Unit 2 chapter 8

Question 1

anabolic catabolic endergonic exergonic and metabolism

Answer 1

Anabolic those endergonic metabolic pathways involved in biosynthesis, converting simple molecular building blocks into more complex molecules, and fueled by the use of cellular energy. Conversely, the term catabolism refers to exergonic pathways that break down complex molecules into simpler ones.
Reactions that are spontaneous and release energy are exergonic reactions, whereas endergonic reactions require energy to proceed.
all of the chemical reactions inside a cell is metabolism

Question 2

Compare and contrast autotrophs and heterotrophs as well as the difference between phototrophs and chemotrophs

Answer 2

Autotrophs – “self feeders” that make their own organic molecules from inorganic carbon (ie: CO2)
Heterotrophs – “other feeders” that used organic molecules as their carbon source
Chemotrophs – energy source comes from energy in chemical compounds
Phototrophs – Energy harvested from photons of light

Question 3

Describe the importance of oxidation-reduction reactions in metabolism

Answer 3

The transfer of electrons between molecules is important because most of the energy stored in atoms and used to fuel cell functions is in the form of high-energy electrons. The transfer of energy in the form of electrons allows the cell to transfer and use energy incrementally;

Question 4

Describe why ATP, FAD, NAD + , and NADP + are important in a cell

Answer 4

The energy released from the breakdown of the chemical bonds within nutrients can be stored either through the reduction of electron carriers or in the bonds of adenosine triphosphate (ATP). In living systems, a small class of compounds functions as mobile electron carriers, molecules that bind to and shuttle high-energy electrons between compounds in pathways.

Molecules in the cell that are capable of accepting high energy electrons include
- NAD+ (NADH when reduced)
- FAD (FADH2 when reduced)

Ultimately the energy is converted to a universal “energy currency” called ATP

Question 5

Identify the structure and structural components of an enzyme

Answer 5

enzymes lower the amount of energy required to complete a reaction

Substrates bind to the enzyme’s active site, altering the structures of both the active site and the substrate and favoring transition-state formation; this is known as induced fit

Cofactors: inorganic ions that stabilize enzyme conformation and function
Coenzymes: organic molecules required for proper enzyme function and often derived from vitamins
Apoenzyme: an enzyme lacking a cofactor or coenzyme
Holoenzyme: an enzyme with a bound cofactor or coenzyme

Question 6

Describe the differences between competitive and noncompetitive enzyme inhibitors

Answer 6

Competitive inhibitors regulate enzymes by binding to an enzyme’s active site, preventing substrate binding.
Noncompetitive (allosteric) inhibitors bind to allosteric sites, inducing a conformational change in the enzyme that prevents it from functioning

Question 7

Compare and contrast the electron transport system location and function in a prokaryotic cell and a eukaryotic cell

Answer 7

The four major classes of electron carriers involved in both eukaryotic and prokaryotic electron transport systems are the cytochromes, flavoproteins, iron-sulfur proteins, and the quinones.

In each transfer of an electron through the ETS, the electron loses energy, but with some transfers, the energy is stored as potential energy by using it to pump hydrogen ions (H+) across a membrane. In prokaryotic cells, H+ is pumped to the outside of the cytoplasmic membrane (called the periplasmic space in gram-negative and gram-positive bacteria), and in eukaryotic cells, they are pumped from the mitochondrial matrix across the inner mitochondrial membrane into the intermembrane space.
. In prokaryotic cells, H+ flows from the outside of the cytoplasmic membrane into the cytoplasm, whereas in eukaryotic mitochondria, H+ flows from the intermembrane space to the mitochondrial matrix.

Question 8

Compare and contrast the substrate-level phosphorylation and oxidative phosphorylation

Answer 8

1- Substrate-level phosphorylation
When PO43- is transferred from an organic molecule directly to convert ADP  ATP
Glycolysis
Krebs cycle / citric acid cycle / tricarboxylic acid cycle

oxidative phosphorylation, which occurs during cellular respiration. Cellular respiration begins when electrons are transferred from NADH and FADH2—made in glycolysis, the transition reaction, and the Krebs cycle—through a series of chemical reactions to a final inorganic electron acceptor (either oxygen in aerobic respiration or non-oxygen inorganic molecules in anaerobic respiration). These electron transfers take place on the inner part of the cell membrane of prokaryotic cells or in specialized protein complexes in the inner membrane of the mitochondria of eukaryotic cells. The energy of the electrons is harvested to generate an electrochemical gradient across the membrane, which is used to make ATP by oxidative phosphorylation.