Lecture 1 - Chemistry of Life, Macromolecules, DNA

Question 1

Chemistry of life: Biological molecules are mainly made from ____

Answer 1

Carbon molecules

Question 2

Carbon usually forms _____

Answer 2

covalent bonds where electrons
are shared with hydrogen, oxygen, nitrogen and
phosphorous.

Question 3

Salts make _____

Answer 3

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.

Question 4

Hydrogen bonds are important ___

Answer 4

biological molecules

Question 5

Cells are constructed from four classes of macromolecules:

Answer 5

Carbohydrates (Simple sugars and large polymers)
Lipids (Fats and oils, phospholipids, and steroids)
Proteins (Polymers of amino acids)
Nucleic Acids (Polymers of nucleotides)

Question 6

What are Carbohydrates?

Answer 6

sugars are the main source of energy

Examples:
Polysaccharides (glycogen)
▪ Disaccharides (lactose, maltose,
sucrose)
▪ Monosaccharides (glucose,
galactose, fructose)

Question 7

sugars in the body (carbohydrates) are ____

Answer 7

six carbon molecules that are joined by glycosidic
bonds.

Question 8

common polysaccharides in humans (carbohydrates) is ____

Answer 8

Glycogen

Question 9

Fats and Lipids - What are Triglycerides?

Answer 9

major energy storage molecules and can be brown
down to provide energy

• the main form of stored fat in the body

Question 10

Fats and Lipids - What are Phospholipids?

Answer 10

are needed for membranes

Question 11

Fats and Lipids - What are the functions of Cholesterol and related molecules?

Answer 11

to form some fat-soluble substances such
as hormones

Question 12

Fats and lipids: What is common in phospholipids and triglycerides?

Answer 12

Both are composed of glycerol with two or three fatty
acid chains attached

Question 13

fats and lipids: What makes phospholipids different from triglycerides?

Answer 13

the third fatty acid chain is replaced by a phosphate group

Question 14

Steroids serve many roles including ____

Answer 14

hormones

Question 15

What are Proteins?

Answer 15

encoded by the DNA genome

Question 16

Proteins - In a polymer of amino acids how many are essential and how many are common?

Answer 16

20 common amino acids and nine essential

**essential meaning we cannot make them so need to get them in our food.

Question 17

Proteins - Proteins have a ____ ___ ___ which allows ___

Answer 17

highly specific shape, function

Question 18

Proteins - Proteins are ____

Answer 18

not stored long term and instead are broken down to generate energy

Question 19

Proteins - Proteins serve many functions including

Answer 19

enzymatic machines, structural functions, channels,
recognition molecules

Question 20

Proteins - Structure of a short peptide (a portion of proteins)

Answer 20

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

Question 21

Nucleic Acids - What is the purpose of nucleic acids?

Answer 21

DNA forms the genome and is transcribed to produce mRNA

Question 22

Nucleic Acids - DNA is a double-stranded helix composed of ___

Answer 22

deoxynucleotides

Question 23

Nucleic Acids - DNA is the _____

Answer 23

blueprint of the cell

Question 24

Nucleic Acids - Where is DNA located ___

Answer 24

in the nucleus and never leaves it

Question 25

Nucleic Acids - DNA is ____

Answer 25

1. replicated to give new DNA
2. transcribed into RNA —> mRNA
3. RNA is translated into proteins