lecture 5

Question 1

gene

Answer 1

a segment of DNA specifying a protein (via mRNA), a tRNA, an rRNA, or any other noncoding RNA

Question 2

genetic element

Answer 2

a structure that carries genetic information, such as a chromosome, a plasmid, or a virus genome

Question 3

genome

Answer 3

the total complement of genes contained in a cell or virus

Question 4

DNA (deoxyribonucleic acid)

Answer 4

a polymer of deoxyribonucleotides linked by phosphodiester bonds; the deoxyribonucleotide sequence encodes genetic information

Question 5

RNA (ribonucleic acid)

Answer 5

a polymer of ribonucleotides linked by phosphodiester bonds that plays many roles in cells, in particular, during protein synthesis

Question 6

informational macromolecule

Answer 6

any large polymeric molecule that carries genetic information, including DNA, RNA, and protein

Question 7

nucleotide

Answer 7

a monomer of a nucleic acid containing a nitrogenous base (adenine, guanine, cytosine, thymine, or uracil), one or more molecules of phosphate, and a sugar, either ribose (in RNA) or deoxyribose (in DNA)

Question 8

polynucleotide

Answer 8

a polymer of nucleotides bonded to one another by covalent bonds called phosphodiester bonds

Question 9

pyrimidine

Answer 9

one of the nitrogenous bases of nucleic acids that contain a single ring; cytosine, thymine, and uracil

Question 10

purine

Answer 10

one of the nitrogenous bases of nucleic acids that contain two fused rings; adenine and guanine

Question 11

phosphodiester bond

Answer 11

a type of covalent bond linking nucleotide together in a polynucleotide

Question 12

primary structure

Answer 12

the precise sequence of monomers in a macromolecule such as a polypeptide or a nucleic acid

Question 13

complementary

Answer 13

nucleic acid sequences that can base-pair with each other

Question 14

antiparallel

Answer 14

in reference to double-stranded DNA, the two strands run in opposite directions (one runs 5’ -> 3’ and the complementary strand 3’ -> 5’)

Question 15

DNA gyrase

Answer 15

an enzyme found in bacteria and most archaea that introduces negative supercoils in DNA

Question 16

messenger RNA (mRNA)

Answer 16

an RNA molecule that contains the genetic information to encode one or more polypeptides

Question 17

DNA ligase

Answer 17

an enzyme that seals nicks in the backbone of DNA

Question 18

transfer RNA (tRNA)

Answer 18

a small RNA molecule used in translation that possesses an anticodon at one end and has the corresponding amino acid attached to the other end

Question 19

ribosomal RNA (rRNA)

Answer 19

the types of RNA found in the ribosome; some participate actively in protein synthesis

Question 20

replication

Answer 20

in cells, synthesis of DNA using DNA as a template

Question 21

transcription

Answer 21

the synthesis of an RNA molecule complementary to one of the two strands of a double-stranded DNA molecule

Question 22

translation

Answer 22

the synthesis of protein by a ribosome using the genetic information in a messenger RNA as a template

Question 23

chromosome

Answer 23

a genetic element, usually circular in prokaryotic cells, carrying genes essential to cellular function

Question 24

plasmid

Answer 24

an extrachromosomal genetic element that is usually not essential to the cell

Question 25

transposable element

Answer 25

a genetic element able to move (transpose) from one site to another on host DNA molecules

Question 26

bacteriocin

Answer 26

a toxic protein secreted by bacteria that inhibits or kills other, related bacteria

Question 27

semiconservative replication

Answer 27

DNA synthesis yielding two new double helices, each consisting of one parental and one progeny strand

Question 28

DNA polymerase

Answer 28

an enzyme that synthesizes a new strand of DNA in the 5’ -> 3’ direction using an antiparallel DNA strand as a template

Question 29

primer

Answer 29

an oligonucleotide to which DNA polymerase attaches the first deoxyribonucleotide during DNA synthesis

Question 30

primase

Answer 30

the enzyme that synthesizes the RNA primer used in DNA replication

Question 31

replication fork

Answer 31

the site on the chromosome where DNA replication occurs and where the enzymes replication the DNA are bound to untwisted, single stranded DNA

Question 32

DNA helicase

Answer 32

an enzyme that uses ATP to unwind the double helix of DNA

Question 33

lagging strand

Answer 33

the new strand of DNA that is synthesized in short pieces and then joined together later

Question 34

leading strand

Answer 34

the new strand of DNA that is synthesized continuously during DNA replication

Question 35

replisome

Answer 35

a DNA replication complex that consists of two copies of DNA polymerase III, DNA gyrase, helicase, primase, and copies of single-strand binding protein