Molecular Genetics Flashcards
Studying for biology 30 Molecular Genetics Unit Test (33 cards)
What is the structure of DNA?
A double helix made of nucleotides, each containing a phosphate group, deoxyribose sugar, and a nitrogenous base (A, T, C, G).
What are the base-pairing rules in DNA?
A pairs with T, and C pairs with G.
What is RNA?
RNA (Ribonucleic Acid) is a single-stranded nucleic acid that helps in protein synthesis.
How does RNA differ from DNA?
RNA has ribose sugar instead of deoxyribose, is single-stranded, and uses uracil (U) instead of thymine (T).
What are the three types of RNA and their functions?
mRNA (Messenger RNA) – Carries genetic code from DNA to ribosomes.
tRNA (Transfer RNA) – Brings amino acids to the ribosome.
rRNA (Ribosomal RNA) – Makes up ribosomes.
When does DNA replication occur?
During the S-phase of the cell cycle before cell division.
What enzyme unwinds the DNA helix?
Helicase.
What enzyme adds new nucleotides during replication?
DNA polymerase.
What is the difference between the leading and lagging strand?
The leading strand is synthesized continuously, while the lagging strand is synthesized in short Okazaki fragments.
What enzyme joins Okazaki fragments?
DNA ligase.
What is transcription?
The process of converting DNA into mRNA.
What enzyme carries out transcription?
RNA polymerase.
Where does transcription occur?
In the nucleus.
What is translation?
The process of decoding mRNA into a protein.
Where does translation occur?
At the ribosome in the cytoplasm.
What are codons?
Sequences of three nucleotides in mRNA that code for specific amino acids.
What are the three stop codons?
UAA, UAG, UGA
What are the two binding sites on tRNA?
Anticodon site – Matches the mRNA codon.
Amino acid attachment site – Carries the corresponding amino acid.
What is a mutation?
A change in the DNA sequence.
What are the two main types of mutations?
Point mutations – Affect a single base.
Frameshift mutations – Shift the reading frame by inserting or deleting bases.
What are three types of point mutations?
Silent Mutation – No change in amino acid.
Missense Mutation – Changes one amino acid.
Nonsense Mutation – Creates a stop codon.
How can mutations be caused?
Radiation, chemicals, replication errors.
What are the effects of mutations?
They can be beneficial, harmful, or neutral.
What is biotechnology?
the use of living organisms or DNA manipulation for practical applications.
