DNA: THE CODE OF LIFE Flashcards
What are nucleic acids?
Molecules that have the capacity to store the information that controls cellular activity
what are the two types of nucleotides
- Deoxyribonucleic acid (DNA)
- Ribonucleic acid (RNA)
What are the functions of nucleic acids and how do they perform these functions
They control the specialisation of cells to form tissues and the arrangement of tissues into organs. They do this by controlling the synthesis of proteins
where is DNA found
mainly in the nucleus of a cell where is forms an import part of chromosomes that make up the chromatin network
Some DNA is found in the mitochondria of plants and animals and the chloroplast in plant- this is called extranuclear DNA
What are chromosomes
long thread-like structures made up of a strand of DNA wound around a protein called histones
Why are DNA molecules coiled
They are coiled so that the long structure can fit inside the nucleus
how do chromosomes occur in body cells
In body (somatic) cells chromosomes occur in homologous pairs. The chromosomes of a homologous pair are the same size and shape and have the same genes on the same place and with the centromere at the same place
What is a nucleosome
A nucleosome is a basic unit of DNA packaging in eukaryotes, consisting of a segment of DNA wound in sequence around eight histone protein cores
what are genes
sections of DNA molecules that control hereditary characteristics ( they are the basic units of heredity in living organisms)
Who discovered the structure of the DNA molecule
James Watson and Francis Crick (1953). They analyzed the x-ray collected by Maurice Wilkins and Rosalind Franklin and others. They then build a model and realized that nucleic acids are arranged on a twisted ladder, with two runners made of phosphates and sugars and a series of rungs made of pairs of organic compounds known as bases.
Who won the noble prize?
Watson, Crick and Wilkins won he Nobel prize for physiology /medicine, Franklin had died
What is the structure of DNA
3-dimensional double helix
What are nucleotides
The double-stranded DNA molecule is made up of repeating units, building blocks (monomers) called nucleotides linked together to form log nucleic acid chains, (polymers)
Name the parts of nucleotides
- Sugar molecule -deoxyribose (S)
- phosphate molecule (P)
- nitrogenous base which may be
- adenine (A)
- thymine (T)
- guanine (G)
- cytosine (C)
