nucleic acids

Question 1

what elements are in nucleic acids

Answer 1

carbon
hydrogen
oxygen
nitrogen
phosphorous

Question 2

name 3 components the makeup nucleotides

Answer 2

pentose monosaccharide (sugar) containing 5 carbon atoms
phosphate group- negatively charged
nitrogenous base- carbon rig +nitrogen

Question 3

how are sugar phosphate backbones formed

Answer 3

phosphate group of 5th carbon on pentose sugar forms covalent bond with hydroxyl group 3rd carbon on another pentose sugar adjacent nucleotide
phosphodiester bonds

Question 4

name the pentose sugar in RNA

Answer 4

ribose

Question 5

name the pentose sugar in DNA

Answer 5

deoxyribose

Question 6

name and describe pyrimidines

Answer 6

smaller bases with single carbon ring structure

• cytosine
• thymine- DNA
• uracil- RNA

Question 7

name and describe purines

Answer 7

larger bases with double carbon ring structure

• adenine
• guanine

Question 8

what type of bond holds the 2 strands of polynucleotides together in a DNA helix

Answer 8

hydrogen

between bases

Question 9

define antiparallel

Answer 9

the 2 strands run in opposite directions

Question 10

(in DNA) which bases pair together

Answer 10

adenine+ thymine

guanine+ cytosine

Question 11

what happens to DNA helix when cell prepares to divide

Answer 11

strands separate and act as template

Question 12

how is complementary base pairing useful in DNA replication

Answer 12

ensures 2 new strands will be identical

Question 13

describe semi-conservative replication

Answer 13

helix unwinds
free nucleotides pair with complementary base
hydrogen bonds form
nucleotides join adjacent ones forming phosphodiester bonds
each of 2 new mols reduced has 1 old and 1 new strand

Question 14

what enzyme separates the 2 stands of DNA helix

Answer 14

DNA helicase

catalyses reactions that break hydrogen bonds between base pairs

Question 15

wat enzymes helps form new strand

Answer 15

DNA polymerase

catalyses formation of phosphodiester bonds

Question 16

what is the genetic code

Answer 16

DNA codes for sequence of amino acids in proteins

universal- same in all organisms

Question 17

what is a triplet code

Answer 17

sequence of 3 bases (codon) that codes for an amino acid

Question 18

explain the degenerate code

Answer 18

some amino acids coded for by more than 1 codon
only 1 start codon so code is non-overlapping
3 stop codons that don’t code for any amino acids
64 possible codons

Question 19

name the stand that codes for protein during transcription

Answer 19

sense strand

other is anti-sense

Question 20

what are the differences between transcription and replication

Answer 20

in transcription, RNA uracil binds to adenine

RNA polymerase catalyses formation of phosphodiester bonds

Question 21

what is the product of transcription

Answer 21

messenger RNA
detached from template and leaves through nuclear pore
DNA helix reforms

Question 22

what is translation

Answer 22

mRNA binds to smaller subunit of ribosome

decoded into sequence of amino acids

Question 23

what 3 types of activity do cells need ATP for

Answer 23

synthesis
transport
movement

Question 24

name structures in ATP

Answer 24

nitrogenous base (adenine)
pentose sigar
3 phosphate groups

Question 25

how does ATP release energy

Answer 25

hydrolysis occurs simultaneously with energy requiring reactions- releases energy
-forms ADP + phosphate ion