brownbag-science

Cell Structure and DNA

Structure of a Model Cell

(figure from cancer.gov)

Cell Composition

Cells are made up of

• water
• DNA and RNA (nucleic acids; genetic material)
• proteins (amino acids; enzymes)
• lipids (membrane)
• metabolites (e.g. carbohydrates, ATP, etc)

Chromosomes

Chromosomes, tightly wound strands of DNA, are located in the nucleus.

(figure taken from my46.org)

DNA Double Helix and Base Pairs

(figures taken from nature.com)

DNA vs RNA

RNA is very similar to DNA:

1. has uracil instead of thymine
2. has 3’ hydroxyl group on ribose sugar (vs de-oxyribose)
3. usually single stranded (vs double stranded)

Proteins

Proteins do almost all of the work in the cell, ranging from intracellular receptors, making ATP, and carrying out life-essential functions in the cell.

Proteins are composed of folded strands of amino acids.

(figure taken from pnas.org)

(figure taken from wikipedia.org)

(figure taken from nature.com)

Fun Pictures

Check out these illustrations from digizyme.com:

Also: Molecular Dynamics Simulations

FYI

Human genome

• 46 chromosomes (23 pairs)
• ~ 3 billion base pairs
• DNA sequence for any two people is about 99.9% identical

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