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HEAL1500 > UNIT 2 - CELL STRUCTURE AND FUNCTION > Flashcards

UNIT 2 - CELL STRUCTURE AND FUNCTION Flashcards

1
Q

what is a cell?

A

-the basic unit of life

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2
Q

how do new cells arise?

A

-from preexisting cells

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3
Q

what is common among all living organisms?

A

-organized
-acquire materials + energy
-homeostatic
-respond to stimuli
-reproduce and have potential for growth
-evolutionary history

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4
Q

why are cells small?

A

-to maintain a high SA-V ratio
-large amount of SA in comparison to volume
-critical to survival

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5
Q

why is it important for cells to have a larger surface area in comparison to their volume? are there limits to this?

A

-allows for more nutrients and wastes to be cycles in/out of the cell
-a cell can get too large and not be efficient/metabolically active

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6
Q

what are the two categories of cells?

A

-prokaryotes + eukaryotes

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7
Q

what are distinct features of prokaryotic cells?

A

-lack a nucleus
-have 2 groups of bacteria (archaebacteria and eubacteria)

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8
Q

what are distinct features of eukaryotic cells?

A

-have a nucleus
-includes animals, plants, fungi, and protists

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9
Q

what do both eukaryotes and prokaryotes have?

A

-plasma membrane
-cytoplasm

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10
Q

what is the plasma membrane made of? what is its purpose?

A

-phospholipid bilayer
-contains proteins attached + embedded
-to separate the cells internal and external environments

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11
Q

what is special about the phospholipid bilayer?

A

-selectively permeable (controls what comes in and out)

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12
Q

what is the cytoplasm?

A

-semifluid substance inside the cell
-includes organelles

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13
Q

what were the first cells on earth? what evolved from these cells? what was specific about the atmosphere at this time?

A

-prokaryotes (archaeans)
-eukaryotes evolved
-it contained no oxygen

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14
Q

do archaeans survive today?

A

-in very inhospitable conditions (acid, hot, salt aka thermal vents)

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15
Q

how do we predict organelles developed in the eukaryotic cells? what is this idea called?

A

-eukaryotes engulfing prokaryotic cells
-endosymbiosis

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16
Q

how did cells gain a nucleus?

A

-from invagination of the plasma membrane
-eventually surrounding dna with a double membrane

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17
Q

how did the endomembrane system come about?

A

-proliferation of membranes (rapid growth of new parts of the membrane)

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18
Q

how did the cell gain mitochondria and chloroplast organelles?

A

-engulfing aerobic and photosynthetic bacteria (prokaryotes)

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19
Q

how does the behaviour of phospholipids cause the plasma membrane to form?

A

-when placed in water, they will naturally form a spherical bilayer
-hydrophilic heads = towards cytoplasm + extracellular fluid
-hydrophobic tails inward

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20
Q

what is the model used to describe the plasma membrane? why is it described this way?

A

-fluid mosaic model
-elements such as proteins are able to move freely laterally in the membrane

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21
Q

what helps support the plasma membrane?

A

-cholesterol

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22
Q

what 2 molecules act as receptors to identify cells as foreign or self? what kind of function is this?

A

-glycoproteins
-glycolipids
-immune

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23
Q

what makes glycoproteins and glycolipids/

A

-attached carbohydrate chains

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24
Q

what substances/molecules are able to pass freely through the plasma membrane? what are some examples?

A

-small hydrophobic substances
-ex: gases (oxygen, carbon dioxide, estradiol)

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25
Q

what substances/molecules need help passing the plasma membrane? what are examples?

A

-ions and larger molecules
-ex: water, Na+, K+

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26
Q

what is the membrane channel protein that allows water to pass through?

A

-aquaporin

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27
Q

what is simple diffusion?

A

-the random movement of molecules from a high to low concentration
-passive movement (no energy)

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28
Q

when does simple diffusion occur until?

A

-until molecules are equally distributed
-equal #s of molecules moving in and out of the cell

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29
Q

what is to be said about the movement of molecules in simple diffusion?

A

-move in both directions
-net movement is from high to low concentration

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30
Q

what is osmosis?

A

-the diffusion of water molecules from high to low water concentration
-passive movement (no energy)

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31
Q

what does it mean for a solution to be isotonic? how do cells react when placed in an isotonic solution (body fluid)?

A

-same concentration of impermeable solutes in comparison to a body fluid or cell
-cells do not change size (no net movement)

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32
Q

what does it mean for a solution to be hypotonic? how do cells react when placed in a hypotonic solution?

A

-solution with fewer solutes
-cells will swell and burst (more water movement into the cell)what

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33
Q

what is a cell swelling + bursting also referred to as?

A

-lysis (membrane breaking down)

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34
Q

what does it mean for a solution to be hypertonic? how do cells react when placed in a hypertonic solution?

A

-solution with more solutes
-cells will shrink (water movement out of the cell)

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35
Q

what is a cell shrinking also referred to as?

A

-crenation

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36
Q

what drives osmosis?

A

-osmotic pressure

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37
Q

what is facilitated transport?

A

-transport of molecules from a high to low concentration via a protein carrier
-passive movement (no energy)
-protein transporters are specific and only move certain molecules

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38
Q

what are the 2 main transport proteins?

A

-channels ( gated or ungated)
-uniporter carriers (open one side, close, then open other side)

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39
Q

what is active transport?

A

-movement of molecules from low to high concentration

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40
Q

what is primary active transport?

A

-a pump using ATP as energy
-uniport (one molecule)
-cotransport (2 different molecules going different ways)

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41
Q

what is secondary active transport?

A

-energy is provided by one molecules gradient and another molecule is moved using that energy
-symport (2 molecules move in the same direction)
-antiport (2 molecules move in opposite directions)

42
Q

what is bulk transport?

A

-movement of large molecules across the membrane using endocytosis or exocytosis methods

43
Q

what is endocytosis? what are the 3 methods that are used?

A

-transports molecules or cells into the cell via invagination of the plasma membrane to form a vesicle
-phagocytosis
-pinocytosis
-receptor-mediated endocytosis

44
Q

what is phagocytosis?

A

-endocytosis of pathogens (bacteria)
-done by white blood cells

45
Q

what is pinocytosis?

A

-endocytosis of fluid with small particles (solutes)
-microvilli of small intestine

46
Q

what is receptor-mediated endocytosis?

A

-particles must bind to receptors in the plasma membrane to initiate endocytosis
-receptors cluster to form coated pits
-brings in useful substances (typically)

47
Q

what is exocytosis?

A

-transports molecules outside the cell via the fusion of a vesicle with the plasma membrane
-reverse endocytosis

48
Q

what is the nucleus?

A

-contains genetic instruction for making proteins involved in cell function
-contains DNA in chromatin form typically

49
Q

do all cells contain the same genes?

A

-YES

50
Q

what is the nucleoplasm?

A

-fluid inside the nucleus

51
Q

what is the nucleolus?

A

-dark region inside the nucleus
-produces ribosomal RNA (rRNA)

52
Q

what is the nuclear envelope?

A

-a double membrane (phospholipid bilayer) around the nucleus

53
Q

what are the nuclear pores?

A

-holes in the nuclear envelope
-allow substances to pass in + out

54
Q

what is the endomembrane system?

A

-series of membranous organelles that function to process and transport materials for the cell
-also for compartmentalization

55
Q

what are ribosomes?

A

-made of rRNA and protein
-sites of protein synthesis
-attached to the outer nuclear membrane and the rough endoplasmic reticulum or free floating the cytoplasm

56
Q

what are groups of free floating ribosomes called?

A

-polyribosomes

57
Q

what organelles make up the endomembrane system?

A

-nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, and vesicles

58
Q

what is the rough endoplasmic reticulum?

A

-folded membrane studded with ribosomes
-proteins made here go to nearly all areas of the cell

59
Q

where do the proteins made by the free floating ribosomes go?

A

-cytosol
-mitochondria
-nucleus

60
Q

what is the smooth endoplasmic reticulum?

A

-folded membrane that lacks ribosomes
-synthesizes lipids

61
Q

what is the golgi apparatus?

A

-flattened membrane sacs
-modify proteins and lipids
-help in processing, packaging, and secreting

62
Q

what are vesicles?

A

-small membranous sacs (phospholipid bilayer) used for transport
-break off from ER or golgi apparatus

63
Q

what are lyososomes?

A

-vesicles containing hydrolytic enzymes that break off from the golgi apparatus
-break down molecules into smaller parts
-common in white blood cells (engulf disease causing microbes)

64
Q

what is the cytoskeleton?

A

-protein fibers that help maintain cell shape + anchor and/or move organelles in the cell
-3 fibers

65
Q

what are the 3 fibers that make up the cytoskeleton?

A

-microtubules
-intermediate filaments
-actin filaments

66
Q

what are the characteristics/functions of microtubules?

A

-maintain cell shape
-largest fiber of the cytoskeleton
-help organelles move (act as tracks)
-assembly controlled by the centrosome
-forms spindle apparatus during cell division to help move chromosomes
-dynamic structure (elongates + shortens)

67
Q

what are the characteristics/functions of intermediate filaments?

A

-internal structure + cohesion (anchoring) of cells (strength)
-consist of keratin or vimentin proteins

68
Q

what are the characteristics/functions of actin filaments?

A

-cell movement (flagella + muscle)
-smallest fiber of the cytoskeleton
-long and very thin
-made of actin protein

69
Q

what is characteristic of flagella and cilia? where can we see each?

A

-both contain microtubules
-both are used in movement
-cilia : respiratory tract to move mucus
-flagella : sperm cells to propel to the egg

70
Q

what is the extracellular matrix?

A

-protective mesh of proteins and polysaccharides
-surrounds the cell that produces it

71
Q

what is contained within the extracellular matrix?

A

-collagen (resists stretching)
-elastin (resilience/elasticity)
-fibronectin (adhesive protein) binds to integrin (integral membrane protein) connected to the cytoskeleton (role in cell signalling)

72
Q

what are the types of cell junctions?

A

-adhesion junctions
-tight junctions
-gap junctions
-desmosomes
-nanotubes

73
Q

what are adhesion junctions?

A

-attach cytoskeletons of adjacent cells (velcro belt)
-attach actin filaments

74
Q

what are tight junctions?

A

-waterproof barrier

75
Q

what are gap junctions?

A

-fuse of 2 channels (create clusters of joined channels)
-allows for communication between cells

76
Q

what are desmosomes?

A

-strong disk like junctions joining 2 cells cytoskeletons
-attach intermediate filaments

77
Q

what are nanotubes?

A

-actin containing protrusions that connect cells
-can form tunnels to transfer signals and various things (proteins, soluble molecules, and organelles (mitochondria))

78
Q

what is special about the mitochondrion membrane?

A

-has an inner and outer membrane surrounding the matrix (space between)
-inner membrane is folded into cristae which contain enzymes for cellular respiration

79
Q

what is the main function of the mitochondrion?

A

-convert chemical energy from glucose into ATP

80
Q

what does cellular respiration use up? what does it give off?

A

-uses up oxygen
-gives off carbon dioxide

81
Q

do mitochondria have their own DNA?

A

-YES
-mitochondrial DNA (some for proteins, tRNA, and rRNA)
-meaning they can multiply

82
Q

what is the basic idea of what cellular respiration does?

A

-breaks down glucose into carbon dioxide and water

83
Q

what are the 4 main steps of cellular respiration?

A

-glycolysis
-intermediate reaction
-citric acid cycle (Krebs cycle)
-electron transport chain

84
Q

why do we say that 30 ATP are made per glucose molecule when 32 are actually produced/

A

-2 ATP are used to bring 2 NADH from glycolysis into the mitochondria

85
Q

is NAD+ the oxidized or reduced form?

A

-oxidized
-oxidation is loss of electrons

86
Q

is NADH the oxidized or reduced form?

A

-reduced
-reduction is gain of electrons

87
Q

does NADH OR NAD+ act as the electron transporter?

A

-NADH

88
Q

what are the basics of glycolysis?

A

-breaks glucose into 2 pyruvates
-occurs in the cytoplasm
-anaerobic (does not need oxygen)
-produces 2 NADH and 2 ATP molecules

89
Q

what happens in the first half of glycolysis?

A

-2 ATP molecules are needed to phosphorylate glucose

90
Q

what happens in the second half of glycolysis?

A

-phosphorylation occurs without the need of ATP
-2 NADH, 4 ATP, and 2 pyruvates are formed

91
Q

what is the intermediate reaction?

A

-occurs when oxygen is available
-occurs in the mitochondria
-produces 2 NADH and 2 CO2 per glucose (1/2 per pyruvate)
-prepares pyruvates for the Krebs cycle
-pyruvates become acetyl CoA

92
Q

what is the citric acid cycle?

A

-series of enzymatic reactions
-occurs in the matrix of the mitochondria
-completes the breakdown of glucose (breaks carbon bonds)
-produces 6 NADH, 2 FADH2, and 2 ATP per glucose (1/2 per acetyl CoA)
-releases 4 CO2

93
Q

what carries hydrogen and electrons away in the citric acid cycle? where are the electrons taken?

A

-NADH
-FADH2
-electron transport chain

94
Q

what can be converted into compounds that can enter the citric acid cycle?

A

-fats
-proteins

95
Q

what makes up the electron transport chain?

A

-carrier protein complexes embedded in the mitochondrion’s cristae

96
Q

what occurs along the electron transport chain?

A

-each carrier accepts 2 electrons and passes them along
-H+ ions get transferred between the inner and outer mitochondria membrane (more from NADH, less from FADH2)
-oxygen is the final acceptor

97
Q

is the electron chain anaerobic or aerobic?

A

-aerobic (needs oxygen)

98
Q

what happens once the oxygen accepts the electron?

A

-combines with hydrogen atoms to become water

99
Q

how does our breathing relate to cellular respiration?

A

-we breath in oxygen to be used as the electron acceptor

100
Q

what are the total net products of cellular respiration?

A

-30 ATP
-10 NADH
-2 FADH

101
Q

what is fermentation?

A

-occurs when oxygen is not available (anaerobic)
-glycolysis still occurs
-produces lactate (toxic) instead of acetyl CoA
-cori cycle gets rid of lactate
-2 ATP produced per glucose

HEAL1500 (12 decks)

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