topic 2.2

Question 1

rod-shaped bacteria or bacterium

Answer 1

bacilli

Question 2

spherical shaped bacteria or bacterium

Answer 2

cocci

Question 3

wavy shaped bacteria

Answer 3

spiral

Question 4

bacteria arranged into irregular clusters

Answer 4

staphylococcus

Question 5

bacteria arranged into chain clusters

Answer 5

streptococci

Question 6

bacteria arranged into pair clusters

Answer 6

diplo

Question 7

usually produced from gram positive bacteria, very toxic, a protein substance

Answer 7

exotoxin

Question 8

present in the cell wall of gram negative bacteria, liposaccharide, very toxic

Answer 8

endotoxin

Question 9

tiny hairlike structures to assist in attachment of bacteria to tissue and share genetic material

Answer 9

pili

Question 10

primary method of reproduction of bacteria

Answer 10

binary fission

Question 11

method to differentiate bacterial species into two large groups (gram-positive and gram-negative)

Answer 11

gram staining

Question 12

bacteria that do not retain the crystal violet stain because they have a thin peptidoglycan cell wall

Answer 12

gram-negative

Question 13

bacteria that give a positive result in Gram stain testing, due to thick peptidoglycan cell wall

Answer 13

gram-positive

Question 14

bacteria that can live and grow in the presence of oxygen

Answer 14

aerobic

Question 15

bacteria that can live and grow in the absence of oxygen

Answer 15

anaerobic

Question 16

what generally comprises a human cell?

Answer 16

a plasma membrane, a nucleus and cytoplasm

Question 17

what is the main difference between eukaryotic and prokaryotic cells?

Answer 17

eukaryotic cells contain a nucleus while prokaryotic cells do not

Question 18

compare the DNA in both human and bacteria cells

Answer 18

human: DNA is linear, double stranded and accompanied by 23 chromosomes

bacteria: DNA is circular, double stranded and accompanied by 1 chromosome

Question 19

compare the ribosomes in human and bacteria cells

Answer 19

human: 60 size top unit, 40 size bottom

bacteria: 50 size top unit, 30 size bottom

Question 20

compare the layers of a gram-negative and gram-positive cell

Answer 20

cytoplasmic membrane: no difference
peptidoglycan: neg has 1 layer, pos has 30
outer membrane: neg has, pos doesn’t
lipopolysaccharides: only in neg

Question 21

which bacteria will have cells presenting a pink colour after conducting a Gram stain test?

Answer 21

cells in gram-negative bacteria will stain pink

Question 22

other than bacterial identification, what is a purpose of the Gram-stain test?

Answer 22

to identify the best antibiotic to kill of the particular bacteria

Question 23

explain exotoxins

Answer 23

• produced inside pathogenic bacteria + secreted into surrounding medium
• relatively unstable over 60 degrees
• highly toxic to human cells

Question 24

explain endotoxins

Answer 24

• present in cell wall of gram-negative bacteria only
• lipid portion of lipopolysaccharides, thus very heat tolerant
• at low concentrations, may stimulate protective responses (fever, inflammation)