Back to AI Flashcard MakerBiology /Biology IB HL - 8.2 Cell Respiration Part 6
How are electron micrographs produced via electron tomography?
Samples are repeatedly imaged using a transmission electron microscope. Following each image, the sample is tilted to a different angle relative to the electron beam. The images are then compiled and used to computationally reconstruct a 3-D representation (called a tomogram).
Tap or swipe ↕ to flip
Swipe ←→Navigate
1/18
Key Terms
Term
Definition
How are electron micrographs produced via electron tomography?
Samples are repeatedly imaged using a transmission electron microscope. Following each image, the sample is tilted to a different angle relative to th...
How are samples prepared for electron tomography?
When dealing with biological materials, samples are first prepared by either fixing and dehydrating or freezing (cryogenics). This stabilises the biol...
What 3 findings have electron tomography identified in features of active mitochondria?
The cristae are continuous with the internal mitochondrial membrane. The intermembrane space is of a consistent width throughout the entire mitochondr...
What is the purpose of anaerobic respiration?
The purpose of anaerobic respiration is to restore stocks of NAD+ – as this molecule is needed for glycolysis.
Why is restoring NAD+ necessary?
By restoring stocks of NAD+ via anaerobic pathways, the organism can continue to produce ATP via glycolysis.
What tissue requires large amounts of ATP and why?
Muscle contractions require the expenditure of high amounts of energy and thus require high levels of ATP.
Related Flashcard Decks
Study Tips
- Press F to enter focus mode for distraction-free studying
- Review cards regularly to improve retention
- Try to recall the answer before flipping the card
- Share this deck with friends to study together
| Term | Definition |
|---|---|
How are electron micrographs produced via electron tomography? | Samples are repeatedly imaged using a transmission electron microscope. Following each image, the sample is tilted to a different angle relative to the electron beam. The images are then compiled and used to computationally reconstruct a 3-D representation (called a tomogram). |
How are samples prepared for electron tomography? | When dealing with biological materials, samples are first prepared by either fixing and dehydrating or freezing (cryogenics). This stabilises the biological structures and prevents aqueous contents (i.e. water) from expanding and exploding. |
What 3 findings have electron tomography identified in features of active mitochondria? | The cristae are continuous with the internal mitochondrial membrane. The intermembrane space is of a consistent width throughout the entire mitochondrion. The relative shape, position and volume of the cristae can change in active mitochondria. |
What is the purpose of anaerobic respiration? | The purpose of anaerobic respiration is to restore stocks of NAD+ – as this molecule is needed for glycolysis. |
Why is restoring NAD+ necessary? | By restoring stocks of NAD+ via anaerobic pathways, the organism can continue to produce ATP via glycolysis. |
What tissue requires large amounts of ATP and why? | Muscle contractions require the expenditure of high amounts of energy and thus require high levels of ATP. |
Why will muscles respire anaerobically during exercise? | When exercising at high intensity, the cells’ energy demands will exceed what the available levels of O2 can supply aerobically. Hence the body will begin breaking down glucose anaerobically to maximise ATP production. |
What will an increase in anaerobic respiration cause in muscle cells? | This will result in an increase in the production of lactic acid, which leads to muscle fatigue. |
What happens in the muscles when an individual stops exercising? | When the individual stops exercising, oxygen levels will increase and lactate will be converted back to pyruvate. |
What can the products of anaerobic respiration/fermentation in yeast be used for? | In yeasts, fermentation results in the production of ethanol and carbon dioxide – which can be used in food processing: Bread – Carbon dioxide causes dough to rise (leavening), the ethanol evaporates during baking. Alcohol – Ethanol is the intoxicating agent in alcoholic beverages (concentrations above ~14% damage the yeast). |
What can the fermentation of bacterial cultures be used for? | Bacterial cultures can also undergo fermentation to produce a variety of food products. Yogurt / Cheese – Bacteria produce lactic acid anaerobically, which modifies milk proteins to generate yogurts and cheeses. |
What is a respirometer? | A respirometer is a device that determines an organism’s respiration rate by measuring the rate of exchange of O2 and CO2. |
Where is the living specimen kept? respirometer | The living specimen (e.g. germinating seeds or invertebrate organism) is enclosed in a sealed container. |
What can be used to measure CO2 production? respirometer | Carbon dioxide production can be measured with a data logger or by pH changes if the specimen is immersed in water. |
How can O2 consumption be measured? respirometer | When an alkali is included to absorb CO2, oxygen consumption can be measured as a change in pressure within the system. The pressure change can be detected with a data logger or via use of a U-tube manometer. |
What factors may affect respiration? | Factors which may affect respiration rates include temperature, hydration, light (plants), age and activity levels. |
What will an increase in CO2 indicate? respirometer | An increase in carbon dioxide levels will indicate an increase in respiration (CO2 is a product of aerobic respiration). |
What will a decrease in oxygen indicate? respirometer | A decrease in oxygen levels will indicate an increase in respiration (O2 is a requirement for aerobic respiration). |