Nucleic acids (3)

what type of molecule is a nucleotide

a monomer

what type of molecule is a nucleic acid

a polymer

what is a nucleic acid

a molecule made up of one or more polynucleotide chains

what type of reaction forms polynucleotides

a condensation reaction

describe the formation of polynucleotides

nucleotides join together through condensation reactions forming phosphodiester bonds between the phosphate group of one nucleotide and the hydroxyl group of the pentose sugar of another

what are the 2 main examples of nucleic acids

DNA and RNA

what does DNA stand for

deoxyribonucleic acid

what does RNA stand for

ribonucleic acid

why does DNA start with ‘deoxy’

the sugar molecule in DNA has one less oxygen atom than a normal ribose sugar

whats the name of the pentose sugar involved in DNA

deoxyribose

what is a chain of nucleotides called

polynucleotides

what is a nucleotide made up of

a pentose sugar,phosphate group and nitrogen containing organic base

what bond holds together the phosphate group and pentose sugar in a nucleotide

an ester bond

what bond holds together the pentose sugar and the nitrogenous base

a glycosidic bond

what bond holds bases together

hydrogen bonds

which carbon on the pentose sugar does the phosphate group bond with

carbon-5

what are the 4 possible nitrogenous bases in DNA

adenine, guanine, cytosine or thymine

what are the 2 categories of bases

purines and pyrimidines

what are purine bases

larger bases that have two carbon rings

what are two examples of purines

adenine and guanine

what are two examples of pyrimidines

cytosine and thymine

what are pyrimidine bases

smaller bases which have one carbon ring

what is the structure of DNA

a double helix with two polynucleotide strands

how is a constant distance maintained between the two sugar phosphate backbones

a larger purine base always pairs with a smaller pyrimidine base

what is a sugar phosphate backbone

a chain of phosphates and sugars

what is complementary base pairing

the specific hydrogen bonding between nitrogenous bases

what are the complementary base pairs in DNA

adenine with thymine and guanine with cytosine

how many hydrogen bonds form between adenine and thymine

2 hydrogen bonds

how many hydrogen bonds form between guanine and cytosine

3 hydrogen bonds

how are the 2 polynucleotide strands in DNA described

antiparallel

why are the polynucleotides in DNA described as antiparallel

each strand runs in opposite directions

what is the main function of DNA

to store genetic information that codes for protein

what is the other function of DNA

it passes genetic information from one generation to the next

how is the sugar phosphate backbone useful

it protects the nitrogenous bases

how does DNA being double stranded make it suited for replication

each strand can act as a template for new complementary strands

how does DNA being large make it suited for storage

can store lots of information

how does a double helix shape help DNA being suited for storage

makes DNA compact which allows it to fit inside cells

how does complementary base pairing make DNA suited for replication

ensures accurate DNA replication

how do the weak hydrogen bonds between bases make DNA suited for replication

makes it easy for strands to separate during replication

what is the main function of RNA

use information from DNA to synthesise proteins

what’s the difference between the sugars in DNA and RNA

DNA contains deoxyribose and RNA contains ribose

what are the nitrogenous bases in RNA

adenine, guanine, cytosine, uracil

what’s the difference between the nitrogenous bases in DNA and RNA

DNA has thymine but RNA has uracil instead

how many polynucleotide strands are in RNA

one

what is the difference between the size of DNA and RNA

DNA is much longer than RNA which is short

how do you describe DNA not wound around histone proteins

naked

who discovered the structure of DNA

watson and crick in

in eukaryotic cells where is DNA found

in nucleus

what are histone proteins

structural proteins that DNA molecules wrap tightly around because DNA is very long

what is chromatin

a complex of DNA and histone proteins

what are phosphorylated nucleotides

nucelotides that have more than one phosphate group

how many phosphate groups does adenosine diphosphate have

two

how many phosphate groups does adenosine triphosphate have

three

what is dna replication

the process in which DNA makes a copy of itself before cell division

what stage of cell division does dna replication occur

interphase

why does dna have to be replicated

so the daughter cell has the same genetic information

why is dna replication referred to as semi-conservative

made up of one original strand and one newly synthesised strand

what is DNA helicase

an enzyme that catalyses the unwinding and separating of polynucleotide strands

what is DNA polymerase

an enzyme that catalyses the formation of phosphodiester bonds between adjacent nucleotides

what is the function of DNA ligase

catalyses condensation reactions to join the sugar-phosphate backbones of okazaki fragments together