Biochemistry Chapter 1

Question 1

What are the four major types of biomolecules?

Answer 1

1. Amino Acids
2. Carbohydrates
3. Lipids
4. Nucleotides

Question 2

What groups do Amino acids contain

Answer 2

Amino Group (-NH2)
Carboxyl Group (-COOH)
R group (that may contain N, O, or S)

Question 3

How can you easily identify a Carbohydrate

Answer 3

A cyclic ring which contains many (-OH) groups

Question 4

What makes up a Nucleotide?

Answer 4

A five-carbon sugar (usually ribose)

One or more phosphate groups (mono, di or tri)

Nitrogen containing ring (adenine, thymine, guanine or cytosine)

Question 5

What are the characteristics of Lipids

Answer 5

They are poorly soluble in water (amphipathic)

Contain a long chain of alkenes which are nonpolar

Contains one end that has a carboxylic acid (polar)

Question 6

What are the three major kinds of biological polymers?

Answer 6

1. Proteins
2. Nucleic Acids
3. Polysaccharides

Question 7

What makes up a protein/polypeptide

Answer 7

Polymers of amino acids

Question 8

How are the residues of proteins linked together

Answer 8

By amide bonds called peptide bonds

They form between the amino group of one reside and the carboxyl group of the other residue

Question 9

How is the exact conformation of proteins/polypeptide chains decided

Answer 9

Since the 20 amino acids contain different shapes, sizes and chemical properties, the conformation depends on the amino acid composition and sequence.

Question 10

What is the importance of proteins in the body

Answer 10

They help to mediate chemical reactions and provide structural support

Question 11

What are polymers of nucleotides called?

Answer 11

Polynucleotides or Nucleic acids (DNA and RNA)

Question 12

What makes up a Nucleic Acid

Answer 12

They are made up of 4 different nucleotides
RNA:
1. Uracil
2. Cytosine
3. Adenine
4. Guanine

DNA:
1. Thymine
2. Cytosine
3. Adenine
4. Guanine

Question 13

What bonds form between nucleic acids?

Answer 13

Polymerization involves the phosphate and sugar groups of the nucleotides to be linked by phosphodiester bonds

Question 14

What is the job of polysaccharides

Answer 14

They perform essential cell functions by serving as fuel-storage molecules and by providing structural support.

Question 15

What linkage is found in polysaccharides

Answer 15

Glucose residues are linked by glycosidic bonds

Question 16

Of the three biopolymers (proteins, nucleic acids and polysaccharides) which:

-Encode information
-Carry out metabolic processes
-Store energy
-Support cellular structures

(major and minor functions)

Answer 16

Encode Information:
-Nucleic acid (major function) and Polysaccharides (minor)

Carry out Metabolic Processes:
-Proteins (major) and Nucleic acids (minor)

Store Energy:
-Proteins (minor) and Polysaccharides (major)

Support Cellular Structures:
-Proteins (major), Nucleic acids (minor) and Polysaccharides (major)

Question 17

Define Gibbs Free Energy
What are its units?
What makes up this energy?
What is its equation?

Answer 17

The energy relevant to a biochemical system

J/mol

Enthalpy and Entropy

G= H - TS

Question 18

Define Enthalpy (H)
What are its units?

Answer 18

The equivalent of the heat content of a system

J/mol

Question 19

Define Entropy (S)
What are its units?

Answer 19

The measure how the energy is dispersed within the system
(its disorder or randomness)

J/K x mol

Question 20

What happens to entropy when temperature (K) increases in a system

Answer 20

The entropy of a substance increases when it is warmed because more thermal energy has been dispersed within it.

Temp increases: Entropy increases

Question 21

Differ between exothermic reactions and endothermic reactions

Answer 21

exothermic= release of energy from a system
(H final-H initial= H < 0

endothermic=absorbs heat from surrounding
H > 0