Lecture 13: Central Dogma - Biomed

What describes the flow of genetic information through a biological system?

The Central dogma of Molecular Biology

What is the Central Dogma of Biology?

What are the building blocks of DNA and RNA?

Nucleotides

Nucleotides are monomeric units of ______________ _________.

Nucleic acids

What does a nucleoside consist of?

A nitrogenous base and a pentose sugar

What does a nucleotide consist of?

A nitrogenous base, pentose sugar, and a phosphate

What are the two types of nucleic acids?

- DNA (deoxyribose nucleic acid)

- RNA (ribose nucleic acid)

What are the 4 different nitrogenous bases in DNA?

- Adenine (A)

- Guanine (G)

- Cytosine (C)

- Thymine (T)

Which of the nitrogenous bases are purines?

Purine bases:

- Adenine

- Guanine

Which of the nitrogenous bases are pyrimidines?

Pyrimidine bases:

- Cytosine

- Uracil

- Thymine

What is the pentose sugar in DNA called?

Deoxyribose sugar

Carbon atoms of the pentose sugar are numbered 1' - 5' when a ________ is attached. Carbon atom linked to the _____________ ________ is labeled 1'.

- base

- nitrogenous base

DNA and RNA are polynucleotides consisting of linear sequences of nucleotides joined together by___' - ____' _______________ bonds between the sugars

- 3'-5' phosphodiester bonds

Which carbon does the phosphate attach to on the sugar?

The 5' carbon

Which carbon does the phosphate attach to on the next nucleotide?

The 3' carbon

What does the structure of DNA look like?

Does a DNA strand exhibit polarity?

Yes, (5' and 3' end)

What did the scientists, Rosalind Franklin, Maurice Wilkins, James Watson and Francis Crick, do?

Contribute to the discovery of the structure of DNA

DNA consists of _____ polynucleotide strands held together by ______________ bonds between the bases of each strand

- two

- hydrogen bonds

________________ base pairing occurs between nitrogenous bases.

Complementary

Adenine forms a bond with _______________.

Thymine

Cytosine forms a bond with ________________.

Guanine

How many hydrogen bonds do A and T have?

2 hydrogen bonds

How many hydrogen bonds do C and G have?

3 hydrogen bonds

The two polynucleotide strands run __________________ to one another.

Antiparallel

The overall structure of DNA is _______ hand double helix

right

Structure is further stabilized by ________ _______________. (hydrophobic interactions)

base stacking

Bases in Helix are ______ Å apart and complete turn of double helix consist of ____ base pairs with distance of _____ Å.

- 3.4

- 10

- 34

What are the 3 different forms of DNA?

- A-DNA

- B-DNA

- Z-DNA

Where does A-DNA predominate?

Predominates in DNA-RNA hybrids

What is the helical sense of A-DNA?

Right handed

What is the diameter of A-DNA?

~26 Å

How many base pairs per helical turn are there for A-DNA?

11

What is the helix rise per base pair for A-DNA?

2.6 Å

Where does B-DNA predominate?

Predominant DNA in cells

What is the helical sense of B-DNA?

Right handed

What is the diameter of B-DNA?

~20 Å

How many base pairs per helical turn are there in B-DNA?

10.5

What is the helix rise per base pair for B-DNA?

3.4 Å

Where does Z-DNA predominate?

Traces in cell, associated with transcription

What is the helical sense of Z-DNA?

Left handed

What is the diameter of Z-DNA?

~18 Å

How many base pairs per helical turn are there in Z-DNA?

12

What is the helix rise per base pair for Z-DNA?

3.7 Å