Lecture 3 Flashcards
What’s the ratio of RNA and DNA in our body?
- 1% RNA and 0.1% DNA.
What are the features of Eukaryotic?
1-Human, plan and animal cells.
2-Store DNA mainly in the nucleus, additionally mitochondria and chloroplasts (only plants).
What are the features of Prokaryotic cells ?
1-Bacteria
2-Stores the DNA in nucleoid and also in small circular pieces called plasmids.
3-Horizontal gene transfer.
What is a DNA structure?
1- A nucleotide:
- Phosphate part with different bases.
-Sugar with phosphate group
- 4 types of bases:
-Adenine (A)
- Cytosine (C)
-Guanine (G)
- Thymine (T)
2-Nucleotides are put in polynucleotides.
3- The phosphodiester links nucleotides together.
What is the base pairing between two strands A.T-G.C ?
Hydrogen bonding
What is the difference between nucleoid and nucleus.
The nucleoid is the area in procaryotic cells where the genetic information is.
The nucleus holds the genetic information in eukoryatic cells.
Why does scientists take so long to figure out where does our DNA lay?
Because the prime subject was proteins and scientists thought proteins are complicated enough and they should also contain the DNA.
What is the discovery of the double helix?
1- Rosalin Frankin made photo 51, and in that picture, she figured out that DNA is a double helix.
3- Scientists figured that proteins are just the DOERS not the brain of the system.
What is the central dogma of molecular biology?
1-Explanation of the flow of genetic information within a biological system. (Francis crick)
2-3 steps of DNA were discovered: Replication, Transcription, translation
During DNA replication why is the lagging strand done by fragments?
Because 5 side of the strand isn’t open yet.
Transcription
process where a gene’s DNA sequence is copied into messanger RNA so the cell can use it to make a protein.
How does Transcription work?
There are regions in the DNA that promote or suppress the RNA polymerase. So these regions function as signals to get more (or less) of an RNA - and consequently- of a protein.
Differences between DNA nad RNA?
1- Deoxyribose versus ribose
2-Thymine versus Uracil
3-Double-stranded versus single-stranded
4- RNA molecules are shorter than DNA molecules.
5-DNA is more stable
6-RNA lifespan is really short
What are types of RNA’s
1-Coding RNA: transcripts of protein-coding genes will be translated into protein. Only 4%of RNA.
2-Non-coding RNA: number of different functions performed by RNA molecule itself. ex: transfer RNA and ribosomal RNA.
Important ones: mRNA, rRNA, tRNA
What is the translation process?
From mRNA to protein.
What is a practical consequence of this redundancy in genetic code?
It helps protect against mutations.
- Since multiple codons can code for the same amino acid, some mutations (changes in the DNA sequence) do not affect the final protein.
What’s the role of chromosome?
1-Transition of genetic code, helps with organization.
2-Makes the genetic code compact
3- DNA is exteremely long if it streched it woud be aroun 2ms.
What are sources of variations?
1-Mutations
2-Meiotic crossover ( breaks apart traits (black hair,colored eyes)
3-Germ cells are numerous.
4-Epigenetics
5-Expression of gene is time and tissue dependent
Omics
1-The study of all genomics, all genetic variation in genetics
2-All steps involving DNA are influenced by enviroment.
