Gas exchange

Question 1

what is the neeed for gas exchange in living organisms?

Answer 1

Gas exchange allows organisms to obtain the gases required for cellular processes such as aerobic respiration and photosynthesis, and remove waste gases produced in metabolic reactions

Question 2

what r the properties of gas exchange surfaces, describe em, what makes them different etc? what makes them efficient at exchanging gases like oxygen or co2?
what shit does an organ in a living organism (lungs, plants etc) need to be able to exchange gasses in the most efficient manner?

Answer 2

1. large surface area - more membrane surface available for gases to diffuse across
2. permeability - exchange surface needa have pores or holes or sum to allow gasses to be exchanged
3. composed of a thin tissue layer - short distance for the gasses to move ACROSS/THROUGH
4. moist surface - helps to dissolve gases before they diffuse across the exchange surface
5. concentration gradient - there needs to be a diff in gradients in that gas exchange surface/organ for diffusion to occur, there needs to be a difference in the amount of that molecule in a specific area etc etc
   The gas will move from an area of higher concentration to an area of lower concentration.

Question 3

define diffusion - how does gas exchange occur?

Answer 3

Gas exchange occurs via a process called diffusion . Diffusion is the random net movement of particles from an area of higher concentration to an area of lower concentration, leading to equilibrium

Question 4

Explain how concentration gradients are maintained at exchange surfaces in animals.

Answer 4

there r adaptations in animals to help maintain steep concentration gradients (steep = big diff in where the molecules r)

Question 5

what does it mean by concentration gradients?

Answer 5

Concentration gradient refers to the difference in concentration of a substance between two areas. The bigger the difference in concentration, the steeper the concentration gradient, and the faster the rate of diffusion

Question 6

what are the adaptations in animals in their exchange surfaces (lungs) that allow them to maintain steep concentration gradients?

Answer 6

1. dense network of blood vessels (u have a lot of things that help carry blood thru out the body, and there is a lotta blood in em) - there is much opportunity for substances to be exchanged between the surface and the blood - easy for oxygen to go to blood naaaa
2. continuous blood flow - ensures that as soon as substances move into the blood, they are transported away by the continuous blood flow, ensuring a low concentration of that substance in the blood supply close to the exchange surface. - so if there is a low concentration of that substance cuz its being moved away due to the blood flow = more effective diffusion cuz steeper concentration g.
3. ventilation (inhale and exhale type shit) - ensures the air or water rich in the desired gas is moved across the exchange surface.
   so whatever ur taking in is moved across the body and available to all parts.

Question 7

what r blood vessels?

Answer 7

things that carry blood thru out the body
there r 3 main types
1. arteries - take heart blood n give to organs
2. veins - take organ blood n give to heart
3. capillaries - small vessels that connect arteries and veins.

Question 8

Describe the adaptations of mammalian lungs for gas exchange, what r they?

Answer 8

1. Alveolar fluid/surfactant - cells in the alveoli (pneumocytes) secrete a surfactant which moistens the surface of the alveoli allowing gases to dissolve into the surfactant before diffusing across the wall of the alveoli and capillary into the blood.
2. A highly branched network of bronchioles - bronchioles extend to alveoli (exchange surface of the lungs) which increases the surface area for gas exchange = increasing the rate of gas exchange - means that the molecules that r being exchanged can happen quickly. The high degree of branching also ensures that air is distributed throughout the lungs.
3. Extensive capillary beds surrounding the alveoli - This means that there is a very short distance for oxygen to diffuse from the air in the alveoli into the blood and for carbon dioxide to diffuse from the blood into the alveoli.
4. Many alveoli - create a larger surface area = there is lots of area across which carbon dioxide and oxygen can be exchanged.

Question 9

how r mammals able to maintain steep concentration gradients and how is this possible?

Answer 9

by separating oxygenated and deoxygenated blood. This is possible because of a double circulatory system which helps to ensure that blood transported to respiring cells is highly oxygenated.

Question 10

what is a double circulatory system?

Answer 10

To go around the body once, blood has to pass through the heart twice.

Question 11

what r pneumocytes

Answer 11

cells in alveoli

Question 12

what is the surfactant in alveolar fluid made up of / the pneumocytes

Answer 12

the surfactant that the alveolar fluid contains is a mix of lipids n protiens

Question 13

what is the key role of a surfactant?

Answer 13

reducing the surface tension of the alveoli and this helps to prevent alveolar collapse during exhalation.

Question 14

why is the small diameter of the bronchioles imp?

Answer 14

helps to slow down rate of the airflow, increasing the efficiency of gas exchange.

Question 15

where r the capillaries located

Answer 15

around the alveoli

Question 16

Explain the process of ventilation - rs between volume n pressure

Answer 16

When you inhale, the volume of your thoracic cavity increases. This means that particles have more space to move, and so collide less frequently with each other and the walls of the lungs. As a result, pressure in the lungs decreases, allowing air from outside the body to rush into the lungs. When you exhale, the volume of your thoracic cavity decreases, so particles have less space to move and collide with each other and the walls of the lungs more frequently. This results in an increased pressure in the lungs, forcing air out of the body.

Question 17

what r the muscles involved in ventilation?

Answer 17

The diaphragm, a sheet of muscle found below the ribs.
The intercostal muscles, a group of muscles found between and anchored to the ribs. There are two types of intercostal muscles, the internal and external intercostal muscles, which are antagonistic due to their opposing actions on the ribs during breathing.
The abdominal muscles.

Question 18

define thoracic cavity

Answer 18

The volume or space within your chest.

Question 19

describe the process of inspiration/inhaling

Answer 19

The diaphragm contracts and moves downward.
The external intercostal muscles contract, and the internal intercostal muscles relax, causing the rib cage to move up and out.
This increases the volume of the thoracic cavity, and so decreases the pressure in the lungs.
As a result, air moves down its pressure gradient into the lungs.

Question 20

what is the diaphragm?

Answer 20

a muscle that helps you inhale and exhale (breathe in and out). This thin, dome-shaped muscle sits below your lungs and heart.

Question 21

describe the process of quiet breathing expiration/exhaling

Answer 21

The diaphragm relaxes, moving upwards and inwards.
The external intercostal muscles relax, and the internal intercostal muscles also relax, causing the rib cage to move down and in.
This results in a decreased volume of the thoracic cavity, and so increases the pressure in the thoracic cavity.
As a result, air moves down its pressure gradient out of the lungs.

Question 22

describe the process of forced breathing expiration/exhaling

Answer 22

The diaphragm relaxes, moving upwards and inwards.
The external intercostal muscles relax, and the internal intercostal muscles contract, causing the rib cage to move down and in forcefully.
This results in a decreased volume of the thoracic cavity, and so increases the pressure in the thoracic cavity.
As a result, air moves quickly down its pressure gradient and forcefully out of the lungs.

Question 23

what is forced vital capacity?

Answer 23

The volume of air you can exhale with maxiumum effort after inhaling the maximum possible volume of air.

Question 24

what is total lung capacity?

Answer 24

The total volume of air in your lungs after inhaling the maximum possible volume of air.

Question 25

what is residual volume

Answer 25

The volume of air remaining in the lungs that cannot be exhaled even after maximum expiration.

Question 26

what is tidal volume

Answer 26

The volume of air that moves into and out of your lungs with every normal breath.

Question 27

what is the inspiratory reserve?

Answer 27

The extra volume of air that can be inhaled with maximum effort beyond the volume of air inhaled in a normal inspiration.

Question 28

what is the expiratory reserve?

Answer 28

The extra volume of air that can be exhaled with maximum effort beyond the volume of air exhaled after a normal exhalation.

Question 29

how can u measure lung volume?

Answer 29

using a pulmonary function test called spirometry , a technique that involves a person breathing into a machine called a spirometer (Figure 4). The volume and speed of exhaled air is measured and used to evaluate lung function and diagnose respiratory conditions such as asthma and COPD.

Question 30

what is photosynthesis

Answer 30

the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product
this is a chemical r which produces glucose and oxygen from co2 and water.
co2 + h2o — glucose n oxygen as a nutrient/energy source.
produces energy

Question 31

define respiration in plants

Answer 31

this is the opp of photosynthesis. its a chemical r which releases energy from glucose.
glucose + oxygen — co2 + h2o
releases energy

Question 32

what happens when the rate of photosynthesis is higher than the rate of respiration - what is happening during the day when the plant is producing energy in the form of glucose n oxygen?

Answer 32

carbon dioxide will diffuse (spread out into) into the leaf, and excess oxygen will diffuse out.

Question 33

what happens when the rate of respiration is higher than the rate of photosynthesis - during the night, when the plant is releasing that stored energy is produced?

Answer 33

Water vapour is transported from the roots to the leaves in the xylem

Question 34

what does the combination of glucose and oxygen make

Answer 34

The combination of glucose (a simple sugar) and oxygen undergoes a chemical reaction known as cellular respiration. This process releases energy, carbon dioxide (CO2), and water (H2O). So, the combination of glucose and oxygen makes energy, carbon dioxide, and water.

Question 35

define transpiration

Answer 35

Transpiration is the loss of water vapour through the leaves, stems, and other above-ground parts of the plant. (diffusion of water vapor)

Question 36

how do Dicotyledonous leaves perform gas exchange of oxygen, water vapor and carbon dioxide - what r their adaptations?

Answer 36

1. thin n flat leaves - large surface area, gasses can diffuse across n absorb sunlight
2. waxy cuticle covers the upper epidermis (skin of plant) - wax=hydrpphobic - resist water doesn’t allow it to penetrate easily thus, prevents water loss and dehydration.
3. epidermis (below waxy cuticle) - regulates the exchange of gases between the leaf and the external air through small pores called stomata
4. stomata - prevents excess water loss, main way water vapor diffuses outta leaves.
5. spongey mesophyll layer - provides air spaces also - allows gasses 2 diffuse from 1 part of the leave to another.
6. veins transport water from roots to leaves (made of xylem n phelom tissue)

Question 37

what is mesophyll

Answer 37

The mesophyll layer is a specialized tissue found within the leaves of plants. It’s sandwiched between the upper and lower epidermis. This layer contains chloroplasts, where photosynthesis primarily occurs, making it crucial for the plant’s ability to convert sunlight into energy.

Question 38

what r guard cells location also?

Answer 38

Guard cells are specialized cells found in the epidermis of plant leaves, particularly in the leaf’s lower epidermis. They surround and control tiny openings called stomata. Guard cells regulate the opening and closing of stomata, which allows for the exchange of gases like oxygen, carbon dioxide, and water vapor between the plant and the surrounding atmosphere.

Question 39

what r the xylem and phelem tissues responsible for in the plant? (vascular bundles)

Answer 39

Xylem tissue transports water and dissolved minerals, and phloem tissue transports sugars and amino acids. This water will diffuse out of the leaf in the process of transpiration .

Question 40

what does the The diffusion of water out into the atmosphere through the stomata result in?

Answer 40

a negative pressure (lower peassure/amount of that molecule inside the plant n more of it outside), which pulls on water molecules in the xylem in a process called capillary action - like the process of exhaling in humans

Question 41

what other role does transpiration play other than allowing a plant to absorb water and nutrients from the soil, and transport these throughout the plant

Answer 41

regulating the temperature of the plant. Water that is transpired can carry away excess heat, helping to keep the plant cool.

Question 42

how to measure the rate of transpiration - how much water vapor is in plant and/or has been diffused outta it

Answer 42

The rate of transpiration can be estimated using a potometer. A potometer measures the volume of water taken up by a plant, which will be approximately equal to the volume of water lost from the plant in the process of transpiration during that time.

Question 43

what are the four factors that affect the rate of transpiration - how much and how fast water vapor can be diffused outta the plant/leaves itself.

Answer 43

1. temperature - The higher the temperature, the more kinetic energy water molecules have, and so the faster they evaporate and diffuse out of the stomata. - also air is able to hold more water vapour molecules cuz temp increases saturation point.
2. humidity - The higher the humidity of the surrounding air, the more water vapour molecules in the air outside the leaf. As a result, there is a lower concentration gradient between the leaf and the surrounding air, slowing the rate of diffusion of water vapour. (diffusion - high 2 low, so if there is low 2 high, rate will b slower).
3. wind intensity - The higher the wind speed, the faster water molecules are moved away from the leaf once transpiration has occurred. This results in an increased concentration gradient between the stomata and the air outside the leaf, increasing the rate of diffusion of water molecules. (more water v in leaf n less out of leaf - high 2 low = faster d)
4. light intensity - When light intensity is higher, guard cells cause the stomata to open wider to allow more carbon dioxide to diffuse into the leaf for photosynthesis. This means that more water evaporates from the plant.
   (THWL)

Question 44

what does it mean by stomatal density in plants?

Answer 44

Stomatal density is the number of stomata in a particular unit of area of a leaf or other plant organ.

Question 45

why is it useful to know the stomatal density of a plant

Answer 45

1. increased rate of transpiration if there is more stomata - faster and more water v will be able to diff
2. Changes in stomatal density in different environments can help us to understand the effect of climates and climate change on plant physiology.
3. Similarities and differences in stomatal density can indicate phylogenetic relationships between plants.
4. Stomatal density of plant fossils can be used as an indicator of past environmental conditions.

Question 46

what do u needa know to determine the stomata density

Answer 46

1. area of field view - usually pi r squared.
2. the number of stomata in the field view - count it.