Cell Biology

Question 1

9 Differences between Prokaryotes and Eukaryotes

Answer 1

1. Size: P = 1-2 microns, E = 5-100 microns
2. Nucleus
3. DNA P = circular + single, E = linear, multiple + proteins
4. Cell division P = binary fission
5. Internal membranes P = rare E= lots
6. Ribosomes P = 70s (50 + 30), E= 80s (60 +40)
7. Cytoskeleton P = absent, E = microtubules
8. Motility P= rotary motor -> flagellum, E= dynein drives eukaryotic flagellum, cilia, kinesin, myosin

Question 2

3 categories of organisms

Answer 2

Eubacteria, Archae and Eukaryota

Question 3

Taxonomy:

1. B___
2. S____
3. Kingdom
4. Phylum
5. S____
6. S____
7. Class
8. S____
9. Order
10. S____
11. I_____
12. P____
13. S____
14. Family
15. Genus
16. Species

Answer 3

Biota, Superkingdom, Subphylum, Superclass, Superorder, Suborder, Infraorder, Parvorder, Superfamily

Question 4

3 types of globin protein

Answer 4

Hemoglobin, Myoglobin, Leghemoglobin

Question 5

Evolutionary trees of proteins are

Answer 5

Gene trees

Question 6

Outline cell cycle

Answer 6

G1 -> S -> G2 -> M 
In between G1 + S = G0 where resting cells lie 
G = RNA + protein synthesis
S = DNA replication
M = Mitosis

Question 7

Ploidy

Answer 7

Number of sets of chromosome in a cell

Question 8

Euploidy

Answer 8

Having an integral number of sets

Question 9

Aneuploidy

Answer 9

Not having Euploidy e.g. trisomy 21

Question 10

Differentiated cells are produced by

Answer 10

Asymmetric cell division

Question 11

Parent cell =

Answer 11

Stem cell

Question 12

Peroxisomes

Answer 12

Convert H2O2 to H2O

Question 13

Cytoskeletal fibers

Answer 13

1. Forms networks: microtubules, microfilaments and intermediate filaments
2. Support membranes, organize organelles
3. Important for cellular movement

Question 14

Why do different membranes have different phospholipids?

Answer 14

Different phospholipids are different lengths. Length determines formation of hydrophobic tails. Tails determine fluidity and organization of phospholipids.

Question 15

Types of centrifugation

Answer 15

1. Differential

2. Density-gradient

Question 16

Differences between types of centrifugation

Answer 16

1. Differential -> organelles are separated in homogenate by size -> not pure
2. Density-gradient -> Organelles separated by slight changes of density e.g. use of sucrose to create resistance for organelles which they push against when centrifuged

Question 17

How to measure electrophysiology?

Answer 17

1. Patch-clamp

2. Radioactive tracers

Question 18

Outline fluorescence-activated cell sorting (FACS)

Answer 18

1. Rapid separation of large number of cells
2. Purify -> every cell is enclosed into a charged jar dependent on cell charge
3. Isolate depending on market

Question 19

Outline flow cytometry analysis

Answer 19

1. Measures the levels of various markers on large number of cells
2. How light is being separated -> focuses on live cells

Question 20

How is intracellular signaling measured?

Answer 20

Ca2+ sensitive dyes are used to measure Ca2+ conc. In cells -> a.p.

Question 21

Benefits of GFP

Answer 21

1. Label neurons + transgenic animals

2. Brainbow demonstrates how brain is used -> every neuron and interaction seen

Question 22

How is FRAP used?

Answer 22

Fluorescence recovery after photobleaching measures the mobility of proteins in cells

Question 23

6 Differences between Light, TEM and SEM microscopy

Answer 23

1. Resolution: L 200 nm, T 1 nm, S 10 nm
2. Depth of focus + Field of view: L low, T medium, S high
3. Ease: L + S easy, T - requires skill
4. Speed: L+S - rapid, T - slow
5. Cost: L low, T + S high

Question 24

Outline electron microscopy

Answer 24

Relies on GFP or fluoroform. All the beams that pass through cause a white pattern.

Question 25

Outline SEM

Answer 25

Looking at how electron bounces back -> metal replica created by evaporated platinum + carbon

Question 26

Outline super-resolved microscopy

Answer 26

Extra detail beyond light microscopy using tricks to resolve light interference