Chapter 8: Microbial Genetics study guide

Question 1

What are introns?

Answer 1

a segment of a DNA or RNA molecule which does not code for proteins and interrupts the sequence of genes.

Question 2

what are exons?

Answer 2

regions of DNA expressed

Question 3

what are snRNPs?

Answer 3

small nuclear ribonucleoproteins
remove introns and slice exons together to help form mRNA

Question 4

which cell type uses introns, exons, and snRNPs? where exactly?

Answer 4

eukaryotes ONLY
within the nucleus

Question 5

How is constitutive different from inducible enzymes?

Question 6

What are the two types of nucleic acids?

Answer 6

DNA
RNA

Question 7

What are the three parts of a nucleotide?

Answer 7

sugar
nitrogenous base
phosphate group

Question 8

What are the four types of nitrogenous bases used in RNA?

Answer 8

A U C G

Question 9

What are the four types of nitrogenous bases used in DNA?

Answer 9

A T C G

Question 10

What are the enzymes given in class that are involved with DNA replication?

Answer 10

leading strand: DNA polymerase

lagging strand: DNA polymerase
RNA primase
DNA ligase

Question 11

Describe the meaning of semiconservative replication.

Answer 11

the process by which DNA makes copies of itself, each strand, as it separates, synthesizing a complementary strand.

Question 12

How is bacterial DNA replication different than eukaryotic DNA replication?

Answer 12

eukaryotic DNA replication consists of vertical gene transfer
bacterial DNA replication consists of horizontal gene transfer

Question 13

How is an RNA nucleotide different than a DNA nucleotide?

Answer 13

DNA: deoxyribose sugar and is double helix
RNA: ribose sugar and is single strand

Question 14

What are the four nitrogenous bases used to make RNA?

Answer 14

adenine, cytosine, uracil, and guanine

Question 15

Know the three basic forms of RNA and what they do.

Answer 15

ribosomal RNA (rRNA)
transfer RNA (tRNA)
messenger RNA (mRNA)

Question 16

What does ribosomal RNA (rRNA) do?

Answer 16

integral part of ribosomes

ribozyme which carries out protein synthesis in ribosomes

Question 17

What does transfer RNA (tRNA) do?

Answer 17

transports amino acids during protein synthesis

Question 18

What does messenger RNA (mRNA) do?

Answer 18

carries coded information from DNA to ribosomes

Question 19

What is transcription?

Answer 19

When a portion of a DNA molecule is used to make mRNA molecule

Question 20

Which polymerase is used in transcription?

Answer 20

RNA polymerase

Question 21

what is the end goal of transcription?

Answer 21

DNA -> mRNA

Question 22

Where does transcription occur in a prokaryote?

Answer 22

Cytoplasm

Question 23

Where does transcription occur in a eukaryote?

Answer 23

nucleus

Question 24

What is the enzyme that allows for transcription?

Answer 24

RNA polymerase

Question 25

What is translation?

Answer 25

the process through which information encoded in messenger RNA (mRNA) directs the addition of amino acids during protein synthesis mRNA --> Protein

Question 26

Where does translation take place?

Answer 26

occur in cytoplasm and ribosomes of either eukaryotes/prokaryotes

Question 27

What is a codon?

Answer 27

mRNA language includes groups of three nucleotides such as AUG, GGC, or AAA

Question 28

What does degeneracy mean?

Answer 28

several codons can signal the same one amino acid

Question 29

What is the first amino acid? What is the codon for this amino acid?

Answer 29

Methionine AUG

Question 30

What are the three stop codons? Why do these codons cause translation to end?

Answer 30

UAA UAG UGA in order to signal end of protein synthesis

Question 31

What are the possible results of base substitution (point mutation)?

Answer 31

missense mutation nonsense mutation frameshift mutation

Question 32

What is a silent mutation?

Answer 32

change in DNA base sequence that causes no change

Question 33

how does UV radiation cause mutations?

Answer 33

cause thymine dimers

Question 34

What are three possibilities that would allow for a silent mutation?

Answer 34

1. degeneracy of genetic code (might still code for the same amino acid) 2. function of protein may not change if amino acid is non-vital portion of protein 3. changed amino acid is chemically similar

Question 35

What are the two major ways DNA can become mutated?

Answer 35

- base substitution - chemical mutations

Question 36

how does ionizing radiation cause mutations?

Answer 36

causes the formation of ions that oxidize nucleotides and break the deoxyribose phosphate backbone

Question 37

how does UV radiation cause mutations?

Answer 37

cause thymine dimers

Question 38

how does UV radiation cause mutations?

Answer 38

cause thymine dimers

Question 39

What are some examples of enzymes that repair mutagen damage?

Answer 39

photolyases separates thymine dimers

Question 40

What is the baseline error rate for DNA polymerase?

Answer 40

1 in a million

Question 41

What is the error rate once mutagens are added into the picture?

Answer 41

1 in a thousand

Question 42

What is the difference between horizontal and vertical gene transfer?

Answer 42

Vertical gene transfer: transfer of genes from an organism to its offspring Horizontal gene transfer: transfer of genes between cells of the same generation

Question 43

Which type of gene transfer can humans do?

Answer 43

Verticle

Question 44

Where does DNA come from in transformation?

Answer 44

Genes transferred from one bacterium to another as "naked" DNA THis "naked DNA" can come from dead or lysed cells

Question 45

Do cells need to be in contact for transformation?

Answer 45

does NOT require a living donor cell but only requires the presence of persistent DNA in the environment.

Question 46

What is conjugation?

Answer 46

plasmids transferred from one bacterium to another

Question 47

Do cells need to be in contact for conjugation?

Answer 47

- Requires cell-to-cell contact via sex pili - Must be of opposite mating type

Question 48

Which cell structure transfers the plasmid from one cell to the other?

Answer 48

via a pilus

Question 49

What happens to the recipient cell after conjugation is complete?

Answer 49

cell now has a plasmid that it can also transfer to other bacteria

Question 50

What is an Hfr cell?

Answer 50

high-frequency recombination cell Hfr cells contain the F factor on the chromosome

Question 51

What is transferred during conjugation with an Hfr cell?

Answer 51

part of the chromosome of Hfr cell

Question 52

What happens to the recipient cell after conjugation is complete with a Hfr cell?

Answer 52

a recombinant F- cell results

Question 53

What is transduction?

Answer 53

DNA is transferred from a donor cell to a recipient via a bacteriophage Transduction is the process by which a virus transfers genetic material from one bacterium to another

Question 54

what does transduction require in order to happen?

Answer 54

bacteriophages

Question 55

True or False DNA replication is when a cell makes a genetically different new strand of DNA

Answer 55

False DNA replication is the process by which the genome's DNA is copied in cells

Question 56

What is the ultimate goal of a bacterial cell (or any cell) going through transcription and then translation?

Answer 56

The goal of transcription is to make a RNA copy of a genes DNA sequence

Question 57

which type of mutation is the worst kind and is also most common?

Answer 57

frameshift mutation