PRMS 8th Grade Science - DNA Flashcards

Chromosomes and DNA Structure

• Chromosomes consist of DNA and proteins, forming the genetic material within cells.
• The full name of DNA is Deoxyribonucleic Acid; its structure resembles a twisted ladder or double helix.
• DNA is made from repeating units called nucleotides, which include a nitrogen base, a sugar (deoxyribose), and a phosphate group.
• The "backbone" of a DNA molecule is composed of alternating sugar and phosphate units.
• There are four nitrogen bases in DNA: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).

Nucleotide Information

• A nucleotide includes three components: a nitrogen base, a sugar, and a phosphate group.
• Nitrogen bases bond in specific pairs: Adenine pairs with Thymine, and Guanine pairs with Cytosine, following the "Base-Pair Rule."
• The sequence of nitrogen bases in DNA encodes genetic information necessary for building proteins.

RNA Characteristics

• RNA, or Ribonucleic Acid, differs from DNA by being single-stranded and containing Uracil (U) instead of Thymine (T).
• RNA is found mainly in the nucleus and acts as a messenger, relaying instructions from DNA to ribosomes for protein synthesis.

Key Scientists and Discoveries

• The double helix structure of DNA was identified by James Watson and Francis Crick, with contributions from Rosalind Franklin and Maurice Wilkins.
• Friedrich Miescher was the first to discover nucleic acids, laying groundwork for DNA research.

Genes and Proteins

• A gene is a specific segment of DNA that codes for a particular protein, influencing various traits.
• Proteins serve as the building blocks of organisms and are produced based on the instructions encoded in DNA.
• Some regions of DNA that do not code for proteins are referred to as introns or "junk DNA," while coding segments are called exons.

DNA Replication and Function

• DNA replicates during Interphase through a process of making exact copies to ensure new cells inherit accurate genetic information.
• The nucleus functions as the control center of the cell, managing activities through the genetic instructions contained in DNA.
• Cells can block the expression of certain genes, allowing different cell types (e.g., brain cells, skin cells) to develop despite having identical DNA.

Overall Significance

• DNA is described as the "Blueprint of Life" due to its role in defining how organisms develop and function.
• Understanding DNA and RNA functionality is crucial for studying genetics, heredity, and biological processes.