M01 Introduction to Biochemistry

Question 1

What is the hierarchy of simple to complex in the human body?

Answer 1

Atoms → Molecules → Macromolecules → Organelles → Cell → Tissue → Organ → Body System of Organism

Question 2

What are the most abundant elements found in living systems?

Answer 2

C, N, O, H

Question 3

What are polysaccharides component monomers?

Answer 3

Monosaccharides (carbohydrates)

Question 4

What is the ultimate source of energy for planet earth?

Answer 4

The sun

Question 5

What are the four major types of biomolecules?

Answer 5

• Amino acids
• Lipids
• Nucleotides
• Carbohydrates

Question 6

What is the general structure of amino acids?

Answer 6

Central carbon atom is bonded to a carboxyl group, an amino group, a hydrogen, and the R group

Question 7

What is the general structure of lipids?

Answer 7

Long chains of hydrocarbons and poorly soluble in water

Question 8

What is the general structure of nucleotides?

Answer 8

Composed of a five-carbon sugar, a nitrogen-containing ring, and one or more phosphate groups

Question 9

What is the general structure of carbohydrates?

Answer 9

• Compounds of C, H, O
• General formula - (CH₂O)n where n is at least 3
• Simplest form - monosaccharides, or sugars

Question 10

What do functional groups determine?

Answer 10

Chemical reactivity and molecular structure

Question 11

What are monomers?

Answer 11

Small molecules that combine to form polymers

Question 12

What are polymers?

Answer 12

Macromolecules formed by bonding of smaller units

Question 13

What are the 3 types of polymers?

Answer 13

• Proteins
• Nucleic acids
• Polysaccharides

Question 14

What are proteins component monomers?

Answer 14

Amino acids

Question 15

What are nucleic acids component monomers?

Answer 15

Nucleotides (DNA and RNA)

Question 16

What is the key difference between prokaryotic and eukaryotic cells?

Answer 16

Presence of sub-cellular organelles

Question 17

Which type of biological molecules does not form polymers? Why?

Answer 17

Lipids do not form polymers due to lack of common functional groups

Question 18

What does it mean to be an informational macromolecules?

Answer 18

Order of monomers important

Question 19

Which polymers are informational?

Answer 19

Proteins and nucleic acids

Question 20

What are some of the properties of enzymes?

Answer 20

• Biological catalysts
• Some enzymes are protein and some are RNA
• Catalytic activity

Question 21

What is catalytic activity?

Answer 21

Ability to increase rate of reaction

Question 22

What does catalytic effectiveness of an enzyme depend on?

Answer 22

Depends on its amino acid sequence

Question 23

How are changes in energy calculated?

Answer 23

Calculated as the final minus the initial state

Question 24

What type of energy change is associated with spontaneous reactions?

Answer 24

• If change in free energy is negative (free energy decreases), rxn is spontaneous
• If change is positive (free energy increases), rxn will not occur unless energy supplied

Question 25

What is a spontaneous reaction?

Answer 25

Reaction or process that takes place without inside intervention

Question 26

What is the 1st law of thermodynamics?

Answer 26

Energy can neither be created nor destroyed

Question 27

What is the 2nd law of thermodynamics?

Answer 27

Total entropy of a system must increase over time

Question 28

What is the definition of Gibbs free energy?

Answer 28

𝚫*G* = 𝚫*H* – *T*𝚫*S* - Energy relevant to biochemical systems

Question 29

What is enthalpy (*H*)?

Answer 29

Heat constant of a system (*heat of a reaction at constant pressure*) - Exothermic: heat released (–) - Endothermic: heat absorbed (+)

Question 30

How does enthalpy (*H*) relate to *G*?

Answer 30

A (–) change in enthalpy contributes to a (–) change in Gibbs free energy (a spontaneous reaction)

Question 31

If a reaction is exothermic, will enthalpy be positive or negative?

Answer 31

Negative

Question 32

If a reaction is endothermic, will enthalpy be positive or negative?

Answer 32

Positive

Question 33

What is entropy (*S*)?

Answer 33

- Measure of the dispersion of the energy of the system - Measure of disorder or randomness

Question 34

How does entropy relate to *G*?

Answer 34

- As it increases it contributes to spontaneity of change - (+) change in entropy is associated with a tendency toward spontaneity (–) free energy change

Question 35

How does temperature relate to entropy and *G*?

Answer 35

Temperature and entropy are proportional - ↑ temperature → greater kinetic energy (molecules move faster) → higher randomness → ↑ in enthalpy - (+) change in enthalpy is associated with a tendency towards spontaneity (–G)

Question 36

Under what conditions would 𝚫*G* always be a negative value?

Answer 36

If 𝚫*H* is negative and 𝚫*S* is positive, 𝚫*G* will always be negative and the reaction is spontaneous at all temperatures

Question 37

How does the principle of spontaneity relate to 𝚫*G*?

Answer 37

- 𝚫*G* > 0 - nonspontaneous or endergonic - Endergonic: energy-absorbing - 𝚫*G* < 0 - spontaneous or exergonic - Exergonic: energy-releasing

Question 38

What are the general principles associated with the Big Bang Theory?

Answer 38

- All matter originally confined to comparatively small volume of space - An explosion resulted in rapid expansion of fireball

Question 39

What gases were present in early Earth?

Answer 39

NH₃, H₂S, CO, CO₂, CH₄, N₂, H₂, and H₂O

Question 40

What was the general way in which the heavier elements were produced?

Answer 40

Formed by thermonuclear reactions in stars, explosions, and cosmic rays

Question 41

What defines prokaryotes?

Answer 41

Lack nucleus and internal organelles - Archaea and bacteria

Question 42

What defines eukaryotes?

Answer 42

* Most often larger than prokaryotic cells * Contain nucleus and intracellular compartments * Unicellular or multicellular

Question 43

What are the intracellular compartments of eukaryotes?

Answer 43

- Nucleus - Endoplasmic reticulum - Golgi apparatus - Mitochondria - Ribosomes - Lysosome - Peroxisome - Glyoxysome - Chloroplast

Question 44

What is the nucleus?

Answer 44

Location of main genome; site of most DNA and RNA synthesis

Question 45

What is the endoplasmic reticulum?

Answer 45

Continuous membrane throughout the cell; rough parts studded with ribosomes

Question 46

What is the Golgi apparatus?

Answer 46

Series of flattened membranes; involved in secretion of proteins from cells and in reactions that link sugars to other cellular components

Question 47

What is the mitochondria?

Answer 47

Site of energy-yielding oxidation reactions; has its own DNA

Question 48

What are ribosomes?

Answer 48

Sites of protein synthesis

Question 49

What are lysosomes?

Answer 49

Membrane-enclosed sacs containing hydrolytic enzymes

Question 50

What are peroxisomes?

Answer 50

Sacs that contain enzymes involved in the metabolism of hydrogen peroxide

Question 51

What are glyoxysomes?

Answer 51

Found in plant cells only; contain enzymes that catalyze the *glyoxylate cycle*, a pathway that converts some lipids to carbohydrates with glyoxylic acid as an intermediate

Question 52

What is a cholorplast?

Question 53

What are the two classification systems?

Answer 53

- 3-Domain - 5-Kingdom

Question 54

What is the 3-domain classification system based on?

Answer 54

Uses the sequences of ribosomal RNA of each species

Question 55

What are the domains in the 3-domain classification system?

Answer 55

- Prokaryotes - Bacteria - Archaea - Eukaryotes - Eukarya

Question 56

What is the 5-kingdom classification system?

Answer 56

Classification system that takes into account differences between prokaryotes and eukaryotes - Provides classifications for eukaryotes that are neither plants nor animals

Question 57

What are the kingdoms in the 5-kingdom classification system?

Answer 57

- Monera - Protista - Fungi - Plantae - Animalia