Chapter 4: Biology of the Cell Flashcards Preview

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Flashcards in Chapter 4: Biology of the Cell Deck (310):
1

What are the functions of Rough ER?

Production of proteins
Formation of transport vehicles
Storage of proteins to be exported from the cell

2

Which of the following describe the general functions of the cell. Choose all that apply.

Dispose of wastes
Maintain shape of the cell
Obtain nutrients

3

Sodium diffusion into the cells occurs _____ to the loss of K+.

before

4

Cells usually die by one of the two mechanisms: chemical/mechanical damage or _____.

apoptosis

5

The two types of organelles found in cells are _____ and _______.

membrane bound
non-membrane bound

6

Both Na+ and K+ are pumped by the Na/K pumps _______ their concentration gradients in maintaining the resting membrane potential.

up

7

Old or worn out organelles in a cell are removed by what organelle?

lysosomes

8

_____ junctions allow small solutes to travel between adjacent cells.

Gap

9

Where might you find tight junctions in the body?

urinary bladder
small intestine

10

The replication of the DNA molecule during Interphase occurs during the ______ phase.

S Phase
or synthesis

11

Peroxisomes break down harmful substances including:

hydrogen peroxide
alcohol
fatty acid molecules

12

Also called intracellular fluid

cytosol

13

It contains many solutes, proteins and carbohydrates.

cytosol

14

Cytosol has a high ____ content.

water

15

A codon can code for:

an anticodon of mRNA

16

True or False:
Peroxisomes are usually smaller in diameter than lysosomes.

True

17

Bulk transport refers to the movement of macromolecules across a selectively permeable membrane are two categories of bulk transport mechanisms, _____ and ______.

endocytosis
exocytosis

18

DNA double helix wound around a cluster of histones

Nucleosome

19

finely filamented mass of DNA and protein

chromatin

20

become visible only when the cell is dividing

chromosomes

21

Internally, cilia and flagella contain cytoplasym and ______. They are enclosed in the plasma membrane.

microtubules

22

the study of cells

cytology

23

the use of a microscope to view small-scale structures

microscopy

24

produces a two dimensional image by passing visible light through the specimen.

light microscope (LM)

25

a beam of electrons to "illuminate" the specimen - high resolution

electron microscope (EM)

26

directs and electron beam through a thin-cut section of the specimen resulting in a 2 dimensional image focused onto a screen for viewing or onto photographic film.

TEM or transmission electron microscope

27

For detailed three-dimensional study of a specimen's surface

scanning electron microscope (SEM)

28

the electron beam is moved across the surface of the specimen, and reflected electrons generate a surface-topography image captured on a television screen.

scanning electron microscope (SEM)

29

Most cells are microscopic in size, but some are large enough to be seen with the _____.

naked eye

30

the shape of red blood cells

bioconcave disc

31

A relationship exists between the size and shape of a cell and its _____ in the body.

function

32

teh cell membrane that forms the outer, limiting barrier separating the internal contents of the cell from the external environment.

plasma membrane

33

Modified extensions of the plasma membrane include ____, _____, and _____.

cilia
flagellum
microvilli

34

the largest structure within the cell and is enclosed by a nuclear envelope.

nucleus

35

much of the internal content of the nucleus is the _______, ______.

genetic material, deoxribonucleic acid (DNA)

36

the fluid of the nucleus

nucleoplasm

37

all cellular contents located between the plasma membrane and the nucleus

cytoplasm

38

The three primary components of the cytoplasm are the ____, ______, and _____.

cytosol
organelles
inclusions

39

Also called the intracellular fluid (ICF)

cytosol

40

Is the viscous, syruplike fluid of the cytoplasm.

cytosol

41

means little organs

organelles

42

complex, organized structures within cells that have unique characteristics shapes and functions

organelles

43

Two categories of organelles

non-membrane-bound
membrane-bound

44

The cytosol of some cells temporarily stores _____.

inclusions

45

are not considered organelles, but are rater aggregates (clusters) of a single type of molecule

inclusions

46

The general functions of the cell.

maintain integrity and shape of a cell obtain nutrients and form chemical building blocks
dispose of wastes

47

The plasma membrane contains several different types of lipids including ______, _____, _______.

phospholipids
cholesterol
glycolipids

48

Most of the plasma membrane lipids are _____.

phospholipids

49

The basic structure of the plasma membrane frame work is called the _______.

phospholipid bilyaer

50

The phospholipid bilayer ensures that _____ remains inside the cell, and interstitial fluid remains ______.

cytosol
outside

51

Scattered within the hydrophobic regions of the phospholipid bilayer.

cholesterol

52

Cholesterol ______ the membrane and stabilizes it at ______ extremes.

strengthens
temperature

53

Lipids with attached carbohydrate groups that are located only on the outer phospholipid layer of the membrane, exposed to interstitial fluid.

glycolipids

54

the carbohydrate portion of the glycolipid molecules and the glycoprotein molecules help to form the _____.

glycolax

55

Only ____ and _____ substances can readily penetrate the plasma membrane.

small and nonpolar

56

Cholesterol is a component of plasma membranes found only in _____ cells, not in plant cells.

animal

57

Lipids form the main component of the plasma membrane, the proteins dispersed within the lipids make up about ______ of the plasma membrane by weight.

half

58

2 types of membrane proteins

integral or peripheral

59

_________ are embedded within, and extend across, the phospholipid bilayer.

integral proteins

60

Many integral membrane proteins are ______ that are carbohydrates exposed to the interstitial fluid.

glycoproteins

61

________ are not embedded within the lipid bilayer and are attached loosely either to the external or internal surfaces of the membrane and are often "anchored" to the exposed parts of an integral protein.

peripheral proteins

62

Membrane proteins are also categorized functionally based upon the ______ they serve.

specific role

63

Provide a means of regulating the movement of substances across the plasma membrane.

transport proteins

64

What are the different types of transport proteins?

channels
carriers
pumps
symporters
antiporters

65

__________ bind specific molecules that are called ligands.

cell surface receptors

66

molecules that bind to macromolecules.

ligands

67

An example of a cell surface receptor is a ligand is a ________ released form a nerve cell that binds to the cell surface receptor of a muscle cell to initiate contraction.

neurotransmitter

68

_____ communicate to other cells that they belong to the body.

identity markers

69

Cells of the immune system use identity markers to distinguish _____, healthy cells from foreign, _____, or infected cells that are to be destroyed.

normal
damaged

70

_______ may be attached either to the internal or external surface of a cell for catalyzing chemical reactions.

Enzymes

71

________ secure the cytoskeleton (the internal, protein support of a cell) to the plasma membrane.

Anchoring sites

72

_____________ are for cell-to-cell attachments in which proteins form membrane junctions perform a number of functions including binding cells to one another.

Cell-adhesion proteins

73

The __________ serves as the physical barrier between a cell and the fluid that surrounds it call the interstitial fluid.

plasma membrane

74

The plasma membrane regulates movement of materials into and out of a cell through __________, establishes and maintains electrochemical gradients across the plasma membrane, functions in cell communication.

membrane transport

75

Obtaining and eliminating substances across the plasma membrane occur through several different processes that are collectively called _________.

membrane transport

76

Membrane transport is divided into 2 major categories based upon the requirement for expending cellular energy.

passive processes
active processes

77

This form of transport does not require cellular energy and depends upon the kinetic energy inherent within a substance as it moves down its concentration gradient.

passive process

78

__________ differ because they require cells to expend energy that involves either a substance being pumped up its concentration gradient or the release of a membrane-bound vesicle.

active processes

79

The 2 major energy requiring processes of transport.

active transport
vesicular transport

80

The net movement of a substance from where it is more concentrated to where it is less concentrated is called ____.

diffusion

81

Diffusion, if unopposed, occurs until the substance reaches _______.

equilibrium

82

The rate that substances diffuse is not constant, but is dependent upon environmental condition including _______ and _______.

the "steepness" of it concentration gradient
temperature

83

Steepness of a concentration gradient is a measure of the difference in concentration of a substance between _____. A faster rate of diffusion occurs with a _______ concentration gradient.

two areas
steeper

84

When the ____ is higher, there is a greater random movement of the molecules and ions composing a substance, resulting in a faster rate of diffusion.

temperature

85

Solutes that are ____ and _____ move into or out of a cell down their concentration gradient by simple diffusion.

small
nonpolar

86

The molecules that are transported through simple diffusion do not require a _______.

transport protein

87

What moves through simple diffusion

O2
C02
small nonpolar fatty acids
ethanol
urea

88

Small solutes that are charged or nonpolar are effectively blocked from passing through the plasma membrane by the nonpolar phopholipid bilayer and must be transported by plasma membrane proteins.

transport via facilitated diffusion

89

2 types of facilitated diffusion

channel mediated diffusion
carrier mediated diffusion

90

the movement of small ions across the plasma membrane through water filled protein channels.

channel-mediated diffusion

91

Each channel is typically specific for one type of ion. there are 2

leak and gated channels

92

a continuously open channel mediated diffusion

leak channel

93

a channel that is closed, opens only in response to a stimulus and then stays open for just a fraction of a second before it closes.

gated channel

94

Channel mediated diffusion is important in the normal function of both ______ and ____ cells.

muscle and nerve

95

The movement of small polar molecules, such as simple sugars or amino acids that are assisted across the plasma membrane by a carrier protein.

carrier mediated diffusion

96

_______ transport substances such as glucose across the plasma membrane.

carrier proteins

97

A carrier protein moves a substance _____ its gradient.

down

98

A carrier protein that transports only one substance.

uniporter.
glucose carriers are uniporters

99

The number of channels and carriers in a plasma membrane determines the maximum rate at which a substance can be ______.

transported

100

A cell can alter the transport rate of a given substance down its concentration gradient by changing the number of __________ in the plasma membrane.

channel or carrier proteins

101

Osmosis is unlike the other types of passive membrane transport, because it involves _____ movement and does not involve the movement of solutes.

water

102

Osmosis is a _______ movement of water through a _____ membrane.

passive
selectively permeable

103

The plasma membrane is a selectively permeable membrane that allows the passage of water, but is phospholipid bilayer ______ the movement of most solutes.

prevents

104

Water molecules cross the plasma membrane in one of two ways:

They either "slip between" the molecules of the phospholipid bilayer or they move through integral protein water channels

105

water molecules that cross the plasma membrane through integral protein water channels called ______ during osmosis.

aquaporins

106

Cells can alter the amount of water that crosses the plasma membrane by changing the number of ______.

aquaporins

107

In the context of osmosis, solutes are classified into two categories based upon whether their passage across the plasma membrane is prevented by the phospholipid bilayer.

permeable
non permeable

108

solutes pass through the bilayer

permeable solutes
i.e. small and nonpolar solutes

109

solutes that are prevented from crossing the bilayer.

non-permeable solutes
i.e. charged, polar, or large solutes

110

When a solute concentration exists, a water concentration _______.

also exist

111

A solution with a greater concentration of solutes contains a lower concentration of ______ .

water

112

The net movement of water by osmosis is dependent upon the concentration gradient between the ______ and the solution in which the cell is immersed.

cytosol

113

Water moves toward the solution with the lower ______ concentration.

water

114

the pressure exerted by the movement of water across a semipermeable membrane due to a difference in solution concentration.

osmotic pressure

115

In osmotic pressure, the steeper the gradient, the ____ amount of water moved by osmosis and the higher the osmotic pressure.

greater.

116

the pressure exerted by a fluid on the inside wall of its container

hydrostatic pressure

117

the ability of a solution to change the volume or pressure of the cell by osmosis is called _____.

tonicity

118

both the solution and the cytosol have the same relative concentration of solutes.

isotonic

119

the solution has a lower concentration of solutes, and there is a higher concentration of water than in the cytosol.

hypotonic.
i.e. pure water

120

if the difference in concentration is large enough the cell can rupture or _____.

lysis

121

the specific term for rupturing erythrocytes

hemolysis

122

solution has a higher concentration of solutes, and thus a lower concentration of water than in the cytosol.

hypertonic

123

If the difference in concentration is large, the cell shrinks, a process called _____.

crenation
i.e.e this prevents us from being able to replace fluid by drinking seawater.

124

Active processes of membrane transport are those that require the expenditure of _____.

cellular energy

125

Active processes are organized into _____ and _____.

active transport
vesicular transport

126

The movement of a solute against its concentration gradient (from low to high concentration) across a cellular membrane.

active transport

127

Active processes are responsible for maintaining concentration gradients between the ____ of a cell and _____.

cytosol
interstitial fluid

128

The _____ source of energy for active transport determines whether the movement is called primary active transport or _____ active transport.

direct
secondary

129

_______ transport uses energy derived directly from the breakdown of ATP.

primary active

130

The addition of a phosphate to a protein is called _____.

phosphorylation

131

Cellular protein pumps that move ions across teh membrane are more specifically called _____.

ion pumps

132

Ion pumps are a major factor in a cell's ability to _____ its internal concentrations of ions.

maintain

133

An _____ pump moves one type of ion into a cell against its concentration gradient, while moving another type of ion out of the cell against its concentration gradient.

exchange

134

The sodium-potassium pump is a type of _____ pump, because it move Na+ out of the cell and K+ into the cell.

exchange

135

___ Na+ ions are pumped out of the cell for every ____ K+ ions that are pumped into the cell.

three
two

136

Secondary active transport is also called _________ or coupled transport.

cotransport

137

In secondary active transport a substance moves against its concentration gradient using energy provided by the movement of a ________ substance down its specific concentration gradient.

second

138

If two substances are moved in the same direction, these transport proteins are called.

symporters

139

If the two substances are moved in opposite directions, then the transport proteins are called ______.

antiporters

140

The Na+ concentration gradient has potential energy that is harnessed as Na+ moves down its concentration gradient in _____ transport.

secondary ative

141

Vesicular transport is also called ______ transport.

bulk

142

Vesicular transport is organized into processes of ______ and ________.

exocytosis
endocytosis

143

It involves energy input to transport large substances (or large amounts of a substance) across the plasma membrane by a vesicle.

vesicular transport or
bulk transport

144

The means by which either large substances or large amounts of substances are secreted from the cell.

exocytosis

145

The cellular uptake of large substances or large amounts of substances from the external environment into the cell

endocytosis

146

What are the three types of endocytosis?

phagocytosis
pinocytosis
receptor-mediated endocytosis

147

How are the different types of endocytosis differentiated?

based upon the specific material being transported and the mechanism involved.

148

means cellular eating

phagocytosis

149

means false feet

pseudopodia

150

a nonspecific process that occurs when a cell engulfs or captures a large particle external to the cell by forming membrane extensions that are called pseudopodia.

phagocytosis

151

Only a few types of cells are able to perform ______.

phagocytosis

152

known as cellular drinking

pinocytosis

153

process occurs when the cell internalizes droplets of interstitial fluid that contain dissolved solutes.

pinocytosis

154

uses receptors on the plasma membrane to bind molecules within the interstitial fluid and bring the molecules into the cell.

receptor-mediated endocytosis

155

Receptor mediated endocytosis enables the cell to obtain bulk quantities of certain substances, even though those substances may not be very ________ in the interstitial fluid.

concentrated

156

The transport of cholesterol from the blood to a cell is an example of ________.

receptor-mediated endocytosis

157

The _______ also functions in establishing and maintaining an electrochemical gradient at the plasma membrane called the _____________.

plasma membrane
resting membrane potential (RMP)

158

Cells have an electrical charge ______ at the plasma membrane.

difference

159

The electrical charge difference represents ________ and thus is appropriately called the membrane potential.

potential energy

160

The membrane potential when a cell is a rest is more specifically called _____.

the resting membrane potential (RMP)

161

Two conditions for establishing and maintaining a RMP

an unequal distribution of ion and molecules across the plasma membrane
the relative amounts of positive and negative charges are not equally distributed at the plasma membrane

162

Cell types vary in the specific value of their resting membrane potential, which typically range between -50 millivolts and ____ mV.

-100

163

Neurons have a RMP of _____.

-70 mV

164

The net movement of each of these (Na+ and K+) is dependent upon both the number of its ____ channels and the ____ gradient, which is the combination of the electrical gradient at the plasma membrane.

leak channels
electrochemical gradient

165

_______ diffusion is the most important factor in establishing the specific value of the resting membrane potential.

Potassium

166

Movement of K+ is dependent upon its __________.

elctrochemical gradient

167

Potassium ions exit the cell through K+ leak channels moving down their relatively _____ chemical concentration gradient from the cytosol into the interstitial fluid.

steep

168

The movement of K+ to the outside of a cell, however, opposed by the ______.

electrical gradient.

169

Sodium diffusion into cells occurs ______ the loss of K+, and is also dependent upon its electrochemical gradient.

before

170

Sodium ions enter the cell through Na+ leak channels moving _____ their chemical concentration gradient from the interstitial fluid into the cytosol.

down

171

The _____ pumps are significant in maintaining the gradients of both K+ and Na+ following their diffusion.

Na+/K+

172

_____ or _____ contact between two cells is important in the normal functioning of some cells, especially those of the immune system.

Physical or direct contact

173

An example of _____ contact between cells is the contact that occurs between _____ and ____ during the process of fertilization.

direct
sperm and oocyte

174

Direct contact is also critical in the process of development and in _________ following injury.

cellular regrowth

175

Programmed cell death occurs both to promote proper development and to remove harmful _____.

cells

176

Cells of our immune system promote programmed cell death in some virus-infected cells to reduce further spread of ______.

infection

177

Cells die by one of two mechanisms

1. they are killed by harmful agents or mechanical damage
2. they are induced to commit suicide, a process of programmed cell death

178

Mitotic Phases

a Prophase
b Metaphase
c Anaphase
d Telophase

179

Interphase Phases

a G1
b S
c G2

180

Chromosomes appear due to coiling of chromatin.
Nucleolus breaks down
Spindle fibers begin to form from centrioles.
Centrioles move toward opposing cell poles
Nuclear envelope breaks down at the end of this stage.

Prophase

181

Chromosomes uncoil to form chromatin.
A nucleolus reforms within each nucleus.
Spindle fibers break up and disappear.
New nuclear envelope forms around each set of chromosomes.
Cytokinesis continues as cleavage furrow deepens.

Telophase

182

Spindle fibers attach to the centromeres of the chromosomes extending from the centrioles.
Chromosomes are aligned at the equatorial plate of the cell by spindle fibers.

Metaphase

183

Sister chromatids are separated by spindle fibers and moved toward opposite ends of the cell.
During this process centromeres that held sister chromatids together seperate; each sister chromatid is now a chromosome with its own centromere.
Cytokinesis begins.

Anaphase

184

Centriole replication is completed and enzymes and other structures needed for cell division are synthesized.

G2 Phase
(the second gap phase)

185

_______ of the cell cycle cells grow and produce new organelles, and other structures needed for DNA replication.
Replication of the centrioles to produce two centriole pairs is also initiated in this phase.

G1 Phase
(the first gap stage)

186

The 46 double helix strands of DNA are replicated.
Forming DNA requires large numbers of deoxyribonucleotides and the enzyme DNA polymerase. All of these components are located in the nuceloplasm within the nucleus.

S Phase
(synthesis)

187

The cell cycle depicts the steps in the replication of a _________.

somatic cell

188

The cell cycle consists of all the changes the cell undergoes as it divides into two identical cells called ___________.

daughter cells

189

The two major phases in the cell cycle are ________ and _______ phase.

interphase
mitotic

190

On average, the cell is in interphase for approximatel ____ hours, and going through the mitotic phase for ____ hours.

23, 1

191

_______ are all of the cells in the body other than the sex cells.

somatic cells

192

Mitosis occurs in ____, when cells divide their nucleus.

somatic cells

193

Meiosis occurs in ______, when cells divide their nucleus.

sex cells

194

Sex cells either form _____ or ______ .

sperm or oocytes

195

A _______ is a structure containing a pair of perpendicularly oriented cylindrical centrioles located in close proximity to the nucleus.

centrosome

196

sister chromatids

?

197

centromere

?

198

chromosome

?

199

Body cells communicate to our immune cells that they both belong to the body and are healthy through direct contact that involves the _________.

glycocalyx

200

The glycocalyx is the coating of ______ on the external surface of a cell.

carbohyrates

201

The immune system is able to distinguish normal, healthy cells from unwanted cells by making direct contact with a cell to determine if it exhibits the same pattern of sugars of the ________ as the body's cells.

glycocalyx

202

Most communication between cells occurs through ____

ligands

203

Ligands involved in communication include ________ from nerve cells and ________ from endocrine cells.

neurotransmitters
hormones

204

The cell that receives the information has a receptor that can bind the ligands which initiates mechanisms for controlling the ______, _________, and other ______ of individual cells.

growth, reproduction, and other cellular processes

205

Three types of receptors that bind ligands

Channel linked receptors
Enzymatic receptors
G protein-coupled receptors

206

receptor that permits ion passage either into or out of a cell in response to ligand binding

channel-linked receptors

207

receptor that function as protein kinase enzymes are activated to directly phosphorylate other enzymes within the cell

enzymatic receptors

208

receptors that involve protein kinase activation

G protein-coupled receptors

209

Membrane-bound organelles within the cytoplasm are surround by a membrane that separates the organelle's contents from ____.

the cytosol

210

Each organelle differs in is shape, _____ and associated enzymes.

membrane composition

211

Membrane bound organelles (5)

ER
Golgi aparatus
lysosomes
peroxisomes
mitochnodria

212

The ___ typically extends from the nuclear envelope to the plasma membrane and composes about one-half of the membrane within a cell.

ER

213

The extensive ER ______ surface serves as a point of attachment for ______.

membrane
ribosomes

214

The ribosomes of rough ER produce _____ that will be released from the cell, incorporated into the plasma membrane, and serve as digestive enzymes of lysosomes.

proteins

215

Transport from the ER occurs when small, enclosed membrane sacs pinch off from the ER.

transport vesicles

216

Transport vesicles shuttle proteins from the rough ER lumen to the _______ for further modicfication.

Golgi apparatus

217

The amount of rough ER is greater in cells producing large amounts of ____ for secretion, such as a cell in the pancreas that releases insulin to control blood glucose.

protein

218

The ER also helps form ____.

peroxisomes

219

Smooth ER functions include _____, ______, and _____.

synthesis
transport
storage of different types of lipids

220

This organelle is responsible for carbohydrate metabolism and detoxification of drugs and poisons.

smooth ER

221

Abundant amounts of smooth ER occur within the cells in the liver to ______ alcohol

detoxify

222

The ______ is typically composed of several elongated, flattened saclike membranous structures called cisernae.

golgi apparatus

223

The golgi body has two poles called the ____ and ____.

cis-face and trans-face

224

The cis-face is closer in proximity to the ____ and the diameter of its flattened sac is larger compared to the trans-face.

ER

225

One of the primary functions of the golgi apparatus is to _____, ______, and ______ that are made by the rough ER.

modify, package, and sort proteins

226

Transport vesicles arrive from the ER and fuse with the _____ of the Golgi apparatus.

cis-face

227

The ______ is referred to as the "warehouse" center.

Golgi apparatus

228

At the ____, in the Golgi apparatus, secretory vesicles form and carry both the modified and newly formed molecules away.

trans-face

229

Molecule arrive at the receiving region, ____, are modified and packaged within the lumen, are then shipped out at the shipping region, _____.

cis-face
trans-face

230

The small organelle which are membranous sacs that contain digestive enzymes, which are immersed in acidic fluid.

lysosomes

231

Within a healthy cell,_____ digest the contents of endocytosed vesicles.

lysosomes

232

Lysosomes also digest molecular structures of _______ organelles which is called _____.

damaged
autophagy

233

When a cell is damaged or dies, ______ from its lysosomes are eventually released into the cytosol.

enzymes

234

The _____ is called the "garbagemen" because of their cleanup activities and "suicide packet" because of their function in autolysis.

lysosomes

235

Organelles that are membrane enclosed sacs that contain over 50 different enzymes that vary by cell type.

peroxisomes

236

______ are usually smaller in diameter than lysosomes.

peroxisomes

237

Peroxisomes are initially formed by _____ first pinching off from the rough ER.

vesicles

238

Bound ribosomes are used to ______ proteins destined for export out of the cell, to become an integral part of the plasma membrane, or to serve as enzymes within lysosomes.

synthesize

239

Non-membrane bound organelles are composed of either protein alone or protein and ____.

RNA

240

Peroxisomes engage in _____ synthesis.

lipid

241

Peroxisomes were first named based on their role in _____ digestion, which involves removal of hydrogen from a molecule with the accompanying production of hydrogen peroxide.

chemical

242

Peroxisomes function in both ____ and ____ of molecules

digestion and synthesis

243

An extensive array of membrane-bound structures that includes (5)
*All of these structures are either directly attached to one another or connected through vesicles that move between them

ER
Golgi apparatus
vesicles
lysosomes
perozisomes

244

The plasma membrane and _______ are also considered part of this membrane system.

nuclear envelope

245

_______, are the only membrane-bound organelles that are not components of the endomembrane system.

mitochondria

246

Oblong shaped organelles with a double membrane with the folds of the inner membrane called cristae.

mitochondria

247

The matrix, which is the inner region of a mitochondrion, contains a small, unique circular fragment of _____ that has genes for producing mitochondrial proteins.

DNA

248

Mitochondria engage in ______ respiration to complete the digestion of glucose and other fuel molecules, such as fatty acids.

aerobic cellular

249

Mitochondria numbers within cells increase with greater demands for ______.

ATP production

250

Free ribosomes are suspended within the ____.

cytosol

251

In general, all other proteins that function within the cell are _______ by free ribosomes.

synthesized

252

The cytoskeleton has a central role in numerous cellular activities that include intracellular _______ and ________ organelles, ______, and movement of materials.

structural support and organization of organelles, cell division, and movement of materials

253

The cytoskeleton is formed by a framework of ______.

diverse fibrous proteins

254

The cytoskeleton extends throughout the interior of a cell and ____ proteins in the plasma membrane.

anchors

255

The three separate types of protein molecules that form the cytoskeleton.

microfilaments
intermediate filaments
microtubles

256

The smallest components of the cytoskeleton with a diameter of about 7 nanometers.

microfilaments

257

Microfilaments are composed of ____ protein monomers that are organized into two thin, intertwined protein filaments similar to two twisted pearl strands.

actin

258

Microfilaments help maintain ______, form internal support of microvilli, separate the two cells formed during cytokinesis, facilitate cytoplasmic streaming, and participate in ____.

cell shape
muscle contraction

259

Hollow cylinders that are approximately 25 nanometers in diameter composed of long chains of a globular protein called tubulin.

microtubules

260

More rigid than microfilaments and support cells structurally and stabilize junctions between them. i.e. Keratin

Intermediate filaments

261

A structure typically in close proximity to the nucleus and contains a pair of perpendicularly oriented cylindrical centrioles surround by protein that is amorphous.

centrosome

262

The primary function of centrosome is _______ microtubules within the cytoskeleton.

organizing

263

Large barrel shaped protein complexes that are major protein digesting organelles located within both the cytosol and nucleus of cells.

proteasomes

264

The garbage disposal for unwanted protein.

proteasomes

265

_____ and _____ flagella are extensions of the plasma membrane involved in movement.

Cilia and flagella

266

______ are structures that increase the surface area of the plasma membrane.

Microvilli

267

Cilia contain both ______ and supportive _____ proteins.

cytoplasm and microtubule

268

Flagella are ____ than cilia but have the same basic shape.

longer

269

The only example of a human cell with flagellum is ____.

sperm

270

The movement of both cilia and flagella occurs through the _______ within their core.

microtubules

271

Thin, microscopic membrane extensions from the surface of the plasma membrane.

microvilli

272

Microvilli provide a more extensive plasma membrane surface are for more efficient _______.

membrane transport

273

Membrane junctions ____ and ____ cells.

connect and support

274

Three major types of membrane junctions

tight junctions
desmosomes
gap junctions

275

Composed of plasma membrane proteins that form strands or rows of proteins.

tight junctions

276

______ junctions function to seal off the intercellular space and prevent substances from passing between the cells.

Tight

277

Tight junction requires all materials to move _____ rather than between the cells.

through

278

This type of membrane junction is composed of several different proteins that bind neighboring cells.

desmosomes

279

The nucleus is enclosed within a double membrane that is called the ____.

nuclear envelope

280

The nuclear envelope separates the cytoplasm from the ____.

nucleoplasm

281

This boundary controls the movement of materials between the nucleus and the surrounding cytoplasm. Each of the two layers of the nuclear envelope is a phospholipid bilayer and is continuous with the rough ER.

nuclear envelope

282

open passageways formed by proteins that extend through fused regions of the nuclear envelope.

nuclear pores

283

A nucleolus is not membrane bound and is composed of _____ and ____ and is responsible for producing the large and small subunits of ribosomes.

protein and RNA

284

Steps of transcriptions

1 DNA is unwound and RNA polymerase attaches to the promoter of the gene
2 RNA polymerase forms an RNA copy of the gene
3 The RNA strand is released from the DNA strand

285

_____ is the cell division that takes place in somatic cells.

Mitosis

286

Chromatins are composed of ____ and _____.

DNA and proteins

287

One of the main factors that influences membrane permeability is ____.

concentration gradient

288

Are microscopic projections of the plasma membrane and function to increase the surface area of the plasma membrane.

microvilli

289

move chromosomes during cell division

microtubules

290

The ____ is a general term for all cellular contents between the plasma membrane and the nucleus.

cytoplasm

291

_______ form a nucleic acid biomolecule is formed by repeating monomers

nucleotides

292

DNA is specifically composed of ______.

deoxyribonucleotides, which includes five-carbon sugar deoxyribose, a phosphate, and one of four nitrogenous bases

293

The four nitrogenous bases

Adenine
Cytosine
Guanine
Thymine

294

Nucleotide monomers are linked through the phosphate groups by ____ to form a polymer strand.

phosphodiester bonds

295

Adenine only pairs with ___, which is a complementary base pairing.

thymine

296

Cytosine pairs only with ____, which is a complementary base pairing.

guanine

297

Adenine is only found in ____.

DNA

298

Uracil is only found in ____.

RNA

299

DNA serves as the template to form an ____ molecule that is complementary to the sequence of the nucleotides in the gene.

RNA

300

Forming RNA during transcription requires both large number of ____ and the enzyme ______.

ribonucleotides
RNA polymerase

301

Process of transcription

Initiation - DNA is unwound
Elongation- Hydrogen bond forms between bases of DNA and the newly forming RNA molecule
Termination - RNA polymerase reaches the terminal region of the gene; newly formed RNA strand is released from the DNA strand

302

The synthesis of a new protein and takes place at ribosomes within the cytosol.

translation

303

Pre mRNA includes ____, which are noncoding regions.

introns

304

Translation requires ribosomes, ____, ____ and large numbers of free amino acids.

mRNA, tRNA

305

Three functional types of RNA are required for protein synthesis

ribosomal RNA
messenger RNA
transfer RNA

306

The ____ gradient is dependent on the combination of the ____ gradient and the chemical concentration gradient.

electrochemical
electrical

307

What are the common cell shapes?

spherical
cube-like
column-like

308

The cytosol close to the plasma membrane contains relatively more ____ than does the interstitial fluid that is close to the plasma membrane.

K+

309

The synthesis of steroid hormones occurs in the ____.

smoothe er

310

Simple diffusion is a ____ form of transport.

passive