Cells and Tissues of the Body Flashcards

1
Q

What is glycocalyx?

A

a covering made of glycoprotein and glycolipid that surrounds the cell membrane of the epithelial cell

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2
Q

What are functions of glycocalyx?

A
  • cell recognition
  • cell signalling
  • cell adhesion
  • protection
  • permeability barrier
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3
Q

What are functions of the cell membrane?

A
  • maintaining structure and functional integrity of the cell
  • separating the intracellular space from the extracellular space
  • allowing diffusion of some substances
  • controlling passage of substates into and out of the cell
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4
Q

How does cholesterol maintain fluidity of the cell membrane when the body temperature is high and low respectively?

A
  • high - reduces the fluidity of the cell membrane
  • low - increases the fluidity of the cell membrane
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5
Q

What does TTX do?

A

prevent muscle contraction by blocking sodium channels in nerve cell membranes

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6
Q

What are the functions of the cytoplasm?

A
  • cellular respiration, energy production
  • synthesis of proteins
  • waste handling
  • growth and repair
  • cell division (mitosis and meiosis)
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7
Q

What are the 4 levels of organisation within the cytosol?

A
  • ion concentration gradients
  • protein complexes
  • protein compartments e.g. proteasome
  • cytoskeleton
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8
Q

What do proteasomes do?

A

regulate the concentration of particular proteins and degrade misfolded proteins

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9
Q

What does ubiquitin do?

A

tag proteins for degradation catalysed by ubiquitin ligases

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10
Q

In an H&E stain, what does the H and E stain respectively?

A
  • H - nucleus of the cell blue/purple
  • E - cytoplasmic proteins red/pink
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11
Q

What are cytoplasmic inclusions?

A

metabolic products stored in the cytoplasm, typically in long-lived cells e.g. hepatocytes, neurons, and cardiac muscle cells

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12
Q

What are functions of the cytosol?

A
  • protein synthesis
  • metabolic pathways
  • metabolite transport
  • signal tranmission
  • cell division
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13
Q

What are the 3 cytoskeletal fibres?

A
  • MTs
  • IFs
  • microfilaments
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14
Q

What are microfilaments made up of?

A

G-actin monomers which form F-actin polymers which in turn form double helix microfilaments

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15
Q

What are functions of microfilaments?

A
  • cell migration
  • cell division
  • cellular extensions
  • cell junctions
  • muscle contraction
  • membrane transport
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16
Q

What are the 5 types of IF and where are they found?

A
  1. lamin found in the nucleus
  2. keratin found in epithelial cells
  3. vimentin found in fibroblasts
  4. desmin found in muscle cells
  5. neurofilaments found in neuronal cells
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17
Q

What do desmosomes do?

A

tether intermediate filaments to the plasma membrane in cardiac tissue and the epithelium

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18
Q

What do hemidesmosomes do?

A

anchor cells to the underlying basement membrane

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19
Q

What are MTs made up of?

A

alpha and beta tubulin

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20
Q

Where are MTs found?

A

centrioles, cilia and flagella

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21
Q

Where are the + and - ends of the MT respectively?

A
  • plus - towards the periphery
  • minus - towards the nucleus
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22
Q

What is anterograde transport?

A

movement from the negative to positive end of an MT via kinesin

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23
Q

What is retrograde transport?

A

movement from the positive to negative end of an MT via dynein

24
Q

What happens if the cilia structure in the respiratory tract is defective?

A

it can lead to accumulation of mucus secretions

25
Q

How can infertility arise in women?

A

defective cilia in the fallopian tube

26
Q

Give examples of conditions that may arise in the case of defective cilia

A
  • immotile-cilia syndrome
  • situs inversus
  • male sterility
27
Q

What is the nucleus made up of?

A
  • nuclear envelope
  • nucleoplasm
  • nucleoli
  • chromatin/chromosomes
28
Q

What are the 2 forms of chromatin?

A
  • heterochromatin - compact form that does not facilitate gene activity
  • euchromatin - open form that facilitates gene activity
29
Q

What is the nucleolus?

A

production site of ribosomal subunits and rRNA

30
Q

What are the 5 parts of the mitochondria?

A
  • outer mitochondrial membrane
  • inner mitochondrial membrane
  • intermembrane space
  • cristae (space formed by infoldings of the inner membrane)
  • matrix (space within the inner membrane)
31
Q

What do F1 particles do?

A

function in the synthesis of ATP from ADP + Pi comprising 15% of total inner membrane proteins

32
Q

What are functions of the mitochondria?

A
  • release of energy via TCA cycle or ETC
  • heat production
  • storage of cations
  • regulate cell proliferation and programmed cell death
  • some degradation functions e.g. fatty acid β-oxidation
  • contains the mitochondrial genome (which is transmitted from mothers to offsprings)
33
Q

What are functions of the ER?

A
  • protein synthesis
  • protein modification
  • protein folding
  • protein quality control
  • protein sorting into those for transport to other organelles or those meant for export out of the cell
  • limited proteolysis of newly synthesised proteins
34
Q

What is the RER?

A

a tubular structure with a phospholipid bilayer continuous with the nuclear membrane (has ribosomes on surface)

35
Q

What are the 3 fates of vesicles delivered to the Golgi body from the RER?

A
  • incorporated into the cell membrane
  • secretory protein
  • lysosomal protein
36
Q

Give examples of organs rich in RER

A
  • exocrine pancreas
  • goblet cells in GIT
  • plasma cells
  • nissil bodies in neurons
37
Q

What are functions of the SER?

A
  • lipid synthesis
  • steroid synthesis
  • breakdown of endogenous and exogenous compounds
38
Q

Give examples of organs rich in SER

A
  • testis
  • ovaries
  • adrenal cortex
39
Q

Where is the Golgi apparatus?

A

between the ER and the cell membrane

40
Q

What are functions of the Golgi apparatus?

A
  • protein modification
  • concentration, packaging and sorting of proteins
  • delivery of proteins to correct destination
41
Q

What is the Golgi body complex?

A

a disc-shaped membrane-defined cristae arranged like a stack

42
Q

What are the 2 faces of the Golgi body?

A
  • cis - near the RER, thinner forming face
  • trans - near the cell membrane, maturing face
43
Q

What do secretory vesicles contain?

A

protease enzymes that cut and modify secretory proteins at a specific amino acid position, resulting in their activation

44
Q

What is the function of lysosomes?

A

intra-cytoplasmic digestion of waste

45
Q

What is O-linked glycosylation?

A

when a glucose molecule is added to the oxygen molecule on a serine or threonine residue of the newly formed protein

46
Q

Give examples of hydrolytic enzymes

A
  • nucleases
  • lipases
  • proteases
  • glycosidases
  • acid phosphatases
47
Q

What do proton ATPases do in the lysosomal membrane?

A

pump protons into the lysosomal lumen which lowers the pH to ~5 which is optimal for most enzymes

48
Q

What are the 3 processes that bring molecules into the lysosomal cell?

A
  • receptor mediated endocytosis
  • phagocytosis
  • autophagy
49
Q

What are lipofuscin molecules?

A

a pigment left over from the breakdown and absorption of damaged blood cells

50
Q

How do neutrophils release enzymes into the ECM?

A

by eating the bacteria and digesting it with lysosomal enzymes and later spitting out the bacterial antigens into the ECM to alert the immune/lymphatic system to take care of the infection

51
Q

What is autolysis?

A

the cell eating itself when there is extensive cellular damage beyond repair

52
Q

What is apoptosis?

A

programmed cell death

53
Q

What is a peroxisome?

A

a membrane bound organelle that contains enzymes, proteins, and liquid

54
Q

What are peroxisomes involved in?

A
  • β-oxidation of very long chain fatty acids
  • α- oxidation of branched-chain fatty acids
  • catabolism of amino acids and alcohol
  • synthesis of bile acids
  • synthesis of plasmalogens which are important membrane phospholipids especially in white matter of brain
  • conversion of reactive oxygen species e.g. hydrogen peroxide (H2O2) to safer molecules
55
Q

What is Zellweger syndrome?

A

an autosomal recessive disorder of peroxisomal biogenesis due to a mutated PEX gene

56
Q

What is Refsum disease?

A

an autosomal recessive disorder of alpha-oxidation buildup of phytanic acid due to inability to degrade it

57
Q

What is adrenoleukodystrophy?

A

an X-linked recessive disorder of beta oxidation due to mutation of ABCD1 gene; VLCFA buildup in adrenal glands, white matter of brain, testes