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Lex Physiology And Pathphysiology Exam 1 > 2. Structure And Functions Of Cells > Flashcards

2. Structure And Functions Of Cells Flashcards

1
Q

Cellular housekeeping

A

The viability of normal activity of cells depend on a variety of fundamental housekeeping functions that all differentiated cells must perform

Protection
Movement
Absorption
Communication
Catabolism
Energy generation
Excretion
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2
Q

Plasma membrane

A

Protection and nutrient absorption, made up of lipid bilayer (hydrophilic outside and LipoPhillic inside)

Provides a barrier to passive diffusion of large and charged molecules

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3
Q

Passive Transportation

A

Movement of substance from an area of high concentration to an area of low concentration (with concentration gradient)

Can include channel or carrier protein

Diffusion
Osmosis
Facilitated diffusion

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4
Q

Passive diffusion

A

Down concentration gradient, depends on size, electric charge and lipid solubility

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5
Q

Osmosis

A

Passive transport of water down concentration gradient

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6
Q

Facilitated diffusion

A

Movement of molecules across the cell membrane via special transport proteins within the cellular membrane

Ex glucose transporter

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7
Q

Active Transport

A

Movementment of a substance from an area of low concentration to an area of high concentration - against concentration gradient - requires energy

ONLY carrier molecules used - binds and makes conformational change (Na-, K+, ATP pump)

Endocytosis - pinocytosis, phagocytosis
Exocytosis

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8
Q

Endocytosis

A

Process of bringing a substance into a cell

Pinocytosis - cell drinking (engulfing liquid)
Phagocytosis - cell eating (engulfing solids such as bacteria)

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9
Q

Exocytosis

A

Release of materials from inside to the outside of the cell

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10
Q

Cytoskeletal proteins

A

Structure that provides mechanical support and helps cells maintain their shape, polarity and internal organization

Microtubule
Intermediate filaments
Actin mictofilaments

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11
Q

Microtubule

A

(25nm) transportation and cell division, thickest and most diversified, forms flagella, cilia and pulls cells apart during mitosis

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12
Q

Intermediate filaments

A

(10nm) nuclear lamen and structure of nucleus, bears mechanical stress

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13
Q

Actin microfilaments

A

(5-9 nm) thinnest, muscle contraction, plays a role in exocytosis, most abundant fragment in the cell and gives it its shape

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14
Q

Occluding junctions (tight junctions)

A

Prevents diffusion of molecules between cells (paracellular)

Ex: bladder - we do not want to leak urine, kidney

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15
Q

Anchoring Junctions (desmosomes)

A

Mechanically attach cells and their intracellular skeletons to other cells or the extracellular matrix - distribute mechanical stress

Ex: skin, intestine

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16
Q

Communicating junctions (gap junctions)

A

1.5-2 nm pores called connexons formed by connexins - helps pass action potentials

Ex: heart, neurons, retina

17
Q

Endoplasmic Reticulum

A

Site for synthesis of all transmembrane proteins and lipids for plasma membrane and cellular organelles

Smooth ER
Rough ER
Sarcoplasmic reticulum

18
Q

Smooth ER

A

NO ribosomes

Synthesizes steroid hormones or catabolism lipid solvable molecules

Also responsible for sequestering intracellular calcium ( role in apoptosis)

19
Q

Rough ER

A

Has ribosomes

Important role in protein and lipid synthesis

20
Q

Sarcoplasmic reticulum

A

Specialized smooth ER of muscle cells

Responsible for regulating muscle contraction

21
Q

Chaperones

A

Retain proteins in the ER until folding is complete

22
Q

Golgi apparatus

A

Proteins sent from ER to Golgi apparatus

Post office of the cell - receives synthesized proteins and shuttles them to target region

23
Q

Different types of waste disposal mechanisms in the cell

A

Lysosomes - Hererophagy and autophagy, uses acid to break down substances

Proteosomes- can onle degrade proteins, tab them with uB

24
Q

Heterophagy

A

Endoscopes or phagosomes rise with lysosomes to facilitate the degradation of their internalized contents

Comes from outside

25
Q

Autophagy

A

Senescent organelles or denatured proteins are encircled with a double membrane which fuses with the lysosome and degraded

Self eating

26
Q

Process of protests oral degradation

A

Can handle only proteins

Misfolded protein is tagged (ubiqinoine uses lighters to tag misfolded protein) and is chopped into fragments 6-12 AAs long

Errors in this process can lead to diseases such as CF

27
Q

Origin of Mitochondria

A

Evolved from ancestral prokaryotes that were engulfed by primate eukaryotes (1.5 billion years ago) contain their own DNA

28
Q

Functions of Mitochondria

A

Oxidative phosphorylation - process by which we get energy

Apoptosis - cytochrome C leaks enzyme to activate apoptosis

Anabolism - mitochondria synthesize hemoglobin as heme, steroidalgenesis

29
Q

Reactive Oxygen species

A

Oxygen radicals that can cause damage to the cell, side product of chemical reactions

Utilized by antioxidant system, but when there is an increase in ROS and cells are supersaturated then they acculturate and cause damage

Hypoxia, toxic injury increase ROS - damage to DNA structure and cell cycle arrest or apoptosis

30
Q

Two types of cell death

A

Necrosis - always pathological, inflammation

Apoptosis - pathological or physiological, no inflammation

IRREVERSIBLE

31
Q

Necrosis

A

External agents such as toxins, ischemia or trauma, is always pathological

Exposure to these agents affects ATP generation of the cell and the cell Bursts - mitochondrial membrane damage

INFLAMMATION - always bad

32
Q

Apoptosis

A

External or internal agents (DNA damage or IC stress) could be physiological or pathological

Leaky mitochondria 0 cytochrome c released - triggers apoptosis

NO INFLAMMATION

33
Q

Purpose of cell signaling

A

Cells require basic signaling to survive and in the absence will undergo apoptosis

Abnormal signaling - lead to unregulated growth or cancer or in an ineffective response to an extrinsic stress - shock

34
Q

Extracellular Matrix

A

Network of interstitial proteins that constitutes a significant proportion of Any tissue

Cell interactions with ECM are critical for development and healing as well as maintaining normal tissue architecture (proper organ growth)

35
Q

Functions of ECM

A

Mechanical support

Control of cell proliferation

Support for tissue renewal

ECM disruption - defective tissue regeneration and repair (liver cirrhosis)

Tissue micro environment (basement membrane in kidney)

36
Q

Interstitial Matrix

A

Produced by mesenchymal cells such as fibroblasts, type I collagen

Less organized, found in spaces between cells

Main function is to provide support

37
Q

Basement membrane

A

Is the ECM that surround epithelial cells, endothelial cells and smooth muscle cells and separates them from muscle cells

More organized then IM

Type IV collagen and laminitis

Main function is to separate epithelium and blood vessels from underlying tissue, performs specialized functions (kidney - filtration mechanism)

Lex Physiology And Pathphysiology Exam 1 (16 decks)

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