Lecture 2 (Chapter 13)

Question 1

Pathogenic bacteria are ___________

Answer 1

heterotrophs (derive energy from organic carbon sources)

Question 2

Requirements for bacterial growth:

Answer 2

source of carbon and nitrogen, energy source, water, and various ions (i.e zinc and IRON)

Question 3

What is a siderophore?

Answer 3

bacteria synthesizes proteins called SIDEROPHORES to concentrate iron

Question 4

Why do our bodies sequester iron?

Answer 4

to limit its availability to pathogens

Question 5

What is an obligate aerobe?

Answer 5

bacteria that grows in the presence of oxygen

Question 6

What is an obligate anaerobe?

Answer 6

bacteria that cannot grow in the presence of oxygen

Question 7

What is an facultative aerobe?

Answer 7

bacteria that can grow with or without oxygen present

Question 8

What are disease-causing bacteria called?

Answer 8

Pathogens

Question 9

What extracellular pathogen CANNOT be cultured in a lab?

Answer 9

Treponema pallidum

Question 10

Can facultative intracellular pathogens be grown in a lab?

Answer 10

Yes

Question 11

Can obligate intracellular pathogens be grown in the lab

Answer 11

No

Question 12

What are non-pathogenic bacteria that live in/on the hosts

Answer 12

commensals (long term commensals = normal flora)

Question 13

What is catabolism?

Answer 13

the breakdown of organic substrates to generate usable energy

Question 14

What is anabolism?

Answer 14

the synthesis of cellular constituents (i.e proteins, fatty acids, and nucleic acids)

Question 15

Metabolites are converted into the universal intermediate ________

Answer 15

pyruvic acid (pyruvate)

Question 16

Energy is obtained from glucose by:

Answer 16

• aerobic respiration (MOST efficient)
• anaerobic respiration (LESS efficient)
• fermentation (LEAST efficient)

Question 17

What are the 3 main pathways for catabolism of glucose?

Answer 17

• Glycolysis (EMP)
• TCA Cycle (citric acid cycle)
• Pentose Phosphate Pathway

Question 18

Does glycolysis occur under anaerobic or aerobic conditions?

Answer 18

Both

Question 19

How many ATP is required and how many are generated during glycolysis?

Answer 19

2 ATP are required and 4 ATP are generated

Question 20

What process generates the 4 ATP during glycolysis?

Answer 20

substrate-level phosphorylation

Question 21

At the end of glycolysis, what is the net ATP?

Answer 21

2

Question 22

True or False
There are two molecules of pyruvic acid produced at the end of glycolysis

Answer 22

True

Question 23

Aerobic respiration yields how many ATP? How many times more when compared to fermentation?

Answer 23

• 38
• 19x more

Question 24

What form of bacterial reproduction produces two genetically identical cells?

Answer 24

asexual reproduction

Question 25

What is the term for one cell giving rise to two cells?

Answer 25

binary fission

Question 26

What are the two methods bacterial growth is measured by?

Answer 26

- viable counts (plate counts) - non viable methods (optical density [clarity], dry cell mass, quantitative measurement of an individual component)

Question 27

What is the formula to calculate bacterial numbers?

Answer 27

Nt = N0 x 2t/d

Question 28

How many bacteria would be in a culture grown for 2 hours with a doubling time of 20 minutes if you started with 100 bacteria? (don't forget to convert hrs to mins)

Answer 28

6400

Question 29

What are the 3 types of DNA in bacterial cells?

Answer 29

- bacterial chromosomes - plasmids - bacteriophage DNA

Question 30

What is a bacterial chromosome?

Answer 30

a largely covalent closed circular molecule of double stranded DNA

Question 31

What is a plasmid?

Answer 31

extra-chromosomal DNA elements

Question 32

Are plasmids essential?

Answer 32

they're not essential but can contribute to virulence or survival in certain environments

Question 33

What is bacteriophage DNA?

Answer 33

bacterial virus that may replicate extra-chromosomally or integrate into the genome

Question 34

During transcription, DNA is transcribed into what?

Answer 34

mRNA

Question 35

What does transcription require?

Answer 35

DNA-dependent RNA polymerase enzyme

Question 36

What does sigma factor do?

Answer 36

recognizes a specific sequence of nucleotides in the DNA (promoter)

Question 37

What does sigma factor target to the site in order for transcription to begin?

Answer 37

RNA polymerase

Question 38

What is polycistronic mRNA?

Answer 38

a single mRNA being able to be translated into multiple gene products

Question 39

What comprises an operon?

Answer 39

genes of related function transcribed together

Question 40

What do promoter and operon sequences do?

Answer 40

control expression of genes by influencing which sequences will be transcribed

Question 41

What triggers transcription to cease?

Answer 41

Terminator sequences

Question 42

What is translation?

Answer 42

the conversion of the genetic code into a sequence of amino acids

Question 43

What do ribosomes do in translation

Answer 43

they read the mRNA and pair tRNAs with each codon

Question 44

How many ribosomes are made up of two subunits?

Answer 44

70s

Question 45

What is negative regulation of transcription?

Answer 45

genes are expressed unless turned off by a repressor binding to the operator sequence

Question 46

What is positive regulation?

Answer 46

genes are not transcribed unless an apoinducer protein is present

Question 47

What is feedback inhibition?

Answer 47

when the final protein product goes back and inhibits the first step in its formation

Question 48

Where does replication of bacterial DNA occur?

Answer 48

the oriC

Question 49

What does helicase do?

Answer 49

unwind the DNA

Question 50

What does primase do?

Answer 50

lays down a primer to start synthesis from

Question 51

What does DNA-dependent DNA polymerase do?

Answer 51

synthesizes a copy of DNA in the 5' to 3' direction if a primer is present

Question 52

What does topioisomerase do?

Answer 52

helps relieve the stress by breaking and resealing the DNA (makes it not so tangled)

Question 53

Does DNA polymerase have proofreading abilities?

Answer 53

Yes

Question 54

What are mutations?

Answer 54

inheritable changes in the DNA sequence

Question 55

What is a silent mutation?

Answer 55

a mutation that has no effect on the cell

Question 56

What's a missense mutation?

Answer 56

when a different amino acid is incorporated into the protein

Question 57

What's a nonsense mutation?

Answer 57

an amino acid encoding codon becoming a stop codon

Question 58

What are conditional mutations?

Answer 58

mutations that only display their effects under certain conditions

Question 59

What is a frameshift mutation?

Answer 59

mutations insert or remove nucleotides into the DNA sequence

Question 60

What is homologous recombination?

Answer 60

an exchange of two identical or nearly identical pieces of DNA (needs DNA binding protein RecA)

Question 61

What is non-homologous recombination?

Answer 61

an exchange of dissimilar DNA sequences (generally produces insertion or deletions or both)

Question 62

What are the 3 process of Gene transfer?

Answer 62

- transformation - conjugation - transduction

Question 63

What is the process of Transformation?

Answer 63

the uptake of free DNA from the environment

Question 64

What is the process of Conjugation?

Answer 64

the one way transfer or DNA from a donor (male) cell to a recipient (female) requiring a sex pilus (usually between same species)

Question 65

What is the process of Transduction?

Answer 65

genetic transfer via bacterial viruses (bacteriophages)

Question 66

What was the first mechanism of genetic transfer identified?

Answer 66

transformation