Unit Tree Flashcards
(63 cards)
1
Q
What happens to the surface area to volume ratio (SA:V) as the size of an organism increases?
A
As size increases, SA:V tends to decrease.
2
Q
What structures can increase the surface area to volume ratio (SA:V)?
A
- Thin structures * Flat structures * Folded structures * Elongated structures
3
Q
How is surface area to volume ratio (SA:V) calculated?
A
Divide surface area by volume.
4
Q
What is metabolic rate?
A
Amount of energy used up by an organism within a given period of time.
5
Q
How is metabolic rate often measured?
A
By oxygen uptake.
6
Q
What is the relationship between SA:V and metabolic rate?
A
As SA:V increases, metabolic rate increases.
7
Q
What adaptations facilitate exchange as SA:V reduces in larger organisms?
A
- Changes to body shape (e.g., long/thin) * Development of specialized surfaces (e.g., lungs)
8
Q
Describe the tracheal system of an insect.
A
- Spiracles * Tracheae * Tracheoles
9
Q
How do tracheoles in insects facilitate gas exchange?
A
- Thin walls * High numbers of branched tracheoles * Provide tubes full of air
10
Q
What structural and functional compromises do terrestrial insects make for gas exchange?
A
- Thick waxy cuticle * Spiracles can open/close * Hairs around spiracles
11
Q
How are fish gills adapted for gas exchange?
A
- Gills with filaments and lamellae * Thin lamellae wall * Large number of capillaries
12
Q
What is counter current flow in fish gills?
A
Blood and water flow in opposite directions.
13
Q
How are leaves of dicotyledonous plants adapted for gas exchange?
A
- Many stomata * Spongy mesophyll with air spaces * Thin structure
14
Q
What adaptations do xerophytic plants have for gas exchange while limiting water loss?
A
- Thicker waxy cuticle * Sunken stomata * Spines/needles
15
Q
What are the essential features of the alveolar epithelium for gas exchange?
A
- Flattened cells * Folded structure * Permeable surface * Moist environment * Good blood supply
16
Q
Describe how gas exchange occurs in the lungs.
A
Oxygen diffuses from alveolar air space into blood down its concentration gradient.
17
Q
What is the importance of ventilation in gas exchange?
A
Brings in air with higher oxygen concentration and removes air with lower concentration.
18
Q
What occurs during inspiration in human ventilation?
A
- Diaphragm contracts * External intercostal muscles contract * Volume increases
19
Q
Why is expiration normally passive at rest?
A
Internal intercostal muscles do not normally need to contract.
20
Q
What are the effects of lung diseases on gas exchange?
A
- Increases diffusion distance * Reduces surface area * Reduces lung elasticity
21
Q
How do lung diseases affect ventilation?
A
- Reduce lung elasticity * Narrow airways
22
Q
Why do people with lung disease experience fatigue?
A
Cells receive less oxygen, reducing the rate of aerobic respiration.
23
Q
What is the difference between correlations and causal relationships?
A
- Correlation = change in one variable reflects change in another * Causation = change in one variable causes change in another
24
Q
What happens during digestion?
A
Large biological molecules are hydrolyzed to smaller molecules that can be absorbed.
25
Describe the digestion of starch in mammals.
* Amylase hydrolyzes starch to maltose * Maltase hydrolyzes maltose to glucose
26
What role do membrane-bound enzymes play in digestion?
They maintain concentration gradients for absorption.
27
Describe the pathway for absorption of products of digestion in mammals.
Lumen of ileum → cells lining ileum → blood.
28
How are amino acids and monosaccharides absorbed in mammals?
* Na+ actively transported * Na+ enters epithelial cell with glucose via co-transporter
29
What is the process of co-transport in the absorption of amino acids and monosaccharides in mammals?
1. Na+ is actively transported from epithelial cells to blood by Na+/K+ pump.
2. Na+ enters epithelial cells down its concentration gradient with glucose against its concentration gradient via a co-transporter protein.
3. Glucose moves down a concentration gradient into blood via facilitated diffusion.
## Footnote
This process highlights the role of sodium ions in the absorption of nutrients.
30
What role do micelles play in the absorption of lipids by mammals?
Micelles contain bile salts, monoglycerides, and fatty acids that:
* Make monoglycerides and fatty acids more soluble in water
* Carry and release fatty acids and monoglycerides to the cell lining of the ileum
* Maintain a high concentration of fatty acids at the cell lining.
## Footnote
Micelles are crucial for lipid absorption as they enhance the solubility of lipids in the intestinal environment.
31
How are monoglycerides and fatty acids absorbed into epithelial cells?
They are absorbed by diffusion as they are lipid-soluble.
## Footnote
This emphasizes the importance of lipid solubility in nutrient absorption.
32
What is the structure of haemoglobin?
Haemoglobin is a protein with a quaternary structure made of 4 polypeptide chains, each containing a haem group with an iron ion (Fe2+).
## Footnote
This structure is key to its function in oxygen transport.
33
Describe the loading, transport, and unloading of oxygen in relation to the oxyhaemoglobin dissociation curve.
In areas with low pO2:
* Hb has a low affinity for O2
* O2 readily unloads from Hb.
In areas with high pO2:
* Hb has a high affinity for O2
* O2 readily loads onto Hb.
## Footnote
This relationship illustrates the efficiency of oxygen transport in different physiological conditions.
34
What is the Bohr effect?
The Bohr effect describes how increased CO2 concentration lowers the affinity of haemoglobin for oxygen, shifting the dissociation curve to the right.
## Footnote
This physiological mechanism enhances oxygen delivery to tissues during high metabolic activity.
35
Explain how the structure of arteries relates to their function.
Arteries carry blood away from the heart at high pressure due to:
* Thick smooth muscle tissue for contraction
* Thick elastic tissue to withstand pressure surges
* Thick walls to prevent bursting
* Narrow lumen to maintain high pressure.
## Footnote
These structural adaptations enable efficient blood transport.
36
How does the structure of veins relate to their function?
Veins carry blood back to the heart at lower pressure due to:
* Wider lumen to reduce resistance
* Very little elastic and muscle tissue
* Valves to prevent backflow.
## Footnote
This design allows for the effective return of blood to the heart.
37
Describe the formation of tissue fluid.
At the arteriole end of capillaries:
1. Higher blood hydrostatic pressure than tissue fluid causes net outward force.
2. Water and dissolved substances are forced out of capillaries.
3. Large plasma proteins remain in capillaries.
## Footnote
This process is crucial for nutrient delivery and waste removal in tissues.
38
What is cardiac output and how is it calculated?
Cardiac output = stroke volume x heart rate.
## Footnote
This formula is essential for understanding heart function and efficiency.
39
What are risk factors for cardiovascular disease?
Risk factors include:
* Age
* High salt or saturated fat diet
* Smoking
* Lack of exercise
* Genetic factors.
## Footnote
Identifying these factors is important for disease prevention and management.
40
Describe the role of red blood cells in oxygen transport.
Red blood cells contain haemoglobin, which binds to oxygen at high pO2, forming oxyhaemoglobin, and releases it at low pO2 in tissues.
## Footnote
This mechanism is vital for efficient oxygen delivery throughout the body.
41
What is the function of haemoglobin?
To bind oxygen for transport in the blood.
## Footnote
Haemoglobin's role is crucial for oxygen delivery to tissues.
42
What is the primary role of oxygen in cellular processes?
Oxygen is needed for aerobic respiration.
## Footnote
This process generates ATP, which is essential for cellular energy.
43
What structural change occurs in haemoglobin upon the binding of the first oxygen molecule?
It changes the tertiary/quaternary structure of haemoglobin.
## Footnote
This change enhances the affinity of haemoglobin for additional oxygen molecules.
44
How do valves function in the circulatory system?
Valves open and close in response to blood pressure to prevent backflow.
## Footnote
This ensures unidirectional blood flow through the heart and vessels.
45
What is the pressure gradient from arteries to veins?
Pressure drops from arteries, to arterioles, to capillaries, to venules, to veins.
## Footnote
The vena cava has the lowest blood pressure.
46
What causes the formation of tissue fluid from capillaries?
Water (and some dissolved substances) are forced out of capillaries.
## Footnote
This process is driven by hydrostatic pressure.
47
What precautions should be taken when performing a dissection?
Cover cuts, use sharp blades, wear gloves, disinfect surfaces, and ensure safe disposal.
## Footnote
These precautions minimize risks and promote safety.
48
What is an ethical consideration for dissection?
It is morally wrong to kill animals just for dissection.
## Footnote
Using animals already killed for meat is a more ethical approach.
49
What are the steps to prepare a temporary mount of plant tissue?
1. Add a drop of water
2. Place thin section on slide
3. Stain if needed
4. Lower coverslip at an angle.
## Footnote
This method allows for better visualization under a microscope.
50
What are the rules for scientific drawing?
Draw to scale, use clear lines, include magnification, label with straight lines.
## Footnote
These rules ensure clarity and accuracy in scientific communication.
51
What is the function of xylem tissue?
Transports water and mineral ions from roots to leaves.
## Footnote
This is essential for plant hydration and nutrient transport.
52
List adaptations of xylem tissue for its function.
* Continuous tube formation
* No cytoplasm/nucleus
* Thick lignified walls
* Pits for lateral water movement.
## Footnote
These adaptations facilitate efficient water transport.
53
What is the cohesion-tension theory?
Water is pulled up the xylem due to transpiration creating tension, with hydrogen bonds providing cohesion.
## Footnote
This theory explains how water moves against gravity in plants.
54
How is a potometer set up?
1. Cut shoot underwater
2. Assemble potometer
3. Insert shoot underwater
4. Ensure airtight
5. Dry leaves
6. Shut tap.
## Footnote
This setup allows accurate measurement of water uptake.
55
How can a potometer measure transpiration rate?
By measuring the distance moved by an air bubble over time.
## Footnote
This gives an estimate of water uptake, which correlates with transpiration.
56
What environmental variables can affect transpiration rate?
* Light intensity
* Temperature
* Wind intensity
* Humidity.
## Footnote
Each factor influences the rate at which water evaporates from leaves.
57
What is phloem tissue's primary function?
Transports organic substances like sucrose in plants.
## Footnote
This is vital for energy distribution within the plant.
58
Describe the mass flow hypothesis for translocation.
Sucrose is actively transported into phloem, lowering water potential and creating hydrostatic pressure that drives mass flow to sinks.
## Footnote
This process is essential for nutrient distribution.
59
What is a tracer experiment in plant transport studies?
Using a radioactive tracer to track organic substance movement during photosynthesis.
## Footnote
This method provides insights into translocation mechanisms.
60
What evidence is provided by ringing experiments?
A bulge forms above the ring on the phloem, indicating sugar transport.
## Footnote
This shows the role of phloem in transporting nutrients.
61
What common mistake is made regarding transpiration?
Confusing transpiration with the transpiration stream.
## Footnote
Transpiration refers to water loss, while the stream refers to water movement through the plant.
62
Fill in the blank: Translocation involves the movement of _______ through phloem.
[sucrose]
63
True or False: Sucrose moves by simple diffusion into sink cells.
False.
## Footnote
Sucrose moves by active transport or facilitated diffusion, not simple diffusion.
