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BIOL1115 LECTURE > Chapter 6,7,11 > Flashcards

Chapter 6,7,11 Flashcards

1
Q

what are common features found in all cells?

A

cell membrane, cytoplasm, chromosomes, ribosomes, cytoskeleton

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2
Q

what does the cell membrane do?

A

separates and protects interior from exterior environment, selectively permeable

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3
Q

what is the fluid in the cytoplasm called?

A

cytosol

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4
Q

what are cytoskeletons?

A

dynamic network of fibrous proteins providing structural support in the cell

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5
Q

what properties would limit cells from being smaller?

A

cells have to be large enough to fit organelles and other important contents

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6
Q

what properties would impose upper limits on cell size?

A

surface area, cells want to have a high surface area: volume ratio

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7
Q

why does surface are impose an upper limit on size?

A

cell is limited by amount of surface area needed to obtain nutrients from environment and dispose of wastes

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8
Q

what is the fluid mosaic model of the cell membrane?

A

cellular membranes are fluid mosaics of phospholipids, proteins, cholesterols, and other components making membrane diverse

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9
Q

how are phospholipids amphiphatic?

A

they have a polar and hydrophilic head region with a glycerol,phosphate group and a polar group and a nonpolar tail region with fatty acid tails

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10
Q

what do phospholipids do in an aqueous solution?

A

spontaneously arrange themselves into enclosed bilayers which is energetically favourable

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11
Q

how do phospholipids move within the bilayer?

A

drifting laterally within membrane or by flip flopping transversely across membrane (rare)

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12
Q

what forces allow phospholipids to associate with one another?

A

Van der Waals forces between their fatty acid tails

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13
Q

why is the cell membrane fluid?

A

van der waal forces interactions are weak, membrane lipids are able to move

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14
Q

what two factors determine strength of interactions between fatty acid tails?

A

length and shape of the tails

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15
Q

how do kinks in fatty acid tails keep cell membrane more fluid?

A

more space to move, van der waals forces are also weaker

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16
Q

what properties do the membranes have?

A

membranes never have an open end or area due to cohesion, membranes spontaneously reseal, membranes can fuse with other membranes

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17
Q

what is cholesterol?

A

wedged between phospholipids in animal cell membranes, increases or decreases membrane fluidity depending on temperature

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18
Q

how does cholesterol act in room temp?

A

cholesterol restrains movement of phospholipids, reduces membrane fluidity

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19
Q

how does cholesterol act in colder temps?

A

cholesterol prevents phospholipids from packing tightly, increases membrane fluidity

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20
Q

is cholesterol amphiphatic?

A

yes, has hydrophilic head group with rigid planar group of rings and a hydrophobic hydrocarbon tail

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21
Q

what are transporter proteins?

A

channels or carriers, move ions and hydrophilic molecules across membrane

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22
Q

what are receptor proteins?

A

allows cell to receive signals from environment, does not let anything in, only transports signals

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23
Q

what are anchors?

A

anchor proteins attach to other proteins that help maintain cell structure and shape

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24
Q

what kinds of proteins are found in membrane?

A

transporter, receptor, enzymes, anchor proteins

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25
Q

what are integral membrane proteins?

A

permanently embedded in lipid bilayer

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26
Q

what are transmembrane proteins?

A

integral proteins that span entire membrane

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27
Q

what are peripheral membrane proteins?

A

loosely/temporarily associated/embedded in lipid bilayer and can be on internal or external side of membrane

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28
Q

what factors are a result of the selective permeability of the cell membrane?

A

permeability of bilayer and transport proteins

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29
Q

what does the cell membrane actively maintain?

A

homeostasis, a constant and stable environment within cell

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30
Q

what is passive transport?

A

diffusion of solute from a high solute conc. area to a low solute conc. area

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31
Q

does diffusion still occur at equilibrium?

A

yes, but no net movement

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32
Q

what is facilitated diffusion?

A

diffusion with the extra help of channel proteins, speeding up passive movement of hydrophilic molecules across plasma membrane

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33
Q

what is concentration?

A

the ratio of solute to solvent

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34
Q

why does water move quicker through aquaporins?

A

aquaporins are polar channels, water can interact easier with aquaporins than by simply diffusing through membrane

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35
Q

what is turgor pressure?

A

force exerted by water pressing against an object

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36
Q

what kinds of molecules can move through simple diffusion?

A

small molecules, nonpolar molecules

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37
Q

what transport proteins can do facilitated diffusion?

A

channel proteins and carrier proteins

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38
Q

what are channel proteins?

A

provides hydrophilic corridors allowing passage of ions and other polar molecules, specific only for one molecule

39
Q

what are carrier proteins?

A

binds to ions and other polar molecules, changes shape to shuttle them across membrane so are specific only for one molecule

40
Q

how can polar molecules pass through membrane without facilitated diffusion?

A

must go with the conc. gradient

41
Q

passive facilitated transport only works when concentration gradient is

A

high to low

42
Q

what is active transport?

A

movement of substances against concentration gradient which requires energy

43
Q

what is an electrochemical gradient?

A

difference in protons, ex. higher conc of protons outside of cell compared to lower conc. of protons inside cell

44
Q

what is primary active transport?

A

moving substances with a concentration gradient

45
Q

what is secondary active transport?

A

moving substances with an electrochemical gradient

46
Q

how do large substances move through membrane?

A

polysaccharides and proteins transported to an energy heavy process of exocytosis and endocytosis

47
Q

what happens in endocytosis?

A

cell takes in macromolecules by forming vesicles from plasma membrane

48
Q

what happens in exocytosis?

A

transport vesicles migrate to the membrane, fuse with it, and release contents to outside of the cell

49
Q

why is it good that eukaryotic cells have membrane bound organelles?

A

can have multiple incompatible reactions occurring at the same time

50
Q

how do membrane-bound organelles allow for greater efficiency of cellular activities?

A

increases rxn rates by clustering reactants and enzymes in close proximity, allows incompatible rxns to occur simultaneously by physically separating them in diff. compartments

51
Q

what is the nucleus?

A

storehouse for cell’s genetic info and site for RNA synthesis

52
Q

what is the endoplasmic reticulum?

A

involved in both protein and lipid synthesis

53
Q

what is the mitochondria?

A

produces most of ATP that serves as energy currency of cell

54
Q

what is the lysosome?

A

degrades macromolecules

55
Q

what is the cytoskeleton?

A

network of dynamic filamentous proteins that provide structural support for cell

56
Q

what is the golgi apparatus?

A

modifies and sorts proteins and lipids as they move to final destination in or out of cell

57
Q

what is the plant cell wall?

A

rigid barrier composed of polysaccharides such as cellulose

58
Q

what is the chloroplast?

A

enables plant cells to harness energy of sunlight to synthesize sugars

59
Q

what is the central vacuole?

A

water-filled storage compartments that contribute to structural rigidty of plants and maintaining turgor pressure against cell wall

60
Q

what is the endomembrane system?

A

system of interconnected organelles that communicate with each other through direct physical contact or exchange of membranous vesicles

61
Q

what is the nuclear envelope?

A

double membrane enveloping nucleus perforated by protein openings called nuclear pores allowing molecules to move in and out of nucleus

62
Q

what molecule commonly moves out of nucleus into the cytoplasm?

A

RNA

63
Q

what is the outer membrane of the nuclear envelope connected to?

A

endoplasmic reticulum

64
Q

what is the interior of the endoplasmic reticulum called?

A

lumen

65
Q

how is the rough and smooth ER different?

A

rough ER has ribosomes, synthesizes proteins
smooth ER synthesizes lipids

66
Q

where do the ER products go to for further processing?

A

golgi body

67
Q

what are the functions of the golgi body?

A

chemically modifies proteins and lipids sent by ER, sorts proteins and lipids as they move to final destinations, synthesizes cell’s carbohydrates

68
Q

what is the protein transport pathway of the endomembrane system?

A

proteins synthesized by rough ER end up within lumen of endomembrane system ending up in other organelles or excreted out

OR

end up as a membrane protein on membranes of other organelles or on cell membrane

69
Q

where do proteins synthesized by free ribosomes end up?

A

stays in cytoplasm

70
Q

where is cis and trans side of golgi body?

A

cis side is close to rough ER, trans side is close to cell membrane

71
Q

how do lysosomes digest macromolecules?

A

specialized vesicles from golgi body that contain hydrolytic enzymes that animal cells use to digest all types of macromolecules and damaged organelles

72
Q

how do lysosomes maintain a lower pH?

A

thanks to being membrane bound and it uses H+ pumps to transport H+ protons into inside of membrane

73
Q

what is an autophagosome?

A

starts digesting its own organelles

74
Q

what do the deep folds of the inner membrane cristae do in mitochondria?

A

provides more surface area for more cellular respiration reactions to occur

75
Q

why do mitochondria and chloroplast have their own DNA?

A

theorized to have been separate organisms ingested by a larger one, forming the endosymbiosis theory

76
Q

how many membranes do chloroplasts have?

A

three, the thylakoid membrane encompasses the small thylakoids

77
Q

what is endosymbiosis?

A

belief that mitochondria and chloroplast were once bacteria engulfed by a eukaryotic cell and over time evolved their current functions within the cell

78
Q

what type of chromosome do mitochondria and chloroplasts have?

A

circular

79
Q

mitochondrial dna sequences are most closely related to _____

A

Typhus, a proteobacteria

80
Q

chloroplast dna sequences are most closely related to ______

A

cyanobacteria

81
Q

are mitochondria and chloroplasts part of the endomembrane system?

A

No

82
Q

what evidence supports the endosymbiosis theory?

A

both contain own genomes, both have an outer and inner membrane, both grow and multiply independently of other membrane compartments

83
Q

what types of skeletal proteins are there?

A

microtubules - thickest
intermediate filaments - middle
microfilaments - thinnest

84
Q

what are microtubules?

A

tube-like structures that are polymers of tubulin dimers, radiates from a centrosome, supports cell shape and rigidity, separates replicated chromosomes, acts as tracks for movement of vesicles, found in cilia and flagella

85
Q

flagella have a ____ motion

A

whip-like

86
Q

cilia have a ______ motion

A

oar-like rowing

87
Q

flagella and cilia are made of a ______________ sheathed by the plasma membrane

A

9 + 2 core of microtubules (9 pairs around 2 central microtubules)

88
Q

are flagella and cilia considered organelles?

A

No

89
Q

how do cilia and flagella move?

A

motor proteins will move pairs relative to one another, causing a bend

90
Q

microtubules function as ________

A

tracks for transport within the cell using motor proteins kinesin and dynein

91
Q

what are microfilaments?

A

polymers of actin subunits organized into a double helix, thinnest of three cytoskeletal fibres and are present in various locations in cytoplasm

92
Q

what do microfilaments do?

A

form an extensive network just inside the plasma membrane to reinforce it and organize membrane proteins, also function as tracks for transport within cell but involves myosin

93
Q

what are intermediate filaments?

A

polymers of intermediate filament proteins that combine to form cable-like structures providing mechanical strength

94
Q

what are desmosomes?

A

cellular junctions between cells that intermediate filaments attach to, providing strong support for cells and greatly strengthening epithelial tissue

BIOL1115 LECTURE (11 decks)

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