2.1.4 The ultra-Structure of eukaryotic cells: membrane bound organelles Flashcards

1
Q

what cells are eukaryotic? structure

A

all animal, plant, fungal and protoctist

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2
Q

what type of cell features membrane-bound organelle

A

eukaryotic ONLY

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3
Q

what is the nucleus surrounded by? structure

A

a double membrane: the nuclear envelope

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4
Q

what does the nuclear envelope contain? structure

A

pores

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5
Q

what are two features of the nucleolus? structure

A

it doesn’t have a membrane around it
it contains RNA

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6
Q

what is cromatin? structure

A

the generic material, consisting of DNA wound around histone proteins

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7
Q

when is the chromatin spread out or extended? structure

A

when the cell is not dividing

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8
Q

what happens to chromatin when the cell is about to divide? structure

A

chromatin condenses and coils tightly into chromosomes (these make up nearly all the organism’s genome

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9
Q

what is the nuclear envelope’s function?
function

A

the nuclear envelope separates the contents of the nucleus from the rest of the cell

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10
Q

what do the outer and inner nuclear membranes do in some regions? function

A

the outer and inner nuclear membranes fuse together in some regions

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11
Q

what happens to the outer and inner nuclear membranes, in some regions to allow for diffusion etc? function

A

they fuse together in some places so dissolved substances and ribsomes can pass through

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12
Q

what do the nuclear pores enable to happen? function

A

larger substances (eg MRNA) to leave the nucleus, and substances (eg steroid hormones) may enter the nucleus, from the cytoplasm

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13
Q

where are ribosomes made?

A

nucleolus

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14
Q

summary of nucleus: 4 points. function

A

-control centre of the cell
-stores the organism’s genome
-transmits genetic information
-provides the instructions for protein synthesis

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15
Q

what is the RER? Rough Endoplasmic Reticulum. structure

A

RER is a system of membranes containing fluid-filled cavities (cisternae) that are continuous with the nuclear membrane

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16
Q

what is the RER coated in? structure

A

ribosomes

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17
Q

what are cisternae? structure

A

fluid filled cavities, in rER, sER, GA

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18
Q

what is the RER? function

A

intracellular transport system

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19
Q

what do the cisternae form in the RER? function

A

channels that transport substances from one area of a cell to another

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20
Q

what does the rER provide for ribosomes?

A

large surface area

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21
Q

what are the ribosomes function? function

A

assemble amino acids into proteins- protein synthesis

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22
Q

describe the route of proteins inside/out of RER. funtion

A
  • ribosomes assemble amino acids into proteins
    -these proteins then actively pass through the membrane into the cisternae
    -they are transported to the Golgi apparatus (for modification and packaging)
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23
Q

what is the SER? Smooth Endoplasmic Reticulum. structure

A

SER is a system of membranes, containing cisternae (fluid-filled cavities) that are continuous with the nuclear membrane

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24
Q

how are the sER and rER different structurally? structure

A

rER has ribosomes whereas the sER do not

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25
Q

what does the SER contain? function

A

enzymes that catalyse reactions involved in lipid metabolism

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26
Q

what do the enzymes the sER contains, that catalyse reaction involved with lipid metabolism, do? function

A

-synthesis of cholesterol
-synthesis of lipids/phospholipids needed by the cell
-synthesis of steroid hormones

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27
Q

what is the SER involved with? function

A

absorption, synthesis and transport of lipids (from the gut) and production, processing and storage of lipids, carbohydrates and steroids

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28
Q

what does the Golgi apparatus consist of? structure

A

stack of membrane bound flattened sacs and cisternae

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29
Q

what brings materials to/from the Golgi apparatus?

A

secretory vesicles bring materials to/from the Golgi apparatus

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30
Q

how are proteins modified in the Golgi apparatus? function

A

-adding sugar molecules
-adding lipid molecules
-being folded into 3D shape

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31
Q

what does adding sugar molecules to proteins make in Golgi apparatus? function

A

sugar molecules + protein ——> glycoproteins

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32
Q

what does adding lipid molecules to proteins make in the Golgi apparatus?

A

lipid molecules + protein ——> lipoproteins

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33
Q

what happens to the proteins once they have been modified in the Golgi apparatus? function

A

the proteins are packaged into vesicles that are pinched off, then they:
-stored in a cell
-or moved to the plasma membrane

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34
Q

why are proteins moved to the plasma membrane? function

A

-to be incorporated into the plasma membrane
-or exported outside the cell

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35
Q

mitochondria/mitochondrion difference

A

-rion ——> singular
-ria ——> plural

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36
Q

what shape can mitochondria be? structure

A

spherical, rod shaped or branched

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37
Q

how long are mitochondria? structure

A

2-5 µm long

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38
Q

what are mitochondria surrounded by? structure

A

two membranes with a fluid filled space between them

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39
Q

what is the inner membrane of mitochondria highly folded into? structue

A

the inner membrane is highly folded into cristae

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40
Q

what is the inner part of the mitochondrion? structure

A

the inner part is a fluid filled matrix

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41
Q

what is the function of a mitochodrion? function

A

it is the site of ATP (energy currency) production, during aerobic respiration

42
Q

where are mitochondria made? function

A

they are self replicating (more can be made if the cell’s energy needs increase)

43
Q

where are mitochondria abundant? function

A

in cells where much metabolic activity takes places
-liver cells
-at synapses between neurones (where neurotransmitter is synthesised and released)

44
Q

how big are chloroplasts? structure

A

large
4-10 µm long

45
Q

where are chloroplasts found? structure

A

ONLY in plant cells and some protoctists

46
Q

what are chloroplasts surrounded by? structure

A

a double membrane or envelope

47
Q

what are thylakoids? structure

A

flattened membrane bound sacs
resemble plates in chloroplast

48
Q

what is the inner membrane of the chloroplast continuous with? structure

A

the inner membrane of the chloroplast continuous with thylakoids

49
Q

what do thylakoids contain? structure

A

chlorophyll

50
Q

what is each stack of thylakoids called? structure

A

each stack of thylakoids called a granum

51
Q

what is the plural of a granum?

A

grana

52
Q

what is the fluid filled matrix in chloroplasts? structure

A

the stroma

53
Q

what do substances do chloroplasts contain? structure

A

loops of DNA and starch grains

54
Q

what is chloroplasts the site of? function

A

site of photosynthesis

55
Q

what happens at the first stage of photosynthesis? the light dependent stage function

A

-it occurs in the grana, the light energy is trapped by chlorophyll and used to make ATP
-water is also spilt to supply hydrogen ions

56
Q

what happens at the second stage of photosynthesis? the light independent stage (Calvin Cycle) function

A
  • hydrogen reduces carbon dioxide, using energy from ATP, to make carbohydrates, which occurs in the stroma
57
Q

where are choloplasts abundant?

A

leaf cells
— palisade mesophyll layer

58
Q

what is the vacuole surrounded by? structure

A

the tonoplast which contains fluid

59
Q

what is the tonoplast? structure

A

a membrane surrounding the vacuole which contains fluids

60
Q

where can a large permanent vacuole be found? function

A

ONLY plant cells have a large permanent vacuole

61
Q

what is the vacuole filled with? function

A

water and solutes

62
Q

what is the function of the vacuole? function

A

maintains cell stability

63
Q

what happens when the vacuole is full? structure

A

it pushes against the cell wall, making the cell turgid

64
Q

why is it ideal for all the plant cells to be turgid? function

A

this helps to support the plant

65
Q

what are lysosomes formed from? structure

A

Golgi apparatus

66
Q

what is a lysosome? structure

A

a small bag, formed from the GA, each is surrounded by a single membrane

67
Q

what do lysosomes contain? structure

A

powerful hydrolytic (digestive) enzymes

68
Q

what cells are abundant in lysosomes? structure

A

phagocycotic cells that can ingest and digest invading pathogens

69
Q

what does hydrolytic mean? structure

A

digestive

70
Q

what is the 2 roles of the lysosomes? function

A

-they keep the powerful hydrolytic enzymes separate from the rest of the cell
-they can engulf old cell organelles and foreign matter, and return the digested components to the cell for reuse

71
Q

what are cilia and undulipodia? structure

A

protrusions from the cell and are surrounded by the plasma membrane

72
Q

what are cilia and undulipodia formed from? structure

A

centrioles

73
Q

what does each cilia and undulipodia contain?

A

microtubules

74
Q

where is cilia abundant? function

A

the epithelial cells lining the airways each have many hundreds of cilia that beat and move the band of mucus

75
Q

what does the cillia that nearly all cell types in the body have, do? function

A

acts as an antenna
-it contains receptors and allows the cell to detect signals about its immediate environment

76
Q

what is the only type of human cell to have an undulipodium? function

A

a spermatozoon

77
Q

what is the difference between a cilia and an undulipodium? structure

A

the undulipodium is a longer cilia

78
Q

what does the undulipodium enable? function

A

the undulipodium enables the spermatozoon to move

79
Q

what is the difference between eukaryotic and prokaryotic ribosomes?

A

eukaryotic has 80s
prokaryotic has 70s

80
Q

what are the two chambers of a chloroplast?

A

thylakoid and stroma

81
Q

what are all cells surrounded by?

A

a plasma membrane which controls the exchange of materials between the internal cell environment and the external environment (partially permeable)

82
Q

what is the plasma membrane formed from?

A

from a phospholipid bilayer

83
Q

what is the diameter of a plasma membrane?

A

0.01µm

84
Q

what connects the cytoplasm to neighbouring plant cells?

A

narrow threads of cytoplasm (surrounded by a cell membrane) called plasmodesmata connect the cytoplasm of neighbouring plant cells

85
Q

what are chromosomes?

A

chromosomes are made of sections of linear DNA tightly wound around histone proteins

86
Q

what is chromatin?

A

the material from which chromosomes are made- found in the nucleus

87
Q

what enzymes does the fluid filled matrix contain?

A

The matrix formed by the cristae contains respiratory enzymes needed for aerobic respiration, producing ATP

88
Q

what other organelle are found in the matrix?

A

Small circular pieces of DNA (mitochondrial DNA) and ribosomes are also found in the matrix (needed for replication)

89
Q

what are grant joined together by in chloroplasts?

A

grana are joined together by lamellae (thin and flat thylakoid membranes)

90
Q

what are lamellae?

A

thin and flat thylakoid membranes, that join grana together

91
Q

what is a ribosome made up of?

A

each ribosome is a complex of ribosomal RNA (rRNA) and proteins

92
Q

what are 70s ribosomes composed of?

A

composed of 50S and 30S subunits

93
Q

what are 80s ribosomes composed of?

A

composed of 60S and 40S subunits

94
Q

where are 70s ribosomes also found?

A

mitochondria and chloroplasts

95
Q

what is a vesicle?

A

a membrane-bound sac for transport and storage

96
Q

what are lysosomes used by most often?

A

used extensively by cells of the immune system and in apoptosis (programmed cell death)

97
Q

what is apoptosis?

A

programmed cell death

98
Q

what is a centriole structure?

A

hollow fibres made of microtubules

99
Q

what is a centrosome? structure

A

two centrioles at right angles to each other form a centrosome

100
Q

what is a centrosome? function

A

organises the spindle fibres during cell division

101
Q

where a centrioles not found?

A

not found in flowering plants and fungi