A nitrogenous base, which can be either adenine, guanine, cytosine, or thymine (in the case of RNA, thymine is replaced by uracil).

A five-carbon sugar, called deoxyribose because it is lacking an oxygen group on one of its carbons.

One or more phosphate groups.

The RNA polymerase must recognize a promoter

Guanine pairs with Cytosine

•  3 Hydrogen bonds between them

Thymine pairs with Adenine

    (Adenine pairs with Uracil in RNA)

•  2 Hydrogen bonds between them.

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3 types of RNA, each encoded by its own type of gene:

1. mRNA (MessengerRNA): Encodes amino acid sequence of a polypeptide.
2. tRNA (Transfer RNA): Brings amino acids to ribosomes during translation.
3. rRNA (Ribosomal RNA): With ribosomal proteins, makes up the ribosomes, the organelles that translate the mRNA[image]

describes the two-step process: transcription and translation

• which the information in genes flows into proteins: DNA → RNA → protein. 

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• is the synthesis of an RNA copy of a segment of DNA. RNA is synthesized by the enzyme RNA polymerase.
• is the process of making an RNA copy of a gene sequence.
• This copy, called a messenger RNA (mRNA) molecule, leaves the cell nucleus and enters the cytoplasm, where it directs the synthesis of the protein, which it encodes.

3' → 5'

Transcription of two genes.

RNA polymerase moves from the 3′ end of the template strand, creating an RNA strand that grows in a 5′ → 3′ direction (because it must be antiparallel to the template strand).

is the process of translating the sequence of a messenger RNA (mRNA) molecule to a sequence of amino acids during protein synthesis.

In the cell cytoplasm, the ribosome reads the sequence of the mRNA in groups of three bases to assemble the protein.

James Watson and Francis Crick

• determined that DNA is a double helix

Rosalind Franklin

• produced the X-ray image of DNA

1)The parental DNA strands (template)

2)Free Nucleotides (ATCG)

         *the building blocks

3)A variety of enzymes that unwind the parental DNA double helix and synthesize new DNA strands.

are Enzymes

• make the covalent bonds between the nucleotides (ATCG) of a new DNA strand.
• Also involved in repairing DNA.
• reads DNA strand to make a RNA strand.

1. Transcription: the transfer of genetic information from DNA into an RNA molecule.

2.Translation: the transfer of information from RNA into a protein.

1)RNA is single stranded

2)RNA has the sugar ribose instead of DNA's sugar, deoxyribose, in its backbone

3)RNA contains the nitrogenous base URACIL (U) instead of THYMINE (T).

adenine (A), guanine (G), cytosine (C) and thymine (T).

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adenine (A), guanine (G), cytosine (C) and uracil (U)

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Guanine has three Hydrogen bonds with Cytosine

Adenine has two hydrogen bonds with Thymine (in DNA) or Adenine has two hydrogen bonds with Uracil (in RNA).

Covalent bonds form between the sugar of one nucleotide and the phosphate of the next.

*Forms a sugar-phosphate backbone

is a triplet of bases, which codes for one amino acid.

*3 bases together

*Codons provide the key that allows these two languages to be translated into each other.

*Of the 64 codons, 61 represent amino acids, and three are stop signals.

is the set of rules that convert a nucleotide sequence in RNA to an amino acid sequence.

• 64 triplets (codon)
• different ways to put together the codon.
• 61 code for amino acids
• 3 are stop codons, instructing the ribosomes to end the polypeptide.

is a nucleotide sequence that is a start transcribing" signal. *located in the DNA at the beginning of the gene. *a specific place where RNA polymerase attaches. *is a region of DNA that initiates transcription of a particular gene. Promoters are located near the transcription start sites of genes, on the same strand and upstream on the DNA (towards the 5' region of the sense strand).

1)Initiation *RNA polymerase attaches to the promoter and RNA synthesis begins

2)Elongation *the RNA grows longer and the RNA strand peels away from its DNA template.

3)Termination *a special sequence of bases in the DNA template that signals the end of the gene that RNA polymerase reaches. *polymerase detaches from the RNA and the gene and the DNA strands rejoin.

RNA molecules that convey genetic information from DNA to the ribosome, where they specify the amino acid sequence of the protein products of gene expression. *"carries the message" *RNA transcripts, modifies and processes before it leaves the nucleus to the cytoplasm for translation by ribosomes.