Lecture 5 - Proteins And Nucleic Acids

Question 1

Proteins

Answer 1

Proteins have a wide variety of functions:
- Structural
- Enzymatic
-Mechanical

A.k.a. polypeptides

Question 2

Amino acids

Answer 2

All amino acids contain an amine group (NH2), acidic carboxyl group (COOH) And a side chain (R)
Is that side chain that varies between amino acids

Question 3

Primary protein structure

Answer 3

Linear sequence and order of amino acids

Question 4

Secondary protein structure

Answer 4

How primary amino acids interact with each other, stabilized by hydrogen

Question 5

Tertiary protein structure

Answer 5

How secondary structures interact with each other, the three-dimensional shape of a polypeptide chain

Question 6

Quanternary protein structure

Answer 6

How two or more polypeptides interact with each other

Question 7

What are fibrous proteins?

Answer 7

Extended, strand like, in soluble molecules that provide mechanical support and tensile strength to tissues

Question 8

What are globular proteins?

Answer 8

Compact, spherical, water soluble and chemically active molecules that oversee most cellular functions

Question 9

What is protein denaturation?

Answer 9

A loss of the specific three dimensional structure of a globular protein, leads to potential loss of function

Question 10

What are enzymes?

Answer 10

Enzymes are globular proteins that act as a biological catalyst to regulate and increase speed of chemical reactions without getting used up in the process

Lower activation rate needed to initiate chemical reaction which leads to an increase in the reaction

Names usually end in -are And are often named after the reaction they catalyze

Question 11

Characteristics of an enzyme

Answer 11

Two parts:
Apoenzyme (protein portion)
Cofactors (helper molecule) or coenzyme (organic)

Together they are called Holoenzymes

Enzymes are easily regulated by the cell to control reactions

Question 12

Enzyme mechanisms

Answer 12

1. Enzyme and substrate meet at active site
2. Enzyme catalyzes reaction and transforms substrates into products
3. When complete, the enzyme is unchanged and free for another reaction

Question 13

What is a nucleic acid?

Answer 13

Nucleic acids are polymers made up of monomers called nucleotides

Composed of:
Nitrogen base
Pentose sugar
Phosphate group

Two major classes:
Deoxyribosenucleic acid (DNA)
Ribonucleic acid (RNA)

Question 14

What is DNA?

Answer 14

A double stranded helical molecule in cells nucleus
Encodes genetic “recipe for synthesis of all your proteins
Controls how cell develops

Contains:
Deoxyribose sugar
Phosphate group
One of four nitrogen bases (adenine, thymine, guanine, cytosine)

Question 15

What is RNA?

Answer 15

A single strand linear molecule outside the cell
Links DNA proteins synthesis

Contains:
Ribose sugar
Phosphate group
One of four nitrogen bases (adenine, uracil, guanine, cytosine)

Types:
Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)

Question 16

What is a mutation?

Answer 16

A change in a nucleotide sequence

Question 17

Nucleotides

Answer 17

DNA nucleotides:
Adenine and guanine are purines (2 Rings of nitrogen) 
Cytosine and thymine are pyrimidines (1 Ring of nitrogen)
Each purine matches with a pyrimidine through hydrogen bonds

RNA nucleotides:
Adenine and guanine, cytosine and uracil

A and T (U) have two hydrogen bonds
G and C have three hydrogen bonds

Question 18

What is Adenosine triphosphate (ATP)

Answer 18

An adenine containing RNA Nucleotide with two additional phosphate groups

energy released from breaking down glucose can be captured in ATP
Rechargeable battery


Question 19

ATP Synthesis

Answer 19

Useful for two main reasons:
Get energy from many sources if turned into ATD and use ATP to power enzymes
You can make ATP in one place , the mitochondria , and use it somewhere else

ATP diffuses throughout cell, gets used to power reaction and ADP diffuses back to mitochondria to charge