Organisms and energy Flashcards
what is respration
respiration is a process used by all living organisms that releases the energy in organic molecules
Explain how the human circulatory system facilitates respiration
a) glucose and oxygen diffuses from capillaries into respiring cells
b) carbon dioxide diffuses from respiring cells into capillaries
Define diffusion
the net movement of particles from an area of high concentration to an area of lower concentration.
Demonstrate an understanding of how aerobic respiration uses oxygen to release energy from glucose and how this process can be modelled using the word equation for aerobic respiration
aerobic respiration uses oxygen from the air to release energy from glucose. the products of aerobic respiration are carbon dioxide and water.
glucose + oxygen > carbon dioxide + water (+ energy)
Investigate the effect of exercise on breathing rate and heart rate
your heart rate and breathing rate increase when you exercise. the harder you exercise the more these rates increase.
Explain why heart rate and breathing rate increase with exercise
during exercise, muscle cells are respiring faster. this means that they need more oxygen and glucose, and release more carbon dioxide:
> a faster heart rate means that blood is pumped faster around the body. the blood takes oxygen and glucose to cells faster and removes carbon dioxide faster
> a faster breathing rate means that oxygen can be taken into the body at a faster rate and carbon dioxide can be released faster
Calculate heart rate, stroke volume and cardiac output, using the equation cardiac output = stroke volume * heart rate
cardiac output = stroke volume * heart rate
Demonstrate an understanding of why, during vigorous exercise, muscle cells may not receive sufficient oxygen for their energy requirements and so start to respire anaerobically
muscle cells may not receive sufficient oxygen for their energy requirements and so start to respire anaerobically. anaerobic respiration releases the extra energy the cell needs but cant get from aerobic respiration.
Demonstrate an understanding of how anaerobic respiration releases energy from glucose and how this process can be modelled using the word equation for anaerobic respiration
anaerobic respiration is the release of energy form glucose without using oxygen. this produces lactic acid.
glucose > lactic acid (+ energy)
Recall that the process of anaerobic respiration releases less energy than aerobic respiration
anaerobic respiration releases less energy from each molecule of glucose than aerobic respiration
Describe how a build-up of lactic acid requires extra oxygen to break it down. This is called excess post-exercise oxygen consumption or EPOC (formerly known as oxygen debt)
lactic acid isn’t removed from the body. it builds up in muscle and blood, and must be broken down after exercise. excess oxygen is needed which is known as EPOC
Explain why heart rate and breathing rate remain high after exercise
to bring extra oxygen into the body. some of this is needed to break down lactic acid produced from anaerobic respiration during the race.
Describe how the structure of a leaf is adapted for photosynthesis
a) large surface area to capture as much light as possible for photosynthesis.
b) containing chlorophyll in chloroplasts to absorb light energy needed for photosynthesis.
c) stomata for gas exchange. allows carbon dioxide to be diffused into the leaf. and oxygen and water vapour to be diffused out of the leaf (carbon dioxide, oxygen and water vapour)
Demonstrate an understanding of how photosynthesis uses light energy to produce glucose and how this process can be modelled using the word equation for photosynthesis
photosynthesis is the process that plants use to make glucose. during this chemical reaction, light energy is used to combine carbon dioxide and water.
carbon dioxide + water > glucose + oxygen
Demonstrate an understanding of how limiting factors affect the rate of photosynthesis
a) light intensity - Increasing the light intensity will boost the speed of photosynthesis.
b) CO2 concentration - Even if there is plenty of light, a plant cannot photosynthesise if there is insufficient carbon dioxide.
c) temperature - If it gets too cold, the rate of photosynthesis will decrease. Plants cannot photosynthesise if it gets too hot.