Cell Biology - exam 1 Flashcards

1
Q

Intracellular compartment

A

contains 2/3 of body weight/water

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2
Q

Extracellular compartment

A

contains 1/3 body weight/water
3/4 outside of blood vessels (interstitial)
1/4 inside blood vessel (plasma)

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3
Q

ICF vs. ECF

A
ICF = higher in proteins, lower in sodium, and higher in potassium
ECF = lower in protein, higher in sodium, and lower in potassium
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4
Q

Roles of plasma membrane

A
  1. controls the transport of materials from ECF and ICF
  2. provides receptors for hormone and other biological active substances
  3. participates in the generation and conduction of electrical currents
  4. aids in the regulation of cell growth and proliferation
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5
Q

Integral proteins

A

Span the entire lipid bilayer and are essentially part of the membrane

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6
Q

Peripheral proteins

A

Are bound to one side of the membrane and do not pass into the lipid bilayer

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7
Q

Functions of membrane proteins

A
  1. receptors
  2. channels/carriers
  3. enzymes
  4. anchors
  5. recognition (antigens)
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8
Q

Cholesterol in membranes

A

Provides fluidity for proteins (allows proteins to move along the membrane)

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9
Q

Plasma membrane receptors bind…

A
  1. hormones
  2. growth factors
  3. neurotransmitters
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10
Q

Types of signal transduction pathways in plasma membranes

A
  1. G-proteins
  2. Enzymes
  3. Ion Channels
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11
Q

G-protein linked receptors

A
  • ligand (1st messenger) binds to the receptor and undergoes a conformation change in the g-protein receptor
  • activation of g-protein leads to increase in an intracellular 2nd messenger
  • 2nd messenger leads to cell response
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12
Q

Enzyme - linked receptor

A
  • Has intrinsic activity or linked to an enzyme
  • Tyrosine kinase most frequent enzyme
  • utilized by many growth factors (cell division)
  • important in some tumorigenesis mechanisms
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13
Q

Ion-Channel Linked Receptors

A
  • receptors act as gated channels for ion flow across membrane
  • ligand binding transiently opens channel allowing ion flow
  • involved in neuro conduction and muscle contraction
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14
Q

What is passive transport?

A
  • relies on gradients (high to low)
  • do not require energy
  • ex: diffusion, osmosis, facilitated diffusion
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15
Q

What is active transport?

A
  • transports molecules against gradient (low to high)

- requires energy

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16
Q

What is vesicular transport?

A
  • cell encloses material in a small spherical membranous sac

- ex: endocytosis, exocytosis

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17
Q

Diffusion

A
  • movement of molecules across membrane from high to low concentration
  • Lipid soluble molecules (steroids, thyroid hormones, gases)
  • stops when concentration is equal on both sides
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18
Q

Osmosis

A
  • diffusion of water toward high solute concentration
  • solutes create osmotic force that attracts water
  • main determinants (Na+, glucose, urea, and proteins)
  • Wherever these molecules go water always follows
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19
Q

Isotonic

A

does not cause osmotic flow of water into or out of cells as concentrations are equal

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20
Q

Hypotonic

A

Less solutes outside the cell causes osmotic flow of water into the cell causing the cell to swell

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21
Q

Hypertonic

A

More solutes outside the cell causes osmotic flow of water out of the cell causing the cell to shrivel

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22
Q

Facilitated diffusion

A
  • carrier proteins transport molecules too large to fit through channel proteins (glucose, amino acids)
  • molecules bind to receptor site on carrier protein
  • protein changes shape so molecule can pass through
  • sites are highly specific
  • finite number of transporters
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23
Q

Carrier-mediated transport

A
  • transports ions and organic substrates (facilitated diffusion or active transport)
  • characteristics: specific, saturable, regulated
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24
Q

Active transport

A
  • requires energy to move substrates against a gradient

- types: electrical, chemical, electrochemical

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25
Primary active transport
- energy used to move substrate against gradient - present in all cell membranes - accounts for 40% of resting ATP expenditure - establishes and maintains cell's electrical gradient across the cell membrane - ex: Na+/K+ ATPase
26
Secondary active transport
- gradient established from primary active transport used to move substrates against gradient - indirectly require energy - ex: Na+ / glucose co-transport (same direction) or Ca+2 / Na+ countertransport (opposite direction)
27
Vesicular transport
- cell membrane engulfs material and encloses it in small spherical membranous sac types: endocytosis, exocytosis ex: phagocytosis - WBC
28
Mitochondria
- vast majority of ATP production - where O2 is used and CO2 is produced - only reason the body requires O2
29
Cellular respiration
- converts potential energy into usable energy (ATP) | - 3 steps: glycolysis, citric acid cycle, electron transport chain
30
Glycolysis
- anaerobic cytoplasmic process - glucose enters the cell, is trapped, split in half, and its electrons are stolen from the 3 carbon molecules (oxidized) - results in 2 pyruvate, 2 NADH, and (net) 2 ATP - Pyruvate then enters mitochondrial matrix or converted to lactic acid
31
Citric acid cycle
- Also called Krebs cycle - occurs in mitochondrial matrix - pyruvate oxidized further - removal of carbons produce CO2 - results in 4 NADH, 1 FADH2, and 1 ATP per pyruvate (2) - Electrons carried by NADH and FADH2
32
Electron transport chain
-also called oxidative phosphorylation -aerobic, occurs on inner mitochondrial membrane -NADH/FADH2 pass electrons to series of carriers -Passage generate proton gradient between membranes -Protons follow from high to low concentrations -creates 32 ATP O2 is the final electron acceptor
33
Membrane potentials
- important in muscle, heart tissue, neurons, and some glands - Is the electrical gradient (polarity) across the cell membrane - created by Na+/K+ ATPase and presence of proteins in ICF - Stimulation of cell results in reversal of polarity in segment of membrane (depolarization)
34
Resting membrane potential
- expressed as ICF compared to ECF - at rest cell is positive on inside and negative on outside - created and maintained by Na+/K+ ATPase - membrane is polarized
35
Action membrane potential
- local changes in membrane potential - causes: neuron stimulation/inhibition, temp, light, pressure - due to opening/closing of specific ion channels - opening of Na+ channels results in Na+ entry (depolarization) - opening of K+ channels results in K+ exit (repolarization) - change in membrane potentials move along cell membrane - results in nerve impulse or muscle contraction
36
Depolarization
- threshold potential results in an action potential - sweeps down the membrane of the cell - adjacent membrane Na+ channels open - depolarization - adjacent membrane K+ open - repolarizaton
37
Action potential process
- stimulus opens Na+ channels - Na+ enters the cell (turns inside positive) - change in polarity causes K+ channels to open - K+ leaves the cell carrying positive charges with is (repolarization) - Na+/K+ pump moves Na+ back out and K+ back in to restore the correct balance
38
Tissues
- cells and extracellular matrix combined | - 4 types: epithelium, connective, muscle, nervous
39
Epithelium
- covers body surface and lining of cavities/hollow organs - hypercellular with little matrix - Avasular - high degree of regeneration (most cancers) - provides protection, permeability, and often secretes substances onto exposed surface - some have microvilli or cilia
40
Apical shapes of epithelium
- squamous - cuboidal - columnar - transition
41
Layers of epithelium
- simple - stratified - pseudostratfied
42
Simple squamous epithelium
- location: lining ventral body cavities; lining heart and blood vessels; portions of kidney tubules; inner lining of cornea; alveoli of lungs - function: reduces friction; controls vessel permeability; preforms absorption and secretion
43
Simple cuboidal epithelium
- location: glands; ducts; portions of kidney tubules; thyroid gland - function: limited protection, secretion, absorption
44
Simple columnar epithelium
- location: lining of stomach, intestine, gallbladder, uterine tubes, and collection ducts of kidneys - functions: protection, secretion, absorption
45
Pseudostratified columnar epithelium
- location: lining of nasal cavity, trachea, and bronchi; portions of male reproductive tract - function: protection, secretion
46
Stratified squamous epithelium
- location: surface of skin, lining of mouth, throat, esophagus, rectum, anus, and vagina (areas that encounter a lot of trauma) - functions: physical protection against abrasion, pathogens, and chemical attack
47
Transition epithelium
- location: urinary bladder; renal pelvis of kidneys; ureters - function: permits expansion and recoil are stretching
48
Connective tissue
- most abundant, most diverse, most complex - fills spaces, supports structures, provides 3D structures - hypocellular and more matrix - matrix comprised of ground substances and proteins
49
Ground substances - connective tissue
-liquid, solid, or gel
50
Protein fibers in connective tissue
- collagen: strong - elastic: stretchy - reticular: in the middle
51
Connective tissue proper
- loose: fibers create loose, open framework (adipose, reticular, areolar) - dense: fibers densely packed
52
Fluid connective tissue
- blood: contained in cardiovascular system | - lymph: contained in lymphoid system
53
Supporting connective tissues
- cartilage: solid, rubbery matrix | - bone: solid, crystalline matrix
54
Muscle
- 3 types: skeletal, smooth, cardiac - contain contractile proteins (actin and myosin) - arranged into sarcomeres (except smooth muscle) - regulated by troponin and tropomyosin
55
Skeletal muscle
- moves skeleton - moves eye, voluntary sphincters - long, multinucleated cells - actin/myosin produce striations - stimulated by somatic motor neuron -voluntary
56
Smooth muscle
-walls of hollow organs (except heart) -produce organ movement or contraction -short, uninucleated cells -no sarcomeres stimulated by autonomic neurons or hormones
57
Cardiac muscle
- present only in heart - short, branched, uninucleated cells - connected by intercalated discs - actin/myosin produce striations - stimulated by conduction system
58
Nervous tissue
- composed of neurons and neuroglia - collects, interprets, and responds to stimulus - glia supports neurons
59
Neurons
- conduct information via nerve impulses - composed of cell body, dendrites, and axon - afferent/sensory - toward CNS - efferent/motor - from CNS - Can me multipolar, unipolar, or bipolar
60
CNS glia
- Astrocytes: part of blood-brain barrier - Oligodendrocytes: responsible for myelination - microglia: phagocytic defense cells - ependymal cells: lining of brain ventricles, source of cerebrospinal fluid
61
PNS glia
- Satellite cells: found in ganglia | - Schwann cells: responsible for myelination
62
Subtypes of connective tissue
- connective tissue proper - fluid connective tissue - supportive connective tissue