Chapter 6

Question 1

explain the way in which we receive energy

Answer 1

it starts off by the energy we receive from the sun, which is know as solar energy; in photosynthetic organisms solar energy is used/absorbed and stored hydrogen carbon bonds of glucose; when we eat glucose, we break these bonds and release high enregy

Question 2

what supplies energy for atp and why

Answer 2

as electrons move they release energy due to the fact that when electrons are lost they move closer to the atomic nucleus which means less energy and when they gain electrons they move further away from the atomic nucleus meaning that they have more energy

Question 3

Endergonic reaction

Answer 3

requires energy to happen; example of this is photosynthesis (6co2 + 6H20 –> C6H12O6 + 6O) this means that the products will have more energy than the reactants because they absorb and store energy from the sun

Question 4

Exergonic reaction

Answer 4

releases energy; an example of this is cellular respiration (where the reactants have more energy than the products)
formula: c6h12o6 + o2 –> 6co2 + 6H20 + ATP

Question 5

what are the role of enzymes in chemical reactions

Answer 5

enzymes lower the activation energy (ea) esp in exergonic reactions where these reactions that happen spontaneously and on their own can take a lot of time; enzymes are used to speed up the reactions

Question 6

what is activation energy

Answer 6

activation energy is the minimum energy required to start a chemical reaction; the higher the Ea the longer the product will take to form without the enzyme

Question 7

what are some characteristics of enzymes

Answer 7

each enzyme has its own substrate, names end in ase, named after their substrates, the DNase enzyme breaks down the DNA and the RNase enzyme breaks down the RNA, sucrase breaks down sucrose, enzymes are reused in chemical reaction (unless there is denaturation or dissociation), many enzymes are proteins in nature, while some of them are ribozymes

Question 8

how do enzymes work

Answer 8

the substrate (ex sucrose- fructose + glucose) binds to the enzymes (sucrase) active site and then and then the enzyme-substrate complex bends the glycosidic bond after binding to make it easier for the water to break the bond between the two molecules in the substrate and with the help of H20 through a hydrolysis reaction the two molecules of fructose and glucose separate the enzyme gets reused

Question 9

what are some factors that control enzymes and enzymatic activity

Answer 9

temperature, pH, inhibitors, and activators

Question 10

explain the ways in which temperature has an affect on enzymatic activity

Answer 10

due to the fact that many enzymes are proteins in nature, proteins at elevated temperatures become denatured and therefore nonfunctional. This is because eukaryotic enzymes have optimal temperatures between 35-40 degrees celsius aka they are thermophobic

Question 11

explain prokaryotic enzymatic activity

Answer 11

prokaryotic enzymes are thermophilic meaning that they live and thrive in hot springs with temperatures that operate at 70 degrees celsius or higher

Question 12

explain the ways in which pH affects enzymatic activity

Answer 12

most human enzymes work best at a pH of 7 anything that is higher or lower will cause denaturation

Question 13

name two enzymes that are heavily affected by pH and explain their function + enzymatic activity at different levels of pH

Answer 13

pepsin and trypsin
pepsin in the stomach works best at a pH of 2 (strong acid) because the stomach has a very acidic environment due to the hydrochloric acid produced by parietal cells and trypsin in the small intestine works best at a pH of 8 (weak base). pepsin and trypsin are proteases enzymes that are used to breakdown proteins by hydrolyzing peptide bonds between amino acids. Trypsin will become denatured in the stomach and pepsin will become denatured in the small intestine

Question 14

where else do we have an acidic ph

Answer 14

inside of our lysosomes, which have enzymes that work best at a ph of 5) - the enzymes inside our lysosomes can break down all four macromolecules

Question 15

what are the two types of inhibitors that prevent enzymatic activity

Answer 15

competitive and non competitive

Question 16

explain competitive inhibition and how we can overcome

Answer 16

during competitive inhibition, inhibitors such as NaF compete with the substrate for the enzymes active site. in order to overcome this, we can add more substrate in order to increase the substrates likelihood of winning

Question 17

explain noncompetitive inhibition and how we can overcome this

Answer 17

during non competitive inhibition, the inhibitor binds to the enzymes allosteric site which is originally made for the activators to bind and then the enzyme undergoes a conformational change to which the substrate can no longer bind. to overcome this, add substances that will bind to the allosteric site so that non competitive inhibitors wont

Question 18

what are activators

Answer 18

they are molecules that bind to the enzymes allosteric site and allow the substrate to fit better into the enzyme

Question 19

what are some examples of enzymes

Answer 19

cofactors (Fe2+, Zn2+, Cu2+, Mg2+), organic non protein molecules such as acetyl CoA, vitamins such as B6 and B12, modified nucleotides such as NADP+, NAD+, and FAD

Question 20

define metabolism

Answer 20

a total of all chemical reactions carried out in an organim

Question 21

explain the differences between catabolic and anabolic reactions

Answer 21

anabolic reactions are where energy is going into the reaction and is an endergonic reaction. Catabolic reactions are where energy is being released and is an exergonic reaction

Question 22

give examples of catabolic + anabolic reactions

Answer 22

photosynthesis is an example of anabolic reactions because of the fact that it uses energy to create larger molecules (dehydration synthesis); cellular respiration is an example of a catabolic reaction because it releases energy in the form of ATP and creates small molecules fro larger ones (hydrolysis)

Question 23

what is a biochemical pathway

Answer 23

a bio cp includes multiple chemical reactions that occur at the same area and the product of one enzyme serves as the substrate for another enzyme until eh end product is reaches

Question 24

positive feedback

Answer 24

its a process in which the final end product promotes the production of itself by stimulating the enzyme above it to produce more substrate to produce more of the end product

Question 25

what is an example of pos feedback

Answer 25

production of oxytocin during childbirth; oxytocin is a hormone produced by the hypothalamus and released by the pituitary glands that allow contractions during childbirth. In this case oxytocin increases its own production via positive feedbacks leading to more contractions and further movement of the body into the birth canal

Question 26

negative feedback

Answer 26

is a process in which the final/end product inhibits its own production by inhibiting one of the enzymes acting early in the pathway by binding to the allosteric site of the first enzyme in the bcp

Question 27

whats an exmaple of negative feedback loop

Answer 27

high concentration of atp inhibits the production of more atp, high blood pressure, fever

Question 28

what do bcps depend on to work

Answer 28

atp

Question 29

what is atp

Answer 29

its a modified nucleotide that consists of three parts (1 5c sugar ribose, 1 nitrogenous base, and three 3-phosphate groups) that are held together by high energy bonds that when broken apart release energy.

Question 30

what is needed to break down atp

Answer 30

hydrolysis

Question 31

how does atp work

Answer 31

atp has three phosphates that when h2o is added and it undergoes hydrolysis, becomes adp with two phosphates and one inorganic free floating phosphorus which will bind to a target molecules to get phosphorylates and the process continues until we are left with AMP (adenosine mono-phosphate with one phosphate group)