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SfM topics > LACL 1 > Flashcards

LACL 1 Flashcards

1
Q

why are cells small? (5)

A
  1. maximises S.A for absorption and molecular processes
  2. allows more room/potential for damage
  3. SA; volume ratio gets smaller as cell gets larger
  4. rapid processes and communication
  5. whole surface needs to react with the environment
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2
Q

what are 6 main properties of prokaryotes? (e.g. bacteria or archaea)

A
  1. usually unicellular
  2. no nuclear membrane
  3. no mitochondria
  4. no membrane bound organelles
  5. contain plasmids and cell wall
  6. singular circular double stranded DNA
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3
Q

what are 6 main properties of eukaryotes? (human cells)

A
  1. multicellular
  2. nucleus with membrane
  3. mitochondria present
  4. membrane bound structures
  5. chromosomes present; each with DNA and associated proteins in the nucleus
  6. no cell walls in animals (only plants and fungi have cell walls)
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4
Q

what are stem cells?

A
  • undifferentiated cells that are able to renew themselves and produce specialised cells
  • they are multipotent
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5
Q

what does multipotent mean?

A

some cells are able to differentiate into many different cell types

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6
Q

what does pluripotent mean?

A

some cells can become ALL cell types that make up the body

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7
Q

are most cells mutlipotent or pluripotent?

A

multipotent

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8
Q

what is an example of a pluripotent cell?

A

embryonic stem cell present in blastocyst stage of development

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9
Q

what is an example of a multipotent cell?

A

adult stem cells/ somantic stem cells present in bone marrow, muscle, liver, pancreas etc.

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10
Q

what stimulates differentiation in cells?

A

gene expression

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11
Q

Pathological stimulus such as injury or disease leads to what?

A

necrosis (passive; damage to neighbouring cells, inflammation)

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12
Q

physiological stimulus such as programmed cell death leads to what?

A

Apoptosis ( active; no damage to neighbouring cells, inflammation)

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13
Q

what is necrosis?

A

death of most or all cells in an organ or tissue due to disease, injury or failure of blood supply

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14
Q

what is apoptosis?

A

death of cells which occurs as a normal and controlled part of an organism’s growth or development

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15
Q

what plays a big role in tissue remodelling in developing embryos?

A

apoptosis (e.g. in formation of body parts)

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16
Q

what is definition of tissues?

A

collection of specialised cells that do the same/particular function

17
Q

what is definition of organs?

A

mixture of different tissues (composed of more than one tissue)

18
Q

what is the definition of a system?

A

cells or organs with similar functional roles/ physiological function

19
Q

characteristics of plasma membrane?

A
  • fluid mosaic model/plasmalemma
  • selective barrier
  • amphipathic membrane lipids ( hydrophillic heads and hydrophobic tails)
20
Q

what is a fluid mosaic model?

A
  • has fluidity due to random arrangement of proteins across it which give it the structure
  • acts as a natural barrier for cells to communicate through
21
Q

what are the 6 main plasma membrane functions?

A
  1. transport
  2. enzymatic activity
  3. receptors for signal transfuction
  4. intrercellular joining
  5. cell-cell recognition
  6. atachment to the cytoskeleton and ECM
22
Q

what is passive diffusion?

A
  • conc. gradient needed (travels along/down its conc. gradient)
  • from high conc. to low conc.
  • lipid soluble molecules pass freely
  • molecules are hydrophobic and non-polar
23
Q

what is active transport?

A
  • travels against its conc. gradient
  • from low conc. to high conc.
  • transport molecule needed to move large molecules using ATP
24
Q

what is facilitated diffusion?

A
  • spontaneous passive transport
  • involves molecular binding to receptor proteins
  • requires carrier molecules
  • conc. gradient needed
  • travels along/down its conc. gradient
25
Q

what is the difference between endocytosis,phagocytosis and pinocytosis?

A

endocytosis: general term for taking molecules in
pinocytosis: taking small molecules in
phagocytosis: taking big molecules in

26
Q

what is exocytosis

A

exocytosis: general term for putting molecules out

27
Q

what is a common example of pinocytosis in nervous system?

A

reabsorption of neurotransmitters

28
Q

why is cell adhesion important? (3)

A
  1. allows cells to communicate in response to environment changes
  2. helps to repair and reproduce cells
  3. bind to ECM for structure and stability
29
Q

what are some properties of occluding/tight junctions? where are they present?

A
  • seals gap between epithelial cells (glue)
  • dependent on Ca
  • creates physical barrier for diffusion
  • tightly stacked to increase max. absorption
  • present in kidneys, intestine, blood brain barrier
30
Q

what are some properties of cell-cell anchoring junctions?

A
  1. adherens junction connects actin filament bundles in two cells
  2. desmosomes connect intermediate filaments in two cells
31
Q

what are some properties of channel forming junctions/gap junctions?

A
  • allows passage of small water soluble molecules from cell to cell
  • links two cytoplasms together
  • made of connexins (6 subunits) which are membrane spanning proteins
  • act as transmembrane pores
32
Q

what are some properties of cell-matrix anchoring junctions? (2)

A
  1. actin linked cell-matrix adhesion anchors actin filaments in cell to ECM
  2. hemidesmosomes anchors intermediate filaments in a cell to ECM
33
Q

what happens if cell adhesion doesn’t occur properly?

A

can lead to possibly cancerous cells detaching and metastasising through capillary network. (malignancy)

34
Q

what are 4 types of cell signalling?

A
  1. contact-dependent
  2. paracrine
  3. synaptic
  4. endocrine
35
Q

what is contact-dependet signalling?

A

direct cell to cell signalling with receptors and direct response. Includes a signalling cell and target cell

36
Q

what is paracrine signalling?

A

cell produces a signal which induces changes to nearby cells through the action of a local mediator

37
Q

what is synaptic signalling?

A

nerve transmission using a neurotransmitter

38
Q

what is endocrine signalling?

A

through release of hormone into bloodstream which binds to target cell

SfM topics (21 decks)

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