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

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

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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
what does the SER contain? function
enzymes that catalyse reactions involved in lipid metabolism
26
what do the enzymes the sER contains, that catalyse reaction involved with lipid metabolism, do? function
-synthesis of cholesterol -synthesis of lipids/phospholipids needed by the cell -synthesis of steroid hormones
27
what is the SER involved with? function
absorption, synthesis and transport of lipids (from the gut) and production, processing and storage of lipids, carbohydrates and steroids
28
what does the Golgi apparatus consist of? structure
stack of membrane bound flattened sacs and cisternae
29
what brings materials to/from the Golgi apparatus?
secretory vesicles bring materials to/from the Golgi apparatus
30
how are proteins modified in the Golgi apparatus? function
-adding sugar molecules -adding lipid molecules -being folded into 3D shape
31
what does adding sugar molecules to proteins make in Golgi apparatus? function
sugar molecules + protein ——> glycoproteins
32
what does adding lipid molecules to proteins make in the Golgi apparatus?
lipid molecules + protein ——> lipoproteins
33
what happens to the proteins once they have been modified in the Golgi apparatus? function
the proteins are packaged into vesicles that are pinched off, then they: -stored in a cell -or moved to the plasma membrane
34
why are proteins moved to the plasma membrane? function
-to be incorporated into the plasma membrane -or exported outside the cell
35
mitochondria/mitochondrion difference
-rion ——> singular -ria ——> plural
36
what shape can mitochondria be? structure
spherical, rod shaped or branched
37
how long are mitochondria? structure
2-5 µm long
38
what are mitochondria surrounded by? structure
two membranes with a fluid filled space between them
39
what is the inner membrane of mitochondria highly folded into? structue
the inner membrane is highly folded into cristae
40
what is the inner part of the mitochondrion? structure
the inner part is a fluid filled matrix
41
what is the function of a mitochodrion? function
it is the site of ATP (energy currency) production, during aerobic respiration
42
where are mitochondria made? function
they are self replicating (more can be made if the cell’s energy needs increase)
43
where are mitochondria abundant? function
in cells where much metabolic activity takes places -liver cells -at synapses between neurones (where neurotransmitter is synthesised and released)
44
how big are chloroplasts? structure
large 4-10 µm long
45
where are chloroplasts found? structure
ONLY in plant cells and some protoctists
46
what are chloroplasts surrounded by? structure
a double membrane or envelope
47
what are thylakoids? structure
flattened membrane bound sacs resemble plates in chloroplast
48
what is the inner membrane of the chloroplast continuous with? structure
the inner membrane of the chloroplast continuous with thylakoids
49
what do thylakoids contain? structure
chlorophyll
50
what is each stack of thylakoids called? structure
each stack of thylakoids called a granum
51
what is the plural of a granum?
grana
52
what is the fluid filled matrix in chloroplasts? structure
the stroma
53
what do substances do chloroplasts contain? structure
loops of DNA and starch grains
54
what is chloroplasts the site of? function
site of photosynthesis
55
what happens at the first stage of photosynthesis? the light dependent stage function
-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
what happens at the second stage of photosynthesis? the light independent stage (Calvin Cycle) function
- hydrogen reduces carbon dioxide, using energy from ATP, to make carbohydrates, which occurs in the stroma
57
where are choloplasts abundant?
leaf cells — palisade mesophyll layer
58
what is the vacuole surrounded by? structure
the tonoplast which contains fluid
59
what is the tonoplast? structure
a membrane surrounding the vacuole which contains fluids
60
where can a large permanent vacuole be found? function
ONLY plant cells have a large permanent vacuole
61
what is the vacuole filled with? function
water and solutes
62
what is the function of the vacuole? function
maintains cell stability
63
what happens when the vacuole is full? structure
it pushes against the cell wall, making the cell turgid
64
why is it ideal for all the plant cells to be turgid? function
this helps to support the plant
65
what are lysosomes formed from? structure
Golgi apparatus
66
what is a lysosome? structure
a small bag, formed from the GA, each is surrounded by a single membrane
67
what do lysosomes contain? structure
powerful hydrolytic (digestive) enzymes
68
what cells are abundant in lysosomes? structure
phagocycotic cells that can ingest and digest invading pathogens
69
what does hydrolytic mean? structure
digestive
70
what is the 2 roles of the lysosomes? function
-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
what are cilia and undulipodia? structure
protrusions from the cell and are surrounded by the plasma membrane
72
what are cilia and undulipodia formed from? structure
centrioles
73
what does each cilia and undulipodia contain?
microtubules
74
where is cilia abundant? function
the epithelial cells lining the airways each have many hundreds of cilia that beat and move the band of mucus
75
what does the cillia that nearly all cell types in the body have, do? function
acts as an antenna -it contains receptors and allows the cell to detect signals about its immediate environment
76
what is the only type of human cell to have an undulipodium? function
a spermatozoon
77
what is the difference between a cilia and an undulipodium? structure
the undulipodium is a longer cilia
78
what does the undulipodium enable? function
the undulipodium enables the spermatozoon to move
79
what is the difference between eukaryotic and prokaryotic ribosomes?
eukaryotic has 80s prokaryotic has 70s
80
what are the two chambers of a chloroplast?
thylakoid and stroma
81
what are all cells surrounded by?
a plasma membrane which controls the exchange of materials between the internal cell environment and the external environment (partially permeable)
82
what is the plasma membrane formed from?
from a phospholipid bilayer
83
what is the diameter of a plasma membrane?
0.01µm
84
what connects the cytoplasm to neighbouring plant cells?
narrow threads of cytoplasm (surrounded by a cell membrane) called plasmodesmata connect the cytoplasm of neighbouring plant cells
85
what are chromosomes?
chromosomes are made of sections of linear DNA tightly wound around histone proteins
86
what is chromatin?
the material from which chromosomes are made- found in the nucleus
87
what enzymes does the fluid filled matrix contain?
The matrix formed by the cristae contains respiratory enzymes needed for aerobic respiration, producing ATP
88
what other organelle are found in the matrix?
Small circular pieces of DNA (mitochondrial DNA) and ribosomes are also found in the matrix (needed for replication)
89
what are grant joined together by in chloroplasts?
grana are joined together by lamellae (thin and flat thylakoid membranes)
90
what are lamellae?
thin and flat thylakoid membranes, that join grana together
91
what is a ribosome made up of?
each ribosome is a complex of ribosomal RNA (rRNA) and proteins
92
what are 70s ribosomes composed of?
composed of 50S and 30S subunits
93
what are 80s ribosomes composed of?
composed of 60S and 40S subunits
94
where are 70s ribosomes also found?
mitochondria and chloroplasts
95
what is a vesicle?
a membrane-bound sac for transport and storage
96
what are lysosomes used by most often?
used extensively by cells of the immune system and in apoptosis (programmed cell death)
97
what is apoptosis?
programmed cell death
98
what is a centriole structure?
hollow fibres made of microtubules
99
what is a centrosome? structure
two centrioles at right angles to each other form a centrosome
100
what is a centrosome? function
organises the spindle fibres during cell division
101
where a centrioles not found?
not found in flowering plants and fungi

2.1 Cell Structure (7 decks)

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