Moduel 3 : Adaptations For Gas Exchange

Question 1

What is the surface area?

Answer 1

The surface area refers to the total area of the organism that is exposed to the external environment.

Question 2

What is the volume?

Answer 2

The volume refers to the total internal volume of the organism (total amount of space inside the organism).

Question 3

What happens that will cause the surface - area-to-volume ratio to decrease?

Answer 3

As the surface area and volume of an organism increases the natio decreases. This is because volume increases much more rapidly than surface area as size increases.

Question 4

What are the steps to investigating sa:v ratio with agar method?

Answer 4

1. Cut coloured agar into cubes or required dimensions.
   2.calculate the surface area, volume and sa:v

Of each cube.
3. Place the agar cubes into boiling tubes containing the diffusions solution.
4. Measure the time taken for the agar cubes to go colourless

Question 5

What is the structure of the leaf?

Answer 5

1.waterproof cuticle
2. Upper epidermis - layer of tightly packed cells.
3. Palisade mesophyl -layer of elongated lens containing chloroplasts.
4.spongy mesophyl - layer of cells that contains an extensive network of air spaces.
5.stomata - pores (usually) on the underside of the leaf which allows air to enter.
6.guard cens-pairs of cans that control the opening and closing of the stroma.
7. Lower epidermis - layer of tightly packed cells.

Question 6

What are the mechanisms of a leaf?

Answer 6

• When guard cans are turgid (full of water) the stroma remains open allowing air to enter the leaf.
• the air spaces within the spongy mesophyll layer allus carbon dioxide to rapidly diffuse into cells.
  -the carbon dioxide is quickly used up in photosynthesis by cells containing chloroplasts - maintaining the concentration gradient.
• No active vertiation is required as the thinness of the plant tissues and the presence of stomata helps to create a short diffusion pathway.

Question 7

What adaptations do plants have that have a plentiful supply of water?

Answer 7

• leaves with a short diffusion distance, through the stomata and a larger surface area provided by the air spaces in the spongy mesophyll.
• however, this makes them venerable to water loss.

Question 8

What adaptations might a plant have that has a limited supply of fresh water?

Answer 8

• Very few stroma
• sunken stomata
• hairs surrounding sterna
• needle-shaped or small leaves
• waxy cuticle.
• plants with these adaptations are described as xerophytic.

Question 9

What does the large surface Area of single - called organisms allow for?

Answer 9

The maximum abscrbtion of nutrients and gases and secretion of waste products.

Question 10

How does gas exchange happen in single celled organisms?

Answer 10

Single celled organisms have a high sa:v ratio which Allans for the exchange of substances to occur via simple diffusion.

Question 11

What is a definition of simple diffusion ?

Answer 11

Diffusion from high to low concentration den the concentration gradient.

Question 12

Why do organisms require a a supply of oxygen?

Answer 12

Organisms require ATP in order to carry out the biochemical processes required for survival. The majority of ATP is produced through aerobic respiration which requires oxygen.

Question 13

Why do organisms require the removal of Carbon dioxide?

Answer 13

Carbon dioxide is a toxic waste product of aerobic respiration.it it accumulates in cells/tissues it alters the pH.

Question 14

What is the metabolic rate?

Answer 14

The metabolic vale ofan organism is the amount of energy expended by that organism within a given period of time.

Question 15

What is the basal metabolic rate (BMR)?

Answer 15

The basal metabolic rate is the metabolic rate of an organism when at rest. The basal metabolic role is significantly lower than when an organism is actively moving.

Question 16

How can the metabolic rate be measured?

Answer 16

• oxygen consumption
• carbon dioxide production
• read production

Question 17

What do effective exchange surfaces in organisms have?

Answer 17

• A large surface area.
• short diffusion distance.
• concentration gradient maintained.

Question 18

How does gas exchange happen in terrestrial insects?

Answer 18

Insects have evolved a breathing system that delivers oxygen directly to all the organs and tissues of their bodies, via holes in the exoskeleton called spiracles.

Question 19

How do spiracles help gas exchange in terrestrial insects?

Answer 19

They have valves that allow them to open and close.
- it allows air to enter the insect and flow into the system of tracrece.
- most of the time, the spiracle is closed to reduce water loss.

Question 20

What are tracheae and new have they adapted for efficient gas exchange in terrestrial insects?

Answer 20

Tracheae are tubes within the insects breathing system which leads to tracheoles (narrow tubes).
-the tracheae walls have reinforcements that keeps them open as the air pressure inside them fluctuates.

Question 21

How does the gas move from the tracheae to muscle fibers in terrestrial insects?

Answer 21

• A large number of tracheoles run between cells and into the muscle fibers - the site of gas exchange.

Question 22

How is a concentration gradient created in terrestrial insects?

Answer 22

A concentration gradient is created as oxygen is used by respiring tissues allowing more to more in through the spiritless by diffusion.
- carbon dioxide produced by the respiring tissues moves out through the spiracles Devon a concentration gradient.

Question 23

How do very active, flying terrestrial insects get a more rapid supply of oxygen?

Answer 23

Very active, flying insects need more rapid supply/intake of oxygen. They create mass flow of air into the tracheal system by: closing the spiracles and using muscles to create a pumping movement for ventilation.

Question 24

What is lactate and what does it ao in the gas exchange in terrestrial insects?

Answer 24

During flight the production of lactate in the respiring muscles, lowers the water potential of muscle cells.
- water found at the narrow ends of the trachooles is thendrewn into the respiring muscle by osmosis.
- this allows gases to diffuse across more quickly.

Question 25

How do terrestrial insects prevent water loss?

Answer 25

-Insects possess a waterproof exoskeleton that prevents water loss. - The waterproof waxy coating of the exoskeleton mares gas exchange by diffusion very difficult. - as a result, insects move evolved a breathing system (the tracheal system) which consists of many tubes that carry oxygen directly to all tissues and cans of the body. - spires are openings in the exoskeleton of insects that are connected to the tracheal system.

Question 26

How is oxygen present in water?

Answer 26

Oxygen dissolves less readily in water. Air contains box more oxygen then water. Fish extract oxygen directly from water.

Question 27

What is the structure of fish gills in bony fish?

Answer 27

-Fish gills are comprised of gill arches, each with two stacks of filaments. - filaments are covered with Neros of lamenae, which are thin, place like structures. - The lamellar contain a dense reswerse of capillaries.

Question 28

What are the mechanisms of gas exchange in a fish?

Answer 28

- Capillary system in lamellae ensures blood flows in the opposite direction to water flow (counter-current system). - counter-current system maintains concentration gradient along the capillary. - water with lowest oxygen concentration is adjacent to the most deoxygenated blood.

Question 29

How does the counter-current system maintain the concentration gradient in a fish?

Answer 29

1.The counter current flow ensures that the concentration gradient of oxygen is maintained along the entire length of filament. 2. Water with a higher oxygen concentration always meats blood with a lower oxygen concentration, facilitating continuous diffusion of oxygen into the blood.

Question 30

How does the counter-current system maximize oxygen uptake in fish?

Answer 30

1. By maintaining the concentration gradient, the counter-currents system allus for more efficient oxygen uptake. 2.fish can extract up to 80 - 90% of the oxygen from the water passing over their gills.

Question 31

How does the counter current system allow for efficient gas exchange in fish?

Answer 31

1. the counter-current system also facilitates the removal of carbon dioxide form the blood into the water. 2. this efficient gas exchange is crucial for the fish's respiration and overall ,metabolic process.

Question 32

how does the air pass through the human respiratory system?

Answer 32

- air enters the respiratory system through the nasal cavity, where it is filtered, warmed, and humidified. - it then passes through the pharynx, a muscular tube that connects the nasal cavity to the larynx. - the larynx, also known as the voice box, is located at the top of the trachea and contains the vocal cords. - from the larynx, air moves into the trachea, a large tube that extends down into the chest cavity. - the trachea divides into two bronchi, each leading to one lung. within the lungs, the bronchi further divide into smaller tubes called bronchioles. these bronchioles continue to branch out and end in tiny air sacks called alveoli. the alveoli are surrounded by a network of capillaries, where gas exchange occurs. - oxygen from the air diffuses into the blood, and carbon dioxide from the blood diffuses into the alveoli to be exhaled.

Question 33

what are tracheal rings and how do they help in gas exchange in humans?

Answer 33

they are made of cartilage (a strong flexible tissue). they help to support the trachea and ensure it stays open, while allowing it to move and flex while we breath.

Question 34

what is ciliated epithelium and how is it useful in gas exchange in humans?

Answer 34

it is a specialized tissue found along the trachea down to the bronchi. each cell has small projections of cilia which sweep mucus, dust and bacteria upwards and away from the lungs and the epithelium itself.

Question 35

What are goblet cells andwhat is there role in the respiratory system of humans?

Answer 35

They are mucus producing cells that secrete mucus which traps dust, bacteria and other microorganisms and prevents them form reaching the lungs. They are located scattered throughout the ciliates epithelium in the trachea. The mucus produced is then swept along by the cilia of the ciliates epithelium upwards and is swallowed. The mucus and any microorganisms will then by destroyed by the acid in the stomach.

Question 36

How does smooth muscle make gas exchange more efficient in humans?

Answer 36

It can be found throughout the walls of the bronchi and bronchioles. It helps to regulate the flow of air into the lungs by dilating when more air is needed and constricting when less air is needed.

Question 37

How does the extensive network of capillaries help provide humans with efficient gas exchange?

Answer 37

Carbon dioxide diffuses out of the capillaries and into the alveoli to be exhaled, while oxygen diffuses the other way from alveoli and into the capillaries to be carried around the body.

Question 38

How is gas’s exchange from the alveoli into the blood in humans?

Answer 38

Oxygen and carbon dioxide are exchanged in a process of simple diffusion. The air in the alveoli contain a high concentration of oxygen, this can diffuse from the alveoli and into the blood capillaries before being carried away to the rest of the body for aerobic respiration. The blood in the capillaries has a relatively low concentration of oxygen and a height concentration of carbon dioxide. The carbon dioxide diffuses from the blood and into the alveoli and is then exhaled.

Question 39

How does the large number of alveoli allow for efficient gas exchange in humans?

Answer 39

The average human adult has about 480-500 million alveoli in their lungs. This equals a surface area of 40-75m^2. The large number of alveoli increases the surface area available for oxygen and carbon dioxide to diffuse across.

Question 40

How do thin walls allow for efficient gas exchange in humans?

Answer 40

The walls of the alveoli are only one cell thunk and these cells are flattened. This means that gases have a very short diffusion distance so gas exchange is quick and efficient.

Question 41

How does the extensive capillary network allow for efficient gas exchange in humans?

Answer 41

The walls of the capillaries are only one cell thick and these cells are flattened, keeping the diffusion distance fr gases short. The constant flow of blood through the capillaries means that oxygenated blood is brought away from the alveoli and deoxygenated blood is brought to them. This maintains the concentration gradient necessary for gas exchange to occur.

Question 42

What mechanisms are required in inhalation in the human respiratory system?

Answer 42

- external intercostal muscles contract. - rib cage moves up and out. - diaphragm contracts and flattens. - volume of thorax decreases. - air is drawn in.

Question 43

What mechanisms are required for exhalation in the human respiratory system?

Answer 43

-external intercostal muscles relax. - recoil of elastic fibres surrounding the alveoli cause air to be forced out. - internal intercostal muscles contract. - abdominal muscles contract. Rib cage moves down and in. Diaphragm relaxes and becomes dome shaped. - volume of thorax increases. -air is forced out.

Question 44

How can breathing be effected by activity?

Answer 44

When at rest, breathing is shallow and steady. When exercising, breathing is deeper and more frequent.

Question 45

What is the tidal volume?

Answer 45

The volume of air inspired per breath when at rest.

Question 46

What is the breathing rate?

Answer 46

The number of breaths taken per minute.

Question 47

How can you show volume changes in the lungs?

Answer 47

Using the results from a spirometer.

Question 48

What is the Pulmonary Ventilation Rate (PVR) ?

Answer 48

The volume of air breathed (in or out) in one minute.

Question 49

How do you calculate the PVR?

Answer 49

PVR= tidal volume x breathing rate

Question 50

How does cancer effect the normal workings of the lungs?

Answer 50

Tumours develop if mutations occur in oncogenes or tumour-suppressor genes of the bronchial epithelial cells. If the tumour becomes large because it has no method of programmed cell death, it survives by developing its own blood supply. The tumour interfears with the normal working of the longs, such as by squeezing against blood vessels or cancer cells entering the lymphatic system. Symptoms include coughing up blood, a persistent cough, increased mucus, back or shoulder pain, wheezing, breathing difficultly and sudden weight loss.

Question 51

What is COPD and what is its key symptoms?

Answer 51

Chronic bronchitis and emphysema. Symptoms: shortness of breath, chronic cough, crest tightness, wheezing, and difficulty breathingduring physical activity.

Question 52

What does COPD stand for?

Answer 52

chronic Obstructive Pulmonary Disease.

Question 53

What happens to the lungs in COPD?

Answer 53

Enlarged goblet cells produce mere mucus, destroying cilia the in trachea and preventing them from sweeping mucus away from the lungs. Much blocks narrow bronchioles, causing coughing, scar tissue und infection.

Question 54

How can COPD affect the alveoli?

Answer 54

Infection attract phagocytes, which release elastase, damaging the elasticity of the alveolar walls. Without enough elastin, alveoli breaking down, creating large air spaces and causing wheezing and breathlessness. Advanced COPD may require a constant supply of oxygen.

Question 55

What chemicals are found in cigarettes?

Answer 55

Tar - a carcinogen (a substance that causes cancer) Nicotine-an addictive substance which narrows blood vessels Carbon monoxide - reduces the oxygen carrying capacity of the blood.

Question 56

How does tar effect air passage?

Answer 56

Tar destroys the cilia (which carry dust and microbes trapped by mucus away from the lungs), causing the buildup of mucus and potentially leading to bronchitis as the lining of the bronchi become irritated.

Question 57

How does tar effect the alveoli?

Answer 57

It contributes to the break down of the alveoli, causing them to merge together. This creates an insufficient SA:V ratio, allowing less gas exchange. This reduces the efficiency of gas exchange, causing emphysema where less oxygen is carried in blood. Tar can also build up and form a layer on top of the alveolar cells which can increase the diffusion distance for gas exchange.

Question 58

What is forced expiratory volume (FEV)?

Answer 58

The volume of air that can be forcibly exhaled from the lungs after taking the deepest breath possible.

Question 59

What is Forced Expiratory Volume in 1 second (FEV1)?

Answer 59

The maximum volume of air that can be forcibly exhaled in one second. In a healthy version, this is usually 80% or higher.

Question 60

Why is FEV1 important?

Answer 60

It is a key indicator of lung function and is used to diagnose and monitor respiratory conditions such as asthma, COPD, and emphysema.

Question 61

How does smoking effect FEV1?

Answer 61

Long term smoking can cause a significant decrease in FEV1, making it harder to breath out quickly and forcefully. Regular measurements of FEV1 can help monitor the progression of lung diseases and the impact of smoking cessation.