Chapter 6/7/8 - Cell Membranes Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Cell Theory

A
  1. All organisms are composed of 1 or more cells , and life process of metabolism and heredity occur within these cells
  2. Cells are the smallest living things and and are the basic unit of organization in all living organisms
  3. Cells arise only by division of pre existing cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

True or false

Life represents a continuous line of descendants from those early cells

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the reason why cell are small ?

A

Diffusion into and out the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The small size of cells allow

A

Diffusion to occur easily

Lower energy expenditure

Lower waste

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Surface are to volume ratio

A

Volume increases rapidly as a cell increases in size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

1-10um in diameter

A

Prokaryotes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

10-100um in diameter

A

Eukaryotes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do we visualize cells

A

With use of technology (microscopes)

  • cells are not visible to the naked eye (resolution)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the purpose of chemical stains

A

Chemical stains aid the resolution of cells, make them more visible through a microscope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 4 major components of a cell?

A
  • nucleoid or nucleus
  • cytoplasm
  • ribosomes (synthesize proteins)
  • plasma membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Production of protein is achieved by

A

Ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How many subunits make up a ribosome

A

2

Large subunit

Small subunit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The area of a prokaryotic cell (simplest organism)

A

Nucleoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Eukaryotes (complex organisms) are contained in the

A

Nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The nucleus is surrounded by a double membrane called the

A

Nuclear envelope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is cytoplasm?

What does it contain?

A

Semi fluid matrix that fills the cells interior

Contains sugars, amino acids, proteins, and organelles used to carry out daily activities.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Cytosol

A

The part of the cytoplasm that contains organic molecules and ions in solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Organelle

A

Specialized part of a cell, small cytoplasmic organ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Separates the inside of the cell from the outside environment

A

plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Plasma membrane is composed of

A

Phospholipids and contains membrane proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is embedded in the plasma membrane

A

Proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Phospholipid molecule make up the

A

Plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is responsible for the cells ability to interact with the environment

A

Proteins of plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Lacks membrane bound nucleus, internal membrane system, and membrane bound organelles

A

Prokaryotes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Prokaryotes are small simple cells surrounded by

A

Cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

True or false

Prokaryotes have no compartments

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Prokaryotes lack

A

Membrane bound organelles

Lack cytoskeleton found in eukaryotes. But have elements of actin and tubulin to help maintain its structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Prokaryotes have

A

Free floating ribosomes to synthesize proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Name two types of prokaryotes

A

Bacteria

Archaea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Bacterial cell wall is composed of

A

Peptidoglycan , a sugar polymer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Functions of bacterial cell wall

A

Protect the cell

Maintain its shape

Prevent excess uptake or loss of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Archaea Cell Wall is composed of various chemical compounds such as

A

Proteins

Polysaccharides

Inorganic compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Archaea Cell Membrane

A

A fatty acid chain (saturated hydrocarbon) that is covalently attached at both ends to glycerol, creating a monolayer rather than a bilayer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Can archaea adapt to changing environmental temperatures?

A

No. Unable to alter the degree of saturation of hydrocarbons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

The cellular machinery that replicates DNA and synthesized proteins in archaea is more closely related to

A

Eukaryotic systems than bacterial systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Long, threadlike structures protruding from the surface of a cell that are used for locomotion(movement)

A

Flagella

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Prokaryotic Flagella

A

Protein fibers that extend out from the cell wall.

(Rotary Motor)Movement powered by proton gradient

There may be one or more per cell, or none depending on species.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Eukaryotic Cells

A

Contains an endomembrane system that allows the inside to be compartmentalized —- this allows biochemical reactions to occur independently and simultaneously through organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Common organelles found in animal, fungi, and plant cells

A
Nucleus 
Nucleolus 
Ribosomes
Cytoplasm
Endoplasmic Reticulum(rough/smooth)
Golgi Apparatus 
Lysosome
Peroxisome
Plasma Membrane 
Mitochondria 
Cytoskeleton (actin filaments, microtubules)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Largest organelle, spherical in shape, typically located in the center of a cell

A

Nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

The nucleus contains ______________

Which are packaged DNA, or gene coding for protein

A

Chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

All eukaryotic cells are supported by an internal protein scaffold called

A

Cytoskeleton

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

DNA are packed to form_____________ which are further packed by proteins to form_______________

A

Chromatins

Chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Two phospholipid bilateral that surrounds the nucleus

A

Nuclear Envelope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Describe the nuclear envelope

A

One layer surrounds the nucleus

The outer phospholipid bilayer forms the endoplasmic reticulum, or cytoplasm interior Membrane system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

The outer phospholipid bilayer of the nuclear envelope forms the

A

Endoplasmic reticulum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Network of intermediate filament fibers that covers the inner surface of the nuclear envelope , which give the nucleus its shape

Involved in the deconstruction and reconstruction of the nuclear envelope that accompanies cell division

A

Nucleus lamins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Found embedded between two phospholipid bilayers

Scattered over the surface of the nuclear envelope

A

Nuclear pores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Nuclear pores allow

A
  • Ion and small molecule exchange or diffuse between nucleus and cytoplasm
  • controlled transport of large proteins and RNA, RNA - protein complexes into and out of the nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Nucleolus is found within

A

The nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Houses ribosomal RNA genes, RNAs, and ribosomal proteins within itself during ribosome production

A

Nucleolus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Manufactures ribosomal RNA subunits (ribosomes) needed to synthesize protein

A

Nucleolus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Organelle within a cell that is important in synthesizing protein

A

Ribosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Newly made protein is found in the

A

Cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

The large subunit and small subunit of ribosome is composed of a combination of RNA called

A
  1. rRNA, or ribosomal RNA

2. Proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Subunits of ribosome form only when

A

They are actively synthesizing proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Messenger RNA (mRNA)

A

Carries coding information from DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Transfer RNA (tRNA)

A

Carries amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Ribosomes use the information in mRNA to direct the

A

Synthesis of protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Ribosomes are found

A

Free in the cytoplasm

Associated with internal membranes

Embedded in the ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Contains the message or protein sequence to be made

A

mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Will read the mRNA and translate it into an amino acid chain

A

rRNA(ribosomes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Will provide the amino acids to build the growing peptide chain

A

tRNA(ribosomes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Factories that make proteins

A

Ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Cell interior contains an endomembrane system that

A

Divides the internal cell into compartments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What forms the largest endomembrane?

A

Endoplasmic reticulum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Exists as folded membranes, tubular networks, and other shapes

A

Endoplasmic reticulum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Phospholipid bilayer forms the

A

Endoplasmic reticulum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Cisternal Space/ lumen

A

Interior of ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Two types of ER

A

Rough ER

Smooth ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Rough ER

A

Ribosomes embedded in membrane (hence, rough, bumpy appearance)

Synthesizes proteins on the surface of ER(where ribosomes are located)

72
Q

Fluid component of the cytoplasm containing dissolved organic molecules such as proteins and ions

A

Cytosol

73
Q

What are the two largest compartments in eukaryotic cells

A

Cisternal space

Cytosol

74
Q

Proteins synthesized on the surface of the rough ER are destined to be exported from the cell to

A

Lysosomes or vacuoles

Or

Embedded in the plasma membrane

75
Q

Where is the site for protein synthesis?

A

Rough ER

76
Q

Determines wether the ribosome will become associated with the rough ER or remain a cytoplasmic ribosome

A

The sequence of proteins being synthesized

77
Q

On the surface of the rough ER , synthesized proteins will enter the ____________ of the endoplasmic reticulum , where protein modification occurs

A

Lumen , cisternal space

78
Q

Where are NEWLY SYNTHESIZED proteins modified by the addition of of Carbohydrates to form glycoproteins

A

Endoplasmic reticulum

79
Q

How are newly synthesized proteins modified

A

By the addition of carbohydrates to form glycoproteins

GLYCOPROTEINS - ( destined for secretion, are separated from other products and later packaged into vesicles that move to the Golgi for further modification and packaging for transport of other cellular locations)

80
Q

What type of ER is this?

1) ribosome embedded on surface
2) synthesizes proteins
3) synthesized proteins enter lumen of ER, and are modified
4) proteins are sorted, further packages for the Golgi apparatus
5) proteins exported cytosol, lysosome, or vacuole, or embedded in plasma membrane

A

Rough ER

81
Q

Regions of the ER with very few bound ribosomes

A

Smooth ER

82
Q

Name structures of smooth ER

A

Tubules, flattened sacs, tubular arrays

83
Q

Smooth ER membrane contains

A

Enzymes

84
Q

Enzymes in the ER are involved in the synthesis of

A

Carbohydrates

Lipids

Steroid hormones

85
Q

An important function of the smooth ER is to store

A

Intracellular Ca2+

  • this keeps the cytoplasmic level low , allowing Ca2+ to be used as a signaling molecule
86
Q

What is Ca2 + ?

A

A signaling molecule

87
Q

What does Ca2+ trigger?

A

Muscle contraction

Intracellular contraction

88
Q

Where is Ca2+ stored

A

Smooth ER

89
Q

What does the Smooth ER modify? Why?

A

Foreign substances to make them less toxic , detoxify harmful substances

Ex: liver cells have large smooth endoplasmic reticulum —> neutralizes substances in the liver

90
Q

Collection of flattened sac membranes

A

Golgi apparatus

91
Q

Individual membrane sacs of the Golgi apparatus are called

A

Cisternae

92
Q
  1. Proteins and lipids manufactured on the rough and smooth ER are transported into the _____________ and modified as they go through it ,
  2. materials then bud off as secretory vesicles on the _____________
A

Golgi Apparatus

Trans Face

93
Q

Name three things the Golgi Apparatus does to molecules

A

Assembles

Packages

Distributes

94
Q

cis face?

A

Front of Golgi

95
Q

Trans face?

A

Back of Golgi

96
Q

In plant cells, noncellulose polysaccharides that form part of the cell wall of plants/ are composed here and brought to the plasma membrane

A

Golgi Apparatus

97
Q

Lysosome arise from

A

Golgi Apparatus

98
Q

Lysosomes contain

A

High levels of degrading enzymes

99
Q

What do degrading enzymes in lysosome do?

A

Catalyze the rapid break down of proteins, nucleic acids, lipids, and carbohydrates

Degrades old cellular organelles(makes room for new organelles)

100
Q

As phagocytosis (eats) wastes, a proton pump pushes H+ into the lysosome, decreasing the pH. Why is this significant?

A

Activates digestive enzymes in lysosome

Leads to destruction of old organelle

101
Q

Membrane enclosed vesicles that contain enzymes needed for metabolism

A

Microbodies

102
Q

True or False

Peroxisome is a microbody

A

True

103
Q

Microbody which contains enzymes involved in the oxidation of fatty acids.

A

Peroxisome

104
Q

Peroxisomes form from the __________________, which can ________________________

A

The cushion of ER vesicles

  • ER vesicles can uptake peroxisomal enzymes, grow, and divide
105
Q

Hence peroxisome breaking down fatty acids through oxidation, the resulting byproduct is _______________. Peroxisome contains ______________ to further beak this down

A

Hydrogen peroxide

Catalase (breaks down to water/hydrogen)

106
Q

Tubular organelle

About the size of bacterium

Found in all eukaryotic cells

A

Mitochondria

107
Q

What 2 membranes does mitochondria contain

A

Smooth outer membrane

Inner folded membrane

108
Q

What are the layers in the inner folded membrane called

A

Cristae

109
Q

In mitochondria, What does cristae form

A

Matrix
-inner membrane

Intermembrane space
- outer compartment

110
Q

In the mitochondria, proteins are embedded on________________ which carries out______________ to create atp.

A

The inner membrane (matrix)

Oxidative metabolism

111
Q

Mitochondria is considered a cell within a cell because it has its own

A

DNA , which produce proteins

112
Q

True or false

Mitochondria can divide to form new mitochondria

A

true

113
Q

Supports the cell shape

Anchors organelles

Allows proteins to be distributed throughout the cell

Allows cell movement

What am I?

A

Cytoskeleton

114
Q

What is the cytoskeleton composed of?

A

Protein fibers

Actin filaments

Microtubules

Intermediate filaments

115
Q

Composed of 2 protein chains loosely twined together

Exhibit polarity, has a + and - end.

Concentrated in bundles below the plasma membrane, known as stress fibers

Responsible for cellular movements such as crawling, “pinching” during cell division, formation of cellular extensions

What am I?

A

Actin filament

116
Q

Largest of the cytoskeleton elements

Hollow tubes, each composed of a ring of 13 protofilaments (a- & ß- tubulin polymerize to form ring)

Protofilaments line up side by side around core to form hallow tube, give it shape

What am I?

A

Microtubule

117
Q

Name 3 characteristics of microtubules?

A

Facilitate movement

Organize the cytoplasm

Responsible for moving materials within the cell

118
Q

Formed from proteins such as vimentin, keratin, or neurofilaments

Once formed does not break down

Stability and shape of cell (protein->vimentin)

Most durable element in cytoskeleton in animal cells

What am I ?

A

Intermediate filament

119
Q

Centrioles are found in

A

Animal cells

Most Protists

120
Q

In animal cells, what is found in pairs and at right angles to each other near nuclear membranes

A

Centrioles

121
Q

Region surrounding centrioles is the space called

A

Centrosome

122
Q

Surrounding the centrioles(pairs) in the centrosome is the

A

Pericentriolar material

123
Q

Contains tubulin and materials needed to convert tubulin to microtubules

A

Pericentriolar material

124
Q

Microtubule organizing center

A

Organizes microtubules during cell division

125
Q

Centrosomes of plants and fungi lack

A

Centrioles

***Contain microtubule organizing center

126
Q

Animal Cells: Extracellular matrix

What two proteins are secreted?

Where are the proteins secreted?

What does it form?

A

Glycoproteins and proteoglycans

Into the surrounding space

Forms protective cushion around cell

127
Q

Plant cells: Cell Wall

A

Protects and supports

Primary wall produced in young cells

128
Q

True or false

Chloroplast is absent in animal cells

A

True

129
Q

Plant cells contain a cell wall

True or false

A

True

130
Q

Animal cells lack cell wall.

True or false

A

True

131
Q

The extracellular matrix is composed of

A

Glycoproteins, collagen, and elastin

132
Q

Sticky substance released by plant cells to adhere to adjacent cells

A

Middle lamella (within cell wall)

133
Q

structure found in many plant cells, located between the primary cell wall and the plasma membrane.

Deposited Inside primary wall of fully expanded cells

Ex:

  • cell 1 (primary)
  • cell 2
A

Secondary cell wall

134
Q

Plant cells have specialized membrane bound structures called

A

Vacuoles

135
Q

Tonoplast

A

Membrane surrounding large central vacuole

136
Q

Contains channels that are used to help the cell maintain it tonicity

A

Tonoplast

137
Q

Plant cells: What do vacuoles store?

A

Water

Sugars

Ions

Other molecules

138
Q

Plant Cell:

Vacuole helps to maintain plant cell _____________, which allows plant cell______________

A

Tonicity

Growth

139
Q

Plant Cell:

Found in plant cells and any cell that uses the suns energy to carry out photosynthesis

A

Chloroplasts

140
Q

Plant Cells:

Allows cell to make their own food

A

Chloroplasts

141
Q

Plant Cells:

Outer and Inner membrane , larger than mitochondria

A

Chloroplasts

142
Q

Plant Cells :

Inside the inner membrane of chloroplasts are stacks of membranes called

A

Grana

143
Q

Plant Cells: Chloroplasts

What is grana composed of?

A

Several thylakoid disks

144
Q

Plant Cell: Chloroplasts->Grana

What does the surface of thylakiod disks contain?

A

Photosynthetic pigments , or chlorophyll

145
Q

Plant Cell: chloroplasts-> grana-> thylakoids

Fluid matrix that surrounds thylakoids and contains enzymes to synthesize glucose

A

Stroma

146
Q

Plant Cells:

Chloroplasts is considered a cell within a cell because it contains

A

DNA

147
Q

Plant Cells:

Chloroplasts and Mitochondria arose by

A

Endosymbiosis

148
Q

Plant Cells:

Theory that eukaryotic cell arose by symbiosis between two cell that were once separate

Symbiosis def. - (interaction btw 2,beneficial for both)

A

Endosymbiosis

149
Q

Cell Movements: Intracellular

Transport of materials are performed along_________

A

Microtubules

150
Q

Cell Movements: intracellular

Requires 4 components which are?

A

Vesicles or organelle to be transported

Motor protein that does the moving

Connector molecule that holds the cargo

Microtubule as the track

151
Q

Cell Movements : Extracellular

Why do actin filaments rearrange intracellularly

A

I’m to allow cells to crawl

“Crawl cell” destroy pathogens

152
Q

Cell Movements: Extracellular -> Crawl Cell Process

  1. Actin filaments in leading cell quickly polymerize to ___________________
  2. Then, Microtubules polymerize to __________
  3. Lastly, actin in trailing end depolymerizes to _________________
A
  1. To stretch cell forward
  2. To stabilize the leading end
  3. To contract the cell towards its body
153
Q

Cell Movements: Extracellular

Aids in propelling a cell

Evolved early on in Eukaryotes

Circular shape consisting of 9 microtubule pairs arranged in a ring structure and surrounds 2 central microtubules (9 + 2 structure)

What am I?

A

Flagella

154
Q

Cell Movements: Extracellular -> flagella

What is it’s motor protein?

What does the motor protein cause?

A

Dynein

Causes microtubules to move past each other in UP - DOWN WAVES

155
Q

Cell Movements: Extracellular

More modern and evolved form of flagella used in multi cellular eukaryotes

Similar (9 +2) structure arrangement as flagella

Arranged in rows & shorter than flagella

A

Cilia

156
Q

Cell Movements: Extracellular

What are functions of cilia?

A

Propels water

Increases surface area

Important in secretion and absorption

157
Q

Wall layer deposited during the period of cell expansion

A

Primary wall

158
Q

Cell Communication

Cells need a way to communicate with each other (T/F)

More specializations give rise to different populations of cells(T/F)

A

True

True

159
Q

Cell communication

Set of genes that function to mark the surfaces of cells, identifying them as being a particular type

A

Surface Proteins (MHC)

160
Q

Cell communication : Surface proteins

Tissue specific cell surface maker

On the surface of red blood cells

Responsible for A, O, B blood types

A

Glycolipids

161
Q

Cell Communication: surface proteins

Found on virtually all cells in an organism that communicates “self” from anything that is “non-self”. Ex: cells in immune system defend against invading cells

What am I?

A

MHC proteins

162
Q

Cell communication

Name the various junctions

A

Gap

Adhesive

Communicating

163
Q

Cell Communication

Electrical signal driven by chemical means

A

Action potentials

164
Q

Cell communication

Identifying cell markers?

A

Surface proteins

165
Q

Cell Communication

Name all cell to cell connections

A

Adhesive junction

Adherens junction

Desmosomes

166
Q

Cell Communication

Name all Communicating junction

A
  • gap junction

- plasmodesmata (plants)

167
Q

Cell Communication

Junction found in tissues subject to mechanical stress

Attach cytoskeleton of a cell to cytoskeleton of of other cells or extracellular matrix

Found in all animal species

What am I?

A

Adhesive junction

168
Q

Cell Communication

Based on the protein cadherin (Ca2+) , which is a single transmembrane protein that protrudes into the extracellular space

Can join with cadherin of adjacent cell

A

Adheren junction

169
Q

Cell Communication

Join adjacent cells via the cadherins DESMOCOLLIN & DESMOGLEIN , which interact with intermediate filaments of the cytoskeleton

Unique to vertebrates

Support tissue against mechanical stress

What am I?

A

Desmosomes

170
Q

Cell Communication

Found in both invertebrates and vertebrates

Forms a barrier to seal off a sheet of cells

A

Separate junction

171
Q

Cell Communication

Found in vertebrates

Contains claudins (protein)

Blocks substances from passing between cells

Creates sheets of cells to prevent substances from crossing (nutrients absorbed from food must pass through sheet) Ex: stomach

A

Tight Junction

172
Q

Cell Communication

Allows diffusion of molecules between cells through small openings

Permit small molecules or ions to pass from one cell to the other

A

Communicating junction

173
Q

Cell Communication: communicating junction

Direct communication channels between cells

Found in invertebrates & vertebrates

In invertebrates I AM formed by pannexins

In vertebrates I AM formed by connexons

I AM found in ANIMAL CELLS

What am I ?

A

Gap Junction

174
Q

Cell Communication:

Pannexin/ connexon from two cells line up to form a

A

Gap junction

175
Q

Cell Communication:

Cytoplasmic connections that form across the touching plasma membranes

A central tube that connects the Endoplasmic reticulum from 2 adjacent plant cells

In plants, cell to cell junctions occur only at holes or gaps in walls

What am I?

A

Plasmodesmata (in plants)