Topic 1.2: Ultrastructure of Cells Flashcards
(116 cards)
1
Q
Define prokaryotes
A
are organisms whose cells lack a nucleus
2
Q
What are organisms whose cells lack a nucleus called?
A
prokaryotes
3
Q
Define archaebacteria
A
bacteria found in extreme environments like high temperatures, salt concentrations or pH
4
Q
Define eubacteria
A
traditional bacteria including most known pathogenic forms
5
Q
What are found in extreme environments like high temperatures, salt concentrations or pH called?
A
archaebacteria
6
Q
What are traditional bacteria including most known pathogenic forms called?
A
eubacteria
7
Q
Define cytoplasm
A
internal fluid component of the cell
8
Q
Define nucleoid
A
region of the cytoplasm where the DNA is located (DNA strand is circular and called a genophore)
9
Q
Define plasmids
A
autonomous circular DNA molecules that may be transferred between bacteria (horizontal gene transfer)
10
Q
Define ribosomes
A
complexes of RNA and protein that are responsible for polypeptide synthesis (prokaryote ribosome = 70S)
11
Q
Define cell membrane
A
Semi-permeable and selective barrier surrounding the cell
12
Q
Define cell wall
A
rigid outer covering made of peptidoglycan; maintains shape and prevents bursting (lysis)
13
Q
Define slime capsule
A
a thick polysaccharide layer used for protection against dessication (drying out) and phagocytosis
14
Q
Define flagella
A
Long, slender projections containing a motor protein that enables movement (singular: flagellum)
15
Q
Define pili
A
Hair-like extensions that enable adherence to surfaces (attachment pili) or mediate bacterial conjugation (sex pili)
16
Q
What is the internal fluid component of the cell called?
A
cytoplasm
17
Q
What is the region of the cytoplasm where the DNA is located (DNA strand is circular and called a genophore) called?
A
nucleoid
18
Q
What is the autonomous circular DNA molecules that may be transferred between bacteria (horizontal gene transfer) called?
A
plasmids
19
Q
What are complexes of RNA and protein that are responsible for polypeptide synthesis (prokaryote ribosome = 70S) called?
A
ribosomes
20
Q
What is the Semi-permeable and selective barrier surrounding the cell called?
A
cell membrane
21
Q
What is the rigid outer covering made of peptidoglycan; maintains shape and prevents bursting (lysis) called?
A
cell wall
22
Q
What is a thick polysaccharide layer used for protection against dessication (drying out) and phagocytosis called?
A
slime capsule
23
Q
What are Long, slender projections containing a motor protein that enables movement (singular: flagellum) called?
A
flagella
24
Q
What are Hair-like extensions that enable adherence to surfaces (attachment pili) or mediate bacterial conjugation (sex pili) called?
A
pili
25
Define binary fission
a form of asexual reproduction used by prokaryotic cells
26
What is a form of asexual reproduction used by prokaryotic cells?
binary fission
27
What are the 3 steps to binary fission?
The circular DNA is copied in response to a replication signal
The two DNA loops attach to the membrane
The membrane elongates and pinches off (cytokinesis), forming two cells
28
What is the first step to binary fission?
The circular DNA is copied in response to a replication signal
29
After The circular DNA is copied in response to a replication signal What is the next step to binary fission?
The two DNA loops attach to the membrane
30
After The two DNA loops attach to the membrane What is the next step to binary fission?
The membrane elongates and pinches off (cytokinesis), forming two cells
31
Define eukaryotes
organisms whose cells contain a nucleus
32
What are organisms whose cells contain a nucleus?
eukaryotes
33
What are the two types of bacteria?
archaebacteria and eubacteria
34
What are the four kingdoms of eukaryotes?
protista, fungi, plantae, animalia
35
What makes a eukaryote a protista?
unicellular organisms; or multicellular organisms without specialised tissue
36
What makes a eukaryote a fungi?
have a cell wall made of chitin and obtain nutrition via heterotrophic absorption
37
What makes a eukaryote a plantae?
have a cell wall made of cellulose and obtain nutrition autotrophically (via photosynthesis)
38
What makes a eukaryote a animalia?
no cell wall and obtain nutrition via heterotrophic ingestion
39
What kingdom of eukaryotes are unicellular organisms; or multicellular organisms without specialised tissue?
protista
40
What kingdom of eukaryotes have a cell wall made of chitin and obtain nutrition via heterotrophic absorption?
fungi
41
What kingdom of eukaryotes have a cell wall made of cellulose and obtain nutrition autotrophically (via photosynthesis)?
plantae
42
What kingdom of eukaryotes have no cell wall and obtain nutrition via heterotrophic ingestion?
animalia
43
What is the structure of ribosomes?
Two subunits made of RNA and protein; larger in eukaryotes (80S) than prokaryotes (70S)
44
What is the function of ribosomes?
Site of polypeptide synthesis (this process is called translation)
45
What is the structure of cytoskeleton?
A filamentous scaffolding within the cytoplasm (fluid portion of the cytoplasm is the cytosol)
46
What is the function of cytoskeleton?
Provides internal structure and mediates intracellular transport (less developed in prokaryotes)
47
What is the structure of plasma membrane?
Phospholipid bilayer embedded with proteins (not an organelle per se, but a vital structure)
48
What is the function of plasma membrane?
Sem-permeable and selective barrier surrounding the cell
49
What is the structure of nucleus?
Double membrane structure with pores; contains an inner region called a nucleolus
50
What is the function of nucleus?
Stores genetic material (DNA) as chromatin; nucleolus is site of ribosome assembly
51
What is the structure of endoplasmic reticulum?
A membrane network that may be bare (smooth ER) or studded with ribosomes (rough ER)
52
What is the function of endoplasmic reticulum?
Transports materials between organelles (smooth ER = lipids ; rough ER = proteins)
53
What is the structure of golgi apparatus?
An assembly of vesicles and folded membranes located near the cell membrane
54
What is the function of golgi apparatus?
Involved in the sorting, storing, modification and export of secretory products
55
What is the structure of mitochondria?
Double membrane structure, inner membrane highly folded into internal cristae
56
What is the function of mitochondria?
Site of aerobic respiration (ATP production)
57
What is the structure of peroxisome?
Membranous sac containing a variety of catabolic enzymes
58
What is the function of peroxisome?
Catalyses breakdown of toxic substances (e.g. H2O2) and other metabolites
59
What is the structure of centrosome?
Microtubule organising centre (contains paired centrioles in animal cells but not plant cells)
60
What is the function of centrosome?
Radiating microtubules form spindle fibres and contribute to cell division (mitosis / meiosis)
61
What is the structure of chloroplasts?
Double membrane structure with internal stacks of membranous discs (thylakoids)
62
What is the function of chloroplast?
Site of photosynthesis – manufactured organic molecules are stored in various plastids
63
What is the structure of vacuole?
Fluid-filled internal cavity surrounded by a membrane (tonoplast)
64
What is the function of vacuole?
Maintains hydrostatic pressure (animal cells may have small, temporary vacuoles)
65
What is the structure of cell wall?
External outer covering made of cellulose (not an organelle per se, but a vital structure)
66
What is the function of cell wall?
Provides support and mechanical strength; prevents excess water uptake
67
What is the structure of lysosome?
Membranous sacs filled with hydrolytic enzymes
68
What is the function of lysosome?
Breakdown / hydrolysis of macromolecules (presence in plant cells is subject to debate)
69
What structure is Two subunits made of RNA and protein; larger in eukaryotes (80S) than prokaryotes (70S)?
ribosomes
70
What structure has the function of Site of polypeptide synthesis (this process is called translation)?
ribosomes
71
What structure is A filamentous scaffolding within the cytoplasm (fluid portion of the cytoplasm is the cytosol)?
cytoskeleton
72
What structure has the function of Provides internal structure and mediates intracellular transport (less developed in prokaryotes)?
cytoskeleton
73
What structure is Phospholipid bilayer embedded with proteins (not an organelle per se, but a vital structure)?
plasma membrane
74
What structure has the function of Sem-permeable and selective barrier surrounding the cell?
plasma membrane
75
What structure is Double membrane structure with pores; contains an inner region called a nucleolus?
nucleus
76
What structure has the function of Stores genetic material (DNA) as chromatin; nucleolus is site of ribosome assembly?
nucleus
77
What structure is A membrane network that may be bare (smooth ER) or studded with ribosomes (rough ER)?
endoplasmic reticulum
78
What structure has the function of Transports materials between organelles (smooth ER = lipids ; rough ER = proteins)?
endoplasmic reticulum
79
What structure is An assembly of vesicles and folded membranes located near the cell membrane?
golgi apparatus
80
What structure has the function of Involved in the sorting, storing, modification and export of secretory products?
golgi apparatus
81
What structure is Double membrane structure, inner membrane highly folded into internal cristae?
mitochondria
82
What structure has the function of Site of aerobic respiration (ATP production)?
mitochondria
83
What structure is Membranous sac containing a variety of catabolic enzymes?
peroxisome
84
What structure has the function of Catalyses breakdown of toxic substances (e.g. H2O2) and other metabolites
?
peroxisome
85
What structure is Microtubule organising centre (contains paired centrioles in animal cells but not plant cells)?
centrosome
86
What structure has the function of Radiating microtubules form spindle fibres and contribute to cell division (mitosis / meiosis)?
centrosome
87
What structure is Double membrane structure with internal stacks of membranous discs (thylakoids)?
chloroplast
88
What structure has the function of Site of photosynthesis – manufactured organic molecules are stored in various plastids?
chloroplast
89
What structure is Fluid-filled internal cavity surrounded by a membrane (tonoplast)?
vacuole
90
What structure has the function of Maintains hydrostatic pressure (animal cells may have small, temporary vacuoles)
?
vacuole
91
What structure is External outer covering made of cellulose (not an organelle per se, but a vital structure)?
cell wall
92
What structure has the function of Provides support and mechanical strength; prevents excess water uptake?
cell wall
93
What structure is Membranous sacs filled with hydrolytic enzymes?
lysosome
94
What structure has the function of Breakdown / hydrolysis of macromolecules (presence in plant cells is subject to debate)
?
lysosome
95
How do electron microscopes work?
Electron microscopes use electron beams focused by electromagnets to magnify and resolve microscopic specimens
96
What type of microscopes use electron beams focused by electromagnets to magnify and resolve microscopic specimens?
electron microscopes
97
What does a Transmission electron microscopes (TEM) do?
generate high resolution cross-sections of objects
98
What type of electron microscope generate high resolution cross-sections of objects?
Transmission electron microscopes (TEM)
99
What does a Scanning electron microscopes (SEM) do?
display enhanced depth to map the surface of objects in 3D
100
What type of electron microscope display enhanced depth to map the surface of objects in 3D?
Scanning electron microscopes (SEM)
101
What are the two advantages electron microscopes have over light microscopes?
They have a much higher range of magnification (can detect smaller structures)
They have a much higher resolution (can provide clearer and more detailed images)
102
What is one disadvantage of electron microscopes?
they cannot display living specimens in natural colours
103
Define micrograph
a photo or digital image taken through a microscope to show a magnified image of a specimen
104
What is a photo or digital image taken through a microscope to show a magnified image of a specimen?
micrograph
105
What are the 3 differences between prokaryotes and eukaryotes when it comes to DNA?
Prokaryotes: DNA is naked, DNA is circular, usually no introns
Eukaryotes: DNA bound to protein, DNA is linear, usually has introns
106
What are the 3 differences between prokaryotes and eukaryotes when it comes to organelles?
Prokaryotes: no nucleus, no membrane-bound, 70S ribosomes
Eukaryotes: has a nucleus, membrane-bound, 80S ribosomes
107
What are the 2 differences between prokaryotes and eukaryotes when it comes to reproduction?
Prokaryotes: binary fission, single chromosome (haploid)
Eukaryotes: mitosis and meiosis, chromosomes paired (diploid or more)
108
What is the difference between prokaryotes and eukaryotes when it comes to average size?
Prokaryotes: smaller (1-5 micrometers)
Eukaryotes: larger (10-100 micrometers)
109
What is the difference between plant and animal cells when it comes to plastids?
Plant: have plastids (chloroplasts)
Animal: do not have plastids
110
What is the difference between plant and animal cells when it comes to cell wall?
Plant: have a cell wall (made of cellulose)
Animal: do not have a cell wall
111
What is the difference between plant and animal cells when it comes to vacuoles?
Plant: have a large, central vacuole
Animal: have small, temporary vacuoles (if any)
112
What is the difference between plant and animal cells when it comes to plasmodesmata?
Plant: may have plasmodesmata
Animal: do not have plasmodesmata
113
What is the difference between plant and animal cells when it comes to centrioles?
Plant: do not have centrioles
Animal: have paired centrioles within centrosomes
114
What is the difference between plant and animal cells when it comes to cholesterol?
Plant: do not have cholesterol in cell membrane
Animal: have cholesterol in the cell membrane
115
What is the difference between plant and animal cells when it comes to storing glucose?
Plant: store excess glucose a starch
Animal: store excess glucose as glycogen
116
What is the difference between plant and animal cells when it comes to shape?
Plant: generally have a fixed, regular shape
Animal: generally have an amorphouse shape
