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MCAT - Bio/Biochem > Bacteria > Flashcards

Flashcards in Bacteria Deck (55):
1

What shape is E. Coli?

Bacillus

2

What is the term for flagella used in naming bacteria?

Trichous

3

What is the difference between a prokaryotic and eukaryotic flagella?

x

4

What piece anchors the flagella in the membrane? What does it do?

The basal unit

Generates a proton gradient between the membrane and the periplasmic space to cause rotation

5

What is the whip like portion of the flagella called?

The filament

6

What is the bacterial cell wall made of?

Peptidoglycan

7

What makes a bacteria gram +? What color does it stain?

Thick peptidogylcan layer which stains dark purple

8

What makes a bacteria gram -? What color does it stain?

Additional outer membrane outside of a thinner peptidoglycan layer. Thus they stain poorly--a light pink.

9

What is a mesophile?

A bacteria that likes middle temperatures, non-extreme

10

What is a thermophile?

Bacteria that loves very hot temps

11

What is a psychrophile?

Bacteria that loves cold temps

12

What is an obligate aerobe?

Cannot survive in the absence of oxygen

13

What is a facultative anaerobe?

Can use oxygen OR do fermentation, quite likes oxygen actually

14

What is a tolerant anaerobe?

An anaerobe that is not killed by oxygen, but cannot use oxygen to survive. Instead ferments

15

What is an obligate anaerobe?

Dies in the presence of oxygen

16

What does auxotroph mean?

"Can't do or make something" or if its a sugar, cant metabolize that sugar

17

What is the growth cycle via binary fission?

Lag -> Log -> stationary -> death

Does not increase genetic diversity, but can greatly increase colony size

18

What is an F+ bacterium?

A bacterium that contains an (F) plasmid. Considered a "male" bacterium

19

What is an F- bacterium?

A bacterium lacking a plasmid. Considered a "female" bacterium

20

How does bacterial conjugation occur?

A conjugation bridge, aka a "sex pilus" connects an F+ bacterium and an F- bacterium. The plasmid is replicated in the male and a copy is sent via the bridge to the female.

The female cell now has more genetic diversity

21

What things should you know about fungi?

1. Eukaryotes (think yeast!)
2. Cell wall is chitin
3. Reproduce via vegetation, asexual spores, or sexual spores
4. Adults are haploid
5. Hierarchy = hyphae -> mycelium -> thallus

Thallus is the largest, visible fungus e.g. hunk of bread mold

22

Although most proteins start AND finish translation in the cytoplasm, what are the 4 types that finish in the rough ER?

1. Secreted protein
2. Transmembrane proteins
3. Lysosomal proteins
4. ER/Golgi resident proteins

23

How do proteins that finish translation in the ER (e.g. secreted proteins and membrane bound proteins) know how to

Secreted protein:

A signal sequence is translated in the first few amino acids.
*note, the signal is actually removed at the end of translation).

Membrane bound:

A signal can be ANYWHERE in the amino acid sequence and is not removed during translation.

24

Where do the signal sequences of transmembrane proteins end up?

In the hydrophobic/nonpolar part of the PM (the tails)

25

Can proteins flip in the PM?

No!

26

What is the Vant Hoff factor?

The number of ions a molecule splits into. e.g. NaCl would be 2
CaCl2 would be 3

27

What are colligative properties?

Properties that depend on the NUMBER of solute particles (Vant Hoff factor) but NOT their identity. Properties affected:

1. Freezing point depression
2. Vapor point depression
3. Boiling point elevation
4. Osmotic pressure increase

28

What is the equation for freezing point depression?

FP depression = (delta)T = Kf x i x m

where Kf = a solvent-dependent constant
i = Vant Hoff factor
m = molarity

Note, in physiological systems, Kf always = 1.8

29

What effect does an increase in particle number/solutes have on vapor pressure?

decrease

30

What effect does an increase in particle number/solutes have on freezing temperature?

decreases

31

What effect does an increase in particle number/solutes have on the boiling point?

increases

32

What is the equation for boiling point elevation?

BP elevation = (delta)T = Kb x i x m

where Kb = a solvent-dependent constant
i = Vant Hoff factor
m = molarity

Note, in physiological systems, Kb always = 0.5

33

Remember that osmosis is a ________ property.

Colligative (based on particle NUMBER)

34

What does the Na/K ATPase do?

Pumps 3 Na out of the cell and 2 K into the cell

35

How is glucose transported across intestinal cells into the bloodstream?

Na/glucose co-transporter

36

What cellular roles do microtubules play?

mitotic spindle
intracellular transport
cilia and flagella

37

What cellular roles do microfilaments play?

muscle contraction
pseudopod formation
cytokinesis

38

What cellular roles do intermediate filaments play?

structural

39

What are the phases of the cell cycle?

G1 -> S -> G2 -> M

40

What is the most heavily regulated phase/point in the cell cycle?

G1/S phase junction

41

What are the phases in mitosis?

Prophase -> Metaphase -> Anaphase -> Telophase

42

During mitosis, what is the name of the two homologous chromosomes joined at the centromere?

Sister chromatids

43

What is cytokinesis?

Cell pinching and separation conducted by actin filaments at the end of anaphase

44

At what stage are cells haploid?

At the end of meiosis I

1n2x

45

What is a polymorphic trait?

A trait with several varieties. e.g. hair color

46

What is a polygenic trait?

A trait that is coded for by multiple genes (pretty much all traits are polygenic!)

47

What is incomplete dominance?

Blending of two dominant traits. e.g. pink

48

What is codominance?

2 alleles are expressed simultaneously but independently. eg blood type

49

What is a test cross?

A cross between a homozygous recessive and an unknown dominant.

50

What are linked genes?

Genes that are close together on the same chromosome might NOT sort indepdently.

51

Crossing over is more likely to occur with genes that are __________.

Farther apart

52

What is the expected ratio for a double heterozygote cross? (for 2 genes)

1:3:3:1

53

What are the 2 Hardy-Weinberg equations?

Allele frequency = p + q = 1

Genotype frequency = p^2 + 2pq + q^2 = 1

54

How many generations does it take to return to Hardy-Weinberg equilibrium?

ONE! (assuming all the HW conditions are met)

55

What are the Hardy-Weinberg conditions?

1. No mutations
2. No natural selection
3. Totally random mating
4. Large population
5. No migration