Exam 2: Ch 10 Flashcards
First to identify DNA
Fredrick Miescher
Who documented patterns of heredity in pea plants?
Johann Gregor Mendel
Structure of DNA
Structure of DNA - in detail
* the sugar phosphate backbones are on the outside of the double helix and purines and pyrimidines form the “rungs” of the DNA helix ladder
* The two DNA strands are anti-parallel to each other
* The direction of each strand is identified by numbering the carbons one through five in each sugar molecule. The 5 end is the one where carbon number five is not bound to another nucleotide; the 3 and is the one where carbon number three is not bound to another nucleotide
The structure of RNA
- made of ribbon nucleotides that are linked to phosphodiester bonds
- contains ribose instead of deoxyribose
- Single stranded
- Has uracil instead of thymine
- C-G
- A-U
Chargaffs Rule
- A=T
- C=G
Three components of deoxyribonucleotide
- five carbon sugar called deoxyribose
- phosphate group
- nitrogenous space
What are sugar phosphate bonds called?
Phosphodiester bonds
Base pairing
takes place between peeing and pyrimidine
* in DNA adenine and thymine are complementary base pairs
* In DNA cytosine and guanine are also complementary base pairs
anti-parallel directions of the DNA double strands
- The two strands of DNA are anti-parallel, meaning they run in opposite directions to each other. This refers to the orientation of the sugar-phosphate backbones of the two strands.
- 5’ to 3’ Direction: One DNA strand runs in the 5’ to 3’ direction, meaning it has a phosphate group attached to the 5’ carbon of the sugar (deoxyribose) and a hydroxyl group attached to the 3’ carbon. This strand is called the “leading strand” during DNA replication.
- 3’ to 5’ Direction: The other DNA strand runs in the 3’ to 5’ direction, with the hydroxyl group at the 3’ carbon and the phosphate group at the 5’ carbon. This strand is the “lagging strand” during DNA replication.
Flow of information - from DNA to RNA to protein
First, DNA is transcribed into RNA through the process of transcription. The RNA is then processed (in eukaryotes), and it is translated into a protein through the process of translation
Transcription
Transcription is the process of copying a segment of DNA into RNA, specifically messenger RNA (mRNA)
* occurs in the nucleus of eukaryotes
* occur occurs in the cytoplasm of prokaryotes
* takes DNA to mRNA
Translation
The process of translation, or protein synthesis, the second part of gene expression, involves the decoding by a ribosome of an mRNA message into a polypeptide product
* Translation is the process by which the mRNA is decoded to build a protein. The ribosome reads the mRNA sequence in sets of three nucleotides (codons), each of which specifies an amino acid.
* occurs in the cytoplasm, specifically at the ribosomes
* the product of translation is that it forms a polypeptide chain
* takes mRNA to a protein
Codons
formed by three nucleotides in mRNA
Anticodons
a three-nucleotide sequence that bonds with an mRNA codon through complementary base pairing, seen in tRNA
Stop codons
UAA, UAG, and UGA (do not code to any amino acids that is why they are stop codons)
Start codons
AUG
Messenger RNA
carries a message from the DNA in the nucleus to the ribosomes in the cytoplasm, indirect protein synthesis
* serves as the intermediary between DNA and the synthesis of protein products during translation
Ribosomal RNA
ensures, protein, alignment of the mRNA, tRNA, and the ribosomes
* a type of stable RNA that is a major constituent of ribosomes. It ensures the proper alignment of the mRNA and the ribosomes during protein synthesis and catalyzes the formation of the peptide bonds between two aligned amino acids during protein synthesis
Transfer RNA
transfers, amino acids, and D codes mRNA, forms, peptide, chain of proteins
* a small type of stable RNA that carries an amino acid to the corresponding site of protein synthesis in the ribosome
Pyrimidines
Cytosine and thymine
Purines
Adenine and guanine
Watson and Crick
propose a double helix structure of DNA
How many codons are there in the genetic code?
64 codons
Griffiths Experiment
aka the “transformation experiments” transform non-pathogenic bacteria strains to pathogenic (mice)
