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Flashcards in Chapter 6 Deck (185):
1

All organisms are made of

cells

2

The cell is the

simplest collection of matter that can live.
They have the 7 qualities of life

3

Cell structure is correlated to

cellular function

4

All cells are related by their

descent from earlier cells.

5

Though usually too small to be seen by the unaided eye,

cells can be complex

6

Scientists use microscopes to

visualize cells to small to see with the naked eye

7

In a Light Microscope (LM),

visible light passes through a specimen and then through glass lenses

8

Lenses refract (bend) the light, so that

the image is magnified

9

Three important parameters of microscopy

Magnification
Resolution
Contrast

10

Magnification

the ratio of an object's image size to its real size

11

Resolution

the measure of the clarity of the image, or the minimum distance of two distinguishable points.
(how clear you can see the image and magnify it)

12

Contrast

visible differences in parts of the sample

13

Light Microscopes (LMs) can magnify to about

1,000 times the size of the actual specimen

14

Various techniques enhance

contrast and enable cell components to be stained or labeled

15

Most subcellular structures, including organelles,

are too small to be resolved by a Light Microscope (LM)

16

Organelles

membrane-enclosed compartments

17

Two basic types of Electron Microscopes (EMs) that are used to study subcellular structures

Scanning Electron Microscopes (SEMs)
Transmission Electron Microscopes (TEMs)

18

Scanning Electron Microscopes (SEMs)

focus a beam of electrons onto the surface of a specimen, providing images that look 3-D.

-Allows you to see the surface!!

SURFACE (SSS)

19

Transmission Electron Microscopes (TEMs)

focus a beam of electrons through a specimen
-allows you to see the little things inside
internal ultrastructures

-Disadvantage: only dead specimen

20

Cell fractionation

takes cells apart and separates the major organelles from one another

-so you can study just the parts you're interested in.

It starts out slow and short spins, then it ends up with fast and long spins

21

Centrifuges fractionate cells into

their component parts

22

Cell fractionation enables scientists to

determine the functions of organelles

23

Biochemistry and cytology help correlate

cell function with structure

24

The order the organelles fall out during Cell fractionation

1. nucleus
2. mitochondria and chloroplast
3. microsomes
4. ribosomes

25

The basic structural and functional unit of every organism is one of two types of cells:

prokaryotic or eukaryotic

26

Prokaryotic Cells

Domain Bacteria and Domain Archaea

27

Eukaryotic Cells

Kingdoms:
plants, animals, fungi, protists (protista)

28

Basic features of ALL cells

plasma membrane
semifluid substance called cytosol
chromosomes (carry genes. DNA)
ribosomes (make proteins)

29

Every cell needs to be able to

make proteins

30

Prokaryotic Cells are characterized by having

no nucleus
DNA in an unbound region called the nucleoid
no membrane-bound organelles
cytoplasm bound by the plasma membrane

31

Eukaryotic Cells are characterized by having

DNA in a nucleus that is bounded by a membranous nuclear envelope
membrane-bound organelles
cytoplasm in the region between the plasma membrane and nucleus

32

Eukaryotic cells are generally much larger than

prokaryotic cells

33

The plasma membrane is a

selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell

34

The general structure of a biological membrane is a

double laye of phospholipids

35

Metabolic requirements set upper limits on the size of

cells

(Eukaryotic cells?)

36

The surface area to volume ratio of a cell is

critical

37

As the surface area increases by a factor of n^2,

the volume increases by a factor of n^3

38

Small cells have a greater surface area relative

to volume.

(this is how eukaryotic cells can be so big)

39

Cells need enough surface area for their

work, metabolism.

40

All of the membranes are put together into a eukaryotic cell and that is what

makes the surface area so big

41

A eukaryotic cell has internal membranes that partition the cell into

organelles

42

Organelles participate in

metabolism (enzymes built into their membranes)

43

Organelles provide

local environments for specific reactions

44

Plant and animal cells have most of the same

organelles

45

In animal cells but not plant cells

lysosomes
centrioles
flagella (in some plant sperm)

46

In plant cells but not animal cells

chloroplasts
central vacuole and tonoplast
cell wall
plasmodesmata

47

The nucleus contains most of the

DNA in a eukaryotic cell

48

The genetic instructions are

how a cell know what to do

49

Ribosomes use the information from the DNA to

make proteins

50

The nucleus and the ribosomes work

together in eukaryotic cells

51

Nucleus function

hold the DNA

52

Ribosomes function

make proteins

53

The nucleus contains

most of the cell's genes and is usually the most conspicuous organelle

54

The nuclear envelope

encloses the nucleus separating it from the cytoplasm

55

The nuclear membrane is a

double membrane. (it folds back over)
-membrane is continuous at the pores
-pore complexes line the pore

56

Pores regulate the entry and exit of molecules from the

nucleus

57

The shape of the nucleus is maintained by the

nuclear lamina, which is composed of protein

58

Nucleus job

hold DNA

59

In the nucleus, DNA is organized into discrete units called

chromosomes

60

Each chromosome is composed of

a single DNA molecule associated with proteins

61

The DNA and proteins of chromosomes are together called

chromatin

62

Chromatin condenses to form discrete

chromosomes as a cell prepares to divide

63

The Nucleolus (not a membranous organelles) is located within the

nucleus and is the site of ribosomal RNA (rRNA) synthesis

64

The nucleolus is where we

put together ribosomes

65

The nucleolus is located within the

nucleus
(the dense region)

66

Nucleolus function

make RNA to make ribosomes

67

Ribosomes are particles made of

ribosomal RNA and protein
-site of protein synthesis

68

Ribosomes carry out protein synthesis in two locations

in the cytosol
and
on the outside of the endoplasmic reticulum or the nuclear envelope

69

The ribosomes that carry out protein synthesis in the cytosol are

free ribosomes-they float around free

-proteins for use in the cytosol

70

The ribosomes that carry out protein synthesis on the outside of the endoplasmic reticulum or the nuclear envelope are

bound ribosomes- they are physically stuck to the thing. they will have proteins that end up outside the membrane.

-proteins for membranes, packages, or secretion

71

Ribosomes function

make proteins
(important!!!)

72

Endomembrane system

a series of physically connected structures

73

Components of the Endomembrane system

1st- Nuclear Envelope
2nd- Endoplasmic Reticulum
3rd- Golgi Apparatus
4th- Lysosomes
5th- Vacuoles
6th- Plasma Membrane

-The components go through the endomembrane system through this order

74

The components of the endomembrane system are either continuous or connected via transfer by

vesicles

75

The endoplasmic reticulum (ER) accounts for

more than half of the total membrane in many eukaryotic cells

76

The ER membrane is continuous with the

nuclear envelope

77

There are two distinct regions of ER

Smooth ER, which lacks ribosomes
Rough ER, surface is studded with ribosomes

78

Functions of Smooth ER

-synthesizes lipids
(sex hormones, steroids, etc.)
-metabolizes carbohydrates
-detoxifies poison (liver) (alcohol)
(increased use leads to higher tolerance)
-stores calcium (takes the calcium and holds it inside if you want to get cells attention, let the calcium out.

79

Smooth ER detoxifies alcohol but when

you havent drank alcohol in awhile, you wont have enough smooth ER anymore to get the alcohol out and detoxify

80

Functions of Rough ER

-Has bound ribosomes, which secrete glycoproteins (proteins covalently bonded to carbohydrates. (proteins with sugar on them))
-distributes transport vesicles, proteins surrounded by membranes
-is a membrane factory for the cell
-makes proteins=main purpose/job

81

glycoproteins

proteins covalently bonded to carbohydrates.
proteins with sugar on them.

82

The Golgi apparatus consists of

flattened membranous sacs called cisternae

83

Functions of the Golgi apparatus

-Modifies products of the ER
-Manufactures certain macromolecules
-Sorts and packages materials into transport vesicles (then pops off?)
---Cis face (near ER)
---Trans face (far side)

It ships and packages.
Modifies, packaging, and shipping.

84

A lysosome is a

membranous sac of hydrolytic enzymes that can digest macromolecules

85

Lysosomal enzymes can hydrolyze

proteins, fats, polysaccharides, and nucleic acids

86

Lysosomal enzymes work best in

the acidic environment inside the lysosome

87

Lysosomes=

digestive
animal cells only.
its a vesicle with digestive enzymes. (package)

88

Some types of cell can engulf another cell by

phagocytosis; this forms a food vacuole

89

2 ways lysosomes function

-A lysosome fuses with the food vacuole and digests the molecules
-Lysosomes also use enzymes to recycle the cell’s own organelles and macromolecules, a process called autophagy

-digest food
-recycle used up old orangelles

90

Vacuoles

plants only

91

A plant cell or fungal cell may have one or several

vacuoles, derived from endoplasmic reticulum and Golgi apparatus

92

Food vacuoles are formed by

phagocytosis

93

Contractile vacuoles,

found in many freshwater protists, pump excess water out of cells.

-vacuoles fill up with water and before they explode, they pump the water out

94

Central vacuoles,

found in many mature plant cells, hold organic compounds and water

95

vacuoles look like an

empty spot in a cell

96

The endomembrane system is a

complex and dynamic player in the cell’s compartmental organization

97

Proteins destined for secretion are synthesized on the

inside of the endomembrane system.

secreted in the inside, proteins end up outside cell??

98

Mitochondria

are the sites of cellular respiration, a metabolic process that uses oxygen to generate ATP.

Cells make ATP

99

Chloroplasts,

found in plants and algae, are the sites of photosynthesis

important functionals

100

Peroxisomes are

oxidative organelles

-moving electrons around in interactions

101

Mitochondria and chloroplasts are NOT part of

the endomembrane system

102

Mitochondria and chloroplasts have similarities with bacteria

-Enveloped by a double membrane
-Contain free ribosomes and circular DNA molecules
-Grow and reproduce somewhat independently in cells

-2 membranes on outside
-has its own DNA and ribosomes
-do what they want when they want. independent.

103

The Endosymbiont theory

-An early ancestor of eukaryotic cells engulfed a nonphotosynthetic prokaryotic cell, which formed an endosymbiont relationship with its host
-The host cell and endosymbiont merged into a single organism, a eukaryotic cell with a mitochondrion
-At least one of these cells may have taken up a photosynthetic prokaryote, becoming the ancestor of cells that contain chloroplasts

(this helps us describe why we have mitochondria and chloroplasts.

104

Chloroplast function

photosynthesis

105

mitochondria function

cellular respiration, make ATP

106

Mitochondria are in nearly all

eukaryotic cells

107

Mitochondria have a

smooth outer membrane and an inner membrane folded into cristae
(the folds/loopy thing)

108

The inner membrane creates two compartments:

intermembrane space and mitochondrial matrix

109

Some metabolic steps of cellular respiration are catalyzed in the

mitochondrial matrix

110

Cristae present a large surface area for enzymes that

synthesize ATP

111

anything that is a eukaryote has a

mitochondria.
this is because they all need to make energy

112

Parts of mitochondria

outer membrane, inner membrane, intermembrane space, cristae, matrix, DNA, ribosomes

113

Chloroplasts contain the green pigment

chlorophyll, as well as enzymes and other molecules that function in photosynthesis

114

Chloroplasts are found in

leaves and other green organs of plants and in algae

115

Chloroplast structure includes

-Thylakoids, membranous sacs, stacked to form a granum. (a single membrane sac)
-Stroma, the internal fluid (the dense goopy stuff)

granum- a bunch of thylakoids together

116

The chloroplast is one of a group of plant organelles, called

plastids

117

DNA and ribosomes are in the

stroma in the chloroplast

118

Parts of Chloroplast

outer membrane, inner membrane, intermembrane space, thylakoid, granum, stroma, DNA, ribosomes

119

Peroxisomes are

specialized metabolic compartments bounded by a single membrane

(a sac with hydrogen peroxide in it surrounded by a single membrane

120

Peroxisomes produce

hydrogen peroxide and convert it to water
-Oxygen is used to break down different types of molecules (oxidation)

121

Peroxisomes perform reactions with

many different functions

122

How peroxisomes are related to other organelles is

still unknown
-They do not bud off the endomembrane system

123

The cytoskeleton is a

network of fibers extending throughout the cytoplasm

(a series of tubes, lines, and building blocks that help a cell retain its shape

124

The cytoskeleton organizes the cell’s

structures and activities, anchoring many organelles

125

The cytoskeleton helps to

support the cell and maintain its shape

126

The cytoskeleton interacts with

motor proteins to produce motility

127

Inside the cell, vesicles can travel along

“monorails” provided by the cytoskeleton

128

Recent evidence suggests that the cytoskeleton may

help regulate biochemical activities

129

roles of the cytoskeleton

support and motility

130

Three main types of fibers make up the cytoskeleton

microtubules
microfilaments
intermediate filaments

131

Microtubules

, are the thickest of the three components of the cytoskeleton
(big)

132

Microfilaments

, also called actin filaments, are the thinnest components
(small)

133

termediate filaments

are fibers with diameters in a middle range
(medium)

134

Microtubules functions

-Shaping the cell
-Guiding movement of organelles
-Separating chromosomes during cell division


Centrosomes
Centrioles
Cilia/Flagella

135

In many cells, microtubules grow out from a

centrosome near the nucleus

136

The centrosome is a

“microtubule-organizing center”

137

In animal cells, the centrosome has a pair of

centrioles, each with nine triplets of microtubules arranged in a ring

138

plants don't have

centrioles

139

centrioles are made of

microtubules.

they have a 3/9 pattern which creates the centriole

140

Microtubules control the

beating of cilia and flagella, locomotor appendages of some cells

141

Cilia and flagella share a common structure

-A core of microtubules sheathed by the plasma membrane
-A basal body that anchors the cilium or flagellum
-A motor protein called dynein, which drives the bending movements of a cilium or flagellum (the back and forth flapping movement)

142

basal body looks identical to centriole structure, but

they have different functions

143

cilia/flagella have a

2/9/2 pattern

144

How dynein “walking” moves flagella and cilia

-Dynein arms alternately grab, move, and release the outer microtubules
-Protein cross-links limit sliding
-Forces exerted by dynein arms cause doublets to curve, bending the cilium or flagellum

145

motor proteins interact with

microtubules to get movement of cilia and flagella

146

Microfilaments (Actin Filaments) are

solid rods

147

The structural role of microfilaments is

to bear tension, resisting pulling forces within the cell

148

Microfilaments

form a 3-D network called the cortex just inside the plasma membrane to help support the cell’s shape

149

Microfilaments that function in cellular motility contain the protein

myosin in addition to actin

150

microfilaments are how are

muscles move.
Microfilaments interaction with anysoin, actin

151

In muscle cells, thousands of actin filaments are arranged

parallel to one another

152

Thicker filaments composed of myosin interdigitate with the

thinner actin fibers

153

Localized contraction brought about by actin and myosin also drives

amoeboid movement

154

Pseudopodia (cellular extensions) extend and

contract through the reversible assembly and contraction of actin subunits into microfilaments

155

Cytoplasmic streaming is a

circular flow of cytoplasm within cells.
-This streaming speeds distribution of materials within the cell

156

In plant cells, actin-myosin interactions and sol-gel transformations drive

cytoplasmic streaming

157

Intermediate filaments support

cell shape and fix organelles in place

158

Intermediate filaments are more

permanent cytoskeleton fixtures than the other two classes

-stable

159

Most cells synthesize and

secrete materials that are external to the plasma membrane

160

These extracellular structures include

-Cell walls of plants
-The extra cellular matrix (ECM) of animal cells (plants dont have)
-Intercellular junctions (how 2 cells join and communicate)

These structures help provide connections between adjacent cells, determine cell shape, and transmit information
-important- we need all of this!

161

The cell wall is

an extracellular structure that distinguishes plant cells from animal cells

162

Prokaryotes, fungi, and some protists also have

cell walls.
(but made of different things)

fungi cell wall- chitin
plant cell wall- cellulose

163

The cell wall protects the

plant cell, maintains its shape, and prevents excessive uptake of water

164

Plant cell walls are made of

cellulose fibers embedded in other polysaccharides and protein

165

Plant cell walls may have multiple layers

primary cell wall
middle lamella
secondary cell wall


plasmodesmata

166

Primary cell wall:

relatively thin and flexible

167

Middle lamella:

thin layer between primary walls of adjacent cells

168

Secondary cell wall (in some cells):

added between the plasma membrane and the primary cell wall

169

Plasmodesmata are

channels between adjacent plant cells
(how they talk to eachother)

170

Animal cells lack cell walls but are covered by an elaborate

extracellular matrix (ECM)

171

The ECM is made up of

glycoproteins such as collagen, proteoglycans, and fibronectin

172

ECM proteins bind to

receptor proteins in the plasma membrane called integrins

173

Functions of the extracellular matrix (ECM)

-Support
-Adhesion
-Movement
-Regulation

174

Neighboring cells in tissues, organs, or organ systems often adhere, interact, and communicate through direct physical contact

Intercellular junctions facilitate this contact

175

There are several types of intercellular junctions

Plasmodesmata -found in plant cells only
Tight junctions -found in animal cells only
Desmosomes -found in animal cells only
Gap junctions -found in animal cells only

176

Plasmodesmata are

channels that perforate plant cell walls

177

Through plasmodesmata,

water and small solutes (and sometimes proteins and RNA) can pass from cell to cell

178

At tight junctions,

membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid

179

tight junctions

pressed together tightly so there is no gap

180

Desmosomes (anchoring junctions) fasten cells together into

strong sheets

181

Gap junctions (communicating junctions) provide cytoplasmic channels between

adjacent cells

182

gap junctions

tubes between cells that allow things to get from one to another

183

desmosomes

one cell is anchored and allows everything to act as a unit instead of individual cells

184

Cells rely on the integration of structures and organelles in order to function

For example, a macrophage’s ability to destroy bacteria involves the whole cell, coordinating components such as the cytoskeleton, lysosomes, and plasma membrane

185

The Cell:

A Living Unit Greater Than the Sum of Its Parts