hereditary diseases affecting tissues with high
energy demands

134
Q

centrioles

centriole

A

a short cynlindrical assembly of microtubles arranges in 9 groupd of 3 microtubules each

135
Q

centrioles

two centrioles lie perpendicular to each other within the

A

centrosome–small clear area in cell
* play important role in cell division

136
Q

centrioles

form basal bodies of cilia and flagella

A

each basal body is a centriole that originated in centriolar organizing center and then miggrated to the membrane

137
Q

inclusions

two kinds

A
  • stored cellular products
  • foreign bodies

  • never enclosed in a unit membrane
  • not essential for cell survival
138
Q

inclusions

stored cellular products

A

glycogen granules
pigments
fat droplets

139
Q

inclusions

foreign bodies

A

viruses
intracellular bacteria
dust particles
other debris phagocytized by a cell