Module 2: The chemical Basis of Life

Question 1

What is hypothesized that the earliest cells were made up of?

Answer 1

Nucleic acids and membrane

Question 2

What are polar molecules?

Answer 2

Molecules with a symmetric distribution of charge.

Question 3

What are non-polar molecules?

Answer 3

Molecules that lack electronegative atoms and strongly polarized bonds.

Question 4

What 3 kinds of non-covalent bonds are there?

Answer 4

1. Ionic bonds
2. Hydrogen bonds
3. Van der Waals forces

Question 5

What is an ionic bond?

Answer 5

Attraction between charged atoms.

Question 6

What is a hydrogen bond?

Answer 6

Partially positive when covalently bonded to electronegative atom, can approach second electronegative atom to form hydrogen bonds.

Question 7

What are Van der Waals forces?

Answer 7

Hydrophobic interaction, non-polar molecules lack charged regions and forced into aggregates to reduce water exposure.

Question 8

Does an acid release or accept protons?

Answer 8

Release protons.

Question 9

Does a base release or accept protons?

Answer 9

Accepts protons.

Question 10

What are amphoteric molecules?

Answer 10

Act as either acid or base.

Question 11

What is a buffer?

Answer 11

Resist changes in pH.

Question 12

How is acidity measured?

Answer 12

Measured in the pH scale.

Question 13

What are the four macromolecules?

Answer 13

Proteins, nucleic acids, polysaccharides, and certain lipids.

Question 14

Define: Carbohydrates

Answer 14

Includes simple sugars and all larger molecules constructed of sugar building blocks.

Question 15

What is the primary function of carbohydrates?

Answer 15

Stores of chemical energy and as material for biological construction.

Question 16

Why are sugars highly water soluble?

Answer 16

Due to hydroxyl groups

Question 17

Define: Polysaccharides

Answer 17

Identical sugar monomers but different properties, polymers of sugars joint by glycostatic bond.

Question 18

Define: Glycogen

Answer 18

Animal product, made of branched glucose polymers.

Question 19

Define: Starch

Answer 19

A plant product made
of both branched and
unbranched glucose polymers.

Question 20

What can lipids dissolve in?

Answer 20

In organic solvents but not water.

Question 21

What are three types of lipids?

Answer 21

1. Fats
2. Steroid
3. Phospholipids

Question 22

Describe lipid structure.

Answer 22

Made of a glycerol backbone, 2 fatty acid tails and a phosphate group.

Question 23

What fatty acids are considered saturated? (Double bond, no double bond)

Answer 23

Fatty acids that lack double bonds.

Question 24

What fatty acids are considered unsaturated? (Double bond, no double bond)

Answer 24

Fatty acids with double bonds.

Question 25

What is the structure of a steroid?

Answer 25

Steroids are built around a four-ringed hydrocarbon skeleton.

Question 26

What is the precursor for steroid hormones?

Answer 26

Cholesterol.

Question 27

What is the structure of a phospholipid?

Answer 27

- A phospholipid molecule resembles a fat but has only two fatty acid chains not three (a diacylglycerol). - The third hydroxyl of glycerol is bonded to a phosphate group.

Question 28

What macromolecule carries out the cells activity?

Answer 28

Proteins.

Question 29

What is the building block of a protein?

Answer 29

Amino acids.

Question 30

What do all amino acids have?

Answer 30

There are 20 different amino acids with different chemical properties. They all have a carboxyl and an amino group, separated by a single carbon atom, the alpha-carbon.

Question 31

What helps stabilize proteins shape?

Answer 31

Disulfide bridges.

Question 32

What is the driving force during protein folding and stability?

Answer 32

Hydrophobic interactions are a driving force during protein folding and cntribute substantially to the overall stability of the protein.

Question 33

Define: Primary structure of proteins.

Answer 33

Amino acid sequence of the proteins, linear sequence of amino acid that constitutes the chain.

Question 34

Define: Secondary structure of proteins.

Answer 34

Confirmation of portions of the polypeptide chain

Question 35

Define: Tertiary structure of proteins.

Answer 35

Confirmation of entire polypeptide.

Question 36

What was the first tertiary to structure that was determined?

Answer 36

Myoglobin

Question 37

How is tertiary structure most categorized?

Answer 37

By shape as fibrous proteins that are elongated, or globular which are compact.

Question 38

Define: Quaternary structure

Answer 38

Proteins composed of subunits.

Question 39

Define: Denaturation

Answer 39

Unfolding of a protein.

Question 40

What can cause denaturation?

Answer 40

Detergents, organic solvents, radiation, heat, and compounds like urea.

Question 41

Define: Proteome

Answer 41

Entire inventory of proteins that is produced by an organism and is applied to inventory of all proteins also present in partial tissue, cell, cellular organelle.

Question 42

Define: Proteonomics 

Answer 42

Coined to describe expanding field of proteins biochemistry

Question 43

Define: Nucleic acids

Answer 43

Polymers of nucleotides that store and transmit genetic information.

Question 44

What is DNA what does it stand for? and consists of?

Answer 44

DNA holds the genetic info in all cellular organisms. Deoxyribonucleic acid. Contains the sugar deoxyribose, has a hydrogen atom attached to the 2nd carbon. Double stranded.

Question 45

What is RNA? what does it stand for? and consists of?

Answer 45

Is a single stranded structure. Ribonucleic acid. Contains sugar ribose, has a hydroxyl group bonded to the 2nd carbon. May have catalytic activity, such RNA enzymes are called ribozymes.

Question 46

What holds genetic information in all cellular organisms and some viruses?

Answer 46

DNA

Question 47

What does each nucleotide consist of?

Answer 47

Consists of 3 parts, a sugar, a nitrogenous base, and a phosphate.

Question 48

What transfers information from the DNA?

Answer 48

RNA.

Question 49

What does each base pairs bind to?

Answer 49

Adenine (A) binds to Thymine (T) Cytosine (C) binds to Guanine (G)