Genes & Chromosomes Flashcards
What does DNA stand for
Deoxyribonucleic acid
Packed inside the nucleus of every human cell is nearly 6 feet of what?
DNA
What structure is the DNA in the nucleus
Double helix
What does the nucleuic DNA structure coil around
Proteins called his tones
How is DNA organised
Dense, string like fibres called CHROMATIN
What happens to chromatin just before cellular division
Subdivides further into 46 individual molecules called chromosomes
There is a set number of chromosomes per species
A dog has 78
Mosquito 6
Rat 42
How many pairs in HUMAN SOMATIC CELLS
23
The 23rd pair of chromosomes in human somatic cells determine the gender
What are they?
XX female
Xy male
Y chromosome is much smaller than x
What can lead to some sex-linked, genetic diseases in males eg Haemophilia
If there is a genetic disease on the single X chromosome the y cannot counteract it
There are many thousands of subunits (portions of DNA) on the chromosomes. What are they called
Genes
A gene holds what info
Info to build and maintain cells
Pass on genetic traits to offspring
How many genes may be stored/encoded in one or more chromosomes
Thousands
All body cells (somatic cells) contain the full what
GENOME
the full set of genes
What is the hypothesis that one gene equals?
One protein
The recipe to make 1 protein
Are all the genes working in every cell
Only certain genes are switched on depending on the cells job
