Chapter 27.1 - 27.2 Flashcards Preview

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Flashcards in Chapter 27.1 - 27.2 Deck (31):
1

What domains do prokaryotes make up?

2 out of 3 (archaea and bacteria)

2

What are the three most common shapes of prokaryotes?

Spheres, rods, and spirals

3

How do cell walls benefit prokaryotes?

-Maintain shape
-Provide protection
-Prevent cell from bursting (hypotonic environment)

4

What makes up bacterial cell walls? Archaean cell walls?

Bacteria: peptidoglycan
Archaea: many polysaccharides and proteins (no chitin, cellulose, peptidoglycan)

5

Why are foods soaked in salt?

Prokaryotes will plasmolyze in hypertonic environments, thus killing them

6

What technique separates bacteria into 2 types? How are they separate (by what)?

-Gram staining
-Separated based on composition of cell walls

7

What are the 2 types of bacteria caused by gram staining?

Gram-positive (simpler, more peptidoglycan)
Gram-negative (complex, lipopolysaccharides)

8

What type of bacteria is more dangerous in an infection?

Gram-negative

9

What is a capsule?

Sticky layer of polysaccharide or protein that surrounds most prokaryotic cell walls

10

What's the purpose of a capsule?

-Allows adhering to substrate/others
-Protects against dehydration (hypotonic environment)
-Protects against immune system attacks

11

What are fimbriae?

Protein appendages that allows prokaryotes to stick to substrates or others

12

What are sex pili?

Long protein appendages which pulls cells together for DNA transfer

13

What is the most common feature that makes motility possible?

Flagellum

14

In a uniform environment, how do prokaryotes move by flagella?

In random movements

15

How do prokaryotes move in diverse environments?

They exhibit taxis, moving toward or away from stimulus

16

Prokaryotes that exhibit chemotaxis do what?

Change movement pattern in response to chemicals

17

Difference between positive and negative chemotaxis?

Positive: moving towards nutrients or oxygen
Negative: moving away from toxic substance

18

What do prokaryotes have instead of a nucleus? How is DNA composition different?

-Region of cytoplasm called nucleoid
-Circular with fewer proteins (may have plasmid)

19

How are ribosomes different in prokaryotes and eukaryotes?

Smaller and differ in protein/RNA content in prokaryotes

20

What conditions make prokaryotic reproduction limited?

-Exhausting nutrient supply
-Poisoned by metabolic wastes
-Competition from other microorganisms
-Being consumed by other organisms

21

What three features allow prokaryotic populations to be very large?

-Small
-Reproduce by binary fission
-Have short generation times

22

How are endospores created?

In harsh conditions, cell copied chromosome and surrounds it with tough wall (endospore formed). Water is removed by endospore to halt metabolism and cell disintegrates, leaving only endospore.

23

What 3 factors create genetic diversity among prokarytes?

-Rapid reproduction
-Mutation
-Genetic recombination

24

What 3 processes bring together prokaryotic DNA from different individuals (recombination)?

-Transformation
-Transduction
-Conjugation

25

What is transformation

Uptake of foreign DNA

26

What is transduction

Phages carry bacterial DNA to donor cell; exchange of genes at homologous segments

27

What is conjugation?

Transfer of genetic material between 2 bacterial cells that are temporarily joined

28

What is the basic mechanism of conjugation?

Donor cell uses sex pili to attach to recipient; upon contact, sex pili is retracted, pulling cells together; mating bridge is then formed for DNA transfer

29

What are Hfr cells?

Cells with F factor built into chromosome (donor cell)

30

What is homologous gene transfer?

DNA is exchange at homologous gene segments

31

What are resistant genes? What is an R plasmid?

-Genes that code for enzymes that destroy or hinder specific antibiotics
-Plasmid with resistance genes