Nucleic acid Reading/Learning Goals Notes

A pairs with?

• A with T

• Purine Adenine (A) ALWAYS pairs with pyrimidine thymine (T)

C pairs with?

• C with G

• The pyrimidine cytosine (C) ALWAYS pairs with the purine guanine (G)

Only with ____ are there opportunities to _______?

Only with A & T and with C & G are there opportunities to establish hydrogen bonds (dotted lines) between them

Relationships between C & G and A & T are often called?

Watson-Crick Base Pairing

Amount of guanine (G) = ?

Amount of guanine (G) = Same amount of Cytosine (C)

What is the most important macromolecule for continuity of life?

Nucleic acids

What are the 2 main types of nucleic acids?

Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA)

DNA

Genetic material in all living organisms

RNA

Mostly involved in protein synthesis

What never leaves the nucleus? What does it do instead?

DNA molecules never leave the nucleus and instead use an intermediary to communicate with the rest of the cell

What is the intermediary DNA uses to communicate with the rest of the cell?

RNA (mRNA)

What are other types of RNA involved in?

Other types of RNA (rRNA, tRNA, & microRNA) are involved in protein synthesis and its regulation

What are DNA and RNA comprised of?

Nucleotides

How are polynucleotides formed?

The nucleotides combine with each other to form a polynucleotide (DNA or RNA)

How many components comprise each nucleotide?

3 components

What are the 3 components that comprise each nuceotide?

• A nitrogenous base

• A pentose sugar (5-carbon sugar)

• A phosphate group

What is each nitrogenous base in a nucleotide attached to? What is that attached to?

Each nitrogenous base in a nucleotide is attached to a sugar molecule which is attached to 1 or more phosphate groups

What kind of molecules are nitrogenous bases?

Nitrogenous bases are organic molecules

What do nitrogenous bases contain?

Contain carbon & nitrogen

Why are nitrogenous bases, bases?

They are bases because they contain an amino group that has the potential of binding an extra hydrogen which decreases the hydrogen ion concentration in its environment

What are the 4 nitrogenous bases?

• Adenine (A)

• Guanine (G)

• Cytosine (C)

• Thymine (T)

Purines

Adenine & Guanine

What is the purine’s primary structure?

The purine’s primary structure is two carbon-nitrogen rings

Pyrimidines

Cytosine, Thymine, & Uracil

What is pyrimidines’ primary structure?

They have a single carbon-nitrogen ring as primary sturcture

DNA nitrogenous bases

A,T,G,C

RNA nitrogenous bases

A,U,G,C

Pentose sugar in DNA

Deoxyribose

Pentose sugar in RNA

Ribose

What is the difference between the pentose sugar in DNA and the pentose sugar in RNA?

Difference between the sugars is the presence of the hydroxyl group on the ribose’s 2nd carbon and hydrogen on the deoxyribose’s 2nd carbon

How are the carbon atoms of the sugar molecule numbered?

Numbered as 1’, 2’, 3’, 4’, & 5’ (1’ read as 1 prime)

What forms a 5’-3’ phosphodiester linkage?

Phosphate residue attaches to the hydroxyl group of 5’ carbon  of 1 sugar and the hydroxyl group of the 3’ carbon of the sugar of the next nucleotide

What is DNA’s backbone made up of?

Made up of the sugar and phosphate that lie on the outside of DNA’s double helix structure

What is in the interior of the helix?

Nitrogenous bass are stacked in the interior of the helix

What binds pairs to eachother

Hydrogen bonds

0.34nm

Every base pairs is separated from the next base pair by 0.34 nm (in double helix)

Antiparallel orientation

5’ carbon end of 1 strand will face the 3’ carbon end of its matching strand

Antiparallel orientation is important to?

Important to DNA replication and in many nucleic acid interactions

Base complementary rule

DNA strands are complementary to eachother

What happens during DNA replication?

During DNA replication, each strand copies itself, resulting in a daughter DNA double helix containing 1 parental DNA and a newly synthesized strand

RNA is mainly involved in?

Mainly involved in the process of protein synthesis under the direction of DNA

RNA is usually?

Usually single-stranded and comprised of ribonucleotides that are linked by phosphodiester bonds

What does a ribonucleotide in the RNA chain contain?

A ribonucleotide in the RNA chain contains ribose (the pentose sugar), one of the four nitrogenous bases, and the phosphate group

How many types of RNA are there?

4 types of RNA

What are the 4 types of RNA?

• Messenger RNA (mRNA)

• Ribosomal RNA (rRNA)

• Transfer RNA (tRNA)

• MicroRNA (miRNA)

mRNA

mRNA carries the message from DNA, which controls all of the cellular activities in a cell

• If a cell requires synthesizing a certain protein, the gene for this product turns “on” and the messenger RNA synthesizes in the nucleus

Is the base T present in RNA?

In RNA, the base T is absent and U is present instead

mRNA is read in? 

mRNA is read in sets of 3 bases (also known as codons)

What does each codon do?

Each codon codes for a single amino acid

• mRNA is read and the protein product is made

Ribosomal RNA (rRNA)

Major constituent of ribosomes on which mRNA binds

What does rRNA ensure?

Ensures proper alignment of the mRNA and the ribosomes

What does the ribosomes rRNA have?

Has an enzymatic activity (peptidyl transferase) and catalyzes the peptide bond formation between 2 aligned amino acids

Transfer RNA (tRNA)

Carries the correct amino acid to the protein synthesis site

What type of RNA is the smallest of the 4 types of RNA?

tRNA (70-90 nucleotides long)

Polypeptide chain

The base pairing between the tRNA and mRNA that allows for the correct amino acid to inset itself in polypeptide chain

Micro RNAs are?

micro RNAs are the smallest RNA molecules

Role of micro RNA

Their role involves regulatory gene expression by interfering with the expression of certain mRNA messages