DNA Structure & Function
What is the basic building block of DNA?
Nucleotide.
What is the main difference between RNA and DNA?
RNA is single-stranded and contains the sugar ribose, whereas DNA is double-stranded and contains the sugar deoxyribose.
What is a mutation?
A mutation is a change in the DNA sequence that can lead to a different genetic trait or function.
What is genetic recombination, and when does it occur in meiosis?
Genetic recombination is the process where homologous chromosomes exchange genetic material, and it occurs during Prophase I of meiosis.
What is the structure that holds two sister chromatids together during cell division?
Centromere.
What are the four nitrogenous bases found in DNA?
Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
Which type of RNA carries the genetic instructions from DNA to the ribosome for protein synthesis?
Messenger RNA (mRNA).
What type of mutation occurs when a single nucleotide is replaced with another?
Point mutation.
What structure is responsible for holding homologous chromosomes together during crossing over in meiosis?
The synaptonemal complex.
During which phase of the cell cycle do chromosomes replicate to form sister chromatids?
S phase (Synthesis phase).
Which nitrogenous bases pair together in the double helix structure of DNA?
Adenine pairs with Thymine, and Cytosine pairs with Guanine.
What process involves copying a segment of DNA into mRNA?
Transcription.
What is a frameshift mutation, and how does it affect protein synthesis?
A frameshift mutation occurs when nucleotides are inserted or deleted, changing the reading frame of the genetic code, which can lead to a completely different protein.
What is the role of the enzyme DNA polymerase in DNA repair?
DNA polymerase helps to fix mistakes in the DNA sequence during replication and can also fill in gaps during DNA repair.
What term describes the process by which a single eukaryotic cell divides into two identical daughter cells?
Mitosis.
What is the shape of the DNA molecule?
A double helix.
What is the name of the process in which mRNA is translated into a specific sequence of amino acids to form a protein?
Translation.
What is the term for genetic variation that arises due to the random assortment of alleles during meiosis?
Genetic recombination.
Which DNA repair mechanism is responsible for correcting errors that occur during DNA replication, such as mismatched bases?
Mismatch repair.
What is the name of the phase in meiosis where homologous chromosomes are separated into different cells?
Anaphase I.
What is the function of DNA in cells?
DNA stores and transmits genetic information that is used for the synthesis of proteins and the regulation of cellular activities.
What role do ribosomes play in protein synthesis?
Ribosomes facilitate the translation process by reading mRNA and assembling amino acids into a polypeptide chain (protein).
How can mutations contribute to evolutionary change?
Mutations introduce genetic variation, which, if advantageous, can be passed on to future generations through natural selection, driving evolutionary change.
What is the function of the enzyme ligase in DNA repair and recombination?
DNA ligase seals breaks in the DNA backbone by joining the sugar-phosphate backbones of adjacent nucleotides, completing the repair or recombination process.
How is meiosis different from mitosis in terms of the number of chromosome sets in the daughter cells?
Meiosis reduces the chromosome number by half, producing haploid cells (gametes), while mitosis produces diploid daughter cells with the same chromosome number as the parent cell.