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Flashcards in Biology Class 5 Deck (43)
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1

Pathway of secreted/lysosomal proteins

1. Translation begins in cytoplasm, then finishes in rough ER

2. Signal sequence is detected in membrane of rough ER, while ribosome binds to its receptor in cytoplasm

3. Protein finishes translation & signal sequence is cleaved

4. Protein goes to golgi body, then enters through plasma membrane, then goes to outside of cell

2

Pathway of membrane-bound proteins

1. Translation begins in cytoplasm, then finishes in rough ER

2. Has multiple of signal sequences and each time it is found on the membrane of the rough ER

3. Ribosome binds to its receptor in cytoplasm

4. Final protein is weaved in and out of the membrane of the rough ER

5. Clatherin then cleaves and pulls the protein outwards and creates a vesicle

6. Vesicle fuses with golgi body, then another vesicle fuses with plasma membrane

Signal sequence is not removed from final protein

3

Plasma Membrane components

1. Phospholipids (head = polar, tail is non-polar)
2. Proteins
3. Carbohydrates
4. Cholesterol (helps stabilize & creates fluidity

4

Electrolytes

Free ions in solution produced as a result of dissolving ionic substance

5

Van't Hoff Factor (i)

- Cannot be 0
- # of ions produced per molecule of an electrolyte

6

Colligative properties

Properties that depend on amount of solute particles but not on the identity
- taste is not a colligative propertie

7

Examples of colligative properties

1. Vapour pressure (decreases)
2. Freezing point (decreases)
3. Boiling point (increases)
4. Osmotic pressure (increases)

8

Freezing point depression

Formula: freezing point ΔTf = i x m x Kf
Kf of water = -1.86

Fp ∝ [particles]

9

Vapour pressure depression

Pressure of the vapour that evaporates from the liquid

VP ∝ [particles]
- more solutes will keep the solvent grounded, therefore VP will decrease

10

Boiling Point Elevation

The temperature at which VP is equivalent to atm pressure

Formula: boiling point ΔTb = i x m x Kb
Kb of water = 0.5

bp = [particles]

11

Osmotic Pressure Elevation

Pressure required to resist the movement of water by osmosis

Formula: π = i x R X M X T

12

Diffusion vs Osmosis

Moving particles from high to low []

Moving water from high to low []

13

Hypotonic, Hypertonic, isotonic

Hypotonic: less particles than another solution
Hypertonic: more particles than another solution
Isotonic: equal amount of particles

14

Passive transport vs active transport

Passive
- doesn't require energy
- moved down gradient
1. Simple diffusion
2. Facilitated diffusion

Active
- requires energy
- moves against gradient
1. Primary
2. Secondary

15

Primary vs Secondary active transport

Primary - uses ATP directly to move against gradient
Secondary - uses ATP indirectly to move against gradient

16

Simple vs facilitated diffusion

Simple
- doesn't need help moving down the gradient
- moves hydrophobic, non-polar molecules
Eg. CO2, O2, steroids, cholestrol

Facilitated
- needs help moving down gradient (helper proteins)
- moved hydrophilic, polar molecules
Eg. amino acids, ions, glucose

17

Helper proteins

1. Pores - not specific
2. Channels - highly specific
3. Shape shifters - bind, change shape, then pass through

18

Na+/K+ Atpase

- primary active transporter
- moves 2 k+ in and 3 Na+ out
- RMP is -70mV
- sets up Na+ for secondary transport

19

G-protein adenyl cyclase

1. GDP is bound to g-protein if no ligand is bound to receptor. If a ligand is bound to the receptor, GDP leaves and GTP binds
2. A subunit of the G-protein leaves and binds to adenyl cyclase
3. Adenyl cyclase converts ATP to cAMP
4. cAMP activates cAMP dependent kinases
5. cAMP kinases phosphorylate enzymes
6. Changes enzyme activity in cell and amplify signal which is fast & temporary

20

G-Protein phopholipase C

1. GDP is bound to g-protein if no ligand is bound to receptor. If a ligand is bound to the receptor, GDP leaves and GTP binds
2. A subunit of the G-protein leaves and binds to phospholipase C
3. Phospholipase C breaks down phosphoinositol bisphosphate into inositol triphosphate & diacylglyceral
4. I3 will increase intracellular Ca2+ levels
5. Diacylglycerol will activate kinases which will change enzyme activity

21

Types of filaments of cytoskeleton

Microtubule
Microfilament
Intermediate filament

22

Microtubule

Protein(s): alpha & beta tubulin
Diameter: large
Use: mitotic spindle, cilia & flagella, intracellular transport

23

Microfilament

Protein(s): actin
Diameter: small
Use: muscle contraction, pseudopod formation, cytokinesis

24

Intermediate filament

Protein(s): several different protein types
Diameter: medium
Use: structural roles

25

Cilia vs flagella

Cilia moves things on surface of cell while flagella moves entire cell

26

Cell junctions

Desmosomes - small proteins that hold cells together (general adhesive junctions)
Gap junctions - cell to cell communication (eg. neurons, cardiac cells, smooth muscle cells); exchange of cytosol between cells
Tight junctions - seal lumens & separate environments (eg. intestines & b-b barrier)

27

Cell cycle Overview

Divided into 2 phases: interphase, mitosis

Interphase:
G1 phase - cell growth, cell activity (preparing for S phase
G1/S phase checkpoint - most regulated and if don't have proper signals will not be able to replicate so go into G0 phase (eg. muscle cells, RBC)
S phase - replication
G2 phase - cell growth

Mitosis:
Prophase
metaphase
Anaphase
Telophase
*Cytokinesis happens at end of anaphase and beginning of telophase

28

Interphase

- Chromosomes are homologous if same gene just different alleles
- Once it passes through S phase, will have sister chromatids connected by centromere

29

Prophase

Nuclear membrane breaks down, mitotic spindle forming, DNA condenses

30

Metaphase

Chromosomes align at cell center