Chapter 2: Molecular Biology Test review

What are the steps for the cell cycle

1. Interphase

   1. G1: Cell growth

   2. S: Synthesis

   3. G2: More growth, preparation for mitosis

2. Mitosis

   1. Pro

List Biological tools

1. Restriction Endonucleases

2. DNA Ligase

3. Gel Electrophoresis

4. Plasmids

5. Transformation

Restriction Endonucleases?

• DNA Cutting Enzymes

• Cut at highly specific DNA Sequences

Recombinant DNA?

DNA made from pieces of other organisms

Transgene?

A gene transplanted from one organism into another organisms DNA

Transgenic Organism

Organism that receives a transplanted gene

Steps for Gene Cloning

1. Isolation:

   1. Plasmid needs to be isolated

2. Cutting

   1. Using REN two types of cuts are made

      1. Blunt end (not wanted)

      2. Staggard end (wanted)

3. Prepping transgene

   1. Has to match the cut made to the host

4. Attachment

   1. RNA Recombination + DNA Ligase used to bind the transgene and the plasmid together

mRNA

Messenger RNA
Contains codons for protein synthesis

tRNA?

Adapter for amino acids and mRNA

rRNA

Composes ribosomes

What does the stop codon do?

• UAA, UAG, UGA

• Stops the tRNA from creating amino acids

What does the Start codon do?

• AUG

• Informs tRNA to begin creating scanning and creating amino acids

3 sites of ribosome?

1. P site (peptide site):

   1. Binding site for tRNA

2. A site:

   1. Amino acid creator

3. E site:

   1. Exit

Steps for translation

1. Initiation:

   1. mRNA enters A-site

   2. mRNA is scanned for AUG

   3. tRNA carrying methionine enters P-site

   4. E-site and A-site are vacant at this point

2. Elongation:

   1. mRNA enters through the A-site and the first block of codons is scanned for the start codon (AUG) where the anticodon (UAC) is bonded and AA Methionine is created

   2. The first codon block moves to the P site as the 2nd codon block enters the A-site and is scanned and goes through the whole process of scanning and binding.

   3. When the 2nd codon block’s AA is created the first codon block’s AA binds with the 2nd AA to form a poly peptide bond

3. Termination:

   1. The process ends when the stop codon is scanned (UAG, UGA, UAA)

   2. The subunits of the ribosome detach, as well as the amino acid chain.

   3. The release factor aids in releasing the polypeptide chain.

Transcription?

1. Initiation:

   1. RNA Polymerase binds to the TATA box (promoter region) binds in the 5’-3’ direction and unwinds the DNA, and based on the template strand, creates base pairs as mRNA

2. Elongation:

   1. RNA Polymerase unwinds a portion of the DNA revealing a template strand, where RNA pol creates complementary base pairs

3. Termination:

   1. RNA Polymerase reaches the terminator sequences which informs the RNA Polymerase to stop.

Helicase?

• Unwinding

• Breaks hydrogen bonds

SSBP?

• Single Stranded binding proteins

• Makes sure unwinded DNA strands stay unwinded

Topoisomerase/ DNA Gyrase

• Releases tension

RNA Primase

• Activates DNA Primer (synthesizes RNA Primer)

RNA Primer

• Recruits DNA Polymerase III

DNA Polymerase III

• Recruited for binding bases

DNA Polymerase I

• Removes RNA Primer

• Fills gaps by creating nucleotides

DNA Ligase

• Molecular glue

• Seals gaps between bases and nucleotides

DNA Polymerase II

Proof-reading

Splicosomes

• Cuts exons and introns

What sugar is in DNA?

Deoxyribose sugar

What bond is in DNA

Phosphodiester bonds

What composes Phosphodiester bonds

Phosphates, Bases and Deoxyribose Sugar

What are the DNA complementary base pairs of
ATGC

TACG

What are the RNA complementary base pairs of ATGC?

UTCG

What is an Operon?

Cluster of genes under the control of one promoter and operator in prokaryotic cells

What does lac mean

Lactose

Lac a, Lac z, Lac y

1. Lac A:

   1. Galactosidase Transacetylase

   2. Unknown function

2. Lac Y:

   1. Galactosidase Permase

   2. Transports lactose into the cell

3. Lac Z:

   1. Galactosidase

   2. Converts lactose into glucose and galactose

What happens when Lactose is absent?

• LacI protein serves as a repressor and blocks protein synthesis

• LacI protein binds to the operator which

  • Blocks RNA Polymerase from binding and prevents transcription

What happens when lactose is present?

• Lactose binds to the LacI protein

• Lactose prevents LacI from binding with the operator which allows RNA Polymerase to bind to the promoter region and transcribe

• lac Operon is on

  • lacZ gene can make Galactosidase