Lecture 1 - Chemistry of Life, Macromolecules, DNA Flashcards
Chemistry of life: Biological molecules are mainly made from ____
Carbon molecules
Carbon usually forms _____
covalent bonds where electrons
are shared with hydrogen, oxygen, nitrogen and
phosphorous.
Salts make _____
ionic bonds that
consist of charged atoms or ions
where one atom takes an electron
and is therefore negatively
charged and the other donates an
electron and is therefore
positively charged.
Hydrogen bonds are important ___
biological molecules
Cells are constructed from four classes of macromolecules:
Carbohydrates (Simple sugars and large polymers)
Lipids (Fats and oils, phospholipids, and steroids)
Proteins (Polymers of amino acids)
Nucleic Acids (Polymers of nucleotides)
What are Carbohydrates?
sugars are the main source of energy
Examples:
Polysaccharides (glycogen)
▪ Disaccharides (lactose, maltose,
sucrose)
▪ Monosaccharides (glucose,
galactose, fructose)
sugars in the body (carbohydrates) are ____
six carbon molecules that are joined by glycosidic
bonds.
common polysaccharides in humans (carbohydrates) is ____
Glycogen
Fats and Lipids - What are Triglycerides?
major energy storage molecules and can be brown
down to provide energy
- the main form of stored fat in the body
Fats and Lipids - What are Phospholipids?
are needed for membranes
Fats and Lipids - What are the functions of Cholesterol and related molecules?
to form some fat-soluble substances such
as hormones
Fats and lipids: What is common in phospholipids and triglycerides?
Both are composed of glycerol with two or three fatty
acid chains attached
fats and lipids: What makes phospholipids different from triglycerides?
the third fatty acid chain is replaced by a phosphate group
Steroids serve many roles including ____
hormones
What are Proteins?
encoded by the DNA genome
Proteins - In a polymer of amino acids how many are essential and how many are common?
20 common amino acids and nine essential
**essential meaning we cannot make them so need to get them in our food.
Proteins - Proteins have a ____ ___ ___ which allows ___
highly specific shape, function
Proteins - Proteins are ____
not stored long term and instead are broken down to generate energy
Proteins - Proteins serve many functions including
enzymatic machines, structural functions, channels,
recognition molecules
Proteins - Structure of a short peptide (a portion of proteins)
In general, a peptide consists of at least two amino acids.
–> peptide bond is an amide type of covalent chemical bond linking two consecutive alpha-amino acids from C1 (carbon number one) of one alpha-amino acid and N2 (nitrogen number two) of another, along a peptide or protein chain.
- An oligopeptide is a short chain of amino acids (“a few”).
- A polypeptide is a long chain of amino acids (“many”). Protein contains at least one polypeptide chain folded into correct shapes
Nucleic Acids - What is the purpose of nucleic acids?
DNA forms the genome and is transcribed to produce mRNA
Nucleic Acids - DNA is a double-stranded helix composed of ___
deoxynucleotides
Nucleic Acids - DNA is the _____
blueprint of the cell
Nucleic Acids - Where is DNA located ___
in the nucleus and never leaves it
Nucleic Acids - DNA is ____
- replicated to give new DNA
- transcribed into RNA —> mRNA
- RNA is translated into proteins
