Chapter 11 - Gas Exchange in Humans Flashcards
Why do all cells in the body need energy? (7)
- contracting muscles
- making protein molecules
- cell division
- active transport
- growth
- transmitting nerve impulse
- producing heat inside body
What do cells need to do in order to use glucose absorbed through digestion?
cells need to break down glucose molecules usually by combining it with oxygen
Define aerobic respiration
chemical reactions that take place in the mitochondria, which uses oxygen to break down glucose and other nutrients to release energy for the cell to use
What is the equation for transpiration?
glucose + oxygen → water + carbon dioxide
C₆H₁₂O₆ + 6O₂ → CO₂ + H₂O
Define anaerobic respiration
chemical reactions in cells that break down glucose to release energy without using oxygen
Which is more efficient, aerobic or anaerobic respiration?
aerobic respiration
Where in the cell does anaerobic respiration happen?
in the cytoplasm
Where in the cell does aerobic respiration happen?
in the mitochondria
How does yeast respire often?
anaerobically (important example)
in test say: anaerobic respiration in yeast
What is the equation for anaerobic respiration?
glucose → lactic acid
Can plants respire anaerobically?
yes, but only for short periods of time
What is the equation for anaerobic respiration in yeast?
glucose → alcohol + carbon dioxide
C₆H₁₂O₆ → 2C₂H₃OH + 2CO₂
When does anaerobic respiration happen?
when intense exercise is done and the heart and lungs cannot supply oxygen to muscles cells fast enough
Why will anaerobic respiration take place?
to keep cells going until oxygen is available again
What happens when someone stops running?
there is a lot of lactic acid in their muscles
How is lactic acid then broken down?
by the liver, which combines it with oxygen
After running, do breathing and heart rates go down immediately?
no
How does fast heart rate help lactic acid break down quicker?
by transporting the lactic acid to the liver quicker
Define oxygen debt
extra oxygen that is needed after anaerobic respiration has taken place, to break down the lactic acid produced
How does oxygen get into the body?
by diffusion
Where do animals and plants get their oxygen from?
terrestrial and aquatic (air and oxygen dissolved in water)
Which 2 gases diffuse in and out of the body?
O₂ diffuses in and CO₂. diffuses out
Gas surfaces must be… (5)
- permeable
- thin
- close to an efficient transport system
- large surface area
- good supply of O₂
Why do gas surfaces have to be permeable?
so that O₂ and CO₂ can move easily
Why do gas surfaces have to be thin and have a large surface area?
gases diffuse quickly
What are the 4 steps of air getting into our lungs?
1) air enters body through nose and mouth
2) air passes through trachea
3) air enters thorax
4) air enters alveoli
Define alveoli
tiny air-filled sacs in the lungs where gas exchange takes place
What are the 3 characteristics of the alveoli?
- walls are one cell thick
- tiny capillaries wrap around each alveolus
- O₂ diffuses across alveoli walls into blood
Alveolus have a good supply of oxygen thanks to…
ventilation
Define
This is a diagram of…
an alveolus
Fill in the table
Which 2 muscles help us breathe?
intercostal muscles and diaphragm
How do intercostal muscles help us breathe?
contract and relax to raise and lower rib cage (internal and external)
How does the diaphragm help us breathe?
separates the chest cavity from abdominal cavity (controls ventilation)
Where are the intercostal muscles located?
between ribs
Fill in the table
What are the 2 characteristics of coughing?
- expire extra hard
- abdominals contract to help squeeze extra air out if thorax
