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Cell Structure and Membrane Specializations
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Cell Structure and Membrane Specializations
Cell Structure and Membrane Specializations
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1
Question
What is the basic unit of life capable of independent existence?
Answer
Cell
2
Question
What is the smallest possible cell size mentioned?
Answer
2-3 μm
3
Question
Name at least three possible cell shapes listed.
Answer
Spherical, cubical, columnar (also fusiform, stellate)
4
Question
What are the two major divisions of a cell?
Answer
Nucleus and cytoplasm bounded by a cell membrane
5
Question
Where is the nucleus typically located within the cell?
Answer
Center or near the center of the cell
6
Question
What composes the nuclear membrane?
Answer
Two membranes separated by a narrow perinuclear space
7
Question
What passes through nuclear pores?
Answer
Substances between nucleoplasm and cytoplasm
8
Question
What fluid is enclosed by the nuclear envelope?
Answer
Nucleoplasm
9
Question
What is chromatin made of?
Answer
DNA filaments
10
Question
What are heterochromatin and euchromatin?
Answer
Heterochromatin: coiled, visible; Euchromatin: uncoiled, not visible in LM
11
Question
What are chromosomes during cell division?
Answer
Coiled DNA forming dense rod-like bodies
12
Question
What are the components of the plasma membrane?
Answer
Phospholipids, cholesterol, globular proteins, carbohydrates (glycolipids/glycoproteins)
13
Question
Why is the plasma membrane not well seen under light microscopy?
Answer
It is very thin and not resolvable by LM
14
Question
What is the orientation of the phospholipid bilayer’s hydrophilic and hydrophobic regions?
Answer
Hydrophilic faces outward; hydrophobic faces inward
15
Question
What makes phospholipids amphipathic?
Answer
Hydrophilic head and hydrophobic tail
16
Question
What molecule primarily modulates membrane fluidity?
Answer
Cholesterol
17
Question
Where are receptor, transport, and enzyme proteins located in the membrane?
Answer
Within the lipid bilayer as globular proteins
18
Question
What are oligosaccharides and where are they attached?
Answer
Short sugar chains attached to membrane proteins on the outer surface
19
Question
What is the glycocalyx and its functions?
Answer
Surface coat; aids protection and cell-cell recognition/adhesion
20
Question
Name the free surface specializations of the plasma membrane.
Answer
Microvilli, cilia, flagella
21
Question
What is the primary function of microvilli?
Answer
Increase surface area for absorption
22
Question
What is the primary function of cilia?
Answer
Move fluids, mucus, or debris over the cell surface
23
Question
What is the primary function of flagella?
Answer
Provide motility (e.g., sperm)
24
Question
What are the two main junctional specializations?
Answer
Tight junctions and desmosomes (nexus)
25
Question
What structures connect apposing membranes to seal intercellular space?
Answer
Tight junctions (occluding seal)
26
Question
What structures connect adjacent cell membranes to enable adhesion and communication?
Answer
Desmosomes ( junctional plaques) and connexons forming gap junctions
27
Question
What are the components of the cytoplasm?
Answer
Cytosol and formed elements (organelles)
28
Question
What is the cytosol?
Answer
Semi-fluid matrix where components are suspended
29
Question
What are organelles?
Answer
Organized structures in cytoplasm that participate in metabolism
30
Question
What is the site of most cellular metabolic activities?
Answer
Cytoplasm