1B | More Biological Molecules Flashcards
Outline the function of DNA.
DNA is used to store genetic information - that’s all the instructions an organism needs to grow and develop from a fertilized egg to a fully grown adult.
Give one function of RNA.
One of the RNA’s main functions is to transfer genetic information from the DNA to the ribosomes, wherein polypeptides are made.
Find A,B and C:
https://media.discordapp.net/attachments/352951793187029005/812073655928225842/unknown.png
What is this molecule called?
A = Phosphate group B = Pentose sugar C = Nitrogenous base
Nucleotide
What are the monomers of DNA and RNA?
Nucleotide
What is the sugar in DNA called?
Deoxyribose
What is the sugar in RNA called?
Ribose
List the four bases of DNA.
Guanine
Cytosine
Thymine
Adenine
List the four bases in RNA.
Guanine
Cytosine
Uracil
Adenine
What is a sugar-phosphate backbone?
The sugar-phosphate backbone is a chain of phosphates connected to nucleotides’ pentose sugars.
In what reaction do nucleotides join together?
Condensation reaction
Name B to G:
https://media.discordapp.net/attachments/440608931182673931/812106149150326794/unknown.png
Name this structure.
B = Phosphodiester bond C = Phosphodiester bond D = Base E = Base F = Phosphate Group G = Pentose Sugar
Sugar-phosphate backbone
What is a phosphodiester bond?
A phosphodiester bond is a bond between two sugar groups and a phosphate group.
How many polynucleotide chains are there in DNA?
Two
How many hydrogen bonds are formed between Cytosine and Guanine?
Three
How many hydrogen bonds are formed between Adenine and Thymine?
Two
Adenine is complementary to…
Thymine
Guanine is complementary to…
Cytosine
In a DNA molecule, 20% of the bases are Adenine.
Calculate the percentage of bases which are Thymine.
Calculate the percentage of bases which are Guanine.
Thymine = 20%
This is because it is complementary to Adenine, so it must be a equal percentage.
G and C are the same and must be the same amount as the 2 remaining between the remaining 60%.
60 / 2 = 30
Guanine = 30%
Pick the right word:
In a DNA molecule, the polynucleotide strands are (parallel/antiparallel)
Antiparallel
How many polynucleotide chains are made of RNA?
One
DNA replication is described as semi-conservative.
What does semi-conservative mean in this context?
Semi-conservative replication refers to the fact that half of the new strands in each new DNA molecule are from the original DNA molecule.
Describe the process of semi-conservative DNA replication.
Firstly, DNA helicase, an enzyme, will enter the double stranded molecule of DNA.
DNA helicase separates the two strands in DNA by breaking the hydrogen bonds between the complementary bases.
This makes the helix begin to unwind in order to form two single strands.
Each original single strand acts as a template for a new strand, and so as DNA Helicase goes down the molecule, free-floating bases in the cytoplasm become attracted to the newly exposed bases on the single strands.
Two DNA polymerases, which are both enzymes, start to go down the single strands of exposed DNA and begin to join the complementary, attracted bases to each other by condensation reactions.
This creates two new strands of DNA, each combined with one template strand.
As a result of this, each new DNA molecule has a strand from the original DNA and one new strand.
In a DNA molecule, one polynucleotide strand has a 5’ end at the top and a 3’ end at the bottom.
For the second polynucleotide chain, where would the 5’ and 3’ ends be located?
5’ would be at the bottom
3’ would be at the top
This is due to the fact that polynucleotide chains in DNA are antiparallel.
Two DNA polymerases work on different polynucleotide chains.
DNA polymerase moves from the 3’ end to the 5’ end.
Polynucleotide chain 1 in the DNA has a 3’ end at the top.
Describe what direction (Up or down) DNA polymerase will be going in Polynucleotide chain 1 & 2.
Since DNA polymerase moves from the 3’ end to the 5’ end, this means that DNA polymerase begins at the top of Polynucleotide chain 1 and goes down.
Polynucleotide chain 1 = down
Polynucleotide chains are antiparallel. This means Polynucleotide chain 2 must have a 5’ end at the top and a 3’ end at the bottom.
This means that DNA polymerase starts from the bottom and goes up.
Polynucleotide chain 2 = up