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Week 4: Breast Mass > Organization of the Cell > Flashcards

Flashcards in Organization of the Cell Deck (27)
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1

4 amino acids with non-polar side chains

Glycine
Alanine
Phenylalanine
Leucine

2

What part of a protein dictates its ultimate localization

Aspects of the primary sequence
Signal sequences/patches

3

Signal sequences

Typically at the N-terminal
Removed by signal peptidases after sorting
Can code to go many different places

4

Chaperones

Help guide the folding process
Chaperone synthesis is responsive to increases in misfolding

5

Proteasome

Degrade irretrievably misfolded proteins
Quite big
Breaks proteins down to amino acids

6

What is added to make
1. A
2. B
blood groups?

1. N-acetylgalactosamine
2. Galactose

7

Lipid raft

In trans Golgi
Cholesterol rich domain
Has increase concentration of TM proteins and associated future cargo
Preferentially get sorted into transport vesicles

8

Lysosome

Has an acidic intracellular compartment
Responsible for degradation of endocytized material

9

Proteasome vs lysosome

Proteasome: cytosolic multi-enzyme complex, degrades intracellular proteins that were defective or mutants
Lysosome: membrane bound organelle, degrades endocytosed material and whole organelles

10

Lysozyme

Made by macrophages and released constitutively
Not found in lysosomes!!

11

2 things that determine cell polarity

Cytoskeleton
Cell Junctions

12

2 major morphological types of breast tumors

Ducts
Lobules

13

Lobular breast carcinoma progression

Normal
Hyperplasia (proliferation, but can still see lumens)
Lobular carcinoma in situ (more dysplasia, polarity is disrupted, no lumens)
Infiltrating lobular carcinoma (loss of polarity, cells become invasive)

14

Microfilaments

Smallest ones
Made up of globular actin
Very dynamic
Important in cell adhesion, generation of contractile force, cell shape, and surface projections (microvilli)

15

Intermediate filaments

Medium sized
Formed from overlapping protein rods - very stable
Convey tensile strength within cells and across tissues
Architectural scaffolds
Tissue specific expression of different intermediate filament proteins

16

Different types of intermediate filament proteins in
1. Epithelia
2. Muscle
3. CT
4. Neurons

1. Keratins
2. Desmin
3. Vimentin
4. Neurofilaments

17

Microtubules

Cylinders of globular tubulin (polar)
Highly dynamic (cell division)
Motors can move along them
Found in the cores of motile cell surface projections (cilia, sperm)

18

3 parts of ALL junction/adhesion complexes

Cell surface receptors (TM proteins that bind to other receptors on other cells or ECM)
Linker proteins (link complex to cytoskeleton)
Cytoskeletal elements (often span from one complex to another inside the same cell)

19

Zonula adherens

Form a belt around the cell
Initiate cell-cell adhesion on the lateral aspect of cells

20

Specific proteins for
1. Cell receptors
2. Linker proteins
3. Cytoskeletal elements
for zonula adherens

1. Cadherins
2. Catenins
3. Actin

21

2 functions of catenins

Structural: link cadherins to actin
Proliferative signal transduction: when not in junction can move to nucleus and upregulate cyclin D expression

22

Tight junctions

Receptors bring the membranes on adjacent cells very close together so they form a barrier

23

Desmosomes

Also called macula densa
Not a belt (spots)
Can be located anywhere along lateral surface
Linked to intermediate filaments (increases tensile strength)
Prominent in epithelia of skin

24

Gap junctions

Formed out of connexons
Channels that link cells and allow for the passage of small molecules and ions between cells
Communicating junctions

25

Hemidesmosomes

Anchor cells to ECM
Receptors are heterophilic (bind different proteins)
Attached to intermediate filaments inside the cell
Very stable

26

Focal adhesions

Anchor cells to ECM
Cytoskeletal elements are actin filaments
Can generate contractile force
Critical for cell migration

27

What happens in
1. G1
2. S phase
3. G2

1. cell growth
2. DNA synthesis
3. chromosome condensation, mitotic spindle preparation