Gentics 1

What did Avery, MacLeod, and McCarty demonstrate?

Transformation cannot occur unless DNA is present, proving DNA is the hereditary material.

What did the Hershey-Chase experiment reveal?

Only DNA entered bacteria, confirming that DNA carries viral genetic information.

What are the components of DNA?

Nitrogenous bases (A, T, G, C), deoxyribose sugar, and a phosphate group.

What is the difference between a nucleoside and a nucleotide?

A nucleoside is a nitrogenous base plus sugar; a nucleotide is a nucleoside plus a phosphate.

What are the two major classes of nucleic acids?

DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid).

What is the primary function of DNA?

Genetic storage, replication, and necessary for growth and reproduction.

What is the primary structure of nucleic acids?

The linear sequence of nucleotides defined by the order of bases.

What is the secondary structure of DNA?

A double helix formed by complementary base pairing and stabilized by hydrogen bonds.

What is Chargaff's Rule?

In DNA, %A = %T and %G = %C; total purines equal total pyrimidines.

What are the types of nitrogenous bases?

Purines (Adenine, Guanine) and Pyrimidines (Cytosine, Thymine, Uracil in RNA).

What is the sugar-phosphate backbone of DNA?

Formed by nucleotides joined via 3'-5' phosphodiester bonds, providing directionality.

What does it mean that DNA is antiparallel?

One strand runs 5'→3' while the complementary strand runs 3'→5'.

What are the forms of DNA?

A-Form (compact), B-Form (most common), and Z-Form (left-handed zig-zag structure).

What is a gene?

A DNA sequence that encodes a functional product (protein or RNA).

What is a genome?

The complete DNA content of an organism, including all its genes.

What is the difference between genotype and phenotype?

Genotype is the genetic constitution; phenotype is the observable characteristics.

What is a mutation?

A permanent change in the DNA sequence.

What are point mutations?

Substitution, insertion, or deletion of nucleotides in the DNA sequence.

What is a frameshift mutation?

A mutation caused by insertion or deletion that alters the reading frame of the gene.

Are all mutations harmful?

No, some mutations are neutral or beneficial and can be a source of evolution.

What is the role of mRNA?

Messenger RNA carries genetic code from DNA to ribosomes for protein synthesis.

What is the function of tRNA?

Transfer RNA brings amino acids to the ribosome during protein synthesis.

What is the role of rRNA?

Ribosomal RNA forms the core of the ribosome and catalyzes protein synthesis.

What is the significance of Rosalind Franklin's Photo 51?

Provided crucial X-ray diffraction evidence for the double helix structure of DNA.

What stabilizes the secondary structure of RNA?

Folding back on itself to form structures like hairpins and stem-loops.