3 Cells Flashcards
(88 cards)
1
Q
cell
A
the structural and functional unit of all living things
2
Q
the structural and functional unit of all living things
A
cells
3
Q
the three major regions/parts of all animal cells
A
nucleus
plasma membrane
cytoplasm
4
Q
nucleus
plasma membrane
cytoplasm
A
the three major regions of all animal cells
5
Q
the fluid between the cells
A
interstitial fluid
6
Q
interstitial fluid
A
the fluid between the cells
7
Q
orientation of the three main regions of the generalized cell
A
the nucleus is located near the center
it is surrounded by the semifluid cytoplasm
which in turn is enclosed by the plasma membrane which forms the outer cell boundry
8
Q
nucleus
A
the control center of the cell; site of DNA
9
Q
the control center of the cell
A
nucleus
10
Q
what part of the cell is the site of the genes (DNA)?
A
nucleus
11
Q
what is like the blueprint that contains all of the instructions needed for building the whole body?
A
DNA
12
Q
what has the instructions for building proteins?
A
DNA
13
Q
what happens to a cell that has lost or ejected its nucleus?
A
it is programmed to die
14
Q
what are the three recognizable regions of the nucleus?
A
nuclear envelope
nucleoli
chromatin
15
Q
nuclear envelope
nucleoli
chromatin
A
the three recognizable structures of the nucleus
16
Q
what is bounded by the double membrane barrier of the nuclear membrane (nuclear envelope)?
A
the nucleus
17
Q
nuclear membrane
A
binds the nucleus in its porous double barrier
18
Q
binds the nucleus in its double barrier
A
nuclear membrane
19
Q
the nucleus is bounded by what?
A
a double layer porous membrane called the nuclear membrane (nuclear envelope)
20
Q
another name for nuclear membrane
A
nuclear envelope
21
Q
another name for nuclear envelope
A
nuclear membrane
22
Q
what is between the two membranes of the nuclear envelope?
A
a fluid-filled space (like a moat)
23
Q
at various points where the two layers of the nuclear membrane fuse, what penetrates through the fused regions?
A
nuclear pores
24
Q
nuclear pores
A
tiny holes in the double wall of the nuclear membrane
25
what is the jelly-like fluid in which nuclear elements are suspended
nucleoplasm
26
nucleoplasm
enclosed by the nuclear membrane; the jelly-like fluid in which other nuclear elements are suspended
27
nucleoli
one or more small, dark staining round bodies in the nucleus; the sites where ribosomes are assembled
28
one or more small, dark staining round bodies in the nucleus
nucleoli
29
assembly site for ribosomes
nucleoli
30
protein-synthesizing "factories"
ribosomes
31
ribosomes
assembled in the nucleoli and particularly abundant in the cytoplasm; protein-synthesizing "factories"
32
where are ribosomes particularly abundant?
the cytoplasm
33
what do the large nuclear pores of the nuclear membrane permit?
permit large molecules such as protein and RNA molecules to pass easily
34
the nuclear membrane is similar to other membranes except for what?
except it has particularly large nuclear pores to allow large molecules such as protein and RNA molecules to pass easily
35
when a cell is not dividing, its genetic material is in a threadlike form called this
chromatin
36
chromatin
the threadlike form a cells genetic material is in when it is not dividing
37
where is chromatin located?
it is scattered throughout the nucleus
38
what happens to chromatin when the cell is dividing to form two daughter cells?
the chromatin threads coil and condense to form dense, rodlike bodies called chromosomes
39
plasma membrane
the flexible, fragile, transparent barrier that contains the cell contents and separates them from the surrounding environment
40
the flexible, fragile, transparent barrier that contains the cell contents and separates them from the surrounding environment
plasma membrane
41
what does the structure of the plasma membrane consist of?
two lipid (fat) layers arranged "tail to tail" in which protein molecules float
42
the structure of this is two lipid (fat) layers arranged "tail to tail" in which protein molecules float
plasma membrane
43
why is the plasma membrane described in a "fluid mosaic model"?
because the proteins, some of which are free to move, form a constantly changing pattern, or mosaic
44
most of the lipid portion of the plasma membrane is what?
phospholipids (some with attached sugar groups)
45
besides phospholipids, a substantial amount of what else is found in the plasma membrane?
cholesterol
46
the general function of nucleoli?
nucleoli are the sites of synthesis of ribosomes, which are important in protein synthesis
47
what orients the polar heads and nonpolar tails of the phospholipid molecules in the lipid bilayer of the plasma membrane?
the polar heads are hydrophilic and orient outward and inward toward the intracellular and extracellular fluids; the nonpolar tails are hydrophobic and line up oriented inward
48
what does the cholesterol help do in the plasma membrane?
keeps the membrane fluid
49
what is the advantage of the hydrophilic/hydrophobic orientation of the phospholipids of the plasma membrane?
the self-orienting properties allow the membranes to reseal themselves when torn; makes the membrane relatively impermeable to most water-soluble molecules
50
what are responsible for most of the specialized functions of the plasma membrane?
the proteins scattered in the lipid bilayer
51
besides protecting the cell, what else does the plasma membrane do?
determines which substances may enter or leave the cell and in what amount
52
what determines which substances may enter or leave the cell and in what amount?
plasma membrane
53
most proteins that span the plasma membrane are involved in what activity?
transport
54
what is the major building material of the cell?
protein
55
living matter is over 60% what?
water
56
what percent of living matter is water?
60%
57
a cell is composed of primarily which elements?
C Carbon
H Hydrogen
O Oxygen
N Nitrogen
58
what is the plasma membrane composed of?
a lipid bilayer containing proteins
59
what kind of proteins are many of the proteins in the lipid bilayer of the plasma membrane?
glycoproteins
60
what do the proteins in the plasma membrane do?
Act as enzymes or carriers in membrane transport
Form membrane channels
Provide receptor sites for hormones & other
chemicals (inc. bacteria, virus, toxins)
Play a role in cell-to-cell recognition & interactions
during development and immune reactions
61
glycoprotein
branching sugar groups attached to most of the proteins abutting the extracellular space "sugar-proteins"
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branching sugar groups attached to most of the proteins abutting the extracellular space
glycoproteins
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"sugar-proteins"
glycoproteins
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create a fuzzy, sticky, sugar-rich area on the cell surface called glycocalyx
glycoproteins
65
what is the purpose of protein channels (tiny pores formed by clustered proteins) in the plasma membrane?
water and small water-soluble molecules or ions can move through
66
the three ways cells are typically bound together
Glycoproteins in the glycocalyx act as an adhesive
Wavy contours of the membranes of adjacent cells fit together in a tongue-and-groove fashion
Special membrane junctions are formed which vary structurally depending on their roles
67
glycocalyx
the fuzzy, sticky, sugar-rich surface of the plasma membrane caused by the presence of glycoproteins
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the three common types of membrane junctions
Tight junctions
Desmosomes
Gap junctions
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Impermeable junctions that bind cells together into leak-proof sheets that prevent substance from passing through the extracellular space between cells.
Tight junctions
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Tight junctions
Impermeable junctions that bind cells together into leak-proof sheets that prevent substance from passing through the extracellular space between cells.
71
In these types of membrane junctions, adjacent plasma membranes fuse together tightly like a zipper.
Tight junctions
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In the small intestine, these types of membrane junctions prevent digestive enzymes from seeping into the bloodstream.
Tight junctions
73
Desmosomes
Anchoring membrane junctions scattered like rivets along the sides of abutting cells.
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Anchoring membrane junctions scattered like rivets along the sides of abutting cells.
Desmosomes
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what type of membrane junctions prevent cells subjected to mechanical stress (like skin cells) from being pulled apart?
Desmosomes
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Structurally, these membrane junctions are buttonlike thickenings of adjacent plasma membranes (plaques), which are connected by fine protein filaments
Desmosomes
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desmosomes, structurally
membrane junctions are buttonlike thickenings of adjacent plasma membranes (plaques), which are connected by fine protein filaments. Thicker protein filaments ("guy wires") form the internal connection between the inner walls.
78
In desmosomes, Thicker protein filaments extend from the plaques inside the cells to the plaques on the cell's opposite sides, forming an internal system of strong ________________
strong "guy wires".
79
"guy wires"
In desmosomes, Thicker protein filaments extend from the plaques inside the cells to the plaques on the cell's opposite sides, forming an internal system of strong "guy wires"
80
gap junctions
the neighboring cells are connected by hollow cylinders composed of proteins (called connexons) that span the entire width of the abutting membranes
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in these membrane junctions, the neighboring cells are connected by hollow cylinders composed of proteins that span the entire width of the abutting membranes
gap junctions
82
connexons
in gap junctions, hollow cylinders composed of proteins create water-filled channels that span the entire width of the abutting cell
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in gap junctions, hollow cylinders composed of proteins create water-filled channels that span the entire width of the abutting cell
connexons
84
what kind of membrane junctions function mainly to allow communication?
gap junctions
85
what kind of membrane junctions are commonly seen in the heart and between embryonic cells?
gap junctions
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In which membrane junctions can chemical molecules, such as nutrients or ion, pass directly through the water-filled connexon channels from one cell to another?
gap junctions
87
microvilli
tiny finger-like extensions of the plasma membrane that project from an exposed cell surface to increase the surface area of the cell for absorption
88
tiny finger-like extensions of the plasma membrane that project from an exposed cell surface to increase the surface area of the cell for absorption
microvilli
