8 Gas Exchange and Respiration Flashcards
Define cellular respiration
release of energy from the chemical bonds in food molecules
Features of gas exchange surfaces (4)
Large surface area
short distance over which substances have to diffuse
a good blood supply
good ventilation to supply more oxygen and remove carbon dioxide rapidly
Pathway air takes in human respiratory system
Air enters through mouth and nose —-> Passes through larynx (voicebox) —–> reaches trachea to the lungs ——–> bronchi ——> bronchioles
Define mucus
Slimy liquid that traps microorganisms and dust particles that are breathed in
Define cilia
tiny hairs which are found on the surface of ciliated cells
Where are ciliated cells located in the Human respiratory system (2)
Bronchi
Trachea
How does the mucus and ciliated cells help to prevent dirt and microorganisms from entering the lungs and causing damage/infection (3)
Mucus traps dirt and microorganisms that are breathed in
Cilia sweep in a co-ordinated motion to move the mucus up from the lungs up the trachea to the mouth
Mucus is swallowed, where the
What are goblet cells
cells that secrete mucus
Where are goblet cells located in the human respiratory system (3)
trachea
bronchi
bronchioles
Where is the site of gas exchange
alveoli
Features of alveoli (4)
thin permeable walls - keep diffusion disntace between air and blood minimum
moist lining - gases dissolve before they diffuse across the cell membranes
large surface area - process huge amounts of gas exchange
high conc gradient - because blood is continually flowing, deliving excesss carbon dioxide and taking up oxygen
Differences in composition (oxygen, CO2, water) of inspired air and expired air
▮Inspired air:
oxygen - 21%
carbon dioxide 0.04%
water - variable
▮Expired air
oxygen - 16%
carbon dioxide - 4.5%
water - high
Why does oxygen level in expired air lower than oxygen level in inspired air (2)
oxygen is removed from blood by respiring cells and used for cellular respiration
blood returning to the lungs has a lower concetration of oxygen than blood leaving lung
Why is carbon dioxide level in expired air higher than carbon dioxide level in inspired air (2)
carbon dioxide is produced by respiration and diffuses into blood from respiring cells
blood transports the carbon dioxide to the lungs where it diffuses into the alveoli
Why is water vapour concetration high in expired air
Water evaporate from the moist linings of the alveoli
What is the relationship between the level of activity and the rate and depth of breathing + explain
As level of activity increases, rate and depth of breathing increases
Increased level of activity —-> muslce contract faster —–> cellular respiration increase —–> more carbon dioxide produced ——> Increase CO2 concetration detected as blood flows past receptors —–> receptors send impulses to lungs causing an increase in the rate of depth of breahting —–> CO2 is removed quicker
Why is an increase in the CO2 concetration dangerous (3)
Carbon dioxide is acidic gas that disolves easily in water based solutions
The more carbon dioxide there is in solution, the more acidic the solution is
a change in pH can affect the activity of many cell enzymes
Tabacco smoke related diseases (3)
Chronic obstructive pulmonary disease (bronchitis. emphysema)
lung cancer
coronary heart disease
Toxic components of tabacco (3)
Carbon monoxide - takes the place of oxygen in hemoglobins and prevents the body from absorbing as much oxygen
Nicotine - addictive and narrows nlood vessels, increasing blood pressure and the risk of coronary heart disease
Tar - Sticky substance that coats the cells of trachea, bronchi, and bronchioles leading to coughing and cell damage.
Uses of energy in human cells (6)
produce contraction of muscle cells
protein synthesis
Cell division and cell growth
active transport of molecules across cell membranes
To produce movement of nerve impulses
Maintenance of a constant core body temperature
Define aerobic respiration
chemicalreactions in cells that use oxygen to break down nutrient molecules to release energy
Word equation for aerobic respiraton
Glucose + oxygen —–> water + carbon dioxide (+energy)
Chemical equation for aerobic respiration
C6H12O6 + O2 —–> H2O + CO2 + (energy)
Define anaerobic respiration
chemical reactions in cells that break down nutrient molecules to release energy without using
oxygen
Word equation for anaerobic respiration
glucose —-> lactic acid (+ energy)
Define oxygen debt
amount of oxygen needed after vigorous exercise in order to break down the lactic acid in the muscle and liver cells produced by anaerobic respiration.
Word equation for anaerobic respiration in yeast
glucose —> ethanol + carbon dioxide (+ energy)
Describe the role of anaerobic respiration in yeast during bread-making
the carbon dioxide released forms bubbles in the dough, making bread light and spongy
Aerobic respiration produces more energy per glucose than anaerobic respiration
True or False
True
