Cellular Respiration, Photosynthesis and Gas Exchange

Question 1

Cellular Respiration

Compare cellular respiration and breathing

Answer 1

Cellular respiration is an internal cellular process, while breathing is an external process. But both are machanisms which help obtain oxygen and respirate.

Question 2

Cellular respiration

What is the word equasion and chemical equasion for cellular respiration

Answer 2

Question 3

Cellular respiraton

What are 4 ways the human body uses ATP

Answer 3

1. Synthesis of genetic materials, macromolecules
2. Synthesis of cellular components
3. Muscle movement
4. Molecules transportation

Question 4

Anaerobic and Aerobic respiration

Compare Anarobic and Aerobic respiration

Answer 4

• Oxygen is required for aerobic but not anarobic
• The site of reaction for anarobic respiration is the cell cytoplasim and for aerobic it is mitochondria and the cytoplasm
• Glycolosys is the chemical process involved with anarobic respiration and glycolosys, kerbs cycle and electron transport chain for aerobic
• Anarobic produces 2 ATP and Aerobic produces 32

Question 5

Mitochondria and ATP

Explain why villus cells contain a high number of motochondria

Answer 5

T increase ATP for active transport of nutrients againsed a concentration gradient.

Question 6

Aerobic and Anarobic respiration

Outline the importance of aerobic respiration.

Answer 6

To convert oxygen and food into energy that organisms depend on for life.

Question 6

Anarobic and Aerobic respiration

What are the end products of aerobic respiration

Answer 6

Carbon Dioxide (CO2)
Water (H2O)
Adenosine Triphosphate (ATP)

Question 6

Anarobic and Aerobic respiration

Outline how waste products from respiration are removed from cells, and ultimetly, the body

Answer 6

1.Cellular Level

CO2 and H2O are produced in the mitochondria during respiration.

2. Transport in the Blood
   CO2: Dissolved in plasma.
   Converted to bicarbonate ions (HCO3-) in red blood cells.
   Bound to hemoglobin as carbaminohemoglobin.
   H2O: Diffuses into blood plasma.
3. Transport to the Lungs
   Blood carries CO2 to the lungs.
   Excess water transported to the kidneys.
4. Exhalation of CO2
   In the Lungs:
   Bicarbonate is converted back to CO2.
   CO2 diffuses into alveoli.
   Exhalation: CO2 is expelled during breathing.
5. Excretion of Water
   Kidneys: Filter excess water, excreted as urine.
   Skin: Water lost as sweat.
   Lungs: Water vapor lost during exhalation.

Question 6

Gas Exchange

What are the requirments for a gas exchange surface?

Answer 6

Moist: Gassess must be dissolved to be diffused into/out of cells

Large surface area: The larger the surface area, the greater the rate of gas exchange.

Thin: Diffusion is faster when the diffusion distances is are small. Therefore, gas exchange surfaces are usually very thin (one cell thick) in order to maximise the rate of gas exchange.

Question 6

Gas exchange

What is respiration

Answer 6

The release of energy from food. It occurs in the mitochondrion

Question 6

Gas exchange

What is gaseous exchange?

Answer 6

The swapping of gases across a membrain. It occurs twice; at the primary gas exchange surface and between the transport medium respiring cells. This is a passive process;it does not use ATP

Question 7

Gas exchange surfaces

Diffusion across a membrain

What organisms have this type, and show structure and function

Answer 7

Protozoa: are a small enough for direct diffusion across a membrain

Hydra and jellyfish: these animals have a central activity filled with water. SImple diffusion across a cell membrain is sufficient, as the full thickness of the animal at any one point is only two cells. Oxygen passes in and carbon dioxide passes out.

Question 8

Gas exchange surfaces

Skin Breathers

What organisms have this type, and show structure and function

Answer 8

These animals live in moist habitats. They use their skin as a respiratory surface. To keep it moist they secrete mucus. Just below the skin is a dence network of capillaries that connect to larger vessels which keep the blood moving

Question 9

Gas exchange surfaces

Tracheal systems

What organisms have this type, and show structure and function

Answer 9

• The insect gas exchange system is completley seperate from their blood (kinda) system
• Air moves through tiny openings called spiracels which connect to a system of tubes called trachea
• These lead to small tracheoles, then lead to moist epothelium that reaches every cell
• Some insects have air bags or pump their body to assist in gas exchange

Question 10

Gas exchange surfaces

Gills

What organisms have this type, and show structure and function

Answer 10

Fish have a system of gills, which are external to the body and are bathed in water.
They consist of thin filaments supported by bony gill arch, they are well supplied with blood
Fish constantly pump water through their mouth and out over the gills. Because they use the counter-current exchange method, they can extract 80% of oxygen out of the water

Question 11

gas exchange surfaces

Lungs

What organisms have this type, and show structure and function

Answer 11

Because the lungs are localised and restricted to one place, there has to be an efficient transport system to connect the lungs with the rest of the body. In some animals, such as frogs the lungs are a simple baloon. The lungs of mammals are a vast sponge with a SA of 100m2

Question 12

Gas exchange surfaces

What is the importance of countercurrent flow in fish

Answer 12

Countercurrent flow in fish gills is important because it maximizes oxygen uptake and carbon dioxide removal. By having water and blood flow in opposite directions, it maintains a gradient that allows for efficient gas exchange, enabling fish to extract more oxygen from water and expel CO2 effectively.

Question 13

Diseases

What is the affect of pneumonia and emphysema on gas exchange and the functioninf of the affected individual

Answer 13

Pneumonia and emphysema both hinder gas exchange in the lungs. Pneumonia causes inflammation and fluid buildup, reducing oxygen intake. Emphysema damages lung tissue, decreasing surface area for gas exchange. Both conditions lead to breathing difficulties, fatigue, and reduced physical ability. Treatment includes medication and supportive care for pneumonia, while emphysema management focuses on symptom relief and slowing progression.

Question 14

Anarobic and Aerobic respiration

Outline the progress of aerobic respiration

Answer 14

Glycolysis
* Location: Cytoplasm of the cell.

• Process: Glycolysis is the initial stage of both aerobic and anaerobic respiration. It involves the breakdown of one molecule of glucose (a six-carbon molecule) into two molecules of pyruvate (each a three-carbon molecule).
• ATP Yield: Produces a net gain of 2 ATP molecules per glucose molecule.
  NADH Production: Produces 2 NADH molecules, which carry high-energy electrons to the electron transport chain.

Krebs Cycle (Citric Acid Cycle)
* Location: Mitochondrial matrix.

• Process: Each pyruvate molecule is converted into Acetyl-CoA, releasing one molecule of CO₂ and producing one NADH per pyruvate (2 NADH per glucose). Acetyl-CoA enters the Krebs cycle, where it undergoes a series of chemical reactions to produce energy carriers.
• ATP Yield: Produces 2 ATP molecules per glucose molecule (one ATP per cycle, with each glucose molecule generating two cycles).
• NADH and FADH₂ Production: Produces 6 NADH and 2 FADH₂ molecules per glucose molecule.

Electron Transport Chain (ETC) and Oxidative Phosphorylation
* Location: Inner mitochondrial membrane.

• Process: NADH and FADH₂ donate electrons to the ETC. As electrons move through the chain, protons (H⁺) are pumped across the inner mitochondrial membrane, creating a proton gradient.
• ATP Yield: The proton gradient drives ATP synthase to produce ATP. This process yields about 32-34 ATP molecules per glucose molecule.
• Oxygen’s Role: Oxygen serves as the final electron acceptor, combining with electrons and protons to form water (H₂O).

Question 15

Aerobic and Anarobic Respiration

Outline the process of Anarobic respiration

Answer 15

Glycolysis:
Location: Cytoplasm.
Inputs: Glucose.
Outputs: 2 ATP, 2 NADH, and 2 pyruvate molecules.

Fermentation:
* Lactic Acid Fermentation:
Inputs: Pyruvate, NADH.
Outputs: Lactic acid, NAD⁺.
* Alcoholic Fermentation:
Inputs: Pyruvate, NADH.
Outputs: Ethanol, CO₂, NAD⁺.

Question 16

Aerobic and Anarobic respiration

Explain how the ADP-ATP cycle works

Answer 16

Question 17

Photosynthesis

What is the word equation and chemical equasion for photosynthesis?

Answer 17

Question 18

Photosynthesis

Explain what happens in the two stages of photosynthesis.

Answer 18

Light-dependent phase:
* Occurs in thylakoid membranes of chloroplasts.
* Light energy is absorbed by chlorophyll and other pigments.
* Water (H₂O) is split, releasing oxygen (O₂), protons (H⁺), and electrons (e⁻).
* ATP and NADPH are produced as energy carriers.

Light-independent phase:
* Occurs in the stroma of chloroplasts.
* Use: ATP; Co2; NADPH
* Make: Glucose

Question 19

Nutrients and gas requirments

What are the difference between autotrophs and heterotrophs

Answer 19

Autotrophs are organisms that produce their own food from raw materialks and light. Examples include plants, algae, and some types of bacteria.

Heterotrophs are organisms that dont make their own food. Dogs, birds, fish, and humans are all examples of heterotrophs

Question 20

Nutrient and gas requirments

What is the transpiration-cohesion-tention theory?

Answer 20

1. Water Uptake by Roots: Water is absorbed by the roots from the soil through osmosis. The water enters the root xylem.
2. Ascent of Sap: Due to the strong hydrogen bonding of water molecules they stick together, forming a continuous column. As water evaporates from the leaf surface during transpiration, it creates a negative pressure or tension in the leaf’s air spaces.
3. Pulling Effect: The tension created by transpiration pulls the cohesive water column upward through the plant. This is facilitated by the strong cohesive forces between water molecules and the adhesive forces between water molecules and the walls of the xylem vessels.
4. Water Movement to Leaves: The continuous pull draws water from the roots, through the stem, and into the leaves, where it can be used for photosynthesis, nutrient transport, and other physiological processes.