2.3 Nucleic acids Flashcards
What are nucleotides?
Monomers of nucleic acids, DNA and RNA.
What is the sugar in RNA?
ribose pentose sugar
What is the sugar in DNA?
deoxyribose pentose sugar
What is a nucleotide called when it has more than one phosphate group?
Phosphorylated
What are 2 examples of phosphorylated nucleotides?
ADP (adenosine diphosphate) and ATP (adenosine triphosphate). ATP is an energy-rich end-product of most energy releasing biochemical pathways and drives most energy-requiring metabolic pathways.
What role do nucleotides play in NADP?
Nucleotides are found in the coenzyme NADP (nicotinamide adenine dinucleotide phosphate) which is used during photosynthesis.
What other coenzymes contain nucleotides?
NAD and FAD, used in respiration
What are the 4 DNA nitrogenous bases?
T - Thymine
A - Adenine
C - Cytosine
G - Guanine
What does the structure of a nucleotide look like?
Refer to textbook (page 86)
A nitrogenous base is attached to the pentose sugar at Carbon 1 and a phosphate molecule attached at either carbon 3 or carbon 5
idk how to word this but DNA is a macromolecule in all living organisms
sorry
What is the overall structure of DNA?
DNA is made up of repeating monomeric units in 2 polynucleotide chains
What is it called when the 2 polynucleotide chains run in opposite directions?
antiparallel
What is the covalent bond between the sugar residue and the phosphate group called?
phosphodiester bond
Which bases are purine bases?
Adenine and Guanine
What are purine bases?
Bases with only one ring
What are pyrimidine bases?
Bases with two rings
Which bases are pyrimidine bases?
Thymine and Cytosine
How many hydrogen bonds are there between Adenine and Thymine?
2 hydrogen bonds
How many hydrogen bonds are there between Cytosine and Guanine?
3 hydrogen bonds
Why are the hydrogen bonds between bases useful?
They can unzip for transcription and replication
What does a 5’ (5 prime) chain mean?
The phosphate group is attached to the 5th carbon of the deoxyribose sugar.
What does a 3’ (3 prime) chain mean?
The phosphate group is attached to the 3rd carbon of the deoxyribose sugar.
How does DNA exist within eukaryotic cells?
- in the nucleus
- wraps around histone proteins
- one loop of DNA does not have histone proteins
How does DNA exist within prokaryotic cells?
- DNA is a loop in the cytoplasm (no nucleus)
- not wound around histone proteins (aka naked)
What is the process of semi-conservative replication?
- unwinds (gyrase enzyme)
- unzips (DNA helicase)
- free phosphorylase bases attach to exposed bases
- DNA polymerase catalyzes
- leading strand synthesized continuously, lagging strand discontinuously
Why is it called semi-conservative replication?
One strand of OG DNA is kept within each new helix of DNA.
How often do mutations occur?
every 1 in 10^8. Certain enzymes can proofread and limit mutations, however not all mutations are harmful.
How is RNA different to DNA?
sugar molecule is called ribose sugar
nitrogenous pyrimidine base uracil replaces thymine
polynucleotide is often single stranded
polynucleotide chain is shorter
mRNA (messenger), tRNA (transfer), rRNA (ribosomal)
What are examples for need of specific genetic code?
enzymes need a specific active site
antibodies need a complementary shape to the pathogen
Why is tRNA (messenger) needed?
DNA code cannot pass through the nucleus
Why is genetic code referred to as universal?
In almost all living things, a DNA codon codes for the same amino acids
Why is genetic code referred to as degenerate?
For most amino acids, except methionine and tryptophan, a change in the base triplet can still code for the same amino acid
Why is genetic code referred to as non-overlapping?
The genetic code is only ever read from a fixed point.
What are ribosomes made of?
Ribosomal RNA and proteins in almsot equal parts
What is tRNA (transfer)?
Made in the nucleolus, they are single stranded polynucleotides which can twist into a hairpin shape. It has an anticodon at one end which is complementary to the codon on the mRNA.
What do ribosomes do?
They catalyse the formation of polypeptides
What energy is needed during protein synthesis?
ATP
How does the polypeptide form its 3D shape?
chaperone proteins in the cell help form its shape into a tertiary structure.
