NUCLEIC ACIDS

Nucleic acids

molecules that store information for cellular growth and reproduction.

nucleotides

large molecules consisting of long chains of monomers called _____

• pentose sugar

• nitrogen containing base

• phosphate

The nucleic acids DNA and RNA consists of monomers called nucleotides that consists of a:

• DNA

• mRNA

• tRNA and rRNA

The nucleic acids have the following functions:

• Storage of Genetic information (___)

• Transmission of genetic information (___)

• Protein synthesis (_____)

• Adenine 

• Guanine 

Purines are:

• Cytosine

• Uracil

• Thymine

Pyrimidines are:

N - glycosidic bond

nucleoside has a nitrogen base linked by a _____ to C1’ of a sugar (ribose or deoxyribose)  

phosphate ester

Nucleotide is a nucleoside that forms a _____ with the C5’ – OH group of a sugar (ribose or dexyribose).

Uridine

Cytidine

Adenosine 

Guanosine

Deoxythymidine 

Deoxycytidine

Deoxyadenosine 

Deoxyguanosine

Adenosine 5’-monophosphate

Deoxyadenosine 5’-monophosphate

Guanosine 5’-monophosphate

Deoxyguanosine 5’-monophosphate

Cytidine 5’-monophosphate

Deoxycytidine 5’-monophosphate

Uridine 5’-monophosphate

Deoxythymidine 5’-monophosphate

phosphodiester bonds

nucleotides are joined by _________

Initiation

Helicase unwinds the DNA to produce two strands: leading and lagging strand

Elongation

DNA polymerase adds nucleotides to the leading strand (5' to 3'), Okazaki fragments pair with the lagging strand.

Ligation

DNA ligase seals the gaps between Okazaki fragments on the lagging strand, forming a continuous DNA strand.

Termination

Replication stops when DNA molecule is copied, producing 2 identical double helices

Helicase

____ unwinds the DNA to produce two strands: leading and lagging strand

DNA polymerase

_____ adds nucleotides to the leading strand (5' to 3'), Okazaki fragments pair with the lagging strand.

lagging strand

Okazaki fragments pair with the _____

DNA ligase

______ seals the gaps between Okazaki fragments on the lagging strand, forming a continuous DNA strand.

Messenger RNA 

TYPES OF RNA

carries genetic information from DNA to the ribosomes.

Transfer RNA

TYPES OF RNA

brings amino acids to the ribosome to make the protein.

Ribosomal RNA

TYPES OF RNA

makes up ⅔ of ribosomes where protein synthesis takes place

Ribosomal RNA 

TYPES OF RNA

Function in the cell: Major component of the ribosome 

Messenger RNA 

TYPES OF RNA

Function in the cell: Carries information for protein synthesis from the DNA in the nucleus to the ribosomes

Transfer RNA 

TYPES OF RNA

Function in the cell: Brings amino acid to the ribosomes for protein synthesis

75

TYPES OF RNA: Ribosomal RNA

Percentage of Total RNA: _____

5 - 10

TYPES OF RNA: Messenger RNA

Percentage of Total RNA: _____

10 - 15

TYPES OF RNA: Transfer RNA

Percentage of Total RNA: ______

Chargaff’s Rule

In any double-stranded DNA, the amount of adenine (A) is always equal to the amount of thymine (T), and the amount of guanine (G) is always equal to the amount of cytosine (C). This reflects the complementary pairing of A with T and G with C.

ANTIPARALLEL

Two chains run _______, meaning the base pairs are in OPPOSITE DIRECTIONS

5’ to 3’

Leading strand runs from ___ to ____

3’ to 5’

Lagging strand runs from ___ to ___

DNA replication

genetic information is maintained each time a cell divides.

DNA replication

the DNA strands unwind

DNA replication

each parent strand bonds with new complementary bases.

DNA replication

two new DNA strands form that are exact copies of the original DNA.

tRNA

has a triplet called an anticodon that complements a codon on mRNA.

acceptor stem

tRNA bonds to a specific amino acid at the ______

AMINO ACIDS

tRNA reads the messages of nucleic acids and transform them into _____(then proteins)

transcription

PROTEIN SYNTHESIS 

mRNA is formed from a gene on a DNA strand

translation

PROTEIN SYNTHESIS 

tRNA molecules bring amino acids to mRNA to build a protein

RNA polymerase

During transcription, _____ moves along the DNA template to synthesize the corresponding mRNA.

termination

PROTEIN SYNTHESIS 

the mRNA is released at the _____ point

Transcription

PROTEIN SYNTHESIS 

a section of DNA containing the gene unwinds.

Transcription

PROTEIN SYNTHESIS 

one strand of DNA bases is used as a template

Transcription

PROTEIN SYNTHESIS 

mRNA is synthesized using complementary base pairing with uracil (U) replacing thymine (T).

Transcription

PROTEIN SYNTHESIS 

the newly formed mRNA moves out of the nucleus to ribosomes in the cytoplasm.

Genetic Code 

_____ is a sequence of amino acids in a mRNA that determine the amino acid order for the protein.

AUG

start codon

UAG UGA UAA

stop codons

Initiation

PROTEIN SYNTHESIS 

a mRNA attaches to a ribosome.

Initiation

PROTEIN SYNTHESIS 

the start codon (AUG) binds to a tRNA with methionine.

Initiation

PROTEIN SYNTHESIS 

the second codon attaches to a tRNA with the next amino acid.

Initiation

PROTEIN SYNTHESIS 

a peptide bond forms between the adjacent amino acids at the first and second codons.

Translocation

PROTEIN SYNTHESIS 

the first tRNA detaches from the ribosome.

Translocation

PROTEIN SYNTHESIS 

the ribosome shifts to the adjacent codon on the mRNA

Translocation

PROTEIN SYNTHESIS 

a new tRNA/amino acid attaches to the open binding site

Translocation

PROTEIN SYNTHESIS 

a peptide bond forms and that tRNA detaches.

Translocation

PROTEIN SYNTHESIS 

the ribosome shifts down the mRNA to read next codon

Termination

PROTEIN SYNTHESIS 

all the amino acids are linked

Termination

PROTEIN SYNTHESIS 

the ribosome reaches a "stop" codon: UGA, UAA, or UAG.

Termination 

PROTEIN SYNTHESIS 

there is no tRNA with an anticodon for the "stop" codons.

Termination

PROTEIN SYNTHESIS 

the polypeptide detaches from the ribosome.

Activation 

PROTEIN SYNTHESIS 

a tRNA attaches to its specific amino acid.

Initiation

PROTEIN SYNTHESIS 

a tRNA binds to the AUG codon of the mRNA on the ribosome.

Translocation

PROTEIN SYNTHESIS 

ribosomes move along mRNA adding amino acids to growing peptide chain.

Termination

PROTEIN SYNTHESIS 

a completed peptide chain.

Mutations

alter the nucleotide sequence in DNA.

Mutations

result from mutagens such as radiation and chemicals.

Mutations

produce one or more incorrect codons in mRNA.

Mutations

produce a protein containing one or more incorrect amino acids.

Mutations

produce defective proteins and enzymes.

Substitution

a base in DNA changes a codon in the mRNA.

Substitution

a different codon leads to the placement of an incorrect amino acid in the polypeptide.

Frame Shift Mutation

an extra base adds to or is deleted from the normal DNA sequence.

Frame Shift Mutation

all the codons in mRNA and amino acids are incorrect from the base change

Viruses

are small particles of DNA or RNA that require a host cell to replicate.

Viruses

cause a viral infection when the DNA or RNA enters a host cell.

Viruses

are synthesized in the host cell from the viral RNA produced by viral DNA.

Reverse Transcription

a retrovirus, which contains viral RNA, but no viral DNA, enters a cell.

retrovirus

contains viral RNA, but no viral DNA, enters a cell.

Reverse Transcription

the viral RNA uses reverse transcriptase to produce a viral DNA strand.

Reverse Transcription

the viral DNA strand forms a complementary DNA strand.

Reverse Transcription

the new DNA uses the nucleotides and enzymes in the host cell to synthesize new virus particles.

HIV-1 virus

____ is a retrovirus that infects T4 lymphocyte cells.

HIV-1 virus

decreases the T4 level and the immune system fails to destroy harmful organisms.

HIV-1 virus

causes pneumonia and skin cancer associated with AIDS

protease

Another type of AIDS treatment involves ____ inhibitors such as saquinavir, indinavir, and ritonavir

Protease inhibitors

______ modify the active site of the protease enzyme, which prevents the synthesis of viral proteins.