Biology Flashcards

DNA and Genetic Information

• DNA is a self-replicating molecule found in all living organisms, key to genetic information.
• Genes are units of heredity that determine traits passed from parents to offspring.
• The structure of DNA is a double helix, comprising two intertwined helices.

Molecular Components and Processes

• Nucleotides are the basic units of nucleic acids, composed of a nucleoside and a phosphate group.
• Deoxyribose is the sugar component of DNA, modified from ribose.
• Nitrogen bases are critical for DNA and RNA structure, including adenine, guanine, cytosine, thymine, and uracil.

Key Biological Processes

• Replication is the process of copying DNA before cell division.
• Transcription is the first step in gene expression, where DNA is copied to RNA by RNA polymerase.
• Translation involves ribosomes converting mRNA into proteins, following the genetic instructions.

Structure and Function

• Hydrogen bonds connect nitrogen bases, maintaining DNA's double helix structure.
• The nucleus houses DNA and is vital for cellular functions and growth.
• Ribosomes are responsible for polypeptide synthesis, linking amino acids as dictated by mRNA.

Cell Division and Genetic Variability

• Cell division results in two daughter cells with identical genetic material.
• Interphase is the phase of preparation for cell division between mitotic cycles.
• Mutations, including substitutions, insertions, and frameshift mutations, contribute to genetic diversity and evolution.

Codons and Translation Mechanism

• Codons consist of three nucleotides, coding for specific amino acids in protein synthesis.
• Anticodons in tRNA match codons in mRNA, ensuring correct protein assembly.
• The start codon (AUG) signals the beginning of translation, while stop codons (UAG, UAA, UGA) terminate protein synthesis.

Cellular Organelles

• The Golgi apparatus processes and transports proteins and lipids within cells.
• The endoplasmic reticulum is a network of membranes involved in lipid and protein synthesis, usually ribosome-studded.

Chargaff's Rule

• Chargaff's rule establishes that DNA must maintain a 1:1 ratio of purines (adenine and guanine) to pyrimidines (cytosine and thymine).

Antiparallel Structure

• DNA strands run in opposite directions (antiparallel), which is essential for replication and transcription fidelity.

Test your knowledge with these Biology flashcards focused on essential terms like DNA, genes, and the nucleus. Each card provides definitions to help reinforce your understanding of key concepts in genetics and cellular biology.