Chromosomes, Genes and DNA Flashcards
Where are genes found?
On chromosomes in nucleus
What do genes produce?
Proteins
Where are proteins produced?
In the cytoplasm
What is the passage from gene to protein?
DNA → RNA → protein
How does DNA in the nucleus differ in appearance?
NAME?
When is the DNA in chromosomes?
When its dividing
How many chromosomes are there in humans?
46
What is chromatin?
DNA in the nucleus
What are the two types of chromatin?
- Heterochromatin
- Euchromatin
What is the more condensed form of chromatin?
Heterochromatin
What shape is DNA?
Double helix
What feature does the double helix of DNA have?
Has a major groove and minor groove
What is the aim of the human genome project?
To find cures for diseases
What do we want to know about the human genome?
What the sequence actually does
What has been found about the functionality of the human genome?
That 70-80% of the human genome has function
What is the smallest unit of DNA packaging?
The nucleosome
What is a nucleosome?
DNA wrapped around a histone core
What is between histones?
Bits of DNA
What are the bits of DNA between histones called?
Linker DNA of nucleoosme
What do the histone cores consist of?
Lots of protein
What can happen if the protein complexes in histone cores go wrong?
Can result in disease
Is DNA flexible or rigid?
Flexible
Where can DNA flex?
In the minor groove
What is the result of the flexibility of DNA?
It can wrap around the histone core twice
How are nucleosomes further packaged?
Into solenoids
What is heterochromatin made up of?
Solenoids
Are genes expressed in heterochromatin?
No
Why are genes not expressed in heterochromatin?
Because they are too tightly bound to access
How does euchromatin differ from heterochromatin?
It has a different density, and so the genes are expresseed
What do solenoid loops form?
Chromatids of chromosomes
What are the chromatids called?
NAME?
Are genes expressed in chromosomes?
No
Why are genes not expressed in chromosomes?
Because the DNA is so tightly wound to get into package that it can’t be
What to genes carry?
The code for protein