Chromosomes, Genes And DNA Flashcards
Chromosome
Are long strands of genetic information located in the nuclei of cells
Human characteristics and chromosomes
In all living things, characteristics are passed on the chromosomes that offspring inherit from their parents
All human characteristic therefore have something to do with chromosomes
Cell division
When chromosomes replicate
They are most visible during cell division
Homologous series
Matching chromosome pairs. One of each pair is from your mother and the other from your father
Chromosomes in cells
Most human body cells contain 46 chromosomes (26 pairs of homologous chromosomes)
Genes(units)
Genes are the units of heritance
Chromosomes and genes
Chromosomes and their genes are made of a molecule called DNA.
Each chromosome is a very long molecule of tightly coiled DNA
DNA
DNA stands for deoxyribonucleic acid
DNA molecules carry the code that controls what cells are made of and what they do
DNA molecule structure
Double helix
DNA structure
It is composed of 2 backbones made of sugar(deoxyribose) and phosphates that spiral each other. The 2 back bones are held together by the base pairs
The base pairing rule
“A” always pairs with “T”
“C always pairs with “G”
Name of base pairs
> adenine
guanine
cytosine
thymine
Genetic code
There are million of base pairs in each DNA molecule and in the order of the bases form the genetic code
Protein
Made of long chains of amino acids
There are 20 different types of Amino acids which make up proteins
Proteins and the body
Proteins control every process in the body (enzymes) give colour to hair, eyes and skin and also form structures like tendons and muscle and hair
Genetic code
The code uses groups of three bases to code for a single amino acid- known as triplets
When did Ervin Chargaff discover his discovery?
1950
What method did Erwin Chargaff use?
Chromatography
Erwin Chargaff
He determined that the amount of A=T and and the amount of G=C (base painting rule)
When did Maurice Wilkins and Rosalind Franklin discover their discovery?
1952
What technique did Wilkins and Franklin use?
X-ray crystallography
What did Wilkins and Franklin discover?
Worked out the DNA was a double helix shape
When did james Watson and Francis Crick discover their discovery?
1953
What did Watson and Crick discover?
How all parts of the molecule were held together
How did Watson and Crick discover their discovery?
Using model making
The sugar, phosphates and bases were cut out of sheet metal and clamped together with retort stands, boss head and clamps
