Genetics

Genetic information in cell

Segments of DNA that contain necessary code to make protein

Biochemical material, either RNA or protein resulting from expression of gene

DNA ------> RNA ------>Protein

DNA to RNA through transcription and RNA to Protein through translaction

1. Two strands twisted into a helix

2. Basic unit of DNA structure is a nucleotide

–a 5 carbon sugar - deoxyribose

–a phosphate group

–a nitrogenous base – adenine, guanine, thymine, cytosine

• Nucleotides covalently bond to form a
• sugar-phosphate linkage – the backbone

–each sugar attaches to two phosphates – 5′ carbon and 3′ carbon

DNA strands are complementary

–A pairs with T

–G pairs with C

–Each pair is a “base pair” (bp)

•Template

•Antiparallel

Origin of replication

Semiconservative replication

Replication fork

• 5' -> 3'
• 1. Topoisomerase relieves DNA super coil
• 2. Helocase opens up the DNA structure by breaking hydrogen bonds between complementary base pairs
• 3. DNA polymerase brings in nucleotides complementary 
• 4. DNA polymerase needs help from Primase. OH at 3'. Primase creates a short RNA sequence, called a primer, on a DNA template strand so that DNA polymerase can make a copy of that DNA strand.  
• 5. Ligase facilitates the joining of DNA strands together. Closes gaps
• 6. New strands super coil

are short newly synthesized DNA fragments formed on the lagging strand during the process of DNA replication

•Function: Needed for protein synthesis

•Structure:  Single-stranded

•Bases:

–Adenine (A)  → Uracil (U)

–Guanine (G)  → Cytosine (C)

•Sugar: Ribose

•Phosphate groups

DNA  → RNA

  C  → G

  G  → C

  T  → A

  A  → U

1. Copies the entire chromosome (DNA)


2. Copies from 1 gene (RNA)

to use DNA information to make proteins that control cell activities

1. complementary base sequence of RNA

2. RNA polymerase, RNA nucleotides

•Initiation: Promoter

•Chain elongation

•Termination

to decode nucleic acid

- Translation produces protein

codons - triplets of mRNA that code for specific amino acid

requires ribosome and tRNA

codons per gene: 3

organic molecules that serve as the monomers, or subunits, of nucleic acids like DNA and RNA

Many codons are redundant, meaning that two or more codons can code for the same amino acid

there are many instances in which different codons specify the same amino acid

Ribosome binds to first start codon. F-Met (Methionine)

in prokaryotes transcription & translation occur simultaneously