C6 - Bacterial Genetics

Question 1

discovered DNA

Answer 1

Frederick Miescher(1869)

Question 2

discovered that DNA contained phosphates, five-carbon sugars (cyclic pentose), and nitrogen containing bases

Answer 2

Phoebus A. T. Levine (1920s)

Question 3

→ discovered the helical structure by x-ray crystallography

Answer 3

Rosalind Franklin

Question 4

described the three-dimensional structure of the DNA molecule

Answer 4

James Watson and Francis Crick (1950s )

Question 5

What does genetics study?

Answer 5

Heredity and variation

Question 6

What determines an organism’s ability to maintain viability, adapt, multiply, and cause disease?

Answer 6

Genetic composition

Question 7

What are the three major aspects of microbial genetics?

Answer 7

Structure and organization of genetic material,

replication and expression of genetic information,

mechanisms of genetic information alteration and exchange

Question 8

What is the structure of a DNA molecule?

Answer 8

Double helical chain of nucleotides

Question 9

How is the DNA helix described?

Answer 9

Double strand twisted together, referred to as a “spiral staircase”

Question 10

What determines the information contained in DNA?

Answer 10

Base sequence (Genetic Code)

Question 11

What process involves DNA in the production of RNA?

Answer 11

Genetic information processing

Question 12

What are the components of a nucleotide?

Answer 12

A phosphate group (PO4),

a cyclic five-carbon pentose sugar (deoxyribose),

and a nitrogen-containing base

Question 13

What are the two types of nitrogen-containing bases in nucleotides?

Answer 13

Purine and pyrimidine

Question 14

What is the structure and length of an RNA molecule compared to DNA?

Answer 14

RNA is single-stranded and short

Question 15

What sugar is present in RNA molecules?

Answer 15

Ribose

Question 16

What are the three major types of RNA?

Answer 16

Messenger RNA (mRNA),
Transfer RNA (tRNA),
Ribosomal RNA (rRNA)

Question 17

A DNA sequence that encodes for a specific product (RNA or protein)

Answer 17

gene

Question 18

What term refers to all the genes in an organism?

Answer 18

Genome

Question 19

What organizes the genome into discrete elements?

Answer 19

Chromosomes

Question 20

What type of chromosome do bacteria have?

Answer 20

Single, unpaired (haploid), double-stranded, closed, circular

Question 21

What are double-stranded, closed, circular, autonomously replicating genetic elements called?

Answer 21

Plasmids

Question 22

What are the size ranges of plasmids?

Answer 22

1 to 2 kilobases up to 1 megabase

Question 23

What do plasmids encode for?

Answer 23

Replication and transfer products, specialized functions

Question 24

Do plasmids encode essential viability products?

Answer 24

No

Question 25

What are pieces of DNA that move between genetic elements called?

Answer 25

Transposable elements

Question 26

What are the two types of transposable elements?

Answer 26

Simple Transposon, Composite Transposon

Question 27

What do Simple Transposons (Insertion Sequences) contain?

Answer 27

Movement genes

Question 28

What characterizes Composite Transposons?

Answer 28

Cassette flanked by insertion sequences

Question 29

What do internal genes in insertion sequences often encode?

Answer 29

Accessory functions (e.g., antimicrobial resistance)

Question 30

Extrachromosomal Elements

Answer 30

Plasmids Transposable Elements

Question 31

What is the complex process mediated by various enzymes for DNA replication?

Answer 31

Replication

Question 32

What enzyme is crucial for DNA replication?

Answer 32

DNA polymerase

Question 33

What is the first step in DNA replication?

Answer 33

Unwinding of the chromosome’s supercoiled DNA

Question 34

What happens after unwinding the DNA in replication?

Answer 34

Separation of the complementary strands of the parental DNA

Question 35

What is the third step in DNA replication?

Answer 35

Synthesis of the new DNA strands

Question 36

What marks the end of the DNA replication process?

Answer 36

Termination of replication, releasing two identical chromosomes

Question 37

How long does the replication process typically take in rapidly growing bacteria like E. coli?

Answer 37

Approximately 20 to 40 minutes

Question 38

Expression of Genetic Information

Answer 38

Transcription Translation

Question 39

→processing of information encoded in genetic elements (i.e., chromosomes, plasmids, and transposons) →results in the production of biochemical molecules, including RNA molecules and proteins

Answer 39

Gene expression

Question 40

What is the synthesis of single-stranded RNA from a DNA template called?

Answer 40

Transcription

Question 41

mRNA are considered as __________ due to their ability to encode for several gene products

Answer 41

Polycistronic

Question 42

What process involves translating mRNA into amino acid sequences?

Answer 42

Translation

Question 43

GENETIC EXCHANGE AND DIVERSITY Three basic mechanisms:

Answer 43

Mutation Genetic Recombination Genetic Exchange

Question 44

Genetic Exchange Three mechanisms:

Answer 44

Transformation Transduction Conjugation

Question 45

What is the alteration in the original nucleotide sequence of a gene called?

Answer 45

Mutation

Question 46

What effect does a mutation have on an organism’s genotype?

Answer 46

It changes the genotype

Question 47

What can induce mutations?

Answer 47

Chemical or physical factors (mutagens) or biologic factors

Question 48

What is the process where a segment of DNA from one bacterial cell is exchanged with a segment of another cell’s DNA?

Answer 48

Genetic recombination

Question 49

What type of recombination involves DNA segments with extensive nucleotide sequence similarities?

Answer 49

Homologous recombination

Question 50

What protein plays a central role in homologous recombination?

Answer 50

RecA

Question 51

What is the uptake of naked DNA from the environment by a recipient cell called?

Answer 51

Transformation

Question 52

What happens to DNA during transformation after a bacterial cell dies and lyses?

Answer 52

It is released into the environment and can be incorporated into the recipient’s genome

Question 53

What term describes cells that can take up naked DNA during transformation?

Answer 53

Competent

Question 54

What is the transfer of bacterial genes by a bacteriophage from one cell to another called?

Answer 54

Transduction

Question 55

What happens in generalized transduction?

Answer 55

Bacterial DNA may be randomly incorporated with viral DNA

Question 56

What happens in specialized transduction?

Answer 56

Bacterial DNA is incorporated along with adjacent viral DNA

Question 57

What mechanism involves the transfer of genetic material between two living bacterial cells through direct contact?

Answer 57

Conjugation

Question 58

What structures are involved in the transfer of plasmids and transposons during conjugation?

Answer 58

Plasmids and transposons

Question 59

What mediates contact between donor and recipient cells in conjugation?

Answer 59

Sex pilus

Question 60

What does the sex pilus establish between the donor and recipient cells?

Answer 60

A conjugative bridge for DNA transfer