dna structure Flashcards
. DNA Definition
DNA is a nucleic acid that stores genetic information and controls cellular activities, including protein synthesis.
DNA Structure
DNA consists of nucleotides, which have three components: phosphate group, deoxyribose sugar, and nitrogenous base.
Nucleotide Components
Nucleotides are made up of a phosphate group, deoxyribose sugar, and one of four nitrogenous bases (adenine, thymine, guanine, cytosine).
Complementary Base Pairing
Adenine (A) pairs with Thymine (T), and Guanine (G) pairs with Cytosine (C) through weak hydrogen bonds.
Double Helix
DNA has a double helix structure, where two strands of nucleotides wind around each other. Discovered by Watson and Crick.
Chromosomes
DNA is organized into chromosomes, which are condensed structures containing genes. Humans have 46 chromosomes (23 pairs).
Chromatin Network
DNA exists in a less condensed form as chromatin in the cell nucleus, except during cell division or replication.
Genes
Genes are segments of DNA that code for proteins and are the units of hereditary information.
Sugar-Phosphate Backbone
The phosphate groups and deoxyribose sugars form the backbone of DNA, connecting the nucleotides.
Purines and Pyrimidines
Adenine and Guanine are purine bases with double rings, while Thymine and Cytosine are pyrimidine bases with single rings.
DNA Replication
DNA replication is the process of copying DNA, ensuring genetic information is passed to daughter cells during cell division.
Hereditary Information
DNA carries hereditary information in genes, influencing an organism’s traits and characteristics.
Protein Synthesis
DNA provides instructions for protein synthesis, vital for growth, development, and cellular functions.
Complementary Base Pairing
Adenine pairs with Thymine, and Guanine pairs with Cytosine through hydrogen bonds, ensuring accurate DNA replication and transcription.
DNA Shape
The DNA molecule has a double helix structure with complementary base pairs forming rungs, discovered by Watson and Crick.