Gaseous Exchange in Plants and Animals

Flashcards on Gaseous Exchange in Plants and Animals

What is the definition of Gaseous Exchange?

The movement of respiratory gases across a respiratory surface.

What is the importance of Gaseous Exchange?

Enables cells to obtain oxygen for respiration, facilitates removal of Carbon (IV) oxide, and enables plants to obtain Carbon (IV) oxide for photosynthesis.

During the day, is the rate of photosynthesis faster or slower than the rate of respiration in plants?

Photosynthesis is faster than respiration.

At night, is the rate of respiration faster or slower than the rate of photosynthesis in plants?

Respiration is faster than photosynthesis.

In Experiment 1, boiling tube A, why did the red bicarbonate indicator turn yellow in the absence of light?

The leaf could not photosynthesise, and respiration occurred, leading to the accumulation of Carbon (IV) oxide and acidic conditions.

In Experiment 1, boiling tube B, why did the red colour of bicarbonate remain?

Boiling denatures the respiratory and photosynthetic enzymes, so there is no respiration or photosynthesis, and conditions remain neutral thus the indicator remains red.

In Experiment 1, boiling tube C, why did the bicarbonate colour turn purple?

The Carbon (IV) oxide produced during respiration was used up during photosynthesis, thus increasing the alkalinity.

What are stomata?

Pores for gas exchange present on one or both surfaces of Leaves.

What is the function of stomata?

It allows entry and exit of respiratory gases into the leaf.

What is the function of guard cells?

They control the opening and closing of stomata and are photosynthetic.

What are the adaptations of the guard cells?

Has thicker inner walls and thinner outer walls to allow differential opening, has chloroplasts unlike other epidermal cells, and is bean-shaped.

How does photosynthesis contribute to the opening of stomata according to the Photosynthetic theory?

Sugars produced during photosynthesis increase the osmotic pressure and draw water, causing the guard cells to expand and open the stomata.

How does a lack of photosynthesis contribute to the closing of stomata according to the Photosynthetic theory?

Sugars are converted to starch, lowering the osmotic pressure and causing the guard cells to lose water and close the stomata.

How does the Starch-sugar interconversion theory explain the opening of the stomata?

Increasing pH favors conversion of starch to glucose, increasing osmotic pressure and opening the stomata.

How does Starch-sugar interconversion theory explain the closing of the stomata?

Decreasing pH from accumulating Carbon (IV) oxide favors conversion of glucose to starch, lowering osmotic pressure and closing the stomata.

How does the Potassium ion theory explain the opening of the stomata?

Active transport of potassium ions into the guard cells increases osmotic pressure, drawing water and opening the stomata.

How does the Potassium ion theory explain the closing of the stomata?

Active transport of potassium ions out of the guard cells lowers osmotic pressure, causing the guard cells to lose water and close the stomata.

What are Xerophytes?

Plants that grow in arid areas and have mechanisms to prevent water loss.

How are Xerophytes adapted to their environment?

Stomata are mainly distributed on the lower epidermis, open at night and close during the day, and some plants have sunken stomata.

What are Mesophytes?

Plants that grow in wet areas with moderate water supply.

What are Hydrophytes?

Plants that grow in wet areas with adequate water supply.

How are Submerged Hydrophytes adapted to their environment?

They extract oxygen and carbon (IV) oxide dissolved in water, have wide and thin leaves, and lack a cuticle.

What is the function of Aerenchyma tissue in aquatic plants?

Aerenchyma tissue provides buoyancy and rapid diffusion of gases.

How are Emerged Hydrophytes adapted to their environment?

They have stomata only on the upper epidermis, a waterproof layer of cuticle, and aerenchyma tissue.

What special roots do mangroves have for gaseous exchange?

Pneumatophores that obtain oxygen from the air.

What are Lenticels?

Openings on stems and roots of woody plants that allow gaseous exchange by diffusion.

How does a leaf facilitate gaseous exchange?

The epidermis has stomata connected internally to the spongy mesophyll with air spaces.

What is diffusion?

The movement of oxygen from a region of high concentration to a region of low concentration.

What is ventilation?

The process of maintaining continuous flow of fresh air between a respiratory surface and the environment.

What are the adaptations of a respiratory surface?

Thin epithelial lining, moist epithelium, numerous and extensive surface area, permeable epithelial lining, highly vascularized, and a ventilation mechanism.

What respiratory surface does Amoeba, Paramecium and Euglena use?

Cell Membrane

What respiratory surface do fish use?

Gill filaments

What respiratory surface do insects use?

Tracheoles

What respiratory surface do mammals, birds, amphibians and reptiles use?

Alveoli

What respiratory surface do frogs and earthworms use?

Moist Skin

What structures make up the insect gas exchange system?

Spiracles, tracheae, and tracheoles.

What are the adaptations of the spiracle to its functions?

Muscular valve, tuft of hairs.

What are the adaptations of the tracheae to their functions?

Reinforced with spiral bands of chitin, and hollow.

What are the adaptations of the tracheoles to their functions?

Numerous tubes and branched at the tips, thin epithelial lining, and moist epithelium.

Explain why the tracheolar fluid reduces after strenuous muscular activity e.g. active flight

Lactic acid increases the osmotic pressure of fluids in the muscles, drawing tracheolar fluid in by osmosis. Oxygen diffuses in the muscles faster to enhance oxidation of lactic acid to water, carbon (IV) oxide and energy

How does Gaseous Exchange occur in aquatic insects?

Aquatic insects use tracheal gills or spiracles on the respiratory siphon

What is the mechanism of gaseous exchange in insects?

Muscular movement of the thorax and abdomen facilitates entry and exit of air into the tracheal system.

What structures are involved in gaseous exchange for fish?

Buccal cavity, gills, opercular cavity, operculum.

What is the function of gill bar?

To provide a large surface area for attachment of gill rakers and gill filaments.

What is the function of Gill rakers?

Trap or filter solid particles in water from reaching the delicate gill filaments.

What are the adaptations of the gill filaments?

Thin epithelium, highly vascularised, and numerous.

What is the process of inhalation for gaseous exchange in fish?

Muscles of the mouth contract, the floor of the mouth is lowered, water flows into the buccal cavity. The floor of the mouth is then raised. The operculum to bulge outwards. Water is sucked into the opercular cavity.

What is the process of exhalation for gaseous exchange in fish?

Muscles of the floor of the mouth relax and the floor of the mouth is raised further, mouth remains closed, operculum opens as deoxygenated water is forced out of opercular cavity.

How does gaseous exchange happens across the gill filaments?

Water has a higher oxygen concentration than blood in the gill filaments. Oxygen in the water diffuses through the thin epithelium of gill filaments into the blood capillaries. It combines with haemoglobin to form oxyhaemoglobin. The carbon (IV) oxide in blood tissues diffuses via the thin epithelium of gill filaments into the water.

What is counter-current flow system in fish?

A mechanism where water and blood flow in opposite directions within the respiratory surface.

What is the advantage of counter-current flow system?

Maintains a steep concentration gradient of gases between water flowing over the gills and blood.

What are the parts of the mammalian breathing system?

Nostrils, lungs, trachea, chest cavity, and diaphragm.

What are the adaptations of the nasal cavity?

Hairs and mucus trap dust, blood capillaries warm and moisten the air, and olfactory cells detect smell.

What us the function of Larynx/ voice box? And the Epiglottis?

Muscle fibres and vocal cords control pitch of sound. A flap of cartilage that closes the glottis when swallowing to prevent entry of food particles

What are the adaptations of the trachea?

Incomplete rings of cartilage support it, cilia enhance upward movement of mucus, and secretory cells produce mucus.

What is the function of plueral cavity?

The spongy nature of the lungs is due to presence of tiny air sacs called alveoli., reduces friction thus makes the lungs move freely in the chest cavity during breathing.

What is breathing/ventilation?

The mechanism involved in bringing in fresh air to the lungs and expelling air from the lungs.

What is cellular respiration?

A chemical process by which organic food substances are broken down in the presence of oxygen to release energy, water and carbon (IV) oxide.

What brings about the mechanism of breathing?

Movements of the ribs, intercostal muscles, sternum, vertebral column, and diaphragm.

What happens during inhalation/ inspiration?

External intercostal muscles contract, the diaphragm muscles contract, increasing the volume of the thoracic cavity and forcing air into the lungs to inflate.

What happens during Exhalation/ expiration?

External intercostal muscles relax, the diaphragm muscles relax assuming dome shape, decreases volume of thoracic cavity forces air out of lungs.

What are the adaptations of alveoli?

Thin epithelial lining, moist epithelium, numerous and extensive surface area, permeable epithelial lining, and highly vascularized.

How are breathing movements regulated?

Breathing movements are controlled by the medulla oblongata region of the brain.

What part of the brain controls breathing?

Medulla oblongata

What factors affect the rate of breathing in mammals?

Exercise, temperature, age, emotions, and health.

What is Tidal volume?

The amount of air taken into and out of the lungs during normal breathing.

How does the change in CO2 affect vigorous activities?

During vigorous exercise, concentration of carbon (IV) oxide in the tissues increases which triggers the brain to generate nerve impulses

How are respiratory and circulatory systems adopted to high altitudes?

Enlarged thorax and extensive vascularization.

What causes hypoxia/anoxia in high altitudes?

High altitude areas have low oxygen concentration.

What is asthma?

A respiratory problem caused by allergies to allergens or lung infection.

What is Bronchitis?

An inflammation of the bronchial tubes.

What is an acute bronchitis?

Complication of common cold due to exposure to low temperature

What is Whooping cough?

An acute infection of the respiratory tract by a bacterium called Bordetella pertussis

What is Pneumonia?

An inflammation of the lungs by micro- organisms caused by Streptococcus pneumoniae and Mycoplasma pneumoniae as well as viruses

What is Tuberculosis?

A respiratory disease caused by Mycobacterium tuberculosis. (Airborne)

What are the cause of Lung cancer?

Smoking deposits tar, inhalation of cancer causing substances, exposure to radiations, radioactive substances.

What is the Aim of Lab 1 experiments?

To compare the amount of carbon (IV) oxide in inhaled and exhaled air.

What is the Aim of Lab 2 experiments?

Experiment aim is to demonstrate the role of the intercostal muscles in breathing.