This presentation on essential genetic terms has been made for the 1st year medical undergraduates. This is expected to create a better understanding about genome, gene, DNA, chromosome, chromatin and nucleosome.
2. Complete set of genetic
information
needed
to build and maintain that organism
Genome
1
3. Genome contd…
1. How many chromosomes are there in a complete set of DNA?
23 pairs
2. How many genes are there in the whole genome?
23000
3. Do all cells contain same genome?
Yes, all cells, having nucleus
6. Gene contd…
1. Do genes include only those portion DNA that codes for protein?
No, coding and non coding both are part of genes.
2. Does a single gene always give rise to single protein?
No, single gene give rise to many proteins.
3. How many base pairs does one gene contain?
Few hundred to more than 2 million base pairs
7. Deoxyribonucleic acid is the
hereditary material.
The information stored as a code
made up of four chemical bases
DNA
3
9. DNA contd…
1. Is there any DNA outside nucleus?
Some enzymes and protein needed by mitochondria are produced by
mitochondrial DNA.
2. How identical is DNA of two individual human being?
Almost 99 percent identical
3. What is the number of DNA in a cell?
Each chromosome contains one DNA molecule, if DNA is not
replicated as a preparation for cell division.
4. Does amount of DNA always correspond to the number of chromosome?
Negative
10.
11.
12. DNA molecule packaged into
thread-like structures
visible under a microscope during cell division
Chromosome
4
15. Chromatin contd…
What is euchromatin and heterochromatin?
2 different state of chromatin
Euchromatin- uncoiled, active
Heterochromatin- coiled, inactive
16. Basic unit structure of chromatin
Composed of an octamer of histone proteins
140 base pairs of DNA (approx)
Nucleosome
6
17. Nucleosome contd…
Does nucleosome remain in linear form?
No, it remains as cluster by binding of linker DNA
and other histone protein.
