Biochem

Question 1

Two main types of nucleus acids and what they contain

Answer 1

DNA

• deoxyribonucleic acid
• contains the hereditary code

RNA

• ribonucleic acid
• For protein synthesis

Question 2

Monomers that make up nucleic acids and subunits

Answer 2

Nucleotides

• five carbon sugar “pentose” either deoxyribose or ribose
• phosphate group
• one of the four nitrogenous bases

Question 3

RNA structure

Answer 3

A single strand that folds on itself (Single strand of nucleotides)
- does not necessarily take the shape of a helix

Question 4

DNA structure

Answer 4

• has a double helix shape
• two strands are hydrogen bonded together at the nitrogenous bases
• nitrogenous bases points towards the middle

Question 5

what is DNA base-pairing? what type of bond do they have, and what are the backbones made of?

Answer 5

• complementary base-pairing of nitrogen bases of nucleotides
• certain bases “fit” together
• nitrogenous bases are not covalently bonded.
• They are paired through hydrogen bonding
• The back bones are made of sugars and phosphates as they are bonded by dehydration synthesis

Question 6

DNA base-pairing

Answer 6

• Adenine + Thymine (DNA) or Uracil (RNA)

- Guanine + cytosine

Question 7

ATP (adenosine triphosphate)

Answer 7

• does it’s job as a single nucleotide
• it is an energy carrying molecule (nucleic acid)
• ATP undergoes hydrolysis and energy is released
• produced by cellular respiration in the mitochondria

Question 8

What are enzymes?

Answer 8

• protein catalysts
• speed up rate of chemical reactions without being used
• they speed up chemical reactions by lowering the activation energy for a chemical reaction to occur

Question 9

What do enzymes usually end in?

Answer 9

“Ase” such as lactase

Question 10

Enzyme cofactors

Answer 10

Vitamins and minerals

Question 11

Vitamins

Answer 11

• organic compounds that serve as coenzymes

- help enzyme function

Question 12

Minerals

Answer 12

• inorganic compounds needed by the body in small amounts

- essential components of certain structures

Question 13

What would happen without enzymes in the body?

Answer 13

• Chemical reactions would proceed way too slowly to be of any use to cells
• therefore enzymes are necessary for life to be possible

Question 14

How do enzymes work?

Answer 14

• enzymes act only on specific substrates (reactants) for specific reactions
• substrate fits in the enzymes active site in a “lock and key” arrangement

Question 15

Induced fit model (see notes for diagram)

Answer 15

• enzyme changes shape around the substrate in the active site
• substrate fits well into active site, then enzyme is induced move

Question 16

Enzyme + substrate name, and why it works

Answer 16

• enzyme-substrate complex
• it is an unstable state such that bonds can be broken and new ones form
• The results are reacted products and unchanged enzyme, meaning enzyme can be reused

Question 17

Degradation and synthesis

Answer 17

Degradation is when the substrate is broken down into smaller products

Synthesis is when they are combined to produce a larger product

Question 18

How does temperature affect enzyme activity?

Answer 18

• reaction rate increases as temperature rises
• at a certain point when temperature is too hot, the enzyme becomes denatured as protein begins folding, decreasing reaction rate
• this is because the lock and key arrangement is lost
• therefore there is an optimal temperature range

Question 19

How does pH affect enzyme activity?

Answer 19

• there is an optimal pH (acidity) for each enzyme to make enzyme more effective

Question 20

Inhibitors

Answer 20

• Molecules that attach to enzymes and reduce their ability to bind substrates

Question 21

Competitive inhibitors

Answer 21

• attached to the enzymes active site, competing with the substrate

Question 22

Non-competitive inhibitors

Answer 22

• bind elsewhere on the enzyme, changes the enzymes through the shape, therefore rendering the active site less affective

Question 23

Feedback inhibition

Answer 23

• product of an enzymes rxn acts as an inhibitor for the enzyme

Question 24

Types of enzymes

Answer 24

• carbohydrases (amylase, Maltase, sucrase, lactase)
• lipases
• proteases (trypsin, pepsin, peptidases)
• nucleases, nucleosidases

Question 25

Factors affecting enzymatic speed (6)

Answer 25

• substrate concentration
• temperature
• PH
• enzyme activation
• enzyme inhibition
• enzyme cofactors

Question 26

How does substrate concentration affect enzyme activity?

Answer 26

• There are more collisions between substrate and enzyme

- maximum rate is achieved when all active sites of an enzyme or filled continuously with substrate

Question 27

What is feedback inhibition?

Answer 27

• occurs when an enzyme cannot bind its substrate
• activity of cell enzymes is regulated by feedback inhibition
• poisons are enzyme inhibitors

Question 28

How do enzymes break down carbohydrates?

Answer 28

1. Broken down by amylases (salivary, pancreatic) to disaccharides (maltose, sucrose,lactose)
2. The disaccharides are broken down by carbohydrases (maltase, sucrase, lactase)
3. Result is monosaccharides aka simple sugar (glucose, fructoseX galactose)

Question 29

How do enzymes break down fats?

Answer 29

1. Fats (triglyceride) are broken down by lipase (pancreatic)

Result is glycerol and three fatty acids, aka your monomers

Question 30

How do enzymes break down nucleic acids?

Answer 30

1. Nucleic acids (DNA, RNA) are broken down by nucleases
   Result is DNA or RNA nucleotides (monomer)
2. Nucleotides is broken down by nucleosidases into phosphate group, pentose, and nitrogenous bases

Question 31

How do enzymes break down functional proteins?

Answer 31

1. Broken down by gastric protease (pepsin)
   Result is polypeptides (long chains of amino acids)
2. Broken down by pancreatic protease (trypsin)
   Result is peptides (short chains of A.A)
3. Broken down by peptidases
   Result is amino acid, aka monomer