Quiz 2

Learning Objectives

1. Articulate how information flows in biology through nucleic acids and proteins 

2. Use a baking analogy to represent the central dogma of biology 

3. Compare where the central dogma occurs in eukaryotes and prokaryotes 

4. Distinguish between the primary structures of DNA and RNA

5. Explain how the structures of DNA and RNA influence their functions in information flow

phosphate group

• part of the nucleotide

• negatively charged

sugar

nitrogenous base

nucleotide

monomer that composes nucleic acids, consists of 3 parts

1. 5 carbon sugar

2. phosphate group

3. nitrogenous base

nucleic acid

a polymer of nucleotide monomers

contain the information that encodes life

RNA

ribo-nucleic acid

nucleic acid that serves as a messenger, transferring genetic instructions from DNA to the cell's protein-making machinery

=RIBOSE has a hydroxy on the 2’ carbon

DNA

complex molecule that carries the genetic instructions for the development, functioning, growth, and reproduction of all known living organisms

• Stable

• Able to be copied - heritable

• Able to encode information

=DEOXYRIBOSE has a hydrogen on the 2’ carbon

phosphodiester bonds

the stable covalent bonds in between nucleotides in nucleic acid

sugar phosphate backbone

Phosphodiester linkages form the sugar–phosphate backbone= the negatively charged phospho group links to the 3’ carbon on the sugar

3’ 5’

complementary base pairing

specific pairing between nucleotide bases in DNA and RNA —>held together by hydrogen bonds

important for forming the double helix and encoding complex genetic information.

• run anti parallel

central dogma

genetic information flows from DNA—>RNA—>Proteins

Learning Objectives

1. List the steps needed to make RNA from a DNA template (transcription)

2. Relate the structures of nucleotides to the directionality of transcription 

3. Explain the function of RNA polymerase and how it reads the DNA template to synthesize the complementary RNA transcript  

4. Identify key features of a gene and how they relate to the process of transcription

5’ end

unlinked phosphate

3’ end

unlinked hydroxyl group

• new nucleotides are ALWAYS added to this end.

transcription

the synthesis of RNA from a DNA template

—>determines how dna is used in the cell

1. initiation

2. elongation

3. termination

rna polymerase

an enzyme that binds to DNA, reads it (3’—>5’), and synthesizes complementary RNA (5’—>3’)

template strand

the strand of DNA that serves as the blueprint for the synthesis of a complementary RNA molecule during transcription

initiation of transcription

1. rna polymerase binds to DNA

promoter

stretches of DNA that allow RNA polymerases to “know” where to start transcribing= recruit DNA and serve as a binding site

sigma factor

recognizes and binds to the promoter DNA to help position the RNA polymerase in prokaryotes

general transcription factors

use _______ to recognize promoter regions and position RNA polymerase on the DNA— eukaryotes

transcription elongation

RNA polymerase “reads” the DNA template

to synthesize the complementary RNA

transcription termination

termination site allows RNA polymerase to “know” where to stop transcribing

• prokaryotes: RNA polymerase transcribes a DNA sequence known as the “termination site”

• “termination sequence” of

DNA is transcribed into RNA, it

recruits an enzyme to subsequently

cut the RNA

• Then, the RNA falls off the DNA

•  RNA polymerase stops transcription shortly after

gene

a segment of DNA that is necessary for the synthesis of a product

(typically a protein, but sometimes a functional RNA)

genetic code

• The code is (nearly) universal!

• The code is degenerate or

redundant

• Some codons indicate the same

amino acid

• The code is unambiguous

• One codon never codes for more

than one amino acid

• The code is conservative

• When several codons specify the

same amino acid, the first two

bases are typically identical

tRNA

non-coding RNA molecules that function as adaptors, translating the genetic code from messenger RNA (mRNA) into proteins by delivering specific amino acids to the ribosome during translation.

codon

anticodon

charged states

uncharged states