Cell Respiration

Question 1

What is cell respiration?

Answer 1

Cell respiration is the controlled release of energy from organic compounds in cells

Question 2

What is the molecule of ATP?

Answer 2

Adenosine triphosphate (ATP) consists of a 5-carbon sugar, ribose, which is bonded to a nitrogenous base and 3 phosphate groups.
ATP is a nucleotide
The bond connecting the phosphates are considered high-energy bonds because the phosphates are negatively charged and repel one another. These bonds can be broken by a hydrolysis reaction, thereby releasing energy

Question 3

Why does a cell need ATP?

Answer 3

When ATP splits up to become ADP and phosphate, most of the energy that is released is converted to heat energy and hence all energy eventually ends up as heat.
The heat energy initially can be used to raise the temperature of the organism, … but eventually it is lost to the environment and cannot be used for metabolic processes.

Question 4

How does ATP and ADP work?

Answer 4

The formation of ATP by adding a phosphate and hydrogen ion to ADP is an endergonic reaction: energy is absorbed (stored ATP in bonds). Adding a phosphate group is called phosphorylation

When energy is needed within the cell, ATP is converted to ADP. One of the bonds connecting the
phosphate phosphate is broken and ADP energy is released (exergonic reaction)

Question 5

Differences Between Anaerobic and Aerobic Cell Respiration

Answer 5

If a cell does not have glucose available, other organic molecules may be substituted, such as fatty acids and amino acids.
Cellular respiration can be either aerobic (requires oxygen) or anaerobic (does not require oxygen).
Anaerobic is less efficient in creating energy.

Question 6

What is Aerobic Respiration?

Answer 6

Needs the presence of oxygen to proceed
Aerobic respiration occurs in cells that have mitochondria
A large yield of ATP (36) is given
Water is a waste product recycled in the cell
CO2 is excreted through gas exchange

Question 7

What is Anaerobic Respiration?

Answer 7

Occurs in the absence of oxygen
Carbon dioxide and ethanol are produced in yeast (fermentation)
Lactic acid (lactate) is produced in humans and other animals.
The overall yield of ATP is very low (2)

(Lactic acids can return to pyruvate when oxygen is available)

Question 8

What variables affect the rate of cell respiration?

Answer 8

1. Temperature: The optimal temperature for cell respiration is 30°C. Significantly below will be slower due to less collisions with enzymes and significantly higher temperatures will cause enzymes to denature
2. Carbon dioxide concentration: as carbon dioxide concentration increases, rate of respiration decreases
3. Oxygen concentration: As oxygen concentration increases, so does the rate of cellular respiration.
   The absence cause anaerobic respiration
4. Glucose concentration: as glucose concentration increases so does rate as there will be more collisions with enzymes. Eventually the rate will plateau once all enzymes are saturated
5. Type of cell: some cell require more energy than others. Those that require more ATP will have a higher rate of respiration ex. Muscle cells