Resource Acquisition and Transport in Animals Flashcards

1
Q

What is nutrition?

A

the process of taking large food
items in, breaking them apart, and then
absorbing them into the body

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2
Q

Why must animals eat?

A

To supply their body with:
» Chemical energy (fuel)
» Organic molecules (building blocks)
» Essential nutrients

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3
Q

Why do we have the production of chemical energy and how does it work?

A
  • Activity in animal cells depends on chemical energy harvested from food
  • Breakdown of carbohydrates, proteins and lipids in cellular respiration produces ATP
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4
Q

Draw the production of Chemical energy diagram

A

back of book

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5
Q

What is Biosynthesis?

A
  • The production of complex organic molecules, (proteins, polysaccharides, lipids, nucleic acids …) within living organisms or cells
  • Raw materials to build these molecules come from the diet.
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6
Q

What does biosynthesis need to happen?

A

Biosynthesis requires a source of CHNOPS

» Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulphur

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7
Q

What are the results of an unbalance between intake vs needs?

A

Animals must balance consumption, storage and use of food
» If intake > cellular respiration + biosynthesis → excess stored as fat (weight gain)
» If intake < cellular respiration + biosynthesis → stores of fat utilised (weight loss)
» Insufficient food? = “undernutrition”

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8
Q

Is the storage of food as fat important?

A

Storage of food is important to survive periods of limited supply
» Animals also have adaptations to reduce cellular respiration and biosynthesis for predictable long-term periods of limited supply (eg, hibernation)

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9
Q

What are “essential nutrients”?

A

Materials that animals cannot synthesise from simpler organic precursors, that we require, as well as CHNOPS, for our cellular processes (esp. enzyme function)

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10
Q

What are the different types of essesntial nutrients we need?

A

» Some amino acids and fatty acids
» Vitamins (water-soluble B1-B12 and C; fat-soluble A D, E and K)
» Minerals (Ca, K, Cl, Na, Mg, Fe, F, I, …)

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11
Q

What is the result of a diet lacking in one or more of the essential nutrients?

A

“malnutrition”

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12
Q

What are some examples of the amino acide and fatty acid essential nutrients we need?

A

Amino acids (AA) and fatty acid
» Can make some, but not all …
• Humans can make 12 of the 20 AA, but require 8 from their diet (eg tryptophan,methionine, lysine)
• Likewise, animals cannot synthesise some fatty acids (eg linoleic acid)

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13
Q

What are some examples if the Vitamins and minerals essential nutrients we need?

A

Vitamins and minerals
» Do not make any – need all from the diet
• Humans require 13 vitamins (eg vitamin C) from diet
• Many required in trace amounts (eg iron, copper, manganese, selenium, zinc), and excess amount can be toxic!

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14
Q

What are the different Modes of animal nutrition

A
  • Partial autotrophy (symbiosis with photosynthetic protists)
  • Herbivory
  • Carnivory
  • Omnivory
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15
Q

What are some examples of Partial Autotrophy?

A
  • Invertebrates only

- Zooxanthellae (Mutualistic symbiosis b/w protist and animal cells)

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16
Q

What do all the different modes of nutrition in animals use as food?

A
  • Herbivory: Plants or algae
  • Carnivory: Mostly other animals
  • Omnivory: Regularly consume plants, algae or other animals
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17
Q

What are the main stages of food processing?

A
  • Ingestion
  • Digestion
  • Absorption
  • Elimination
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18
Q

Draw food processing diagram

A

in back of book

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19
Q

What are Ingestion - feeding mechanisms and what are some examples?

A
  • Filter feeding
    » Strain small organisms/food particles from the surrounding medium (whale)
  • Substrate feeding
    » Live in or on the food (catapillar)
  • Fluid feeding
    » Suck nutrient-rich fluid from host (mosquito)
  • Bulk feeding
    » Most animals are bulk feeders, eating large pieces of food (snake)
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20
Q

What is digestion and what are the different types?

A
  • Break food down into molecules small enough to be absorbed
  • Can be:
    » Mechanical digestion (chewing)
    » Chemical digestion = breaking down polymers into monomers by breaking polymer bonds, eg
    • Polysaccharides → simple sugars
    • Proteins → amino acids
    • Nucleic acids → nucleotides
    • Fats and phospholipids → fatty acids
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21
Q

How do animals not digest themselves?

A

Digestion occurs within compartments
- Switching digestive enzyme activity on/off
» Eg, by regulating the pH
- The cells lining these compartments are protected by mucus, and rapidly replaced
- Compartmentalisation both at the
» Intracellular level (within cells) = lysosomes
» Extracellular level (at the level of the organism)

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22
Q

What are Extracellular Compartments and how do they work?

A
  • Large extracellular compartments linked to external environment
  • Digestive enzymes released into compartment breaks down large particles, allowing absorption by phagocytosis
  • Gastrovascular cavity, or alimentary canal (variations on a theme)
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23
Q

What is the general make up of the digestive system in humans?

A

Digestive system = alimentary canal + accessory glands

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24
Q

Draw the Human digestive system with the Accessory Glands

A

in back of book

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25
Q

What is the mouth used for?

A

Mouth
» Ingestion
» Digestion: Mechanical (teeth) and chemical (saliva)

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26
Q

What is the stomach used for?

A

» Chemical digestion (gastric juice, containing HCl and pepsin)

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27
Q

What is the small intestine used for?

A

» Very long canal (6m!), most chemical digestion occurs here
• “small” refers to its diameter …
» Chemical digestion
• Digestive enzymes secreted by pancreas and small intestine itself
• Bile salts from liver and gall bladder, which act as emulsifiers
» Also major site for absorption

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28
Q

How does absorption in the small intestine work?

A
  • Highly folded surface (villi and microvilli) → very large surface area (200 - 300 m2)
  • Both passive and active transport mechanisms in cell lining
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29
Q

What are Gut Microbiome and where are they found?

A

Symbiotic bacteria that live in digestive tract
» Stomach
» Small intestine
» Large intestine

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30
Q

What do gut microbiome do?

A

Ferment undigested polysaccharides, which can then be absorbed and provide a major source of useful energy and nutrients

31
Q

What is the Large intestine used for?

A

» No digestion

» Absorption of water

32
Q

What is the Rectum used for?

A

» Excretion

33
Q

What is the difference between a human digestive system and all mammalian digestive systems?

A

Variations on a common plan, associated to animal’s diet

34
Q

Draw a carnivors digestive system

A

in back of book

35
Q

Draw a herbivors digestive system

A

back of book

36
Q

What are the different types of teeth for mammals?

A
  • Mammals show broad adaptations of teeth types for processing different kinds of foods
  • Non-mammalian vertebrates usually less so, but there are exceptions (eg crocodile)
  • Carnivors usually have Incisors and canines at the front of they mouths for shredding meat. Then premolars and molars to crush the meat
  • Herbivors usually have premolars and molars for frinding plants but have modified incisors and canines for biting off pieces of plants.
  • Omnivors usually have a balance of all four types of teeth as our diet is varied
37
Q

What are the two most important exchanges for animals?

A
  • All animals must exchange materials with the environment
  • Ultimately, this occurs at the cellular level
    » O2 and nutrients in
    » CO2 and other waste products out
38
Q

What happens if there is a difference in concentration in an animals body?

A
- If there is a difference in concentration, small molecules can diffuse from one place to another
» Time taken is proportional to the square of the distance eg, if 0.1 mm = takes 1 second 
1 mm (10× more) = takes 102× more, ie 100 sec 
10 mm (100× more) = takes 1002× more, ie 10,000 sec
» So ok for short distances, but not > a few μm
39
Q

What are the two body plan options to maximise exchange with the environment?

A
  • In unicellular organisms, exchange occurs directly with the external environment
  • In multicellular organisms, direct transfer can be problematic → 2 main strategies
40
Q

What are the two mani stratagies for multicellular organisms to maximise their exchange?

A

» Maximise body shape so that almost all cells are close to environment
» Develop circulatory system to bring gases to cells inside the body

41
Q

What are the three basic components of a circulatory system?

A

» Circulatory fluid
» Interconnected vessels
» Pump (heart)

42
Q

are there different types of circulatory systems?

A

Circulatory systems can be “open” or “closed”

43
Q

What is an open circulatory system?

A

» Open: fluid (“haemolymph”) is also the fluid that bathes body cells (ie, interstitial fluid)
• One or more heart pumps haemolymph into a series of interconnected systems

44
Q

What is a closed circulatory system?

A

» Closed: fluid (“blood”) is confined to vessels and is different from interstitial fluid
• One of more heart pumps blood into large vessels, which branch into smaller ones that infiltrate organs
• Gas and nutrient exchange then occurs between blood and interstitial fluid (and body cells)

45
Q

What organisms have open circulatory systems and which have closed?

A

Open: Arthropods, some molluscs
Closed: Annelids, cephalopods, and all vertebrates

46
Q

Draw a diagram of an open circulatory system

A

book

47
Q

Draw a diagram of a closed circulatory system

A

book

48
Q

What is the general make up of the cardiovascular system?

A

In vertebrates, one heart and extensive network of vessels → cardiovascular system

49
Q

How do capillaries work?

A

Capillaries have very thin walls → diffusion

50
Q

How do arteries and veins work?

A
  • Wall of arteries and veins are thick with muscle and connective tissue (elastic and collagen fibres)
    » High pressure in arteries → thicker muscle layer
    » Veins have valves to maintain unidirectional flow
51
Q

How does the blood flow in a mammalian cardiovascular system work?

A

(1) Right ventricle contracts, pushing blood into
(2) pulmonary arteries to
(3) the lungs, where it is oxygenated. Blood then flow from the lungs via the pulmonary vein to
(4) the left atrium, into
(5) the left ventricle. The ventricle contracts, sending blood to
(6) the aorta, which branches off into upper and lower body arteries and supplies capillary beds of organs in (7) the head and
(8) the lower body. Oxygen depleted (CO2 rich) blood then returns via the
(9) superior and
(10) inferior vena cava into the
(11) right atrium, and the cycle starts again.

52
Q

Label the Mammalian cardiovascular system diagram

A

on lecture slides

53
Q

What does the mammalian cardiovascular system distribute?

A

Remember that cardiovascular system distributes both gases and nutrients
» (O2) Lungs → organs (CO2) → lungs
» (nutrients) GIT→liver→organs (waste) → GIT/kidneys

54
Q

What is mammalian blood composed of?

A

50% Plasma and 45% Cellular elements (white blood cells (Leucocytes), red blood cells (Erythrocytes) and platelets)

55
Q

What is plasma made of?

A
  • water
  • ions (blood electrolytes)
  • plasma proteins
  • substances transported by blood (nutreint, hormones, metabolic waste products and respiratory gases)
56
Q

What are red blood cells?

A
  • RBCs are by far the most numerous blood cells (5-6 million / μL)
  • Main function is to transport O2
    » Donut shape → improves diffusion
    » No nucleus, no mitochondria
    » Packed with haemoglobin, an iron-containing protein that binds O2 (and CO2)
    » 1 RBC can bind 1 billion O2
57
Q

Draw the Respiration at the organism level diagram

A

book

58
Q

What are Partial pressure gradients

A
  • Gases diffuse down pressure gradients
    » Partial pressure is the pressure exerted by a particular gas in a mixture of gases
    » A gas diffuses from a region of higher partial pressure to a region of lower partial pressure
    • eg in lungs and tissues, O2 and CO2 diffuse from region of higher to lower partial pressure
59
Q

What does the rate of diffusion of gases depend on?

A

Gases (such as O2 and CO2) always move by diffusion, never by active transport
- Rate of diffusion will depend on:
» Partial pressure gradient (how big the difference in partial pressures is)
» Surface area of the respiratory surface
» Thickness of the membrane (diffusion distance)

60
Q

How do respiratory surfaces maximise rate of gas exchange?

A

Respiratory surfaces tend to be thin and have large surface area

61
Q

What are the respiratory surfaces in relatively simple organisms?

A

In (sponges, cnidarians, and flatworms):
» Every cell is close to external environment, so no need for respiratory organ or circulatory system, they rely on simple diffusion

62
Q

What are the respiratory surfaces in earthworms and some amphibians

A

» Skin serves as respiratory organ

» Dense network of capillaries underneath skin facilitates gas exchange

63
Q

What are the respiratory surfaces in most animals excluding earthworms, some amphibians and simple organisms?

A

For most animals, body surface area is not sufficient area to exchange gases for the whole organism → development of respiratory organ
» Gills (aquatic), tracheae (insects) and lungs (land vertebrates)

64
Q

Where and how do land animals get their oxygen?

A
  • from the air
    » O2 is plentiful in air (21%), so obtaining O2 from air is easy and does not need to be particularly efficient (eg, humans extract only 25% of O2 from inhaled air)
65
Q

Where and how to aquatic animals get their oxygen?

A
  • from the water
    » There is much less O2 in water than in air, so extracting O2 from water requires more efficient mechanisms
    • Also, water is more dense, so extracting O2 from water requires more energy
66
Q

What are the Respiratory organs in aquatic animals?

A
  • Gills =outfoldings of body surface suspended in water
    » Large surface area for gas exchange, also ion uptake
  • Very diverse morphology
67
Q

Why dont land animals have Gills?

A

Gills are unsuited for land animals
» Lose too much water by evaporation
» Collapse in air, reducing surface area
- So most terrestrial animals have respiratory surfaces within the body, exposed to atmosphere through narrow tubes

68
Q

What are the advantages of breathing air?

A

» Much higher concentration of O2

» Air is less dense, so easier to pump past gas exchange surfaces

69
Q

What is the tracheal system

A
  • in insects
    » Air tubes that connect external environment with internal body environment; largest tubes open to outside, finest branches extend to all cells
    » Air sacs, compressed and expanded by body movement, ventilate tubes (similar to bellows)
70
Q

Why were insects bigger before now?

A
  • O2 level in Carboniferous (359-290 MYA) was 35% (compared to 21% now)
    » Dragonfly with 60 cm wingspan
71
Q

What are lungs used for?

A
  • Lungs are localised respiratory organs
  • Numerous pockets, large surface area
  • Requires circulatory system to bring gases from lungs to rest of the body
72
Q

How does breathing work in different animals?

A

Various mechanisms for moving air in and out of lungs:
» Amphibians: positive pressure (forced airflow)
» Birds: air sacs (function as bellows)
» Mammals: negative pressure (pull air into lungs, by using muscles to expand thoracic cavity)

73
Q

What increases the amount of oxygen that blood can carry?

A

Respiratory pigments greatly increase amount of oxygen that blood can carry
» Most vertebrates and some invertebrates: haemoglobin, with iron as the binder
» Arthropods and many molluscs: haemocyanin, with copper as oxygenbinding component

74
Q

What are some other adaptions that animals have had for gas exchange?

A

» High altitude birds: high haemoglobin counts
» Deep diving mammals (can dive for up to 2h!): store O2 in muscles, minimise muscle activity, use anaerobic fermentation