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Flashcards in Cell and Molecular Physiology Deck (76):
1

maintenance of nearly constant conditions in the internal environment compatible with life

Homeostasis

2

Total Body Weight

60% of body weight

3

Intracellular Fluid (ICF)

40% of body weight

4

Extracellular Fluid (ECF)

20% of body weight

5

also called the internal environment of the body, or the milieu intérieur

Extracellular Fluid

6

• large amounts of sodium, chloride, and bicarbonate ions
• nutrients for the cells, such as oxygen, glucose, fatty acids, and amino acids

Extracellular Fluid

7

• large amounts of potassium, magnesium, and phosphate ions
• special mechanisms for transporting ions through the cell membranes maintain the ion concentration differences between ECF and ICF

Intracellular Fluid

8

considered to be a state of disrupted homeostasis

Disease

9

Fast; neurons; electrical impulse; external environment; for nervous coordination

Nervous Control

10

Slow; hormones; organic message; internal environment; for chemical coordination

Hormonal Control

11

Is separated from the cytoplasm by a nuclear membrane

Nucleus

12

separated from the surrounding fluids by a cell membrane or plasma membrane

Cytoplasm

13

collective term for different substances that make up the cell

Protoplasm

14

Five basic substances of Protoplasm

O Water
O Electrolytes
O Proteins
O Lipids
O Carbohydrates

15

25% of Extracellular Fluid (ECF)

Plasma

16

75% of Extracellular Fluid

Interstitial Fluid

17

• principal fluid medium of the cell
• present in most cells, except for fat cells, in a concentration of 70-85 percent

Water

18

• inorganic chemicals for cellular reactions
• necessary for operation of some of the cellular control mechanisms

Electrolytes / Ions

19

• constitute 10 to 20 percent of the cell mass

Protein

20

Proteins can be divided into

O Structural Proteins
O Functional Proteins

21

• long intracellular filaments that form microtubules and fibrillar proteins

EXAMPLES
- cytoskeleton of cellular organelles
- fibrillar proteins in collagen and elastin fibers

Structural Proteins

22

Composed of combinations of a few molecules in tubular-globular form

EXAMPLES:
- Enzymes

Functional Proteins

23

Substances that catalyze specific intracellular chemical reactions

Enzymes

24

How fast can enzyme speed up chemical reactions?

10^6

25

Soluble in fat solvents but insoluble in water; Eg. Phospholipids and Cholesterol, Triglycerides

Lipids

26

- 2% of total cell mass
- forms the cell membrane and membrane barriers

Phospholipids and Cholesterol

27

- in fat cells, constitutes 95% of the cell mass
- storehouse of energy-giving nutrients
- also called as neural fat

Triglycerides

28

• little structural function in the cell except as parts of glycoprotein molecule
• play a major role in cellular nutrition

Carbohydrates

29

- also called plasma membrane
- thin, pliable, elastic structure (7.5 to 10 nm)
- its basic structure is a lipid bilayer

Cell Membrane

30

Most abundant of the cell membrane lipids

Phospholipids

31

- mainly help determine the degree of permeability of the bilayer to water-soluble constituents of body fluids
- controls much of the fluidity of the membrane

Cholesterol

32

- Act as Guardian of the Cell
- Made up of a lipid bilayer (Fluid Mosaic Model)
- Divides the body into ECF and ICF compartments

Cell Membrane

33

• phosphate end of each phospholipid soluble in water (hydrophilic end)
• fatty acid end soluble only in fats (hydrophobic end)
• repelled by water but are mutually attracted to one another
• natural tendency to attach to one another in the middle of the membrane

Phospholipid Bilayer

34

Possession of both hydrophilic and hydrophobic properties make phospholipids ____ molecules

Amphipathic

35

2 Types of Cell Membrane Proteins

1. Integral Proteins
2. Peripheral Proteins

36

- anchored and embedded in the cell membrane through hydrophobic interactions
- may span the cell membrane (transmembrane proteins)

Integral Proteins

37

- not embedded in the cell membrane
- are not covalently bound to membrane components
- loosely attached to the cell membrane by electrostatic interactions

Peripheral Proteins

38

• loose carbohydrate coat of the cell membrane
• carbohydrates in combination with proteins (glycoproteins) or lipids (glycolipids)

Glycocalyx

39

Are carbohydrate substances bound to small protein cores

Proteoglycans

40

Functions of the glycocalyx include:

o imparts a negative electrical charge
o attachment to glycocalyx of other cells
o receptor substances for binding hormones
o immune reactions

41

• specialized cellular subunit found in the cytoplasm that has a specific function
• usually separately enclosed within its own lipid bilayer (membrane-bound)
• may be identified by microscopy or purified by cell fractionation

Cellular Organelles

42

The jelly-like fluid portion of the cytoplasm in which particles are dispersed

Cytosol

43

• network of tubular and flat vesicular structures in the cytoplasm
• space inside the tubules and vesicles is filled with endoplasmic matrix
• space inside the endoplasmic reticulum is connected with the space between the two membrane surfaces of the nuclear membrane

Endoplasmic Reticulum

44

• also called granular endoplasmic reticulum
• large numbers of ribosomes are attached to the outer surfaces; function in protein synthesis

Rough Endoplasmic Reticulum

45

o Aka agranular endoplasmic reticulum
o has no attached ribosomes
o Functions: Detoxification of substances and Lipid Synthesis

Smooth Endoplasmic Reticulum

46

Protein synthesis bound for Cell membrane, lysosomes and outside of the cell

Ribosomes in Rough Endoplasmic Reticulum

47

create protein bound for the cytoplasmic membrane, mitochondria and cytoplasm

Free Floating Ribosomes

48

• closely related to the endoplasmic reticulum
• composed of four or more stacked layers of thin, flat, enclosed vesicles lying near one side of the nucleus
• functions include: packaging of proteins and molecular tagging
• prominent in secretory cells

Golgi Apparatus

49

• vesicular organelles that form by breaking off from the Golgi apparatus
• intracellular digestive system for damaged cellular structures, food particles and bacteria
• called suicide bags of cells

Lysosomes

50

Programmed cell death/cell suicide; doesn't have inflammation

Apoptosis

51

not programmed cell death; positive for inflammation

Necrosis

52

• differences with lysosomes: formed by self-replication or budding from SER; and contain oxidase and catalase enzymes
• functions include:
o oxidizes many poisonous substances
o degrades free radicals that may damage cells

Peroxisomes

53

• also called secretory granules
• formed by the ER-Golgi apparatus system
• functions include
- storage for enzymes that are not yet activated
- replenish the plasma membrane whenever it forms phagocytic or pinocytic vesicles

Secretory Vesicles

54

storage for enzymes that are not yet activated

Proenzymes

55

- Powerhouse of the cell
- forms adenosine triphosphate (ATP) the universal energy currency

Mitochondria

56

Unique Characteristics of Mitochondria

- self-replicative
- does NOT follow genetic code
- mitochondrial DNA is purely maternally-derived

57

• fibrillar proteins synthesized by ribosomes in the cytoplasm
• function is to provide rigid physical support for certain parts of cells (intracellular scaffolding)

Cytoskeleton

58

• control center of the cell
• contains large quantities of DNA (genes)

Nucleus

59

• also called nuclear envelope
• two separate bilayer membranes
o outer membrane is continuous with the endoplasmic reticulum of the cell cytoplasm

• penetrated by several thousand nuclear pores
o large complexes of protein molecules are attached
o allow molecules up to 44,000 molecular weight to
pass through with reasonable ease

Nuclear Membrane

60

• unlike most other organelles, does not have a limiting membrane
• accumulation of large amounts of RNA and ribosomal proteins
• becomes considerably enlarged when the cell is actively synthesizing protein

Nucleolus

61

Assembly Factory

Rough Endoplasmic Reticulum

62

Mr. Clean

Smooth ER

63

Post Office

Golgi Apparatus

64

Suicide Bag

Lysosomes

65

Taxi

Secretory Vesicles

66

Powerplant

Mitochondria

67

Command Center

Nucleus

68

Scaffolding

Cytoskeleton

69

- secretory vesicles fuse with the cell membrane, extruding their contents outside the cell
- Ca2+-dependent process

Exocytosis

70

- molecules are absorbed and internalized by coating with membrane phospholipids forming a vesicle that detaches from cell membrane
- Maybe Phagocytosis or Pinocytosis

Endocytosis

71

Also known as cell eating

Phagocytosis

72

Process of Phagocytosis

- contact
- invagination
- invagination pinches off from cell membrane
- formation of membrane-enclosed vacuole

73

♣ also known as cell drinking
♣ primarily for absorption of extracellular fluids
♣ involves vesicles much smaller in size
♣ requires considerable amounts of ATP

Pinocytosis

74

- “Crawling” movement; E.g. WBC

Amoeboid Movement

75

- “To-and-fro” whip-like movement; E.g. Respiratory Epithelium and Fallopian Tubes

Ciliary Movement

76

- “rotatory” movement; E.g. flagella of the sperm cell

Flagellar Movement