DNA + RNA

Question 1

what are nucleic acids

Answer 1

polymers made from nucleotide

Question 2

What is DNA composed of?

Answer 2

two very long polynucleotide chains twisted into a double helix

Question 3

What is the DNA double helix made up of?

Answer 3

pentose sugar and phosphate groups forming a sugar-phosphate backbone

Question 4

what are the strands of DNA held together by?

Answer 4

hydrogen bonds between bases forming the rungs of the DNA double helix

Question 5

why is DNA known as a complementary base pairing?

Answer 5

DNA is always made up of one new strand and one old strand

Question 6

what are pyrimidines

Answer 6

cytosine, thymine, and uracil have a single six-membered ring

Question 7

what are purines

Answer 7

adenine, and guanine, have a six-membered ring fused to a five-membered ring

Question 8

why are the two polynucleotide strands in DNA antiparallel

Answer 8

run in opposite directions
one runs 5’ to 3’ while the other runs 3’ to 5’

Question 9

what is the structure of RNA

Answer 9

composed of only one polynucleotide chain (single-stranded)

Question 10

differences between DNA and RNA

Answer 10

DNA - deoxygenated sugar
RNA - oxygenated sugar

Question 11

roles of RNA

Answer 11

regulation and synthesis of proteins

Question 12

differences between the structure of DNA and RNA

Answer 12

• RNA polynucleotide chains are shorter than DNA chains
• pentose sugar is different
  RNA (ribose) DNA (deoxyribose)

Question 13

nitrogen-containing organic bases on RNA and DNA

Answer 13

RNA : A G C U
DNA : A G C T

Question 14

what is DNA replication?

Question 15

where does DNA replication take place?

Answer 15

takes place during interphase in the cell cycle- this is the phase before the cell starts to divide

Question 16

DNA replication in eukaryotes and prokaryotes

Answer 16

occurs in the cytoplasm for prokaryotes and the nucleus for eukaryotes

Question 17

what is the first step of DNA replication

Answer 17

DNA helicase causes the two strands of DNA to separate by breaking the hydrogen bonds between the complementary bases

Question 18

what happens to the strands after DNA helicase breaks them

Answer 18

One of the strands is used as the template and complementary base pairing occurs between the template strand and free nucleotides

Question 19

what is the second step of DNA replication

Answer 19

Primase makes primers (small pieces of RNA) so DNA polymerase knows where to start (since the primer is made from RNA, it is distinguishable from DNA

Question 20

what is the third step of DNA replication

Answer 20

DNA polymerase joins them together by forming phosphodiester bonds through condensation reactions, two identical strands of DNA are formed

Question 21

what is the fourth step of DNA replication

Answer 21

DNA ligase forms phosphodiester bonds (catalyze condensation reactions) between the nucleotides = this closes the gaps between the Okazaki fragments

Question 22

what is a gene

Answer 22

a section of DNA that is used to code for a specific polypeptide

Question 23

what is the leading strand

Answer 23

a strand that is synthesized continuously

Question 24

what is the lagging strand

Answer 24

synthesized in small pieces called Okazaki fragments

Question 25

what do the single-stranded binding proteins do (SSBS)

Answer 25

stop the unwound DNA from coming back together

Question 26

What does topoisomerase do?

Answer 26

prevent DNA from twisting/supercoiling after it is unwound

Question 27

when does DNA replication happen

Answer 27

occurs before cell division (meiosis + mitosis) so that each new cell produced has a complete set of chromosomes

Question 29

what is a replication fork?

Answer 29

The replication fork is the area where the replication of DNA will take place

Question 30

what is transcription?

Answer 30

is the process of making messenger RNA from a DNA template

Question 31

what is translation?

Answer 31

is the process of making proteins by forming a specific sequence of amino acids based on coded instructions in mRNA

Question 32

what are the three types of RNA

Answer 32

mRNA tRNA rRNA

Question 33

what is the function of mRNA

Answer 33

mRNA carries the genetic instruction from the DNA in the nucleus to the ribosomes in the cytoplasm

Question 34

what is the function of tRNA

Answer 34

brings the correct amino acids from the cytoplasm to the triplet bases on the other side that can match with the codon on the mRNA

Question 35

what is the function of rRNA

Answer 35

makes up the ribosomes; holds mRNA + tRNA together during translation

Question 36

what is a genome

Answer 36

the full set of DNA found in an organism

Question 37

what is the proteome

Answer 37

the full range of proteins that can be synthesized from the genome

Question 38

stages of transcription

Question 39

what is the sense strand

Answer 39

other strand; non-template strand

Question 40

what is the antisense strand

Answer 40

strand that is used as a template strand

Question 41

what are exons

Answer 41

sections of DNA that code for proteins

Question 42

what are introns

Answer 42

section of DNA that doesn't code for proteins