Intro to Membranes + Bacterial Cell Structure Flashcards Preview

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Flashcards in Intro to Membranes + Bacterial Cell Structure Deck (29)
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1

What kind of movement is common in the phospholipid bilayer and why

Lateral movement, provides fluidity and flexibility. Flip-flop movement is rare because polar head is not stable in hydrophobic core

2

In high temperatures, there is _____ (more/less) room between phospholipids and the membrane permeability _______ (increases/decreases)

more, increases

3

In low temperatures, there is _____ (more/less) room between phospholipids and the membrane permeability _______ (increases/decreases)

less, decreases

4

How do membranes adapt to high & low temperatures

High: increase hydrocarbon tail length (increase hydrophobicity), decrease C=C bonds (they cause kinks, increase cholesterol content (stiffens/thickens membrane, increases hydrophobicity)
Low: Increase C=C bonds ("kick" apart), decrease tail length, increase cholesterol (acts as a spacer)

5

Non-polar amino acids are

hydrophobic

6

List substances from most permeable to least permeable

hydrophobic (np) molecules (O2, CO2, N2) -> small uncharged polar molecules (H2O, Glycerol, Ethanol) -> large uncharged polar molecules (glucose, sucrose) -> ions (Na+, K+, H+, Cl-)

7

How does passive transport work

Molecules flow from an area of high concentration to low concentration (water follows solute). Water undergoes passive transport by osmosis.

8

What is a risk when water rushes into the cell in animal cells

cells can burst (osmotic lysis)

9

What is a risk when water rushes out of the cell in animal cells

cells can shrink

10

Does facilitated diffusion require energy

no

11

Name the two forms of facilitated diffusion

Channel "tunnel" protein and carrier "revolving door" protein

12

Is facilitated diffusion specific

yes

13

Why perform active transport?

expel waste, concentrate nutrients in cell

14

Describe the sodium potassium pump

Sodium
Out
Potassium
In

Positive
Out
Negative
In
3Na+ out 2K+ in

15

Define coupled transport, give an example

Energy released by one gradient is used to establish another gradient.
Sodium/Potassium pump is used to pull glucose up its gradient into the cell.

16

Explain exocytosis

Bulk transport out of the cell, proteins from golgi transported in vesicle that fuses with plasma membrane to secrete proteins

17

Explain Endocytosis/Phagocytosis

Bulk transport into the cell, non specific, vesicle forms from plasma membrane, transports to lysosome (digestive organelle)

18

Explain Receptor mediated endocytosis

Endocytosis of a specific ligand (anything that binds a receptor) placed in vesicle, receptors recycled, ligand goes to lysosome to be digested/recycled.

19

Bacteria HAVE:

fimbriae, cell membrane, cell wall, cytoplasm, flagella, ribosomes, DNA in nucleoid region

20

Bacteria DO NOT have:

Membrane bound organelles (eg. Golgi, ER, chloroplasts)

21

What is the motile structure of Bacteria, explain it

Bacteria flagellum: rotates like a corkscrew to allow movement, powered by H+ gradient
Basal apparatus anchors filaments into cell wall/membrane

22

What is peptidoglycan

structural polysaccharide

23

What is lipoteichoic acids role

link cell wall to membrane

24

Explain the differences between Gram negative and Gram positive bacterial cell walls

Positive: thick layer of peptidoglycan
Negative: thin layer of peptidoglycan, but has an outer membrane (but not a major permeability layer)

25

What are Fimbriae and Biofilm

Forms of attachment in prokaryotes

26

How does the antibiotic penicillin work

Disrupts transpeptidation step (works well on Gram positive bc more PG)

27

How does colonization begin at birth

"Good" skin bacteria in birth canal so that baby is bathed in it before bad bacteria can reach it, around 600 species of bacteria in breast milk

28

What is humans only source of vitamin K

E Coli

29

Bacteria can aid in....

development of gut, digesting complex carbs, train immune system to distinguish harmful & helpful