2 - Basic Components Of Living Systems🐒 Flashcards
1
Q
Define a prokaryotic cell
A
- no membrane-bound nucleus nor organelles
- single-called
2
Q
Define a eukaryotic cell
A
- membrane-bound nucleus and organelles
- complex
3
Q
What is the cell wall made from in prokaryotes?
A
Peptidoglycan = polymer consisting of sugars and amino acids
4
Q
Eukaryote VS Prokaryote
Cell wall
A
E = sometimes
P = yes
5
Q
Eukaryote VS Prokaryote
Golgi
A
E = yes
P = no
6
Q
Eukaryote VS Prokaryote
Nuclear envelope
A
E = yes
P = no
7
Q
Eukaryote VS Prokaryote
Ribosomes
A
E = 80S (22nm diameter)
P = 70S (10-20nm diameter)
8
Q
Eukaryote VS Prokaryote
Flagellum
A
E = sometimes
P = sometimes
9
Q
Eukaryote VS Prokaryote
Avg diameter size
A
E = 10-100um
P = 0.5-5um
10
Q
Eukaryote VS Prokaryote
Nucleus state
A
E = genetic material bound in membrane
P = no true nucleus
11
Q
Eukaryote VS Prokaryote
DNA
A
E = as chromosomes
P = “naked” DNA - 1 coiled chromosome
12
Q
Which eukaryotes have cell walls made from what?
A
Plants = made from cellulose
Fungi = made from chitin
13
Q
Prokaryotic Components
Define cytoplasm
A
Internal fluid component of the cell
14
Q
Prokaryotic Components
Define nucleoid
A
Irregularly-shaped region of cytoplasm of the prokaryote that contains all or most of the DNA
15
Q
Prokaryotic Components
Define plasmids
A
Autonomous circular DNA molecules that may be transferred between bacteria
16
Q
Prokaryotic Components
Define ribosomes (70S)
A
Complexes of RNA and protein used for protein synthesis
17
Q
Prokaryotic Components
Define cell membrane
A
Selective barrier surrounding the cell
18
Q
Prokaryotic Components
Define cell wall
A
Rigid peptidoglycan covering to maintain shape and prevent lysis (bursting)
19
Q
Prokaryotic Components
Define slime capsule
A
Polysaccharide layer used for protection against desiccation and phagocytosis
20
Q
Define desiccation
A
Drying out of a cell
21
Q
Prokaryotic Components
Define flagella
A
Projection containing motor protein to enable movement
22
Q
Prokaryotic Components
Define pili
A
Hair-like that enable adherence to surfaces or mediate bacterial conjugation
23
Q
Which kingdom to prokaryotes belong to?
A
Prokaryota
24
Q
Domains
What are archaebacteria?
A
Found in extreme conditions like high temp, salt conc, or pH (eg.extremophiles)
25
Domains
What are eubacteria?
Traditional bacteria including most known pathogen forms (eg E.Coli)
26
What are chromosomes?
DNA associates with proteins called histones to form chromatin, which coils and condenses to form chromosomes
27
What is the use of the nucleolus?
- responsible for providing ribosomes
- composed of proteins and RNA
28
How are the necessary ribosomes formed for protein synthesis?
RNA is used to produce ribosomal RNA (rRNA) which combines with proteins
29
What do mitochondria do?
Cellular respiration where the energy stored in bonds of complex molecules is made available for the cell to use by the production of ATP
30
Mitochondria special features
What is cristae and what does this membrane contain?
Highly folded inner membrane forms structures called cristae
Contains enzymes used in aerobic respiration
31
Mitochondria Special Features
What is the matrix?
fluid interior of organelle
32
What are vesicles?
Membranous sacs that have storage and transport roles consisting simply of a single membrane with fluid inside to transport materials in cell
33
What are lysosomes?
Specialised vesicles containing hydrolytic enzymes responsible for breaking down waste material in cells
34
What roles do lysosomes have?
- breaking down waste
- immune system breaking down pathogens ingested by phagocytes
- programmed cell death or apoptosis
35
Cytoskeleton
Define microfilaments
Contractile fibres formed from protein actin
- responsible for cell movement / contraction during cytokinesis
36
Cytoskeleton
Define microtubules
Globular tubulin proteins polymerise to form tubes that are used to scaffold and structure the cell
37
Cytoskeleton
What else do microtubules do?
- act as tracks for movement of organelles eg vesicles
- spindle fibres are composed of microtubules
38
Cytoskeleton
Define intermediate fibres
give mechanical strength to cells and help maintain their integrity
39
Cytoskeleton
Define centrioles
Composed of microtubules
Two centrioles form the centrosome
40
What do centrosomes do?
Involved in the assembly and organisation of the spindle fibres during cell division
41
Define flagella
Enable motility or as sensory organelle detecting chemical changes in environment
42
Define stationary cilia
Present on surface of cells and have important sensory function
43
Define mobile cilia
Beat in a rhythmic manner creating a current causing fluids or object adjacent to cell to move
44
What is the structure of cilia?
two central microtubules surrounded by 9 pairs of microtubules arranged like a “wheel”
Known as the 9+2 arrangement
45
Define the endoplasmic reticulum
a network of membranes, attached to the outer membrane of the nucleus, enclosing flattened sacs called cisternae
46
What does the smooth ER do?
responsible for lipid and carbohydrate synthesis and storage
47
What does the rough ER do?
responsible for the synthesis and transport or proteins
48
What cells have more rough ER than those that do not release proteins?
Secretory cells which release hormones or enzymes
49
What makes a ER rough?
attachment of ribosomes
50
What are ribosomes made of?
- constructed of RNA molecules made in the nucleolus of the cell
51
What organelles contain their own ribosomes?
Mitochondria and chloroplasts
52
What is the Golgi apparatus made from?
formed of cisternae and doesn't contain ribosomes
53
What does the Golgi apparatus do?
role in modifying proteins and 'packaging' them into vesicles
- protein leaving cell = secretary vesicles
- protein staying in cell = lysosomes
54
Protein Production 1
Where are proteins synthesised?
on the ribosomes bound to the ER
55
Protein Production 2
Where do proteins get packaged into transport vesicles?
pass into ER's cisternae (flattened sacs)
56
Protein Production 3
Where do vesicles containing newly synthesised proteins move to and how?
move towards the Golgi via the transport function of the cytoskeleton
57
Protein Production 4
How do the proteins enter the Golgi, and what happens when they are in there?
vesicles fuse with the cis face of Golgi and proteins enter
proteins are structurally modified before leaving in vesicles from its trans face
58
Protein Production 5
How do the proteins leave the cell after leaving the Golgi?
secretory vesicles carry proteins towards and fuse with the cell-surface membrane, releasing their contents by exocytosis
some vesicles form lysosomes containing enzymes for use in the cell
59
Use of cell plant walls (cellulose)
- freely permeable so substances can enter/exit
- gives cell its shape
- contents of cell press up against wall = rigid
- defence mechanism = stops pathogens
60
Describe what vacuoles are
membrane lined sacs in cytoplasm containing cell sap
61
What is the vacuole membrane called?
Tonplast
62
What are the features of vacuoles in animal cells?
small and transient (not permeable)
63
What is the function of vacuoles?
large, permanent, important in maintenance of turgor, so contents of cell push up against cell wall making it rigid
64
What do the internal membranes of chloroplasts provide?
large SA for enzymes, proteins and pigment molecules necessary in photosynthesisi
65
How are chloroplasts similar to mitochondria?
double membrane structure, DNA, ribosomes
66
What is the fluid enclosed in the chloroplast called?
stroma
67
What are thylakoids?
an internal network of membranes forming flattened sacs
68
What are several thylakoids stacked together called?
Granum (plural = grana)
69
What are grana joined by?
membranes called lamellae
70
What do grana contain?
chlorophyll pigments, where light-dependent reactions occur during photosynthesis
71
Define magnification
how many times larger an image is than the actual size of the object being viewed
72
Define resolution
the ability to see individual objects as separate entities
73
Define resolution
the ability to see individual objects as separate entities
74
What limits resolution?
The diffraction of light as it passes through samples and lenses
75
What is diffraction?
The tendency of light waves to spread as they pass close to physical structures such as those present tin specimens studied
76
What can increase resolution?
Using beams of electrons which have a wavelength thousands of times shorter than light, so they can be much closer before they overlap
77
What is the magnification formula?
Mag = image size / actual size
78
What does cell theory state?
- both plants and animal tissue is composed of cells
- cells are the basic unit of all life
- cells only develop from existing cells
79
How does a compound light microscope work?
- objective lens is near the specimen
- eyepiece lens is through which the specimen is viewed
- illumination is provided below sample
80
What is the maximum resolving power using visible light?
200nm
81
What gives a greater resolving power?
- shorter wavelength of light used
- larger value of the lens numerical aprtire
82
What does a stain provide?
Provides congrats to make organelles visible and distinguishable from one another
83
What can be used to stain nuclei?
Acetic orcein, methylene blue, toluidine blue
84
Other than for visibility, why might a stain be added?
To stop dehydration alongside wayer
85
Why are specimens embedded in wax?
It allows the sample to be cut without distorting its structure
86
What can be used to stain cytoplasm?
Eosin = pink stain
87
What colour does toluidine blue stain cells?
Blue
88
What colour does phloroglucinol stain cells?
Red/pink
89
What is the function of a compound light microscope?
Uses visible light to illuminate a thin sample
90
What is the disadvantages to a compound light microscope?
Low resolution compared to others
91
What are compound light microscopes useful for looking at?
- living cells
- living tissues
92
What is the function of confocal laser scanning microscope?
Looks specifically at parts of a cell by labelling them with fluorescence
93
What are the disadvantages of confocal laser scanning microscopes?
- low resolution
- only see fluorescent objects
- can cause artefacts
94
What are confocal laser scanning microscopes useful for looking at?
- living cells
- understanding relationships between cells
95
What is the function of ribosomes?
- protein synthesis via translation of encoded messenger ribonuclease acid
- together specific amino acids to form polypeptides exported to cytoplasm
96
What is the function of a SEM microscope?
Looks at surface of objects at a high reoslution
97
What are the disadvantages of SEM?
- costly
- can’t look at living things
- resolution lower than TEM
98
What are SEMs useful for looking at?
surface of objects in 3D
99
What is the function of a TEM?
Lets users look at a thin cross section of an object
100
What are the disadvantages of TEM?
- costly
- can’t look at living things
101
What are TEMs useful for looking at?
- internal structure
- relationships between cells
- high resolution
102
When using a SEM, what gets knocked off the surface of the sample and then picked up by a detector?
Electrons are knocked off sample, and are called ‘secondary electrons’
103
What special proteins help do what inside the RER lumen?
‘Chaperones’ ensure each protein folds into its correct 3D shape when folding up
104
How do prokaryotic cells reproduce?
Binary fission
105
How do eukaryotic cells reproduce?
Asexual or sexual
