DNA Structure and Function

Study Notes

DNA Structure and Function

DNA, or Deoxyribonucleic Acid, is a molecule carrying life's instructions, composed of nucleotides.
Nucleotides consist of three parts: a phosphate group, a deoxyribose sugar, and a nitrogenous base.
The four nitrogenous bases are Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
A pairs with T (2 hydrogen bonds), and C pairs with G (3 hydrogen bonds).
These base pairings are called complementary base pairings.
DNA is a double helix, forming a twisted ladder shape with the sugar-phosphate backbones as the sides and the base pairs as the rungs.
The bases pair via weak hydrogen bonds, allowing the strands to separate during replication.

DNA's Role in Heredity

Heredity is the passing of traits from parents to offspring.
DNA carries the genetic information for these traits.
DNA is organized into chromosomes, with humans having 46, inherited in 23 pairs from each parent.
Genes are segments of DNA on chromosomes, encoding specific traits.
During reproduction, each parent contributes half their DNA to their offspring.
The DNA sequence determines the proteins produced, ultimately affecting traits like height, eye color, and more.

DNA Replication

DNA replication is the process of creating an exact copy of DNA.
This occurs during the S phase of the cell cycle.
Replication is crucial for:
- Maintaining genetic continuity – ensuring each new cell receives an identical copy.
- Supporting growth, repair, and reproduction – enabling cells to divide, replace old cells, and allow organisms to grow.
- Preventing errors in genetic information – reducing mutations that might alter traits or lead to diseases.

Genetic Code Determination

The sequence of nitrogenous base pairings determines the genetic code.
Specific base sequences form genes, which then code for proteins.
Proteins are vital for traits and functions.

Amoeba Sisters Summary

DNA acts as the blueprint for an organism's traits, inherited during reproduction from parents.
The particular sequence of A, T, C, and G in the DNA determines which proteins are created, and thus what characteristics an organism shows.
DNA replication ensures genetic continuity and assists with cell growth and repair.

Description

This quiz explores the fundamental aspects of DNA, including its structure, the composition of nucleotides, and the importance of base pairings. Additionally, it covers DNA's crucial role in heredity and genetic information transmission. Test your knowledge on these essential biological concepts!