BIOLOGY EXAM 2024

TOPICS; RESPIRATION

  • Define Respiration

  • Where respiration takes place

  • Write chemical formula for aerobic and anaerobic respiration

  • State the difference between aerobic and anaerobic respiration

  • What happens to your muscles when you are in a race and you are deprived of oxygen

  • Why muscles become starved of O2 when running

  • What is produced and how its produced and affects performance (lactic acid)

  • When anaerobic respiration occurs in plants, what is produced and the process

  • Explain the mechanism of breathing

  • Describe gaseous exchange; Draw, Label and Annotate a diagram that illustrates this

  • Discuss the impact of smoking

  • Tell the appearance of the lung of a smoker

  • Benefits on smoking being banned in public places

  • What is the addictive substance in cigarettes?

  • Why humans need oxygen to stay alive

WHAT IS RESPIRATION?

Respiration is the process by which energy in food is made available for a cell to do the work necessary to keep it alive. It is catalysed by enzymes and occurs slowly in a large number of stages.

Cells convert glucose into carbon dioxide and water, and energy

CHARACTERISTICS OF RESPIRATION

  • Takes place in cells

  • A chemical involuntary process

  • Energy is released in form of ATP

  • Intracellular process

  • A large number of enzymes are used

ADENOSINE TRIPHOSPHATE (ATP)

Energy released at each stage during respiration is used to build energy-carrying molecules called ATP. ATP is formed by combining some of the energy released with an adenosine diphosphate or ADP molecule and a phosphate group present in the cell.

ADVANTAGES OF STORAGE AND TRANSPORT OF ENERGY IN ATP

  • Energy can be released rapidly

  • Only a small amount of energy is released when each ATP is broken down.

  • Energy can be released exactly where it is needed in the cell

ENERGY RELEASED BY ATP IS USED BY CELLS:

  • To manufacture complex molecules, like DNA

  • For cell growth and repair

  • For cell division

  • For special functions in specialised cells

WHY IS OXYGEN ESSENTIAL TO SURVIVAL?

In summary, oxygen is crucial because it is essential for cellular respiration, the process by which our cells produce energy, which enables efficient ATP production, powers vital organ functions and supports metabolic processes that are essential for life. Without oxygen, our cells would not have the energy they need to survive, and our organs would cease to function.

AEROBIC RESPIRATION

Aerobic respiration is respiration which uses oxygen. It occurs in most cells and takes place in the mitochondria. It always produces carbon dioxide, water and Energy (about 38 ATP molecules).

CHEMICAL FORMULA

ANAEROBIC RESPIRATION

Anaerobic respiration is respiration without oxygen, that only occurs in some cells in the cytoplasm. In this type of respiration, glucose is not completely broken down. Energy is still produced when cells respire anaerobically, although it is a much smaller amount for each molecule of glucose. Energy is produced because the cells continue to do work (contract and relax).

CHEMICAL FORMULA

C6H12O6 -> 2C3H6O3 (Glucose -> Lactic acid)

IN YEAST CELLS

Yeast cells carry out anaerobic respiration known as fermentation. It produces ethanol, carbon dioxide and 2 ATP molecules per glucose molecules.

FORMULA

IN MUSCLE CELLS

During strenuous exercise, muscle cells need much more energy for the extra work they are doing.

Their breathing rate and heart rate increase in an attempt to get more oxygen to these cells.

Sweating occurs to help lose some of the extra energy as heat. A lot of heat is produced with this increased respiration.

After a while of sustained exercise, the oxygen supply becomes inadequate, even though the body tries to acquire it through increased heart rate and panting. The muscle cells then respire anaerobically since there is no oxygen left.

WHAT IS BREATHING?

Breathing is the process of inhaling and exhaling the air in and out of the lungs. When breathing, oxygen is inhaled and carbon dioxide is exhaled.

CHARACTERISTICS OF BREATHING

  • A physical voluntary process

  • No energy is produced

  • An extracellular process

  • No enzymes are used

  • Takes place through respiratory organs like the lungs, nose, etc.

GASEOUS EXCHANGE

SMOKING

Appearance of a Smoker's Lungs:

Color: Darker (black or brownish), from tar and other chemicals in cigarette smoke.

Texture: Damaged, with possible signs of emphysema (larger air spaces), increased mucus, fibrosis, and scar tissue. Lungs may appear spongy or flaccid because smoking damages the alveoli

Airways: Thickened, inflamed, or obstructed, characteristic of chronic bronchitis or COPD.

Lung Function: Decreased lung capacity, with possible hyperinflation or collapsed areas.

Lung Cancer: Presence of tumors or masses, which may appear as irregular, nodular spots.

Banning smoking in public places offers several key benefits:

1. Improved Public Health: It reduces secondhand smoke exposure, protecting non-smokers from health issues like heart disease, lung cancer, and respiratory problems.

2. Encourages Smoking Cessation: Smoking bans create pressure for smokers to quit or cut down, potentially reducing overall smoking rates.

3. Better Air Quality: Public spaces become cleaner and healthier, with reduced exposure to harmful chemicals found in cigarette smoke.

4. Protection for Vulnerable Groups: It safeguards children, pregnant women, and people with respiratory conditions from the dangers of secondhand smoke.

5. Social Benefits: Smoking bans contribute to healthier public spaces, normalize non-smoking behavior, and help foster a culture of wellness.