Nutrients and Gas Requirements Flashcards
Module 3 (89 cards)
1
Q
Define an autotroph
A
- An autotroph is an organism that can produce its own food using light, water, CO2, or other chemicals.
- Because they produce their own food, they are sometimes called producers
2
Q
Give some examples of autotrophs.
A
- Plants
- Algae (which live in water and whose larger forms are known as seaweed)
- Phytoplankton (sinh vật phù du)
3
Q
What process occur in autotrophs?
A
- Photosynthesis
- Chemosynthesis - do not use energy from the sun to produce food; instead, they make food using energy from chemical reactions, often combining hydrogen sulfide or methane with oxygen
4
Q
Where to find autotrophs that use chemosynthesis
A
- Extreme environments, where the toxic chemicals needed for oxidation are found (eg. bacteria living in active volcanoes)
- Deep ocean, near hydrothermal vents (i.e. narrow crack in the seafloor).
- Seafloor called cold seeps
5
Q
Outline some materials that autotrophs use in chemosynthesis.
A
- Sulfur (extreme environments)
- Hydrogen sulfide (hydrothermal vents)
- Methane (cold seeps)
6
Q
Most plants are described as vascular plants. A small number of plants are called non-vascular plants (e.g. mosses, …) because they do not possess transport system.
A
Information
7
Q
Outline body system of most vascular plants
A
- Root
- Shoot
- Vascular system
8
Q
Function of vascular system
A
- It involved in the transport of substances in plants
- It is composed of two different types of tissues - Xylem and Phloem
9
Q
What separates phloem and xylem?
A
- The thin membrane called cambium, which is a layer of actively dividing cells that is responsible for the growth of stems and roots.
10
Q
One xylem and one phloem also called
A
Vascular bundle
11
Q
What running the length of leaves, stems, and roots of plant?
A
Multiple vascular bundles
12
Q
Function of xylem
A
- The xylem is responsible for the transport of water, along with water-soluble nutrients and minerals, absorbed from the soil through the root system.
- The xylem is responsible for keeping a plant hydrated.
13
Q
Which way does the xylem sap travel?
A
- Xylem sap travels only upwards and has to overcome serious gravitational forces to deliver water to a plant’s upper extremities.
14
Q
Explain how water transports inside xylem ( transpiration-cohesion-tension theory)
A
- Transpiration occurs because individual water molecules are attracted to one another, called cohesion. The movement of water upwards through the plants is called transpiration.
- Water can move up the xylem, because of a property called adhesion, whereby water is attracted to cell walls of the xylem vessels.
- When the water is lost from the intercellular spaces by transpiration, it is replaced by the water from the surface of the mesophyll cells that surround the intercellular spaces => Increasing surface tension which bring water upwards
15
Q
Describe structure of xylem vessel
A
- Tracheids: long thin cells that are connected together by tapered ends.
- Vessel elements: shorter and wider than tracheids and are connected together end-on-end to form a continuous tube for transports of water. The cell contents die, leaving hollow vessels for the easy flow of water
- Xylem cells are dead, elongated and hollow.
- They have secondary cell walls containing lignin - a compound that creates wood. Lignin in tracheids adds structural support to the xylem and the whole plant (can be spirals, rings or other patterns)
- ‘Pits’ (areas where the secondary cell wall is missing)
- The walls of the vessels are reinforced with lignin, which prevent the vessels from collapsing.
16
Q
Function of phloem
A
- Transports important sugars (in form of dissolved sucrose), organic compounds, and minerals around a plant
- These substances are transported from leaves to non-photosynthesizing parts of plant such as roots and stems)
- Sap within the phloem simply travels by diffusion between cells and works it way from leaves down to the roots with help from gravity
16
Q
Structure of phloem
A
- Phloem is conductive tissue composed of thin-walled cells
- Phloem is made from cells called ‘sieve-tube members’ and ‘companion cells’
- Sieve-tube members: the perforated end walls are called sieve-tube plates (allow the sap to diffuse easily from cell to cell), missing some important structures such as a nucleus, ribosomes and a vacuole.
- Companion cells run adjacent to sieve-tube members and are connected by a number of channels called ‘plasmodesmata’. Companion cells are not lacking in any vital organelles and their nucleus and ribosomes serve both the sieve tube and itself.
16
Q
What is translocation
A
- The distribution process of stored starch, sucrose to all parts of the plant. This process is called translocation.
17
Q
Outline the driving force of substances stream in xylem and phloem
A
- Driving forces in the xylem are transpiration, cohesion between water molecules, adhesion between water and the cell wall, and surface tension.
- Driving force in the phloem is caused by the formation of high and low pressure regions within the phloem tissue
18
Q
Explain Source-Sink Theory
A
- The high-pressure region is in close proximity to where the sucrose is produced and is known as source
- At the source, energy is required to actively pump sugars into the phloem tissue and this creates a very concentrated solution in phloem (also absorb water by osmosis from the nearby xylem tissue) => cause the high-pressure region
- The low-pressure region is where the sucrose is required and is known as sink
- At the sink, which could be roots or other parts that requires nutrients, energy is again required to actively remove the sugars from the phloem. This creates a dilute solution, which causes water to leave the phloem by osmosis and return to the xylem tissue= > caus the low-pressure region
- Difference in pressure between source and sink drives the movement of substances in the phloem. Going from source to sink.
18
Q
Directions of flow in phloem
A
- It depends on where the sink areas of the plant are in relation to the source (leaves)
19
Q
Define stomata
A
- These are pores in the epidermis of leaves which the gases O2 and CO2 move into and out of the plant.
20
Q
Where on leaves can find mostly stomata?
A
- Undersurface of the leaf.
- The upper epidermis may also have some, but there are usually fewer than on the lower epidermis
21
Q
How are stomata arranged?
A
- Australian eucalypts’ leaves have stomata distributed on both surfaces
- Float plant on water usually have stomata only on their upper surfaces, while plants that grow underwater often do not have stomata.
22
What controls the stomatal opening and closing?
- The turgor of the guard cells
23
When will the stomata open?
- When water flows into the guard cells by osmosis, turgor increases and they expand. Due to the relatively inelastic inner wall, the guard cells bend and draw away from each other.
24
When will the stomata close?
- When the guard cells lose water due to osmosis, turgor decreases and shrinks.
25
Which organ is responsible for gas exchange in Animals?
- Fish: Gills
- Mammals: Lungs
- Insects: Spiracles
26
Describe the way in which the air enters lungs.
- Air enters the lungs through the trachea, which splits into two bronchi and then smaller bronchioles.
- On the bronchioles are **alveoli**, where gas exchange takes place.
- The alveoli are surrounded by **capillaries** so gases can diffuse between air and blood.
- Diffusion of O2 and CO2 occurs passively due to the pressure difference across the alveoli and capillary membrane ( areas of high pressure to areas of low pressure).
27
Function of mucus in the trachea and bronchioles
Keep the trachea and bronchioles clean and moist.
28
Which condition needed for oxygen can dissolve and then diffuse into blood
The alveoli must stay moist
29
Describe the function of the diaphragm which assists the ventilation (thông khí) of lungs.
- Diaphragm contracting to draw air in
- Then relaxing to push it out
30
What is tidal ventilation?
- It is when air goes in and out the same way.
- This isn't very efficient because not all of the air that is breathed in with each breath is breathed out again, i.e. some of the air in each breath has already lost its oxygen to the blood. Also, some air from each breath doesn't make it as far as the gas exchange surface in the alveoli.
30
How marine mammals breath air/ exchange gases?
- They also breathe air and must come up to the surface of the water to breathe
- They possess small lungs compared to humans in order to reduce problems of nitrogen building up in the blood caused by diving.
- They have to be able to hold their breaths for long periods of time while diving in order not to get water into their gas exchange system.
31
Advantages of gas exchange system in mammals
- They have a circulatory system and the oxygen is absorbed by the blood to be transported to every cell in the body. The size of mammals isn't limited by their gas exchange system; no matter how big the mammals get, every cell will have a capillary that delivers oxygen.
- The large SA : V ratio of the gas exchange surface. The alveoli in the lungs maximise the Surface Area, allowing more O2 to diffuse at once and increasing the efficiency of gas exchange.
32
Limitations of gas exchange system in mammals.
- Limitation is tidal ventilation. I.e. the filtering section of gas exchange works not really effectively because oxygen in the air breathed in is not fully exchanged and absorbed into the blood (some oxygen still exists in the air breathed out)
- Furthermore, usually mammals can only live on land because they only breathe air and their limited holding air time.
33
What effect do emphysema - the alveoli are damaged by coughing have on gas exchange in our lungs? Explain why.
- The process of breathing function less effective due to the effect on alveoli (this is the main organ where occurs gas exchanging)
34
Name three features of the alveolus that are designed to increase the rate of gas exchange, and explain how they achieve this
1. The lining is made of flattered cells (thin walls), i.e. the gases just need to travel a short distance to diffuse through.
2. The structure of capillaries surrounding the alveolus has many branches, which ensures alveoli are in close contact with the blood and then increase the gas exchange through blood
3. Mucus in the trachea and bronchioles keeps them moist and clean which ensures the flow of O2 and CO2 diffuse across the gaseous exchange surface are in dissolved form, enhancing the efficiency of diffusion.
35
What effect does lung cancer - a tumour grows inside the lungs?
- These tums may block the airway through capillaries and through alveoli which reduce the efficiency of gas exchange.
36
What is the gas exchange organ in fish?
- Gills
36
Describe the movement of diaphragm assist the humans' inhalation and exhalation.
- Breathing in occurs when the diaphragm moves down -> the volume of the thorax is made larger -> The pressure is decreased
- Breathing out occurs when the diaphragm moves up -> the volume of the thorax is made smaller -> the pressure is increased
37
What is gill filaments?
- Gill filaments are feathery structures in gills which possess a large surface area for gas exchange
38
What is Lamellae?
- Lamellae are discs supported the gill with blood capillaries to pick up dissolved oxygen in water passing through gills.
39
Describe the pathway of gas exchange in gills
- The rich-oxygen water will go through the mouth and then through the gills. As water goes through gill filaments, the capillary networks pick up oxygen in water and then diffuse directly into all body parts and cells.
- When picking up CO2, it is removed from the body through the gills. After water flows through gills, it exits the body through the opening of the operculum.
40
Describe the relationship between movement of operculum and mouth of marine species including fish,...
- When the mouth is open, the operculum will close over the gills
- When the mouth is close, the operculum will open over the gills.
41
Which organ is responsible for respiratory system in Insects?
- Spiracles
42
Describe the pathway of gas exchange in Insects.
- Insects take in and expel air through spiracles, which are in effect breathing pores.
- The air then goes through tracheal tubes/ tracheae and to the smaller tubes called tracheoles which provide a larger surface area for gaseous exchange.
- At the end of each tracheole, there is water fluid which can be used to dissolve oxygen and then directly diffuse into cells (in the absence of blood capillaries)
- The tracheal tubes are kept open by the spiral rings of tough supportive substances called **chitin**.
43
Identify the main functions of transport systems in multicellular organisms.
- Main function: transport necessary substances (water, mineral ions, sucrose,...) to correct place, to optimise the process of transportation due to small SA:V ratio of multicellular organisms.
43
What normal organs occur in humans but absent in Insects?
- Lungs and Blood Capillaries
44
The number of open and closed spiracles generally controls the rate of respiration in insects - more are open when the insects are active
Informative
45
What is the effect of movement of thorax and abdomen during flying?
It helps to ventilate the tracheal system.
46
Distinguish cohesion and adhesion
- Cohesion: the force between two water molecules
- Adhesion: the force between water molecules and the walls of xylem vessels
47
What is mechanical digestion?
- Mechanical digestion refers to the physical breakdown of foods into smaller pieces which possess higher surface area in order to dissolve easier in enzymes in chemical digestion (e.g. churning motion in stomach; cutting, tearing and chewing in mouth)
48
What is chemical digestion?
- Chemical digestion is the process of using digestive enzymes to digest large, complex compounds into smaller and simpler molecules. For example: proteins -> amino acids, carbohydrates -> glucose, ...
49
Define "Epiglottis"
- Organ that closes over the entrance of the respiratory system (trachea) to prevent the entry of food
50
Outline organ pathway through digestive system.
Mouth -> Oesphagus -> Stomach -> Small intestine -> Large intestine -> Anus
51
Define "oesophagus"
- Organ that contain the process of peristalsis and it is the link between the mouth and stomach.
51
Definition of bolus
- A ball food shape including small pieces of food chewed by mechanical digestion in mouth and some saliva.
52
Define "Chyme"
- The chemical mixture which is produced by gastric juices in stomach
53
Define "Peristalsis"
- The mechanical digestion occur in oesophagus by contraction of muscular tissue
54
Define "Pepsin"
- Enzyme which is used to break down proteins into amino acids
55
Define "Duodenum"
- The start of small intestine
56
Define "Jejunum"
Middle section of small intestine (where most digestive products occur)
57
Define "Bicarbonate ions"
- Acts as a substance which neutralise the acidic chyme leaving stomach
57
Define "Ileum"
End of small intestine
58
Define "Colon"
- Part of large intestine where water and some salts are absorbed back into bloodstream, while undigested material compacting into a more solid
58
Define "Bile"
- Secreted by liver and acts as detergent acts on fats
58
Define "microvilli"
- A further folded form of a villi
58
Describe the digestion in oesophagus.
- Mechanical digestion: peristalsis - muscular contractions move the bolus
- Chemical digestion: the digestion of starch continues here.
58
Define "Elimination"
- Destruction
58
Define "Rectum"
- The part of large intestine locates before anus in the pathway of faeces.
- The rectum is also a place where faeces moved into by peristalsis
58
Define "Emulsify"
- Breakdown
59
Describe the digestion in mouth.
- Mechanical digestion: teeth break foods into smaller pieces (large SA) by cutting, tearing, and chewing.
- Chemical digestion: amylase is produced by salivary glands to emulsify starch into glucose
60
What is the function of mucus lining the stomach?
- Prevent the acid from eating away the walls of the stomach (pH of interior of the stomach to be 2.0 - 3.0)
60
Define "Gastric juices"
- Substances secreted from the wall of the stomach, contain water, HCl, pepsinogen and pepsin
60
Describe the digestion in stomach.
- Mechanical digestion: churning motion in the stomach, relaxation and contraction in stomach as well
- Chemical digestion: enzyme pepsinogen (active form in **pepsin**) is converted long-chained proteins into shorter-chained peptides. Pepsin also breaks down nucleic acids (DNA and RNA) into nucleotides.
- Chyme is produced here by mixing bolus and gastric juices in the stomach.
- The chyme remains in the stomach for about 6 hours.
61
Describe the structure of small intestine
- Start with duodenum - jejunum - ileum
62
Describe the pathway digestion of foods in the small intestine.
- When the chyme enters the duodenum, it stimulates the release of a hormone, which it turn stimulates the release of pancreatic juices into the area.
63
Function of pancreas in digestive system.
- The pancreas release pancreatic juices which include many digestive enzymes, e.g. amylase, trypsin, and lipase as well as bicarbonate ions (used to neutralise the acidic chyme leaving stomach.
64
Function of liver in digestive system.
- Liver exerts **bile** which is then stored in **gall bladder**.
- Bile is not a digestive enzyme but acts as a detergent which breaks down (emulsifies) fats into smaller pieces or fat droplets
- Liver also keeps the sugary, glycogen and protein levels in the body -> Detoxifies the body
65
Where does absorption occur most in the digestive tract?
- Jejunum in the small intestine.
66
Define "Lacteals"
- Lacteals are structure in villi which are surrounded by capillaries network.
67
Which substances are absorbed quickly in the stomach?
- Some substances such as alcohol and drugs
68
Describe the absorption of digestive products in the small intestine.
- Some digestive products such as amino acids, glucose, glycerol, fatty acids, and nucleotides are absorbed by structures called villi (one cell thick).
- Some further folded villi are called microvilli.
- Lacteals, which are surrounded by capillary networks and are connected to another transport system - the lymph system, absorb fatty acids
69
Describe autotrophs.
- These organisms with the ability to produce its own food through photosynthesis or chemosynthesis
70
Pathway digestion in large intestine
- When all required substances are absorbed by the small intestine, the remaining undigested products are moved to the large intestine via the ileocaecal valve.
- This material is composed of water, salts, and dietary fibre. The large intestine consists of two main sections: colon and rectum
- In the colon: water and salts are absorbed back into the bloodstream, while undigested material compacting into a more solid form. Vitamin A and K also can be absorbed here.
- In the rectum, remaining waste products, known as faeces are moved here by peristalsis and secreted out through anus.
71
Function of end products of digestion.
- Can be used to build up the body into useful substances, as either new biological material or an energy source.
72
Comparison of nutrient and gas requirements of autotrophs and heterotrophs.
- Autotrophs:
+ Oxygen gas: diffuses into plant across cell surfaces
+ CO2 gas: diffuses into the plant
+ Water: Diffuses into roots
+ Glucose: Produced by photosynthesis/ chemosynthesis
+ Proteins, lipids: Produced by the plant from glucose and mineral ions.
+ Mineral ions: move into the plant through roots by diffusion and active transport.
- Heterotrophs:
+ Oxygen gas: diffuses through respiratory surfaces
+ CO2 gas: not required
+ Water: ingested into the digestive system
+ Glucose: ingested into the digestive system as either simple or complex carbohydrates, and absorbed into the bloodstream
+ Lipids, proteins: ingested into the digestive system as amino acids and fatty acids
+ Mineral ions: ingested into the digestive system and absorbed into the bloodstream.
72
Describe herbivores, omnivores, and carnivores
- Herbivores - consume plants/ autotrophs but only get 10% energy (as producers already used 90%)
- Omnivores - eat meat and plants -> get 10% energy of herbivores can get -> 1% of the autotrophs
- Carnivores only eat meat. Carnivores are typically the smallest group in an ecosystem, since there is even less energy available. Carnivores need a steady diet of other heterotrophs (only be able to live in locations that contains prey)
