Cytology 1

Question 1

Cell

Answer 1

Smallest living structural and functional unit is human body

Question 2

Cells produced by

Answer 2

Cell division; mostly mitosis

Question 3

Organelles

Answer 3

Specialized structural and functional units inside cells.

Question 4

Parts of a cell

Answer 4

1. Cell membrane
2. Nucleus
   
   • Nucleolus
3. Mitochondrion
4. Ribosome
5. Rough Endoplasmic Reticulum (ER)
6. Smooth Endoplasmic Reticulum (ER)
7. Golgi apparatus
8. Lysosome
9. Phagocytic vesicle
10. Secretory vesicle
11. Centrosome
12. Centrioles
13. Peroxisome
14. Microtubule network
15. Cilia
16. Microvilli
17. Cytoplasm

Question 5

Cellular Functions

Answer 5

1. Covers and lines surfaces (epitheleal)
2. Storage (hepatocytes, adipocytes)
3. Movement (muscle)
4. Attachment and support (fibroblasts)
5. Defense (leukocytes)
6. Communication (neurons)
7. Reproduction (egg, sperm, fertilized egg)

Question 6

Basic animal cell type “Eukaryotic” contains

Answer 6

1. Nucleus
2. Plasma Membrane
3. Cytoplasm
   
   • Organelles
   • Cytosol
   • Inclusions

** Organelles have membrane/double membrane; membrane bound

Question 7

Nucleus structure and function

Answer 7

1. Shape similar to cell
2. Double nuclear membrane w/pores allowing large molecules to move inside
3. Houses DNA
4. Some cells multinucleate (many) or anucleate (none)
5. Nucleoplasm
   
   • Nucleolus
     
     • Organelle in nucleus (non-membranous)
     • assembles ribosomes
   • DNA
     
     • Chromatin (don’t divide) - loose; protein synthesis
     • Chromosomes - dense, rodlike; cell division

Question 8

Plasma Membrane structure

Answer 8

1. Selectively permeable - regulates exchange w/extracellular fluid
2. Limiting factor is mainly cell size
3. Composed of mostly lipids and proteins
   
   • Phospholipid Bilayer is basic structure
   • Proteins determine function

Question 9

Functions of a membrane

Answer 9

1. Communication: contains receptors that respond to molecular signals
2. Intercellular connection: establishes flexible boundary, protects cellular contents, and supports structure
3. Physical barrier: phospholipid bilayer separates substances inside & out
4. Selective permeability: Regulates exit and entry of ions, nutrients, and waste molecules through membrane

Question 10

Phospholipid Bilayer characteristics

Answer 10

Molecules that combine to form polar (Amphipathic molecules***) and nonpolar (Hydrophobic) structure

Question 11

Glycolipd

Answer 11

Glycogen (carbohydrate) attached to a lipid

Question 12

Glycocalyx

Answer 12

Carbohydrate chain

Question 13

Integral Protein

Answer 13

Embedded in phospholipid bilayer cell membrane

Question 14

Peripheral Protein

Answer 14

Hangs on outside of cell membrane

Question 15

Glycoprotein

Answer 15

Glycogen (carb) attached to protein

Question 16

Plasma Membrane

Answer 16

1. Lipids - insoluble in water
   
   • cholesterol
     
     • affects membrane fluidity
     • thermal stability
2. Glycolipids (carb attached to phospholipid)
   
   • outer surface
   • Glycocalyx (carb chain) contributes to cellular recognition

20% is lipid, 5-10% glycolipid

3. Proteins - highly diverse
   
   • Integral - embedded
     
     • channels and carriers
     • receptors
     • enzymes
     • many are glycoproteins
   • peripheral - attached to surface; may float
     
     • enzymes

Question 17

Cytoplasm components

Answer 17

Three components:

1. Cytosol - intracellular fluid
2. Inclusions - temporarily stored substances (nutrients/pigments)
3. Organelles
   
   • diverse structures w/specialized functions
   • vary among cells
   • membrane-bound & non-membranous

Question 18

Organelles

Answer 18

“Little organs”

1. Membrane-bound organelles
   
   • membrane isolates secretions, enzymes or toxins
2. Non-membrane-bound organelles

Question 19

Smooth Endoplasmic Reticulum function

Answer 19

• synthesis of lipids; metabolizes carbohydrates; detoxifies
• storage (synthesized materials or Ca+)
• membranous
• more in liver

Question 20

Rough Endoplasmic Reticulum function

Answer 20

• attached ribosomes
• protein synthesis
• membranous*

Question 21

Golgi Apparatus structure and function

Answer 21

• membranous
  1. Structure: flattened membranous sacs w/vesicles
  2. Function:
  
  • modifies new proteins for lysosomes & protein for secretion
  • packages enzymes for lysosomes & protein for secretion
  • sorts all materials for lysosome secretion and incorporation into plasma membrane

Question 22

Exocytosis

Answer 22

Exiting the cell

Question 23

Lysosome structure and function

Answer 23

• membranous
  1. Structure: vesicles filled with digestive enzymes
  2. Function:
  
  • intracellular digestion (wastes and ingested macromolecules)
  • recycle worn-out organelles via Autophagy*
  • self-digestion of cell via Autolysis*

Question 24

Peroxisomes structure and function

Answer 24

1. Membranous sacs of enzymes (oxidases=use O2 to break down free radicals to a safer form of H2O2)
2. Break down amino acids and fatty acids
3. Detoxify harmful/dangerous substances
   
   • hydrogen peroxide (by-product of oxidization)
   • alcohol
   • formaldehyde
   • free radicals

Question 25

Mitochondria structure and function

Answer 25

1. Structure: double membrane w/cristae & central fluid matrix 2. Function: most ATP synthesis (cellular energy in the presence of O2) 3. Contains DNA 4. Self-replicating 5. More numerous in certain cells and certain individuals (high numbers in cells that require energy, such as muscle cells)

Question 26

Ribosomes structure and function

Answer 26

* NON-membranous 1. Structure: two subunits 2. Function: protein synthesis* 3. Two types: - Free - synthesis of proteins for intracellular use - Fixed - synthesis of proteins for secretion, or incorporation into lysosomes, plasma membrane, or cell membranes; attached to Rough ER

Question 27

Cytoskeleton structure and function

Answer 27

* NON-membranous 1. Network of protein structures 2. Acts as cell's "muscles and bones" 3. Determines cell shape 4. Supports organelles 5. Involved in internal transport & cellular movements

Question 28

Centrosomes structure

Answer 28

1. "Cell center" - closely adjacent to nucleus - builds microtubules in non-dividing cells - forms mitotic spindle during cell division 2. 2 centrioles put together

Question 29

Centrioles structure

Answer 29

1. Paired perpendicular bodies in centrosome 2. Assist in spindle formation 3. 2 centrioles will make a centrosome

Question 30

Cilia structure and function

Answer 30

* Non-membranous 1. Mobile projections of cell surface 2. Contain microtubules 3. Short, numerous, move substances over free surfaces * digestive system

Question 31

Flagella structure and function

Answer 31

* Non-membranous 1. Mobile projections of cell surface 2. Contain microtubules 3. Long, singular, propel human sperm cells

Question 32

Microvilli

Answer 32

Microscopic projections of plasma membrane that increase surface area of cell