cell structures Flashcards
(117 cards)
1
Q
how many micrometers in a mm
A
1000
2
Q
what do you have to use to see the appreance of the cell
A
electron microscope
3
Q
what is the ultrastructure
A
able to see all organnelles of the cell
4
Q
defenition of oraganelle
A
a speciallised structure with a specific function inside a cell
5
Q
what are cell membranes made of
A
phospholipids and proteins
6
Q
what is the advantage of eukaryotic cells having membrane bound organelles?
A
potentially harmful chemicals such as enzymes can be concentrated in one area
rest of the cell cannot be destroyed
7
Q
what is an eukariot
A
cell with a nucleus
8
Q
what does every cell include at some point
A
nucleus
9
Q
what is in the nucleoplasm
A
chromatin
9
Q
what happens when the cell devides (to do with chromatin)
A
chromatin is the dna
appears like a chromosome when the cell divides
9
Q
what is the nucleuolus surrounded by?
A
nuclear membrane
10
Q
what are organelles?
A
small structures which have a specific role
11
Q
what is a plant cell membrane made of?
A
cellulose
12
Q
another name for cytoplasm
A
cytosol
13
Q
% of water in cytoplasm
A
90%
14
Q
what are dissolved in cytoplasm
A
tiny soluble substances
small ions like sodium, chloride
organic molecules - amino acids, ATP
15
Q
size of nucleus
A
10 - 20 um
16
Q
what is in the nucleus
A
dna - with protein comprises the chromosomes
17
Q
how does chromosomes direct protein synthesis
A
site of transcription
18
Q
what happens to chromatin during cell division
A
condenses into chrmosomes
19
Q
what does the nucleolus do
A
sites of formation of rna, constituent of ribosomes
20
Q
what are the 3 parts of the nucleus
A
nuclear envelope
nucleoplasm
nucleolus
21
Q
nuclear envelope structure
A
double membrane
pores to allow large molecules like nucleotides from the nucleus into the cytoplasm but keeping the DNA inside
22
Q
what is the nucleolus
+ function
A
small spheric body
males rna which is neccessary to make ribosomes
23
what are the 3 functions of the nucleus
1 - includes cells genetic information - dna carries codes to produce protein
2- nuclear membrane seperates the nucleus from the rest of the cell but with pores
3- nucleolus produces ribosomes
24
structure of mitochondria
- double membrane - seperated by narrow inter membrane space filled with liquid - folds inwards - cristae
- inside includes organic matrix including numerous chemical compounds like lipids and proteins
25
what is the organic matrix (mitochondria)
solution containing many compounds including lipids and proteins
26
does mitochondria have dna
yes - small rings of dna
to replicate and code for some of its proteins and rna
27
size of ribosomes in a eukaryot
80s
28
what is the function of the mitochondria?
to produce ATP in aerobic respiration
this ATP is used for synthesis of lipids/proteins/ lactose/ exocytosis/ active transport
29
where do the reactions happen in the mitochondria
some in the matrix and some in the inner membrane
30
why is cristae good?
increases surface area for the attatchement of enzymes
31
example of an cell which will have a lot of mitochondria?
liver cells
32
why does mitochondria pictures look so different from each other?
looks different because seen on a different cross section
33
why are mitochondria cylindrical?
benefit of this?
surface area to volume ratio is bigger compared to a sphere
reduces diffusion distance between the edge and center making aerobic respiration more efficient
34
what type of cells need a lot of ATP?
metabollicaly active cells
35
what type of membrane does a chloroplast have?
double
36
where can you find chloroplasts
cells of photosynthestsing tissue
37
length of chloroplasts
5 - 10 um in length
(bigger than mitochondria)
38
what does the stroma include
fluid filled
contains some of the products of photosynthesis including lipid droplets and starch grains
39
what is similar between chloroplasts and mitochondria
circular DNA
70s ribosomes
40
what are the flat sacs in chloroplasts called?
thylakoides
41
what are a stack of thylakoides known as
granum
42
how many thylakoides are in a granum
between 2 and a hundred parallell sacs
43
where can you find chlorophyll in the cell?
thylakoids
43
why are granums beneficial?
large srface area to trap light energy
43
what are plastids
organnelles have a specfific role depending on the type of cell theyre in eg
amyloplast - storing startch in cells
43
what is the endosymbiotic theory?
mitochondria and chloroplasts have their origins in free - living prokaryotes
44
can chloroplasts duplicate themselves?
yes because they have dna
45
what is the er connected to?
nuclear envelope
46
what is the endoplasmic rectilium
elabrote system of paralell double membranes formin flattened sacs with interconnected, fluid filled spaces between them called cristernae
47
what does rough er do
package the protein created by the ribosomes int vesicles and transport them into the golgi body
48
where can you find rough er
present in large amount in cells that make a lot of protein
49
what does smooth er do?
synthesis and transport of lipids
50
what do the ribosomes on the rough ers surface do
synthesise polypeptide chain
then threaded through the pore to the cisternae
51
(rough er) what happens to the polypeptide chain in the cisternae
bends to form a 3d shape
52
how is the polypeptide chain transported to the golgi body
er membrane can break off to form vesicles to carry
53
main function of smooth er
detoxifies drugs and alcohol
54
what do smooth er have on their membranes
enzymes that catalyses the synthesis of lipids
55
smooth er and wine
increase in alcohol, increase in smooth er
broken down much quicker - increases tolerance to the drug - more is needed to provide the same effect
56
size of ribosomes in prokaryot cells
70s
57
size of ribosomes in eukaryot cells
80s
58
structure of ribosomes
one large subunit and one small
made from rRNA and protein
59
where are ribosomes created
nucleolus
60
what is the function of a ribosome
important for protein synthesis within the cell
61
how does the golgi body form
as er is pinched at both ends to form small vesicles - number of theese combine and fuse to form golgi body
62
simply what does the golgi do?
proteins modified and packaged
63
how does the golgi body secrete proteins
exocytosis
64
how are lysosomes formed
small vacuoles formed as parts of the golgi body are pinched off
65
lysosomes structure
single membrane
include and isolate digestive enzymes
66
what are the 3 functions of lysosomes
phagocytosis
autophagy
exocytosis
67
what is autophagy
release digestive enzymes and destroy organelles
68
lysosomes where does autophagy happen
in the cytoplasm with is lined with membranes where a number of lysosomes can release their contents
69
what is phagocytosis baisic definition
digest materials that the cell has ingested
70
how does phagocytosis work
lysosomes fuses with the membrane of thevesicle which has ingested the material and release the enzyme into vesicle
71
what happens after the content of the vesicle is digested in phagocytosis
useful materials absorbed into the cytoplasm
surplus released through exocytosis
72
what is exocytosis?
contents of cytoplasm released through fusion of the cytoplasm membrane with the cell membrane.
73
what type of cells can you find centrioles
found in animal cells not plant
74
where can you find centrioles
situated immediatley outside the nucleus in a bit of cytoplasm called the centrasom
75
structrue of centrioles
contains 2 empty cylinders at right angles to each other
includes nine set of microtububles which are set in cirlce
76
what happens to centrioles during cell division
centrioles duplicate themselved so that each new cell includes a pair of centrioles
77
function of centrioles
synthesise microtubes
78
what are the function of microtubes
1- give the cell shape and support
2- spindle that will form during cell division to seperate the chromosomes have come frommicrotubule
79
structure of vacuole
liquid filled sac surrounded by a single membrane (tonoplast)
80
what is the liquid in the vacuole
cell sap (substance with salt and sugar)
81
what is the name of the single membrane around the vacuole
tonoplast
82
function of vacuole
1 - maintains shape of the plant
2 - food store
3- chemical waste collects here - taste keeps herbivores away
83
what is the cell wall made of
consists of largerly cellulose molecules held together in microfibrilis embedded in a polysaccharide matrix called pectin
84
simply - what are the 3 functions of the cell wall
transport
mechanical strength
communication between cells
85
what is the plasmodesmata
strands of cytpolasm which pass through pores
86
where does plasmodesmata occur?
no cellulose thickenning between 2 cells , strand of cytoplasm runs from one cell to the next
87
what is the network of cytoplasm in connected cells called?
symplast
88
what is the symplast pathway important for?
important in water transport through a plant
89
nucleus function
contains DNA which codes for protein synthesis
90
nuclear pores function
allows the transport of mRNA and ribosomes out of the nucleus
91
nuclear envelope function
seperates the contents of the nucleus from the cytoplasm
92
nucleolus function
produces RNA and ribosomes
93
chromatin function
condenses before cell division to form chromosomes
94
rough er function
packaging and storing proteins
producing transport vesicles which merge to form the golgi body
95
smooth er function
produce, package and transport steroids and lipids
96
golgi body function
packaging and modification of proteins
97
lysosomes function
contains powerful digestive enzymes to break down worn out cells
98
centrioles function
form the spindle durin cell division
99
mitochondria function
ATP synthesis by aerobic respiration
100
chloroplasts function
contains photosynthetic pigments which trap light energy for photosynthesis
101
what is vacuole
contains cell sap and stores solutes such as glucose
swells due to osmosis for turgidity
102
ribosomes function
protein synthesis
103
plasmodesmata function
connects cells via cytoplasm filled canals
104
cell wall function
mechanical strength due to high tensile strength of cellulose microfibrilis
105
what do animal cells use as a store
glycogen grain
106
what do plant cells use as a store
startch grain
107
where are cilia and flagellum present
animal cells
108
where are centrioles present
animal cells
109
in what type of cells are lysosomes present
animal cells
110
where is cytoplasm in an animal cell
throught the cell
111
where is cytoplasm in an plant cell
cytoplasm pushed to the sides of the cell to form a thin layer
112
organelle path in the cell
nucleus
nuclear pore
RER
vesicle
golgi body
secretory vesicle
cell membrane
