B1a DNA and RNA Flashcards
What is DNA an abbreviation for?
Deoxyribonucleic acid
What is the abbreviation for ribonucleic acid?
RNA
The picture shows a DNA nucleotide.
Name parts A, B and C
A = Deoxyribose sugar
B = phosphate
C = Nitrogenous base (adenine, guanine cytosine or thymine)
What is the function of DNA?
Information carrying molecule
What is the function of RNA?
Transfers genetic information from DNA to the ribosomes.
Of what do ribosomes consist?
RNA and proteins.
Name the components of a DNA nucleotide.
Deoxyribose
Phosphate
Nitrogenous organic base - guanine, cytosine, adenine or thymine
Name the components of an RNA nucleotide.
Ribose
Phosphate
Nitrogenous organic base - cytosine, guanine, adenine or uracil.
How many carbon atoms are found in deoxyribose and ribose?
5
Name the type of nucleic acid shown in the diagram
RNA
Name the bond that forms between nucleotides.
Phosphodiester bond
Describe the shape of a DNA molecule
Double helix - two polynucleotide chains held together by hydrogen bonds between specific complementary base pairs.
Give the specific complementary base pairs found in DNA.
Guanine and cytosine
Thymine and adenine.
Name the process involved in the replication of DNA
Semi-conservative replication
What is the function of DNA polymerase?
Reduces the activation energy needed to form phosphodiester bonds which causes the joining of adjacent nucleotides.
Describe the process of DNA replication
Unwinding of double helix
Breaking bonds between complementary bases
Catalysed by DNA helicase.
Diffusion of new DNA nucleotides to exposed bases on template strands and base pairing.
Hydrogen bonds form between complementary bases
Formation of phosphodiester bonds between adjacent nucleotides.
Catalysed by DNA polymerase.
Name the enzyme responsible for breaking the hydrogen bonds between the 2 strands of DNA?
DNA helicase
Name the enzyme used to catalyse the production of phosphodiester bonds between DNA nucleotides
DNA polymerase
Why is DNA replication important?
Ensures genetic continuity between generations of cells.
Give differences between DNA in prokaryotes and eukaryotes.
Prokaryotic DNA is shorter than eukaryotic DNA
Prokaryotic DNA is circular and eukaryotic DNA is linear.
Prokaryotic DNA is not associated with proteins, eukaryotic DNA are condensed on histone proteins to form chromosomes.
Describe the DNA found in mitochondria and chloroplasts
Prokaryotic-like
No histones, short and circular.
Give two differences between a DNA and RNA nucleotide.
DNA contains deoxyribose whereas RNA contains ribose.
DNA contains thymine whereas RNA contains uracil.
DNA is a stable molecule because …
Strong phosphodiester bonds hold nucleotides together.
Sugar phosphate backbone protects the base sequence in centre
Lots of hydrogen bonds provide strength
How are the 2 strands of DNA that make up the double helix held together?
Hydrogen bonds between complementary nitrogenous bases
The base sequence on one strand of DNA is TGACTG
What is the sequence on the other strand?
ACTGAC
What is required for DNA replication to take place?
DNA to be copied
Free DNA nucleotides
DNA helicase
DNA polymerase
ATP
What is meant by ‘semi conservative’ DNA replication?
Each new DNA molecule contains an original and new strand of DNA
Name the scientists who confirmed that the semi conservative model of DNA replication was the valid model
Matthew Meselson
Franklin Stahl
