module 2 - 3.8 nucleic acids

Question 1

what type of reaction is the synthesis of DNA?

Answer 1

anabolic

Question 2

how many chromosomes does almost every human cell contain?

Answer 2

46

Question 3

how many nucleotides does almost every human cell contain?

Answer 3

3 billion

Question 4

what is the length DNA in almost every human cell?

Answer 4

2 metres

Question 5

what is DNA?

Answer 5

the genetic material within organisms

Question 6

why is base pairing important?

Answer 6

allows the molecule to replicate

Question 7

what are nucleotides a type of?

Answer 7

monomers

Question 8

what happens to nucleic acids under neutral conditions?

Answer 8

• the remaining OH group of the phosphate is deprotonated
• the oxygen atom has a negative charge

Question 9

how to base pairs form? (which bond)

Answer 9

they hydrogen bond with each other

Question 10

what are nucleic acids?

Answer 10

polymers of nucleotides

Question 11

how are nucleotides joined together?

Answer 11

by condensation reactions that make PHOSPHODIESTER BONDS

Question 12

how are nucleic acids broken down?

Answer 12

by hydrolysis reactions that break the phosphodiester bonds

Question 13

what are the 3 subunits in a single nucleotide?

Answer 13

• an organic pentose monosaccharide (sugar)
• an inorganic phosphate group PO4^2-
• an inorganic nitrogenous base

Question 14

what does organic mean?

Answer 14

carbon based

Question 15

what does inorganic mean?

Answer 15

not carbon based

Question 16

where are nucleotides from?

Answer 16

food

Question 17

what happens once nucleotides have been broken down in food?

Answer 17

rebuilt for chromosomes in the body and rebuild into nucleic acids

Question 18

which position is the phosphate at?

Answer 18

5 prime carbon

Question 19

what is the difference in number of strands between DNA and RNA?

Answer 19

DNA - double stranded
RNA - single stranded

Question 20

what is the different pentose sugars in DNA and RNA?

Answer 20

DNA - deoxyribose sugar
RNA - ribose sugar

Question 21

what is the difference in nitrogenous bases between DNA and RNA?

Answer 21

DNA - adenine, thymine, guanine, cytosine
RNA - adenine, uracil, guanine, cytosine

Question 22

where is DNA found?

Answer 22

in the nucleus

Question 23

where is RNA found?

Answer 23

inside and outside nucleus

Question 24

what are the base pairs for DNA?

Answer 24

adenine - thymine
guanine - cytosine

Question 25

what are the base pairs for RNA?

Answer 25

adenine - uracil guanine - cytosine

Question 26

what is the difference between ribose (RNA) and deoxyribose (DNA)?

Answer 26

RNA contains one more oxygen atom than DNA

Question 27

why is it important that RNA contains one more oxygen atom than DNA?

Answer 27

allows the enzymes to distinguish between the 2 types of nucleotides

Question 28

what are pyramidines?

Answer 28

SMALLER bases: cytosine and thymine

Question 29

what are purines?

Answer 29

LARGER bases: adenine and guanine

Question 30

what type of molecules are the bases?

Answer 30

planar molecules (flat molecules)

Question 31

what do we encode DNA in the form of?

Answer 31

genes

Question 32

what is a base pair?

Answer 32

double-stranded unit of DNA made of 2 bases bound by hydrogen bonds

Question 33

what do base pairs form and contribute to?

Answer 33

- form building blocks of DNA double helix - contribute to the folded structure of DNA and RNA

Question 34

what does the complimentary nature of the base pairs provide?

Answer 34

provides redundant copy of genetic information encoded in each strand of DNA

Question 35

what is the regular structure and data redundancy make DNA well suited for?

Answer 35

makes DNA well suited to store genetic information

Question 36

what is the regular structure and data redundancy provided by for DNA?

Answer 36

provided by DNA double helix

Question 37

what do incoming nucleotides provide for DNA and RNA polymerase?

Answer 37

provides the DNA polymerase to replicate and RNA polymerase to transcribe DNA into RNA

Question 38

how is a new DNA strand formed?

Answer 38

- hydrogen bonds between nitrogenous base pairs are broken - forming 2 separate strands - a new complimentary strand is formed with the old strand (semi-conservative)

Question 39

when do nucleotides form strong covalent bonds with each other?

Answer 39

when the sugar group of one nucleotide bonds to the phosphate group of another nucleotide

Question 40

which type of bonds hold the polynucleotide together?

Answer 40

strong, covalent sugar-phosphate bonds

Question 41

what does DNA consist of? (strands)

Answer 41

2 polynucleotide strands

Question 42

what is the backbone and how are the bases arranged?

Answer 42

sugar-phosphate backbone the base arrangement - project toward the inside of the double helix

Question 43

what is antiparallel?

Answer 43

the first and second polynucleotide chains run parallel to each other but in opposite directions (left - 3 prime to 5 prime (upwards), right - 5 prime to 3 prime (downwards))

Question 44

how many hydrogen bonds are between adenine and thymine?

Answer 44

2 (pyrimidines)

Question 45

how many hydrogen bonds are between guanine and cytosine?

Answer 45

3 (purines)

Question 46

what is uracil?

Answer 46

demethylated form of thymine (in RNA not DNA)

Question 47

is uracil a purine or pyrimidine?

Answer 47

pyrimidine

Question 48

what does uracil base pair with?

Answer 48

adenine

Question 49

what does it mean if a base pair is 'planar'?

Answer 49

the base pair is flat

Question 50

rather than a double stranded paired molecule, what is RNA's structure?

Answer 50

single stranded molecule that is folded onto itself

Question 51

what is the size difference between RNA and DNA?

Answer 51

RNA molecules are much shorter than DNA molecules

Question 52

what does the hydroxyl group in the ribose backbone do?

Answer 52

makes RNA more unstable than DNA by lowering the activation energy of hydrolysis

Question 53

what does the functional form of single-stranded RNA frequently require and what does this lead to?

Answer 53

- requires a specific tertiary structure - this leads to several recognisable secondary structures

Question 54

what do cellular organisms use messenger RNA (mRNA) for?

Answer 54

to convey genetic information using nitrogenous bases that direct the synthesis of specific proteins

Question 55

how do many viruses encode their genetic information?

Answer 55

using an RNA genome

Question 56

how many strands does a tRNA molecule?

Answer 56

1

Question 57

why does a tRNA molecule appear to be double stranded?

Answer 57

it base pairs with itself, forming hydrogen bonds with itself