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NUR1142 > Module 1 - Cellular Biology > Flashcards

Module 1 - Cellular Biology Flashcards

Objectives covering Cellular Biology

1
Q

What are living cells divided into

A

Eukaryotes and Prokaryotes

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2
Q

Higher animals, plants, fungi, protozoa and some algae are made of what cells?

A

Eukaryotes

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3
Q

Give examples of Prokaryotes

A

cyanobacteria (blue green algea), bacteria, and ricketsaie

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4
Q

Cyanobacteria (blue green algae), bacteria, and ricketsaie are made up of what bacteria?

A

Prokaryotes

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5
Q

List differences between Eukaryotes and Prokaryotes

A
  1. Eukaryotes are larger and have more intensive anatomy and organization than prokaryotes
  2. Eukaryotes have organelles with well defined nucleus. Prokaryotes have no organelles and nuclear materials is not enclosed by nuclear membrane - no distinct nucleus.
  3. Eukaryotes and Prokaryotes differ in chemical composition and biochemical activity
  4. Prokaryote’s nuclei carry genetic information in a singular circular chromosomes while eurkaryotes have several or many chromosomes.
  5. Prokaryotes lack histones
  6. They also differ in protein production and synthesis
  7. They differ in mechanisms of transport across the outer cellular membrane
  8. They differ in enzyme content
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6
Q

What class of protein does prokaryotes lack?

A

Histones

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7
Q

Which type of cell contains histones?

A

Eukaryotes

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8
Q

Which type of cell does not contain histones?

A

Prokaryotes

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9
Q

What are organelles?

A

Membrane bound intracellular compartments

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10
Q

This is defined as membrane bound intracellular compartments?

A

Organelles

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11
Q

Which cell contains organelles?

A

Eukaryotes

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12
Q

Which cell does not contain organelles?

A

Prokaryotes

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13
Q

What does histones do?

A

They bind with DNA and involved in supercoiling of DNA

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14
Q

What process does cells undergo to become specialized?

A

Differentiation or maturation

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15
Q

What is differentiation or maturation?

A

Process by which cells become specialized

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16
Q

Why do cells differentiate?

A

Cells differentiate so that some cells can do certain function and others do other function.

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17
Q

What are the 8 common function of cells?

A
  1. Movement
  2. Conductivity
  3. Metabolic Absorption
  4. Excretion
  5. Secretion
  6. Respiration
  7. Reproduction
  8. Communication
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18
Q

Function of cell: Muscle cells can generate forces that produce this function.

A

Movement

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19
Q

Function of cell: Chief function of nerve cell

A

Conductivity

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20
Q

What is the the chief function of nerve cell?

A

Conductivity

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21
Q

What happens during conductivity?

A

A stimulus creates an action potential across the cell
Membrane which is propagated to other cells and cell components

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22
Q

What cell function describes the following: a stimulus creates an action potential across the cell membrane which is then propagated to other cells and cell components

A

Conductivity

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23
Q

Explain cell
Function metabolic absorption

A

All cells can take in and use nutrients and other substances from their surrounding.

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24
Q

What cell function matches the following description: all cells
Can take in and use nutrients and other substances from their surrounding.

A

Metabolic absorption

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25
Q

Describe Function Secretion

A

Some cells can synthesize new substances from other substances they absorb and secrete them as new substances than can be used elsewhere.

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26
Q

What cell function has the following description: Some cells can synthesize new substances from other substances that they absorb and secrete these new substances to be used elsewhere

A

Cell function - secretion

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27
Q

Describe the cell function excretion:

A

All cells can create waste products based from the metabolic breakdown of nutrients. Lysosomes contain the enzymes that breaks down or digest larger molecules.

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28
Q

Which cell function has the following description: All cells can create waste products resulting from metabolic breakdown of nutrients. The enzyme that breaks down these larger molecules are found in the lysosomes.

A

Excretion

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29
Q

Define Chronic cellular stress

A

When cell struggles to maintain homeostasis but reverts to an adaptive state

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30
Q

List some of cell adaptation

A

atrophy, hypertrophy, hyperplasia and metaplasia states

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31
Q

Cellular adaptation

A

Adaptive changes as a response to their environmental stressors. Adaptive - reversible changes in cell: size/number/phenotype/metabolic activity and cellular function

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32
Q

What is atrophy?

A

Decrease in cellular size but number can stay the same

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33
Q

Give examples of atrophy

A

Aging, MSK lack of use, hormone loss: post menopausal mucosal tissue

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34
Q

Aging, MSK lack of use and hormone loss are examples of what?

A

Atrophy

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35
Q

Hypertrophy

A

Increase in cellular size but number stays the same, no new phenotypical cells

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36
Q

Definition: Increase in cellular size but number stays the same, no new phenotypical cells

A

Hypertrophy

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37
Q

Examples of hypertrophy

A

Increases in organ size, often due to excessive demand, hormone or growth factor stimulation. Often is found with hyperplasia

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38
Q

Increases in organ size, often due to excessive demand, hormone or growth factor stimulation. Often is found with hyperplasia. These are examples of what?

A

Hypertrophy

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39
Q

Hyperplasia

A

Increase in number of cells

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40
Q

Can hyperplasia grow organ size?

A

It can, but now always

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41
Q

Examples of hyperplasia

A

Physiologic: Breast tissue for breastfeeding Pathologic: early predisposed cancer cells

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42
Q

Metaplasia

A

One type (phenotype) of cell is replaced by a different type of cell

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43
Q

Give examples of Metaplasia

A

Common in endothelial and connective tissue disorders.
Simple columnar epithelium change to squamous epithelium (squamous metaplasia)

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44
Q

Dysplasia

A

Deranged cellular growth (not true cellular adaptation but atypical hyperplasia)

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45
Q

Where is metaplasia common?

A

Respiratory and GI

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46
Q

What are the types of cellular injury?

A
  1. Lack of sufficient oxygen ( hypoxia)
  2. Free radicals
  3. Chemical agents
  4. Infectious agents
  5. Physical and Mechanical factors
  6. Immunologic factors
  7. Genetic factors
  8. Nutrition
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47
Q

What is the most common cellular injury?

A

Hypoxia

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48
Q

What cell function has the following description: Cells absorb oxygen which is needed to convert nutrients to energy in the form of ATP. This function occur in the organelles called mitochondria

A

Respiration

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49
Q

Describe cell function respiration

A

Cells absorbs Oxygen. Oxygen is needed to convert nutrients to energy in the form of ATP. Cellular respiration or oxidation occurs in the mitochondria

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50
Q

Where does cellular respiration or oxidation occur?

A

Mitochondria

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51
Q

Describe cell function reproduction

A

Tissue growth occurs when cell enlarges and reproduce. Even without growth, tissue maintenance still require new cells to be produced to replace cells lost through cellular death. Not all cells are capable of continous division

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52
Q

What cell function has the following description: Tissue growth occurs when cells enlarge and reproduce. Even without growth, tissue maintenance requires new cells to be produced to replace the cells lost through cellular death. Not all cells are capable of continous division.

A

Reproduction

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53
Q

What cell function has the following description: Communication is vital for cells to survive in a society of cells. Appropriate communication is important to maintain a dynamic steady state.

A

Communication

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54
Q

Describe cell function communication

A

Communication is vital for cells to survive in a society of cells. Appropriate communication is important to maintain a dynamic steady state.

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55
Q

What are the 3 components of a typical eukaryotic cell?

A
  1. Outer membrane called plasma membrane or plasmalemma
  2. Cytoplasm - fluid filling
  3. Organelles - membrane bound organs of the cell
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56
Q
  1. Outer membrane called plasma membrane or plasmalemma
  2. Cytoplasm - fluid filling
  3. Organelles - membrane bound organs of the cell
A

What are the 3 components of a typical eukaryotes

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57
Q

What surrounds the nucleus?

A

Cytoplasm

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58
Q

Where is the nucleus located?

A

Center of the cell

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59
Q

What is the largest membrane bound organelle?

A

Nucleus

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60
Q

What composes the nuclear envelope?

A

2 pliable membranes

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61
Q

What does the nuclear envelope have?

A

Nuclear pores

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62
Q

What is the function of nuclear pores?

A

It allows chemical messages in and out of the nucleus

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63
Q

What allows chemical message to exit and enter the nucleus?

A

Nuclear pores

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64
Q

The outer membrane is continous with what?

A

Endoplasmic reticulum

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65
Q

What does the nucleus contain?

A

Nucleosus, most of the cellular DNA, and DNA - binding proteins (histones)

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66
Q

What is nucleosus?

A

small dense structure in the nucleus composed mainly of RNA,

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67
Q

A small dense structure in the nucleus which contains mostly of RNA

A

Nucleosus

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68
Q

What are the DNA binding - proteins

A

histones

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69
Q

True or false: DNA chain in eukaryotic cells is so long that it is easily broken

A

True

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70
Q

True or false: DNA chain in eukaryotic cells is so long and it is not easily broken

A

False

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71
Q

What are histones?

A
  • DNA binding proteins
  • Essential for cells division in eukaryotes
  • Binds DNA which causes DNA to fold into chromosomes which decreases risk for breaks in DNA chains
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72
Q

These are DNA binding proteins which are essential for cell division. It binds DNA to fold it into chromosomes which reduces risk in breaks in DNA chains.

A

Histones

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73
Q

What happens when DNA folds into chromosomes?

A

Reduces the risk of breaks in the DNA chains.

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74
Q

What are the function of nucleus

A
  • Primary are cell division and control of genetic information
  • Other include replication and repair of DNA
  • Transcription of information stored in DNA
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75
Q

Which cellular component has the following functions:
1. Cell division and control of genetic information
2. Replication and repair of DNA
3. Transcription of information stored in DNA

A

Nucleus

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76
Q

Most of the processing of RN occurs in the _____________

A

Nucleolus

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77
Q

Genetic information is transcribed into _______ which can be processed into various forms.

A

RNA

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78
Q

What is cytoplasmic matrix?

A

Space between the nuclear envelope and plasma membrane

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79
Q

Space between the nuclear envelope and plasma membrane

A

Cytoplasmic matrix

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80
Q

What is cytoplasm?

A

Also called as cytosol, this is an aqueous solution that fills the cytoplasmic matrix.

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81
Q

What is another name for cytoplasm

A

Cytosol

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82
Q

This is an aqueous solution that fills the cytoplasmic matrix

A

Cytoplasms

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83
Q

Cytosol represents _____the volume of a eukaryotic cells.

A

half

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84
Q

What represents half the volume of eukaryotic cells?

A

Cytosol

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85
Q

What does cytosol contain?

A
  • Thousands of enzymes involved in intermediate metabolism
  • Crowded by ribosomes making protein
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86
Q

What part of the cell has thousands of enzymes which are involved in intermediate metabolism and is crowded by ribosomes making protein

A

Cytosol

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87
Q

The organelles embedded in the cytoplasm have their own _____________.

A

Biological membranes

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88
Q
A
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89
Q

What directs the function of the organelles ?

A

They are directed by coded messages carried from the nucleus by RNA

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90
Q

List some of the functions of organelles?

A
  1. Protein and hormone synthesis and transport
    2 . Maintenance of cellular structure and motility
  2. Cellular metabolism
  3. Processing and elimination of waste including cellular debris and foreign antigen and debris
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91
Q

Cytosol is a storage unit for ?

A

Fat, carbohydrates, and secretory vesicles.

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92
Q

Fat, carbohydrates and vesicles are stored in what part of the cell?

A

Cytosol

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93
Q

What are Ribosomes?

A

RNA protein complexes that (nucleoproteins). They are synthesized in the nucleolus and released into the cytoplasm. They provide sites for cellular protein synthesis.

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94
Q

Where are ribosomes synthesized ?

A

Nucleolus

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95
Q

Where are ribosomes released once synthesized?

A

Cytoplasm

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96
Q

What does ribosome provide?

A

Provides sites for cellular protein synthesis

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97
Q

What is the endoplasmic reticulum ?

A

Endoplasmic reticulum is a network of tubular channels or cisternae that extend throughout the outer nuclear membrane. It specializes in synthesis and transport of proteins and lipid components of most organelles.

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98
Q

What organelle has the following description? It is a network of tubular channels or cisternae that extends throughout the outer nuclear membrane. It specializes in the synthesis and transport of protein and lipid components of most organelles.

A

Endoplasmic Reticulum

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99
Q

What does endoplasmic reticulum specialize in?

A

Synthesis and transport of protein and lipid components of most organelles.

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100
Q

Describe structure and function of Golgi Complex

A

Golgi complex is a network of smooth membranes and vesicles that’s close to the nucleus. It is responsible for processing and packaging proteins onto secretory vesicles that breaks away from the complex and migrates into various intracellular and extracellular destinations including the plasma membrane. Best known vesicles are those with coats that are largely made up of protein called clathrin. Proteins in the structure bind to cytoskeleton which generates tension that helps organelle function and keep the complex’s stretch shape intact.

101
Q

Which organelle has the following description: It is a network of smooth membranes and vesicles that is close to the nucleus. It processes and packages proteins onto secretory vesicles which breaks off the complex and migrates to various intracellular and extracellular destinations including the plasma membrane. The best known vesicles are those with coats that are largely made up of proteins called clathrin. Proteins in the complex binds into the cytoskeleton. This generates tension which helps the organelle function and keep the complex’s stretched shape intact.

A

Golgi complex

102
Q

Describe Lysosomes

A

Lysosomes are sac like structures that originates from the golgi complex and contain enzymes for digestion of cellular substances to their basic forms (amino acids, fatty acid, carbs). Cellular injury leads to the release of lysosomal enzymes that cause cellular destruction.

103
Q

What organelle has the following description: It is a sac like structure that originates from the golgi complex and contains enzymes for digesting cellular substances to their basic forms (amino acides, fatty acids, and carbs). Cellular injury leads to the release of lysosomal enzymes that causes cellular self-destruction.

A

Lysosomes

104
Q

What are the best known vesicles in the golgi complex?

A

Those vesicles that have coats made largely of a protein called clathrin

105
Q

What is the golgi complex responsible for?

A

It is responsible for the processing and packaging of protein onto secretory vesicles that breaks of the bind and migrates to cellular intracellular and extracellular destinations.

106
Q

What are peroxisomes?

A

Peroxisomes are structures similar to lysosomes. They contain oxidative enzymes that produce and use hydrogen peroxide; reaction detoxifies various wastes

107
Q

What organelle has the following description: Structure like lysosomes that contain oxidative enzymes which produce and use hydrogen peroxide.

A

Peroxisomes

108
Q

Describe mitochondria?

A

Structures that contain metabolic machinery that are needed for cellular energy metabolism. Enzymes of respiratory chain which is found in the inner membrane of the mitochondria, generates most of the cell’s ATP. They have a role in osmotic regulation, PH control, calcium homeostasis and cell signalling.

109
Q

What cell organelle has the following description?Structures that contain metabolic machinery that are needed for cellular metabolism. Enzymes of the respiratory chain, which is found in the inner membrane of the mitochondria, generates most of the cell’s ATP. They have a role in osmotic regulation, PH control, calcium homeostasis, and cell signalling.

A

Mitochondria

110
Q

Describe Cytoskeleton

A

Cytoskeleton is the bone and muscle of the cell. It is composed of a network of proteins which includes microtubules and actin filaments (microfilaments). It forms cell extensions such as microvilli, cilia, and flagella.

111
Q

Describe Caveolae

A

Tiny indentations or caves that can capture extracellular material and shuttle it inside the cell or across the cell. It serves as a storage site for many receptors, provide route of transport into the cell, and act as the initiator for relaying signals from several extracellular chemical/ messenger into the cell’s interior

112
Q

Describe Vaults

A

Cytoplasmic ribonucleoproteins that are shaped like octagonal barrels. They are thought to act like truck that shuttles molecules from the nucleus to elsewhere in the cell

113
Q

What cell organelle has the following description: Bones and muscles of the cell. It is composed of a network of proteins which include microtubules and actin filaments (microfilaments). They form cell extension such as flagella, microvilli, and cilia.

A

Cytoskeleton

114
Q

What cell organelle has the following description: Indentation or caves that can capture extracellular material and shuttle it inside the cell or across the cell.

A

Caveolae

115
Q

What cell organelle has the following description: Cytoplasmic ribonucleoproteins shaped like octagonal barrell. They are thought to act like trucks that shuttles molecules from the nucleus to elsewhere in the cell.

A

Vaults

116
Q

How does membranes exert a powerful influence on metabolic pathways?

A

By controlling movement of substances from one compartment to another.

117
Q

What is the benefit with the membrane’s ability to control movement of substances from one compartment to another?

A

Through this ability, the membrane is able to exert powerful influence on metabolic pathways.

118
Q

Every cell is contained within an a.)_________ with b.)______, c.)______, and d.)________.

A

a.) membrane
b.) gates, c.)channel and d.)pumps

119
Q

What are the functions for plasma membrane?

A
  1. Structure
  2. Protection
  3. Activation of cell
  4. Storage
  5. Cell to Cell interaction
120
Q

How is directional transport facilitated?

A
  1. Through distribution of charge within a cell
  2. Differences in structure of one aspect of the cell when compared to another.
121
Q

What maintains normal cell and tissue structure for numerous function?

A

Cell polarity and direction of cellular transport.

122
Q

Describe the plasma membrane function: Structure

A

Plasma membrane is a thicker structure than membranes of organelles. Functions are. Outer surfaces of plasma membranes in many cells are not smooth. They are dimpled with cave like indentations called caveolae. They are also studded with cilia or microvilli - both are capable of movements.
1. Containment of the organelles
2. Maintenance of relationship with cytoskeleton, ER, and other other organelles
3. Maintenance of fluid and electrolyte balance.

123
Q

What membrane function has the following description:Plasma membrane is a thicker structure than membranes of organelles. Functions are. Outer surfaces of plasma membranes in many cells are not smooth. They are dimpled with cave like indentations called caveolae. They are also studded with cilia or microvilli - both are capable of movements.
1. Containment of the organelles
2. Maintenance of relationship with cytoskeleton, ER, and other other organelles
3. Maintenance of fluid and electrolyte balance.

A

Structure

124
Q

Describe the membrane function Protection?

A

It acts as a barrier to toxic molecules or macromolecules such as protein, polysaccharides, nucleic acid. It also acts a barrier against foreign organisms and cells

125
Q

What membrane function has the following description: It acts as a barrier against toxic molecules or macromolecules (protein, nucleic acid, polysaccharides). It acts as a barrier against foreign organisms and cells.

A

Protection

126
Q

Describe the membrane function activation of cell?

A
  1. Hormones (regulation of cellular activity)
  2. Mitogens (cell division)
  3. Antigens (antibody synthesis)
  4. Growth factors (proliferation and differentiation)
127
Q

Describe the membrane function Storage

A
  1. It is a site of storage of many receptors
  2. Transport
  3. Diffusion and exchange diffusion
  4. Endocytosis (Pinocytosis, phagocytosis)
  5. Exocytosis (secretion)
  6. Active Transport
128
Q

Describe the membrane function cell-to-cell interaction?

A
  1. Communication and attachment at junctional complexes
  2. Symbiotic nutritive relationships
  3. Release of enzymes and antibodies to extracellular environment.
  4. Relationship with extracellular matrix.
129
Q

What is the basic structure of the cell membrane?

A

The basic structure of the cell membrane if the phospholipid bilayer.

130
Q

Describe the phospholipid bilayer

A
  • It is a complex structure where lipids and proteins are not uniformly distributed but can separate into discrete units called microdomains, differing in their lipid and protein compositions.
  • Different membranes have varying percentages of protein and lipids.
  • It is composed of 2 layers of lipid molecules - 1 layer with a phospholipid head attached to two fatty acid chains
  • Proteins also span the bilayer to form channels and receptors that later processes inside the cell.
131
Q

What are the 3 physical states or phases of the cell membrane?

A
  1. solid gel phase
  2. fluid-liquid cystalline phase
  3. liquid ordered phase
132
Q

What determines the phases of the cell membranes?

A

It is determined by the physical bond between the larger proteins in the bilayer.

133
Q

Cell membranes are dynamic and can change under physiological factors such as temperature and pressure fluctuations. True or False

A

True

134
Q

Cell membranes are a.____________ and change change under physiological changes such as b.___________________ and c.________________.

A

a. dynamic
b. temperature
c. pressure

135
Q

How can carbohydrates be associated with plasma membrane?

A

They can be associated with plasma membrane when they are chemically combined with lipids and with proteins.

136
Q

What part of the cell membrane provides storage site for many receptors?

A

Caveolae

137
Q

What causes the membrane to spontaneously organize itself into 2 layers?

A

This is caused by the incompatible solubilities. The lipid molecule is polar or amphipathic. This means that one part is hydrophobic and the other part is hydrophilic. The bilayer serves as a barrier to the diffusion of water and hydrophilic substances while allowing lipid soluble molecules (e.g. O2 and CO2) to diffuse through the membrane readily. The structure of the cell membrane also makes it more difficult for water-soluble medications and ionized medications to enter the cell.

138
Q

What are the most abundant lipids in the cell membrane?

A

Phospholipids

139
Q

What forms self sealing lipid bilayers in the plasma membrane?

A

Phospholipids and glycolipids

140
Q

What acts as a molecular glue for structural integrity of the membrane and form the membrane lipid rafts (MLRs)

A

Lipids and associated proteins

141
Q

What does lipids and associated proteins act as?

A

They act as a molecular glue for the structural integrity of the membrane and forms the membrane lipid raft (MLR)

142
Q

What are MLR

A

MLR or membrane lipid rafts appears to be functionally and structurally distinct regions of the plasma membrane that has numerous microdomains that form various interaction of protein to protein, lipid to lipid and lipid to protein interactions

143
Q

What are the functions for MLR?

A
  1. Cellular polarity and corresponding communication of cellular signals
  2. Platform for ECM adhesions and cellular structure through CAMs (cellular adhesion molecules)
  3. Signaling across the membrane which can alter the structure of the cytosol and regulate cell growth, movement and other functions
  4. Entry of viruses, bacteria, toxins, nanoparticles
144
Q

What are proteins made from ?

A

Proteins are made from a chain of amino acids known as polypeptide

145
Q

What are polypetides?

A

Polypeptides are chains of amino acids that makes up protein

146
Q

How many types amino acids are in proteins?

A

There are 20 types of amino acids in proteins

147
Q

True or False: Each type of protein has similar sequence of amino acids

A

False

148
Q

True or False: Each type of protein has unique sequence of amino acids

A

True

149
Q

How is protein synthesized

A

Through the translation of RNA

150
Q

A protein might undergo a series of ____________ that further impact and diversify protein function in the cell.

A

Post Translational modifications (PTMs)

151
Q

What can PTMs do and why is it important?

A

PTMs can alter the activity and function of proteins and have become important in understanding the nature of disease.

152
Q

Researchers have known for decades that _______can interfere with the host’s PTMs.

A

pathogens

153
Q

Where are membrane proteins synthesized?

A

ribosomes

154
Q

Membrane structure is determine by ______________.

A

Lipid bilayer

155
Q

Membrane functions are determine largely by ___________.

A

Proteins

156
Q

Proteins act as a:

A
  1. recognition and binding units for substances going in and out of the cells
  2. pores or transport channels for various electrically charged particles called ions or electrolytes and specific carriers for amino acids and monosaccharides
  3. specific enzymes that drive active pumps to promote concentrations of other ions particulary K within the cell while keeping concentrations of other ions (Na+) less than concentrations found in the extracellular environment.
  4. cell surface markers such as glycoproteins that identify a cell to its neighbor
  5. CAMs or proteins that allow cells to hook together and form attachments of the cytoskeleton for maintaining cellular shape
  6. Catalyst of chemical reactions
157
Q

What are the different ways membrane proteins associate with lipid bilayer?

A
  1. Transmembrane proteins that extend across the bilayer and are exposed to an aqueous environment on both sides of the membrane.
  2. proteins located almost entirely in the cytosol and are associated with the cytosolic half of the lipid bilayer by and alpha helix exposed on the surface of the protein
  3. proteins that exist outside the bilayer, on one side or the other and are attached to the membrane by one or more covalently (or chemically bonded) attached lipid groups
  4. proteins bound indirectly to one or the other bilayer membrane face, held in place by their interactions with the other proteins
158
Q

True or False: Proteins exist in densely folded molecular configurations rather than straight chains

A

True

159
Q

True or false: Proteins exist in straight chains rather than densely folded molecular configurations

A

False

160
Q

Where are most hydrophilic units found?

A

Surface of the molecule

161
Q

Where are most hydrophobic units found?

A

Inside the molecule

162
Q

Where are membrane proteins synthesized?

A

Ribosomes

163
Q

How do membrane proteins make their way to different membrane locations of a cell?

A

Through the process call trafficking

164
Q

Explain the process Trafficking

A

Trafficking is the process that helps membrane proteins make their way to different locations of a cell. Trafficking places unique demands on membrane proteins for folding , translocation, and stability.

165
Q

Where is the primary site for protein folding in the cell?

A

The ER (endoplasmic reticulum)

166
Q

What can alter or decrease the rate of protein folding?

A

ER or cell stress, mutations, or random errors during protein synthesis.

167
Q

What can disrupt the sensitive ER environment?

A

Viral infections, environmental toxins, and mutant protein expressions. Natural processes such as large protein synthesizing load placed on the ER can perturb the ER environment.

168
Q

What can ER perturbations cause?

A

Accumulation of immature and abnormal proteins in cells which leads to ER stress.

169
Q

What is unfolded protein response UPR?

A

These are pathways. The ER can actually mediate intracellular signalling pathways in response to the accumulation of unfolded or misfolded proteins.

170
Q

What are the key components of energy transduction?

A

Membrane proteins.

171
Q

What does ATP enzymes affect?

A

They affect the shape of biological membranes particularly mitochondrial membranes.

172
Q

The cellular protein pool is in a state of __________________.

A

Constant flux

173
Q

The number of copies of a protein in a cell dependent on what factors?

A

It depends on how quickly it is made and how long it survives or is broken down.

174
Q

The adaptable system of protein homeostasis is defined by what network?

A

Proteostasis network

175
Q

What comprises the proteostasis?

A

ribosomes (makers), chaperones (helpers), and 2 protein break down systems (proteolytic systems).

176
Q

What are the 2 proteolytic systems?

A

Lysosomes and UPS (ubiquitin proteasome system)

177
Q

What systems regulate protein homeostasis?

A

Proteolytic systems

178
Q

What conditions does proteolytic systems regulate protein homeostasis under ?

A
  1. Variations in nutrient supply
  2. Existence of oxidative stress or free radicals
  3. Cellular differentiation
  4. Changes in temperature
  5. Presence of heavy metal ions and other sources of stress
179
Q

True or false: Malfunction or failure of the proteostasis network is associated with human disease

A

True

180
Q

True or false: Malfunction or failure of the proteostasis network is not associated human disease

A

False

181
Q

What are the short chains of carbohydrates that are contained within the plasma membrane bound to?

A

Membrane proteins (glycoproteins) and lipids (glycolipids).

182
Q

What are proteoglycans?

A

Long polysaccharide chains that are attached to membrane proteins.

183
Q

What is the glycocalyx?

A

Carbohydrate coating outside the plasma membrane. These carbohydrates are on the glycoproteins, proteoglycans and glycolipids.

184
Q

Explain some of the function of glycocalyx.

A
  1. Protects cells from mechanical damage
  2. Assists with mobility of some cells by making surface layer of the cell slimy (e.g. leukocytes).
  3. Specific cell-cell recognition and adhesion
185
Q

What are cellular receptors?

A

Protein molecules on the plasma membrane, cytoplasm, or on the nucleus that can recognize and bind with specific smaller molecules called ligands.

186
Q

What do you call the region of a protein that associates with a ligand?

A

Binding sites

187
Q

Give examples of ligands that bind to receptors

A

Hormones, neurotransmitters, antigens, complement components, lipoproteins, infectious agents medications, metabolites.

188
Q

What does recognition and binding depend on?

A

Chemical configuration of the receptor and its smaller ligand, which must fit together somewhat like pieces of a jigsaw puzzle.

189
Q

Binding selectively to a protein receptor with high affinity to a ligand depends of what factors?

A
  1. Formation of weak, noncovalent interactions - hydrogen bonds, electrostatic attractions, and Van der Waals attraction
  2. Favourable hydrophobic forces
190
Q

What can happen when ligand binds to receptors?

A

It can activate or inhibit the receptor’s associated signaling or biochemical pathway.

191
Q

How are receptors classified?

A

Receptors are classified based on their location and function even though the chemical nature of ligands and their receptors differ.

192
Q

What does cellular type determine

A

It determines overall cellular function.

193
Q

What determines cellular function?

A

Cellular type

194
Q

What does plasma membrane receptors determine?

A

It determines which ligand a cell will bind with and how the cell will respond to the binding.

195
Q

What determines which ligand a cell will bind with and how the cell with respond to the binding?

A

Plasma membrane receptors

196
Q

Receptors for different medications are found where?

A

Plasma membrane, in the cytoplasm, and in the nucleus.

197
Q

What are the opiate like peptides?

A

Endorphins

198
Q

What happens with endorphins bind to a receptor?

A

1.It changes the cell’s permeability to ions
2. Increases the concentration of molecules that regulate intracellular protein synthesis
3. Initiates molecular events that modulate pain perception

199
Q

Where are membrane receptors for endorphins found?

A

It is found in large quantities in pain pathway of the nervous system

200
Q

Aside from serving as outer boundaries of all cells, what is another function of plasma membranes?

A

It allows groups of cells to be held together robustly, in cell-to-cell adhesions to form tissues and organs.

201
Q

What are the 3 different means that cells are linked?

A
  1. CAMs in the cell’s plasma membrane
  2. ECM
  3. Specialized cell junctions
202
Q

What secretes ECM (extracellular matrix)?

A

Fibroblasts

203
Q

What do you call the cells and matrix within the ECM?

A

Connective tissue because they interconnect cells to form tissues and organs.

204
Q

Describe the ECM

A

ECM is an intricate meshwork of fibrous protein embedded in a watery gel-like substance composed of complex carbohydrates.

205
Q

What are some of the function of the ECM

A
  1. Acts like a glud
  2. Provides pathways fer diffusion of nutrients, wastes and water-soluble substances between the blood and tissue cells.
  3. Matrix helps regulate the function of the cells within it.
206
Q

What are the 3 macromolecules within the matrix?

A
  1. Fibrous structural proteins - elastin and collagen
  2. adhesive glycoproteins - fibronectin
  3. proteoglycans and Hyaluronic acids
207
Q

Describe collagen

A

Forms cablelike sheets or fibers that provides tensile strength or resistance to longitudinal stress.

208
Q

What macromolecule in the matrix has the following description: Forms cablelike sheets or fibers that provides tensile strength or resistance to longitudinal stress.

A

Collagen

209
Q

Describe Elastin

A

Rubberlike protein fibre most abundant in tissues that must be capable of stretching and recoiling. For instance, the lungs have an abundance of elastin, which is responsible for the passive recoil of the lungs on expiration

210
Q

What macromolecule in the matrix has the following description: rubberlike protein fibre most abundant in tissues that must be capable of stretching and recoiling. For instance, the lungs have an abundance of elastin, which is responsible for the passive recoil of the lungs on expiration

A

Elastin

211
Q

Describe Fibronectin

A

large glycoprotein, promotes cell adhesion and cell anchorage

212
Q

What macromolecule in the matrix has the following description:large glycoprotein, promotes cell adhesion and cell anchorage

A

Fibronectin

213
Q

What are specialized cell junctions?

A

Unique membrane regions where cells come into direct physical contact with other cells of the same tissue, and they are classified by their function:

214
Q

What are the functions of cell junctions?

A
  1. Protect the integrity of epithelium through mechanical attachment
  2. provide communication of the cells with each other while maintaining cell polarity.
215
Q

List some of the cell junctions and their functions

A
  1. Tight Junctions: some hold cells together and form a tight seal, some maintain polarity across the apical and basal aspects of individual epithelial cells
  2. adherens junction, desmosomes, hemidesmosomes - provide strong mechanical attachments
  3. Gap junctions: provide a special type of chemical communication which involves the movement of ions and small water-soluble molecules and cause an electrical wave
216
Q

Which cell junction does the following:provides a special type of chemical communication which involves the movement of ions and small water-soluble molecules and cause an electrical wave

A

Gap function

217
Q

Which cell junction does the following:provide strong mechanical attachments

A

adherens junctions, desmosomes, hemidesmosomes

218
Q

Which cell junction does the following:provides a special type of chemical communication which involves the movement of ions and small water-soluble molecules and cause an electrical wave

A

tight junctions

219
Q

What are tight junctions

A
  • They are barriers to diffusion,
  • they prevent movement of substances through transport proteins in the plasma membrane
  • prevents the leakage of small molecules between the plasma membrane of adjacent cells.
220
Q

What are gap junctions:

A

clusters of communicating tunnels or connexons that allow small ions and molecules to pass directly from the inside of one cell to the inside of another

221
Q

What are connexons?

A

Connexons are communicating tunnels , are made of small protein molecules connexins spanning the cell membrane. It extends outwards from each of the adjacent plasma membranes.

222
Q

These are communicating tunnels , are made of small protein molecules connexins spanning the cell membrane. It extends outwards from each of the adjacent plasma membranes.

A

Connexons

223
Q

What factors regulate the gap junction intracellular communication

A
  1. Voltage across the junction
  2. intracellular pH
  3. Intracellular Ca++ concentration
  4. Protein phosphorylation
224
Q

What is the most abundant human connexin ?

A

Cx43

225
Q

What is Cx43

A

Tumor Suppressor, important prognostic maker and target for therapy

226
Q

What is the junctional complex?

A
  • Highly permeable part of the plasma membrane.
227
Q

What controls the permeability of the junctional complex?

A

It is controlled by a process called gating

228
Q

Describe the process gating

A

This is where increased levels of cytoplasmic calcium from injured cells cause decreased permeability at the junctional complex. Gating enables uninjured cells to protect themselves from injured neighbouring cells.

229
Q

What does the gating process enable?

A

It enables uninjured cells to protect themselves from injured neighbouring cells.

230
Q

What are the 4 main reasons why cells need to communicate?

A
  1. For the maintainance of a stable internal environment or homeostatis
  2. Regulation of growth and division
  3. Development and organization of cells into tissues
  4. Coordination of their functions
231
Q

What are the 3 main ways cells communicate with each other?

A
  1. they display plasma membrane–bound signalling molecules (receptors) that affect the cell itself and other cells in direct physical contact
  2. they affect receptor proteins inside the target cell, and the signal molecule has to enter the cell to bind to them
  3. they form protein channels (gap junctions) that directly coordinate the activities of adjacent cells
232
Q

What does alterations in cell communication do?

A

It affects the disease onset and progression.

233
Q

Paracrine

A

Hormones working on nearby cells

234
Q

Autocrine

A

Hormones from the cell target the same cell

235
Q

Give examples of neurohormonal

A

renin-angiotensin-aldosterone and sympathetic nervous system

236
Q

Give examples of neurotransmitter

A

norepinerphone and acetylcholine

237
Q

What does contact dependent signalling require?

A

It requires cells to be in close membrane - membrane contact

238
Q
A
238
Q

This type of signalling requires cells to be in close membrane-membrane contact.

A

Contact-dependent signalling

239
Q

Explain Paracrine signalling

A

In this type of signalling, cells secrete local chemical mediators that are quickly taken up, destroyed, or immobilized. Paracrine signalling usually involves different cell types;

240
Q

Explain autocrine signalling

A

In this type of signaling, cells also can produce signals to which they alone respond.

241
Q

Explain Hormonal Signaling

A

Involves specialized endocrine cells that secrete chemicals called hormones; hormones are released by one set of cells and travel through the bloodstream to produce a response in other sets of cells

242
Q

Explain neurohormonal signaling

A

Hormones are released into the blood by neurosecretory neurons. Like endocrine cells, neurosecretory neurons release bloodborne chemical messengers, whereas ordinary neurons secrete short-range neurotransmitters into a small discrete space (

243
Q

What are the types of plasma membrane receptors?

A
  1. Ion channel coupled
  2. Enzyme coupled
  3. G-protein coupled
244
Q

Describe ion channel coupled

A
  • Also called transmitter-gated ion channel
  • Involve rapid synaptic signaling between electrically excitable cells
  • Channels open and close briefly in response to neurotransmitters, changing ion permeability of plasma membrane of post-synaptic cell
245
Q

Describe enzyme coupled

A

Once activated by ligands, function directly as enzymes or associate with enzyme

246
Q

Describe G-protein coupled

A
  • indirectly activate or inactivate plasma membrane enzyme or ion channel
  • interaction mediated by GTP-binding regulatory protein
  • May also interact with inositol phospholipids which are significant in cell signaling and with molecules involved in inositol-phospholipid transduction pathway.
247
Q

What are transduction pathways

A

They are communication pathways or signalling cascades

248
Q

What happens when cells are deprived of appropriate signals?

A

Most cells undergo a form of call suicide known as programmed cell death, or apoptosis

NUR1142 (112 decks)

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