Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MD2001 Week 1 > Cells and Organelles > Flashcards

Cells and Organelles Flashcards

1
Q

Cell theory?

A

> all organisms consist of one or more cells

> the cell is the basic unit of structure for all organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why are cells so small?

A

to allow diffusion of waste products and nutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What size are cells in relation to a human hair?

A

1/10th of the size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Smaller cell and larger cell?

A

smaller - bacterial

larger - human egg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the properties of a cell?

A

> microscopic packages that act as independent units
originate from preexisting cells - grow and divide
have a finite lifetime - they die
their internal processes allow them to change/adapt/respond - different jobs for different cells/part of body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the plasma membrane?

A

enclose the cell space as an independent reaction container - contains a salty - protein rich solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the structure of the membrane?

A

bilayer of lipid molecules with added protein - phospholipid bilayer

  • semipermeable
  • flexible
  • continuous bag - barrier to water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What function can proteins play in the membrane?

A
  • receptors
  • transporters
  • signalling
  • adhesion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Features of prokaryotes?

A
  • no nucleus - nucleoid instead
  • simple without internal membranes - no organelles - all processes in cytosol
  • few microns in size
  • simplest and smallest are bacteria
  • few microns in size -small and simple
  • circular DNA - not enclosed by membrane
  • simple cell division
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Micron?

A

1x10 -6 of a meter - u

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Features of eukaryotes?

A
  • internal compartments and membranes
  • 10+ microns in size
  • linear DNA arranged in chromosomes - enclosed by membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the three main systems of eukaryotes?

A
  • protein expression
  • secretion pathway
  • uptake and degradation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the stages of protein synthesis?

A

Transcription - DNA copied as mRNA

Translation - mRNA decoded to make protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the purpose of protein synthesis?

A

allows growth and differentiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is DNA arranged in eukaryotes?

A
  • packaged and enclosed by a double membrane in the nucleus - the “nuclear envelope” is the membrane
  • nuclear envelope has nuclear pores - mRNA passes from nucleoplasm to cytoplasm via
  • packaged with histones - forming the complex chromatin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where does translation occur?

A

ribosomes

- mRNA is decoded and proteins are made

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are chromatins?

A

DNA is packaged with proteins called histones forming the complex chromatin
two types - euchromatin, heterochromatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the ways in which chromatin is packaged?

A

> euchromatin - more active genes

> heterochromatin - more dense

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where are ribosomes found?

A
  • free in the cytoplasm

- bound to the ER to make the rough ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the nucleolus?

A

location of production of ribosome - at amplified ribosomal genes

  • found in the nucleus
  • involved in rRNA synthesis
  • composed of RNA and protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the two options for proteins after translation starts?

A

> remain in cytosol for remainder of translation
fed into ER during translation
(all protein synthesis starts in cytosol)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

When do proteins remain in the cytosol for the rest of translation?

A

proteins do not have a signal peptide
- proteins can then be sent to other organelles - mitochondria, chloroplasts, nucleus - organelles not part of the endomembrane system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When do proteins get sent to the ER during translation?

A

have a signal peptide
- proteins bound for organelles part of endomembrane system - ER, Golgi apparatus, lysosome
- or proteins bound for exterior of cell
(makes rough ER)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the endomembrane system?

A

modify, packages and transports proteins and lipids

- includes ER, Golgi apparatus, lysosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the ER?

A

interconnected network of flattened, membrane bound sacs known as cisternae

  • membranes continuous with the outer nuclear membrane
  • makes and packages proteins
  • lumen is the cisternal space
  • rough ER has ribosomes attached
  • when protein is created it is packaged and pinched off in a vesicle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the steps of the secretion pathway?

A

synthesis of proteins in the RER
- (transition) vesicles carry proteins to Golgi apparatus
Modification of proteins at golgi
- vesicles carry modified protein to the plasma membrane for secretion into extracellular environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Function of the Golgi?

A

packaging organelle

  • packages proteins into secretory vesicles for secretion
  • modifies lipids and proteins - grows sugar chains and adds phosphates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How do secretory vesicles release content at the plasma membrane?

A

exocytosis - membrane bound secretory vesicles release contents into the extracellular environment

  • active transport
  • vesicles temporarily bind to membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How do vesicles move towards and away from the Golgi?

A
  • transport along microtubules in one direction
  • they contain instructions telling them where to go
  • use motor proteins attached to vesicle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are the function of microtubules?

A
  • track for vesicles and organelles
31
Q

What is the centrosome?

A

where microtubules emulate from - microtubule organising centre

32
Q

What is uptake process known as?

A

endocytosis

33
Q

What carries out endocytosis of large particles?

A

phagocytosis

34
Q

What carries out endocytosis of small particles?

A

pinocytosis - “cell drinking” of extracellular fluid - non specific

35
Q

What happens to molecules that have been endocytose?

A

delivered to endosomes then passed on to lysosomes for degradation
- some membrane is recycled back to the cell surface

36
Q

What are endosomes?

A

membrane bound vesicles

- deliver cargo from plasma membrane to lysosome

37
Q

What are lysosomes?

A

organelles in cytoplasm containing degradative enzymes enclosed in a membrane
- low pH

38
Q

What is autophagy?

A

parts of the cell itself are walled off and digested in lysosomes

39
Q

What is receptor mediator endocytosis?

A

?

40
Q

What are proteasome?

A

protein complexes which degrade unneeded or damaged proteins
(proteins for degradation are tagged by a small protein called ubiquitin)

41
Q

What is ubiquitin?

A

a small protein that tags damaged proteins for degradation
- signal to other ligases to attach additional ubiquitin - resulting in a polyubiquitin chain that is bound by the proteasome - allowing it to degrade the protein

42
Q

What is the advantage of internal compartments ?

A

specialised reactions can be separated, concentrated and optimised

43
Q

What aids vesicle budding?

A

molecular scaffold supports - eg. clathrin

44
Q

What is the function of mitochondria?

A

produce most of ATP supply

- enables cells to grow bigger

45
Q

What is the structure of mitochondria?

A

> two membranes - inner folded into interior
contain own DNA
reproduce by dividing in two
(> all mitochondria come from your mothers egg)

46
Q

What are the functions of the cytoskeleton?

A

> moving
positioning
supporting
protecting

47
Q

What protein filaments does the cytoskeleton consist of?

A

> microtubules
microfilaments
intermediate filaments

48
Q

Microtubules?

A
  • tiny (25nm) - thickness of ribosome
  • vesicle tracks
  • position/move organelles (mitosis)
  • dynamic
    made of subunits of the protein tubulins
49
Q

Microfilaments?

A
  • thiner than microtubules (7nm) tiny
  • generates contractile forces - enables cell and parts of cell to move, cells to contract
  • dynamic
    made of subunits of actin
50
Q

Intermediate filaments?

A
  • middle thickness (10nm)
  • strength and support
  • found in cytoplasm and nuclear envelope
  • not dynamic
    proteins - keratins, laminins
51
Q

Function of smooth ER?

A

(no ribosomes)

  • involved in lipid, steroid production and detoxification
  • smooth ER expands
52
Q

What are peroxides?

A
  • do oxidative reactions using molecular oxygen
  • break down and oxidise some fatty acids
  • synthesis some specialised lipids
  • generate hydrogen peroxide which is broken down by catalase
53
Q

What determines the type of cell?

A

protein expression

54
Q

What are all cells types derived from?

A

totipotent stem cells

55
Q

totipotent?

A

can become any cell type

56
Q

pluripotent?

A

can become several different cell types

57
Q

Least specialised to most specialised stem cell types?

A

totipotent, pluripotent, tissue specific

58
Q

What are the ways in which cells communicate?

A

> endrocine
paracrine
neuronal
contact dependent

59
Q

Paracrine?

A

relating to a hormone which only has effect in vicinity of gland secreting it

60
Q

How do static cells live together?

A

adhere to each other

61
Q

How do static cells adhere to each other?

A 
> tight junctions
> adherent junctions
> desmosome
> gap junction
> hemidesmosome
62
Q

Tight junctions?

A

seals neighbouring cells together in an epithelial sheet to prevent leakage of molecules between them

63
Q

Adherens junctions?

A

joins an actin bundle in one cell to a similar bindle in a neighbouring cell

64
Q

Desmosome?

A

joins intermediate filaments in one cell to those in a neighbour

65
Q

Gap junction?

A

forms channels that allow small water-soluble molecules including soluble molecules to pass from cell to cell

66
Q

Hemidesmosome?

A

anchors intermediate filaments in cell to the basal lamina

67
Q

What is hypercholesterolemia?

A

defective uptake of lipoproteins
> LDL receptors bind LDL (bad cholesterol) for uptake - 3 causes of this:
- LDLR not properly transported from RER to Golgi for expression on cell surface
- LDLR bound to LDL does not cluster in endocytic vesicles on plasma membrane
- LDLR not recycled back to cell surface

68
Q

Cystic fibrosis cause?

A

misfolding of key protein

69
Q

Hypertension cause?

A

defective cell-cell adhesion in kidney

70
Q

Congenital heart defects cause?

A

errors in cell migration during development

71
Q

Muscular dystrophy cause?

A

defective attachment of plasma membrane to cytoskeleton

72
Q

Lysosomal storage disease cause?

A

defective intracellular transport of enzymes

73
Q

Food-bourne illness cause?

A

salmonella, E.coli

74
Q

Cancer cause?

A

errors in cell division, migration, cell polarity, growth etc

MD2001 Week 1 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions