Nucleic Acids and Protein Synthesis Flashcards
What is a nucleotide?
a nucleotide is the monomer that makes up nucleic acids, made of a pentose sugar, a phosphate group, and a nitrogen base
What is the structure of the nucleotide ATP?
adenine + 3 phosphates
What is the structure of an RNA nucleotide?
ribose sugar, phosphate, and adenine, guanine, cytosine, or uracil
What is the structure of a DNA nucleotide?
deoxyribose sugar, phosphate, and adenine, guanine, cytosine, thymine
What are the nitrogen bases?
adenine, guanine, cytosine, thymine, uracil
What are purines?
adenine, guanine
What are pyrimidines?
cytosine, thymine, uracil
What is base pairing?
hydrogen bonding between nitrogen bases
What is the structure of purines?
double ring structure
What is the structure of pyrimidines?
single ring structure
What is the type of replication by which DNA replicates?
semi-conservative replication
What is the process of DNA replication?
double helix unwinds, hydrogen bonds between complementary bases break, free nucleotides attach to their complementary bases on the template strand, adjacent phosphodiester bonds are formed by DNA polymerase
What is a gene?
code for a polypeptide made of nucleotides on part of dna
What is a gene mutation?
a change in the base sequence of a DNA molecule, which replicates
What is the nucleotide sequence that causes the different alleles of B globin causing sickle cell anaemia?
cat instead of ctt, coded by the Hbs allele of the gene, two copies of the Hbs allele result in sickle cell anaemia
How are polypeptides made?
transcription and translation
How do nucleotides join?
by forming phosphodiester bonds in condensation reactions
What is the structure of a DNA molecule?
double helix, two polynucleotides joined by hydrogen bonding between complementary bases, 3’ and 5’ ends
What are gene mutations caused by?
mutagenic agents such as chemicals and radiation
What is transcription?
in transcription, mRNA is made in the nucleus
DNA uncoils, free nucleotides pair with the antisense strand, forming mRNA, which moves out of the nucleus through a nuclear pore
What is translation?
in translation, mRNA attaches to a ribosome in the cytoplasm, tRNA, carrying an amino acid on one end, attaches its anticodon to the first codon on mRNA, another tRNA binds to the second codon, the amino acids join by peptidyl transferase and the tRNA leave, the process is repeated until a stop codon in reached.
Why is base pairing important?
complementary base pairing allows exact replication of DNA, which allows semi-conservative replication and ensures genetic continuity
How do nucleotides code for amino acid sequences?
each group of three nucleotides (a codon), codes for one amino acid, which decides the sequences of amino acids in a polypeptide
