Chapter 11

Question 1

What are the primary functions of DNA?

Answer 1

Inheritance and directing protein production for growth and reproduction.

Question 2

What is the semiconservative model of DNA replication?

Answer 2

Each new DNA molecule consists of one old strand and one new strand.

Question 3

Why is DNA replication important for bacteria?

Answer 3

It allows bacteria to reproduce via binary fission and maintain genetic continuity.

Question 4

What are the three steps of DNA replication?

Answer 4

Initiation, elongation, termination.

Question 5

What happens during initiation in DNA replication?

Answer 5

Enzymes unwind DNA at the origin of replication.

Question 6

What enzyme adds new nucleotides during elongation?

Answer 6

DNA polymerase.

Question 7

What happens during termination in DNA replication?

Answer 7

DNA replication stops at the termination site, producing two identical chromosomes.

Question 8

What is the role of DNA ligase in replication?

Answer 8

It seals Okazaki fragments on the lagging strand.

Question 9

Why do bacteria replicate DNA in two directions?

Answer 9

Their circular chromosomes allow bidirectional replication.

Question 10

What is the role of RNA primers in bacterial DNA replication?

Answer 10

They provide a starting point for DNA polymerase.

Question 11

What is binary fission?

Answer 11

A type of asexual reproduction where a bacterial cell divides into two identical daughter cells.

Question 12

List the steps of binary fission.

Answer 12

DNA replication, cell elongation, septum formation, cell division.

Question 13

Why is binary fission important for bacterial survival?

Answer 13

It allows rapid reproduction and population growth.

Question 14

What is horizontal gene transfer?

Answer 14

The transfer of genetic material between bacteria without reproduction.

Question 15

What are the three methods of horizontal gene transfer?

Answer 15

Transformation, transduction, conjugation.

Question 16

Define transformation in bacteria.

Answer 16

Uptake of free DNA from the environment.

Question 17

Define transduction in bacteria.

Answer 17

Transfer of bacterial DNA by a virus (bacteriophage).

Question 18

What is bacterial conjugation?

Answer 18

Unidirectional transfer of genetic material from a donor bacterium to a recipient bacterium via a pilus.

Question 19

What is an F plasmid?

Answer 19

A fertility plasmid that enables bacteria to form pili for conjugation.

Question 20

Why is conjugation important for bacterial diversity?

Answer 20

Increases genetic diversity. It allows the spread of genes, including antibiotic resistance.

Question 21

What is the Central Dogma of molecular biology?

Answer 21

DNA → RNA → Protein.

Question 22

What is gene expression?

Answer 22

The process where information from DNA is transcribed into RNA and translated into protein.

Question 23

Why is the Central Dogma unidirectional?

Answer 23

Information flows from DNA to RNA to protein and cannot reverse.

Question 24

What is transcription?

Answer 24

The process of making RNA from a DNA template.

Question 25

What enzyme is responsible for transcription?

Answer 25

RNA polymerase.

Question 26

What are the three stages of transcription?

Answer 26

Initiation, elongation, termination.

Question 27

What occurs during transcription initiation?

Answer 27

The sigma factor of RNA polymerase find & binds to the promoter region. The rest of the RNA pol subunits bind to sigma factor (forms holoenzyme) & begins RNA synthesis.

Question 28

What is the role of the sigma (σ) factor in transcription?

Answer 28

It helps RNA polymerase recognize and bind to the promoter.

Question 29

How does elongation proceed in transcription?

Answer 29

RNA polymerase moves along 1 DNA strand adding complementary nucleotides to the growing RNA strand.

Question 30

What happens during transcription termination?

Answer 30

RNA polymerase reaches a terminator sequence and releases the RNA transcript.

Question 31

How does transcription differ between prokaryotes and eukaryotes?

Answer 31

Eukaryotes have multiple RNA polymerases and process mRNA (splicing, 5' cap, poly-A tail).

Question 32

What is RNA splicing?

Answer 32

The removal of introns and joining of exons in eukaryotic mRNA.

Question 33

What is a polycistronic mRNA?

Answer 33

An mRNA that encodes multiple proteins (common in bacteria).

Question 34

What is translation?

Answer 34

The process in which robosomes use mRNA to synthesize proteins

Question 35

What are the three types of RNA involved in translation?

Answer 35

mRNA (carries genetic info from chromosomes to robosomes), tRNA (delivers AAs to robosomes), rRNA (combines w/ ribobosoaml polypeptides to form ribosome).

Question 36

What are the three stages of translation?

Answer 36

Initiation, elongation, termination.

Question 37

What is the start codon in translation?

Answer 37

AUG (Methionine).

Question 38

What are the stop codons?

Answer 38

UAA, UAG, UGA.

Question 39

What are the three sites on the ribosome?

Answer 39

A site (accepts tRNA), P site (holds growing peptide chain), E site (exit site).

Question 40

What occurs during translation initiation?

Answer 40

Small ribosomal subunit attaches to mRNA at ribosomal binding site to position start codon at P site. tRNA carrying methionine attaches to P site, then larger ribosomal subiunit attaches to form complete ribosomal initiation complex.

Question 41

What happens during translation elongation?

Answer 41

tRNAs bring amino acids to A site of ribosome. Ribozyme (an enzymatic RNA mole.) in larger ribosomal subunit forms a peptide bonds between them. Ribosome moves down mRNA to the next codon, transferring tRNA to E site.

Question 42

How does translation terminate?

Answer 42

Proteins called release factors recognize stop codons and modify the large ribosomal subunit to release the ribosome from the mRNA.

Question 43

How does translation differ between bacteria and eukaryotes?

Answer 43

Bacteria translate while transcribing; eukaryotes separate these processes.

Question 44

Where does translation occur in prokaryotes and eukaryotes?

Answer 44

Cytoplasm for both, but transcription occurs in the nucleus for eukaryotes.

Question 45

Why is genetic diversity important in bacteria?

Answer 45

It allows adaptation to changing environments and resistance to antibiotics.

Question 46

What are resistance plasmids?

Answer 46

Plasmids that carry genes for antibiotic resistance.

Question 47

What are virulence plasmids?

Answer 47

Plasmids that carry genes enhancing pathogenicity.

Question 48

What is the function of helicase?

Answer 48

Unwinds the DNA helix by breaking the hydrogen bonds.

Question 49

What does topoisomerase do?

Answer 49

Relieves supercoiling during DNA replication.

Question 50

What is the role of DNA polymerase I?

Answer 50

Replaces RNA primers with DNA. Removes RNA primers and reseal DNA.

Question 51

How do mutations contribute to genetic diversity?

Answer 51

They create variations in DNA sequences.

Question 52

What is the significance of antimicrobial resistance (AMR) genes?

Answer 52

They enable bacteria to survive antibiotic treatments.

Question 53

What is the purpose of gene transfer in bacteria?

Answer 53

To increase genetic diversity and adaptability.

Question 54

What are operons in bacterial DNA?

Answer 54

Clusters of genes controlled by a single promoter.

Question 55

What is the role of single-strand binding proteins (SSBs)?

Answer 55

They stabilize unwound DNA and prevent the strands from reannealing.

Question 56

What is a holoenzyme in transcription?

Answer 56

RNA polymerase plus sigma factor.

Question 57

What is a peptide bond?

Answer 57

The bond linking amino acids in a polypeptide chain.