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Flashcards in Prokaryotic cells Deck (119)
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1

Give examples of prokaryotic cells

Bacteria, cyanobacteria, and archaebacteria

2

What components do all bacterial cells contain

Cell wall, pili, and flagella, cell surface membrane, plasmids, nucleoid, and 70S ribosome

3

What are bacterial cells usually like

They're hypertonic to the medium around them, so water tends to move into cells by osmosis

4

What does the cell wall prevent

Cell swelling and bursting

5

What does the cell wall help maintain

The shape of the bacterium and gives support and protection to the contents of the cells

6

What do all bacterial cell walls consist

Of a layer of peptidoglycan

7

What is the peptidoglycan made up of

That is made up of may parallel polysaccharide chains with short peptide cross-linkages forming an enormous molecule with a net-like structure

8

What do some bacteria have around their cell wall?

Have a capsule around the cell wall

9

What does a capsule make easier for bacteria
Why

For a bacterium to be pathogenic because it's not so easily identified by the immune system

10

What are pili
where are they found

One to seven hundred thread-like protein projections from their surface
Found is some well-known bacteria such as E.coli

11

What are pili used for

For attachment to a host cell and for sexual reproduction

12

What do pili make more vulnerable

They make bacteria more vulnerable to virus infections

13

How do some bacteria move themselves

using flagella

14

What is a flagella

Many-stranded helices of the contractile protein flagellin found on some bacteria. They move bacteria by rapid rotations

15

What do is it mean that bacteria doesn't have any mitochondria

The cell membrane is the site for respiratory enzymes

16

What are mesosomes

infoldings of the cell membrane of bacteria

17

What are other infoldings of the bacteria cell surface used for

It may be used for photosynthesis by some bacteria species

18

What are plasmids

Small circular pieces of DNA that code for specific aspects of the bacterial phenotypes

19

what do plasmids code for

A particular aspect of the bacterial phenotype in addition to the genetic information in the nuceloid

20

What can plasmids be transferred from
How

Transferred from one bacterium to another
In a form of sexual reproduction using pili

21

What does the genetic material of prokaryotic material consist of

A single length of DNA, which is not contaminated in a membrane-bound nucleus

22

What is a nucleotide

The area in a bacterium where we find the single length of coiled DNA

23

What occurs in the ribosome in prokaryotic cells

Protein synthesis

24

Whats the size of the ribosomes in prokaryotic

Its smaller than the eukaryotic ones 70S

25

What is Grain stain

A staining technique used to distinguish types of bacteria by their cell walls

26

Why is Gram staining so valuable

Different types of bacteria are vulnerable to different types of antibiotics and one pdf the factors that effecting its vulnerability is the type of cell wall

27

Describe the cell wall of gram-positive bacteria
What chemicals does it contain

They have a thick peptidoglycan layer
It contains teichonic acid

28

What happens to the Gram-positive bacteria when stained

It remains the same colour as the stain (purple/blue colour)
It doesn't pick up the red safranin counterstain

29

What does the cell wall of Gram-Negative bacteria have
What is the outer layer made from

A thin layer of peptidoglycan with no teichoic said between two layers of membrane
Its made from lipopolysaccharides

30

What happens when Gram-negtive bacteria is stained

The lipopolysaccharide layer dissolves in the ethanol leaving thin peptidoglycan layers exposed
The crystal violet/iodine complex is washed out and the peptidoglycan takes up the red safranin counterstain, so cell appears red