Chapter 7 - Macromolecules 1

Question 1

What elements make up proteins?

Answer 1

Carbon, hydrogen, oxygen, and nitrogen; some also contain sulfur.

Question 2

What are proteins made of?

Answer 2

Long chains of amino acid monomers linked by peptide bonds.

Question 3

How many amino acids are used to build proteins?

Answer 3

20.

Question 4

What are the four parts of an amino acid?

Answer 4

Amino group (-NH₂), carboxyl group (-COOH), hydrogen atom, and R group (side chain).

Question 5

What type of bond links amino acids together?

Answer 5

Peptide bond.

Question 6

What happens during peptide bond formation?

Answer 6

The carboxyl group of one amino acid reacts with the amino group of another, releasing water (H₂O).

Question 7

What helps proteins fold properly?

Answer 7

Chaperones. (prevent clumping)

Question 8

What is protein denaturation?

Answer 8

Loss of protein shape due to heat, chemicals, or pH changes, causing loss of function.

Question 9

What are the four levels of protein structure?

Answer 9

Primary, secondary, tertiary, and quaternary.

Question 10

What determines a protein’s primary structure?

Answer 10

The DNA sequence of its gene.

Question 11

What stabilizes secondary structures like α-helices and β-sheets?

Answer 11

Hydrogen bonds.

Question 12

What interactions stabilize tertiary structure?

Answer 12

Hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges.

Question 13

What is quaternary structure?

Answer 13

Association of multiple polypeptide chains into a functional protein complex.

Question 14

Give an example of a protein with quaternary structure.

Answer 14

Hemoglobin or DNA polymerase.

Question 15

What is ATP?(Adenosine Triphosphate)

Answer 15

The cell’s primary energy carrier.

Question 16

What are the three parts of ATP?

Answer 16

Adenine (base), ribose (sugar), and three phosphate groups.

Question 17

Where is the energy in ATP stored?

Answer 17

In the bonds between phosphate groups, especially the second and third.

Question 18

What happens when ATP is broken down?

Answer 18

ATP → ADP + Pi + energy.

Question 19

What is phosphorylation?

Answer 19

Adding a phosphate group (requires energy).

Question 20

What is dephosphorylation?

Answer 20

Removing a phosphate group (releases energy).

Question 21

How is ATP regenerated?

Answer 21

ADP + Pi → ATP using energy from cellular respiration or photosynthesis.

Question 22

What types of work does ATP power?

Answer 22

Mechanical (movement), transport (active transport), chemical (biosynthesis), and signaling.

Question 23

What is a chromosome?

Answer 23

A long strand of tightly packed DNA.

Question 24

What is a gene?

Answer 24

A section of DNA that codes for a protein.

Question 25

What is the genome?

Answer 25

The complete set of DNA in a cell.

Question 26

What are the components of a DNA nucleotide?

Answer 26

Deoxyribose sugar, phosphate group, and nitrogenous base (A, T, G, C).

Question 27

What is the base-pairing rule?

Answer 27

A pairs with T, and G pairs with C.

Question 28

Who discovered the DNA double-helix structure?

Answer 28

Watson and Crick (1953).

Question 29

What holds the DNA strands together?

Answer 29

Hydrogen bonds (A–T has 2, C–G has 3).

Question 30

What does “antiparallel” mean in DNA structure?

Answer 30

One strand runs 5’→3’, the other runs 3’→5’.

Question 31

What’s at the 5′ end and 3′ end of a DNA strand?

Answer 31

5′ end has a phosphate group; 3′ end has a hydroxyl group (-OH).

Question 32

How is RNA different from DNA?

Answer 32

RNA is single-stranded, has ribose sugar, and uses uracil instead of thymine.

Question 33

What are the three types of RNA?

Answer 33

mRNA, tRNA, and rRNA.

Question 34

What is the function of mRNA?

Answer 34

Carries the genetic code from DNA to ribosomes.

Question 35

What is the function of tRNA?

Answer 35

Brings amino acids to the ribosomes during protein synthesis.

Question 36

What is the function of rRNA?

Answer 36

Makes up part of ribosomes where proteins are built.

Question 37

What are enzymes?

Answer 37

Protein catalysts that speed up biochemical reactions.

Question 38

How do enzymes speed up reactions?

Answer 38

By lowering the activation energy.

Question 39

What is substrate specificity?

Answer 39

Each enzyme binds only to specific substrates.

Question 40

What model explains enzyme-substrate interaction?

Answer 40

The lock-and-key model.

Question 41

What is competitive inhibition?

Answer 41

When a molecule similar to the substrate competes for the enzyme’s active site.

Question 42

What is allosteric regulation?

Answer 42

A regulatory molecule binds to a site other than the active site, changing the enzyme’s shape.

Question 43

What is feedback inhibition?

Answer 43

The end product of a pathway inhibits the first enzyme to stop overproduction.

Question 44

What are cofactors and coenzymes?

Answer 44

Nonprotein helper molecules that assist enzymes.

Question 45

What is the difference between apoenzyme and holoenzyme?

Answer 45

Apoenzyme = inactive (no cofactor), Holoenzyme = active (with cofactor).