Respiration Flashcards
What is respiration?
Respiration is a series of enzyme-controlled reactions which release chemical energy from glucose.
What carries out respiration?
All living cells (in the mitochondria)
What is an independent variable?
Factor to be changed
What is a dependent variable?
Factor to be measured to judge the effect of the independent variable
What is a controlled variable?
Other variables that are controlled (kept the same)
What is the equation for calculating energy?
Energy = (4.2 x M x T)/1000
M = mass of water (1ml of water weighs 1g)
T = temperature increase of water
Why do cells require energy for cellular processes?
Our cells require energy for cellular processes such as:
- nerve impulse transmission
- muscle cell contraction
- protein synthesis
- cell division
- active transport
What is a high energy molecule which provides energy for cellular processes?
ATP
What is ATP?
ATP is a high energy molecule which provides energy for cellular processes
What 2 chemicals is the compound ATP made up of?
- Adenosine
- Inorganic Phosphate (Pi)
What is the role of ATP?
When a cell gradually breaks down glucose during respiration, it may not require the energy released immediately. This energy is used to build a molecule of ATP. ATP can then be broken down to release the chemical energy stored within it when it is required by the cell. This will produce ADP plus an inorganic phosphate.
What are the two types of respiration?
- Aerobic respiration (requires oxygen)
- Fermentation (no oxygen required)
What are the two stages of respiration?
- Glycolysis
- The aerobic stage
Where does the first stage of respiration take place?
This stage happens in the cytoplasm of the cell
Is oxygen required for glycolysis?
No
What is generated from glycolysis?
2ATP are generated in this stage
From glycolysis, what is glucose broken down into?
Glucose is broken down to 2 pyruvate molecules + oxygen by glycolosis
Where does the second stage of respiration take place?
This stage happens in the mitochondria of the cell
Is oxygen required for the aerobic stage?
Yes, so it is referred to as being the AEROBIC stage
What is generated from the aerobic stage?
A large yield of ATP (38) are generated in this stage
From the aerobic stage, what is pyruvate then broken down into?
Pyruvate reacts with oxygen and is broken down into carbon dioxide and water
What is made from the breakdown of glucose during glycolysis?
Breakdown of glucose releases energy (2 ADP + Pi -> 2 ATP)
What is made from the breakdown of pyruvate (x2) during aerobic respiration?
Breakdown of pyruvate releases energy (ADP + Pi -> large yield of ATP (36))
What are some examples of parts of the body that contain a large number of mitochondria?
Cells that require lots of energy for their function will contain a large number of mitochondria for example :
- muscle (muscle cell contraction)
- nerve (nerve impulse transmission)
- sperm (to swim to the egg)
What happens if oxygen is not always available to cells for respiration?
They switch to fermentation pathway
What do plant and yeast cells make?
Ethanol + Carbon Dioxide
What do animal cells make?
Lactate
What is the equation for the fermentation pathway in animal cells e.g muscle?
Glucose –> Pyruvate –> Lactate=
What happens when you exercise?
Your muscles switch to a fermentation pathway and produce lactate
When this product build up in muscles it:
- Makes them feel sore
- makes them fatigue (tire easily)
What is the equation for fermentation in yeast and plant cells?
Glucose –> Pyruvate –> Ethanol + Carbon Dioxide
What would a layer of oil do on top of yeast?
The layer of oil is added to prevent the yeast from reacting with oxygen
What would be added to provide a source of chemical energy for the yeast?
Glucose
How would you be able to tell if CO2 is given off?
Water can be replaced with lime water. If CO2 is present, the lime water will turn cloudy/milky
What could be done to make the yeast respire faster?
Increase the concentration of glucose
What could be done to ensure the experiment is done correctly?
The water used to make yeast suspension is boiled to kill off any unwanted microorganisms and to remove oxygen
What is made from the breakdown of glucose in fermentation?
Breakdown of glucose releases energy (2 ADP + Pi –> 2 ATP)
What is stage 1 of fermentation?
Glycolysis
What is stage 2 of fermentation?
Fermentation
Where does the first stage of fermentation take place?
This happens in the cytoplasm of the cell
Is oxygen required for the first stage of fermentation?
No
Where does the second stage of fermentation take place?
This happens in the cytoplasm of the cell
Is oxygen required for the second stage of fermentation?
No oxygen required (called anaerobic) - no ATP made
What is made from the breakdown of pyruvate in fermentation of an aminal cell?
Lactate - reversible if oxygen is present
What is made from the breakdown of pyruvate in fermentation of plant and fungal cells?
Carbon dioxide and ethanol
How can the rate of respiration be measured?
Using a respirometer. This measures the rate of oxygen uptake per minute
