Fundamental features of eukaryotic cells Flashcards

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1
Q

What are the fundamental features of a eukaryotic cell that you don’t see in prokaryotic cells?

A

Membranes provide compartments for processes inside the cell

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2
Q

What is the main method of reproduction in Prokaryotes?

A

Binary fission, mostly asexual

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3
Q

What is the main method of reproduction in Eukaryotes?

A

Mitosis or meiosis, mostly sexual

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4
Q

What function does compartmentation in the cell serve?

A

Differences in pH across the membrane inside the cell

Metabolic regulations by keeping enzymes/substrate separate

Isolate toxic substances

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5
Q

What affect does SA:V ration have on a cell?

A

limits the rate of exchange

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6
Q

Why are cells small?

A

Need to be able to communicate with the environment, and quick communication within the cell.

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7
Q

What is a coenocyte?

A

Large cell with multiple nuclei and chloroplast.

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8
Q

What are the main components of the Plasma membrane?

A

bilayer of phospholipids, with various proteins embedded

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9
Q

What makes up a phospholipid?

A

hydrophilic phosphate head, glycerol molecule and hydrophobic two fatty acid tails.

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10
Q

What is an amphiphatic molecule?

A

Has both hydrophilic and hydrophobic parts (polar and non polar)

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11
Q

What is contained within the nucleus?

A

Most of the genes contained within a eukaryotic cell

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12
Q

Describe the membrane around the nucleus

A

Is an envelope, perpetuated by pore structures which are lined by protein complexes that regulate entry and exit of materials.

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13
Q

How is DNA organised in the nucleus?

A

In chromosomes, which are made of chromatin.

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14
Q

How many chromosomes does a human have?

A

46

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15
Q

What processes take place within the nucleus?

A

Synthesis of mRNA with the instructions provided by the DNA.

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16
Q

What does the Endoplasmic Reticulum consist of?

A

network of membranes and tubules called cisternae, connected to the nuclear envelope

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17
Q

What is the role of the SER?

A

varies within cell type, lots of metabolic processes, e.g.. synthesis of lipids, modification of carbs and detoxification of drugs and poisons

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18
Q

What is different about the RER and SER?

A

RER has bound ribosomes

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19
Q

How do proteins leave the ER?

A

In vesicles

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20
Q

What is the name for vesicles in transit?

A

Transport vesicles

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21
Q

What are the roles of the ER?

A

protein processing, phospholipid production and membrane production

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22
Q

How is the RER a membrane making factory?

A

It grows in place by adding membrane proteins and phospholipids to its own membrane.

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23
Q

What is the role of the Golgi apparatus?

A

centre of manufacturing, modification, sorting and shipping

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24
Q

What is the structure of the golgi apparatus?

A

flattened membrane sacs, cisternae, all staked up.

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25
Q

What are the cis and trans ends of the Golgi apparatus?

A

They are the poles, vesicles carrying unprocessed molecules fuse to the cis and, and the trans face gives rise to new vesicles leaving the golgi

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26
Q

What macromolecules does the golgi process?

A

secretes polysaccharides

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27
Q

What is the cisternae maturation model?

A

movement of cis to trans face

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28
Q

How are vesicles identified by the cell?

A

Molecular identification tags, e.g. phosphate groups.

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29
Q

What is the cytoskeleton?

A

a network of fibres that organise structures and activities inside the cell

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30
Q

What is the role of the cytoskeleton?

A

Gives support and maintains cell shape
Involved in cell motility
Regulation og biochemical activities inside the cell

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31
Q

How doe the cytoskeleton provide support in the cell?

A

Stabilised by balance between pressing forces executed by its elements, provides anchorage for organelles

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32
Q

why is the cytoskeleton important in animals?

A

No cell wall for support

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33
Q

How is the cytoskeleton different to the animal skeleton?

A

More dynamic, can be quickly dismantled and reassembled.

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34
Q

How is the cytoskeleton involved in cell motility?

A

Interaction of the cell with motor proteins.

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35
Q

How do motor proteins promote movement of vesicles along cytoskeleton?

A

Attach to receptors on the and can walk them along the microtubule/filaments, pathways called monorails.

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36
Q

How to motor proteins make filaments move?

A

Gripping organelles with microtubules and can slide them against one another

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37
Q

Describe the structure of microtubules

A

Hollow roads made from globular protein tubulin. Each protein is dimer

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38
Q

What does it mean if a protein is a dimer?

A

made of two subunits

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39
Q

What are the two subunits in the globular protein tubular?

A

alpha tubulin and beta tubulin

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40
Q

What is the role of microtubules

A

maintain cell shape, cell motility, chromosome movement, organelle movement

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41
Q

What is the role of the centrosome?

A

an organelle that serves as the main microtubule organizing center of the animal cell
pulling chromatids apart in cell division

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42
Q

Where is the centrosome often located?

A

near the nucleus

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43
Q

How are microtubules arranged within the centromere?

A

There is a pair of centrioles, each composed of nine sets of microtubules arranged in a ring.

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44
Q

What happens to the centriole before division?

A

replicates

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45
Q

What is kinesin?

A

a motor proteins found in eukaryotic cells. Kinesins move along microtubule filaments, generally from the centre of a cell to the periphery

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46
Q

What is dyein?

A

A motor protein. Dyneins are important in sliding microtubules relative to one other during the beating of cilia and flagella

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47
Q

What are ATPases?

A

class of enzyme that hydrolyse ATP to ADP to drive a chemical reaction

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48
Q

Name an ATPase

A

dyein and kinesin

49
Q

What are cilia and flagella?

A

locomotor appendages

50
Q

How are cilia and flagella held in place on the cell?

A

are part of a tissue layer in the cell

51
Q

What is the role of cilia and flagella?

A

move cell or to move fluid over the surface of the cell

52
Q

What is the difference between cilia and flagella?

A

Flagella are larger
Cilia appear in larger numbers
Different beating patterns

53
Q

What is a primary cilium?

A

non motile signal receiver for the cell

54
Q

Describe the ultrastructure of cilia and flagella

A

core of microtubules sheathed in extension of plasma membrane, nine doublets of microtubules arranged in a ring.

55
Q

What is the role of a microfilament?

A

Actin, maintain cell shape, contraction, cytoplasmic streaming, cell motility/division

56
Q

What is the structure of a microfilament?

A

Solid rods, built from globular protein actin, a twisted chain if two subunits

57
Q

What is the structural role of microfilaments?

A

To bear tension

58
Q

What is the cortex?

A

`Semisolid layer of cytoplasm near cell membrane due to network of microfilaments.

59
Q

How are microfilaments important in cell motility?

A

Part of contractile apparatus, Filaments arranged parallel along the length of muscle cell, with thicker myosin filaments, motor proteins on filaments cause shortening of the cell.

60
Q

What is the role of an intermediate filament?

A

maintains cell shape, anchorage, formation of nuclear lamina

61
Q

How can you distinguish an intermediate filament?

A

Longer than microfilament, shorter than microtubule.

62
Q

What are intermediate filaments specialised for?

A

specialised for bearing tension

63
Q

How do intermediate filaments differ in cell types?

A

composed of different subunits

64
Q

What is different about intermediate filaments?

A

more permanent fixtures of the cell than other parts of cytoskeleton, persist even after cell death e.g.. the other layer of skin.

65
Q

What are vacuoles?

A

Diverse, membrane bound, maintenance compartments

66
Q

What are the different types of vacuoles?

A

Food vacuoles
Contractile vacuole
central vacuole

67
Q

What are food vacouoles?

A

formed by phagocytes, digestive function, takes up food by phagocytosis

68
Q

What are contractile vacuoles?

A

found in fresh water protists, pump excess water out of the cell to maintain a suitable concentration of ions and molecules in the cell

69
Q

Where is the central vacuole found?

A

In mature plants

70
Q

How does the central vacuole develop?

A

coalescence of smaller vacuoles that have derived from the ER

71
Q

How does the selectivity of the vacuole membrane affect the cell?

A

Solution inside the vacuole differs from the composition of the cytoplasm.

72
Q

What is the solution inside the vacuole called?

A

cell sap

73
Q

What is the role of vacuoles in seeds?

A

Hold reserves of important organic compounds in the storage cells

74
Q

Give examples of inorganic ions stored in vacuoles

A

Phosphate and Chloride

75
Q

Why is phosphate important in plants?

A

component of nucleic acid structure that regulates protein synthesis, important in growth. Also plays a role in photosynthesis

76
Q

What role does the vacuole play in metabolism?

A

disposal for metabolic waste and by-products that could endanger the cell if they were left to accumulate.

77
Q

How many vacuoles be used in petals?

A

contain pigments to colour the cells

78
Q

How could the vacuole be used to protect against predators?

A

Contain compounds that are poisons that are toxic to animals

79
Q

How are vacuoles involved in the growth of cells?

A

absorb water to make the cells enlarge

80
Q

What is the roles of mitochondria and chloroplasts?

A

change energy from one form to another

81
Q

What is the role of mitochondria?

A

site of cellular respiration

82
Q

What is respiration?

A

the metabolic process that generates ATP by extracting energy from sugars, fats and other fuels with the help of oxygen

83
Q

What are Chloroplasts?

A

The site of photosynthesis

84
Q

Where are chloroplasts found?

A

In plants and some algae

85
Q

What is Photosynthesis

A

Conversion of solar energy to chemical energy using sunlight to drive the synthesis of organic compounds such as sugars, from co2 and water

86
Q

How many membranes do mitochondria have?

A

Two

87
Q

How many membranes do chloroplasts have?

A

Three

88
Q

How are membranes off mitochondria and chloroplasts made?

A

By their own ribosomes, which are smaller than the cell ribosomes

89
Q

How do mitochondria and chloroplasts program protein synthesis?

A

Contain a small amount of their own DNA

90
Q

What does semi autonomous mean?

A

Acting independently to some degree

91
Q

How are mitochondria and chloroplast semiautonomous?

A

Grow and reproduce themselves inside the cell, have their own DNA and ribosomes

92
Q

Where are mitochondria found?

A

In all eukaryotic cells

93
Q

How can you tell how active a cell is?

A

by how many mitochondria it has, more mitochondria in more active cells

94
Q

How big is a mitochondria?

A

1-10 micrometers

95
Q

How is the outer membrane of mitochondria structured??

A

smooth

96
Q

How is the inner mitochondrial membrane structured?

A

Convoluted

97
Q

What are the inholdings of the mitochondrial membrane?

A

Cristae

98
Q

What is the name of the area between the two mitochondrial membranes?

A

Intermebrane space

99
Q

What is inside the mitochondria?

A

Matrix, containing enzymes, DNA and ribosomes

100
Q

What is the benefits of the convoluted inner mitochondria membrane?

A

Much larger surface area for the reactions of respiration to occur

101
Q

What pigments do you find in Chloroplasts?

A

Chlorophylls and carotenoids

102
Q

How long are chloroplasts?

A

2-5 micrometers

103
Q

Where are chloroplasts found?

A

in the leaves and other green organs of plants

104
Q

What is the membranous system inside of a chloroplast?

A

Thylakoids, flattened sacs staked into grana

105
Q

What is the fluid inside of a chloroplast and what does it contain?

A

Stroma, containing the DNA and ribosomes, plus enzymes needed for photosynthesis

106
Q

What are Lysosomes?

A

digestive compartments

107
Q

What is contained within lysosomes?

A

Hydrolytic enzymes used ti digest macromolecules

108
Q

What environments do lysosomal enzymes work in?

A

Acidic

109
Q

Where are lysosomal enzymes made?

A

The ER, transferred to the Golgi for processing?

110
Q

What is different about the membrane of a lysosome?

A

Specialised so it doesn’t destroy itself

111
Q

What is the role of lysosomes

A

intracellular digestion by phagocytosis and recycling of cell materials by autophagy

112
Q

What is autophagy?

A

Organic cell materials are returned to the cytosol for reuse

113
Q

What are protein bodies?

A

Proteins stored for growth and d envelopment, e.g. in seeds.

114
Q

How does the ER control quality of proteins?

A

Incomplete and irregular proteins are recognised in the ER and are degraded by lysosomes

115
Q

What are Chaperones?

A

Proteins that assist in the proper intracellular folding of polypeptides by keeping them separate from bad influences in the cytosol.

116
Q

What Is the model of endosymbiosis?

A

suggests that mitochondria and plastids were formerly small prokaryotes that began living in larger cells

117
Q

What is an endosymbiont?

A

A cell that lives within a larger host cell

118
Q

Why would endosymbiosis of a photosynthetic prokaryote be beneficial to a heterotrophic host?

A

Nutrients released from the endosymbiont can be used, as well as production of oxygen for aerobically respiring host cells.

119
Q

What evidence is there to suggest mitochondria and chloroplasts evolved from prokaryotes?

A

enzymes and transport systems homologous to existing prokaryotes, plus both contain a circular loop of DNA and ribosomes