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Biology Unit 2 > 2.4- Adaptations for nutrition > Flashcards

2.4- Adaptations for nutrition Flashcards

1
Q

(a)

Autotrophic

A

An organism that produces its own food. It manufactures complex organic compounds from simpler inorganic molecules such as water and carbon dioxide. Autotrophic organisms can be photoautotrophic or chemoautotrophic.

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2
Q

(a)

Photoautotrophic organism

A

An organism which obtains its nutrition through photosynthesis.

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3
Q

(a)

Chemoautotrophic organism

A

An organism which obtains its nutrition through inorganic molecules, such as sulfur, in the absence of light..

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4
Q

(a)

Heterotrophic organism

A

An organism that cannot produce its own food. It obtains energy by feeding on organic compounds produced by other organisms.

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5
Q

(b)

Saprotrophic/saprobiotic

A

An organism that derives energy and raw materials for growth from the extracellular digestion of dead or decaying material.

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6
Q

(b)

Extracellular digestion by saprotrophs

A

Release enzymes which catalyse the breakdown of dead plant and animal material into simpler organic matter and also absorbs the products of digestion.

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7
Q

(b)

Holozoic

A

Feeding method of many animals, involving ingestion, digestion, absorption, assimilation and egestion.

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8
Q

(b)

Parasitic nutrition

A

Parasitic nutrition is when an organism obtains nutrients from a living host, which suffers harm and may die.

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9
Q

(c)

Saprotrophic nutrition

A

Saprotrophic nutrition is used by all fungi and some bacteria. They lack a specialised digestive system and secrete enzymes onto food outside their body for extracellular digestion. The soluble products are then absorbed across their membranes by diffusion and active transport.

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10
Q

(d)

Holozoic nutrition

A

Describes a heterotrophic organism that internally digests food substances.

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11
Q

(d)

Processes holozoic nutrition involves

A

Involves ingestion, absorption,
assimilation and egestion.

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12
Q

(e)

Nutrition in unicellular organisms- Ameoba

A

Amoeba use holozoic nutrition. Small nutrients diffuse across the membrane, while larger molecules are taken in by endocytosis into food vacuoles. These fuse with lysosomes, which release enzymes to digest the contents. The nutrients are absorbed into the cytoplasm, and waste is removed by exocytosis. Their large surface area to volume ratio helps nutrient uptake.

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13
Q

(f)

Adaptation of multicellular organisms for nutrition

A

Hydra – single food source
Undifferentiated, sac-like gut with a single opening.

Earthworm – varied foods
A tube gut with different openings for ingestion and egestion
and specialised regions for the digestion of different food.

Human – omnivorous diet
Specialised regions of gut

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14
Q

(g)

Adaptations of the human gut- Serosa

A

Tough outer coat of connective tissue

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15
Q

(g)

Adaptations of the human gut- Muscle

A

Longitudinal muscle contracts to shorten the gut and
circular muscle contracts to reduce diameter. These waves of
contraction called peristalsis force food along the gut.

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16
Q

(g)

Adaptations of the human gut- Submocusa

A

Contains blood and lymph vessels to remove digested food products.

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17
Q

(g)

Adaptations of the human gut- Mocusa

A

Inner layer that secretes mucus for lubrication. In some areas it
secretes digestive juices; in others it absorbs products.

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18
Q

(g)

Adaptations of the human gut- Epithelium

A

Layer of cells in contact with food.

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19
Q

(g)

State the names of the different layers of the gut wall.

A

Epithelium
Mucosa
Submucosa
Muscle layer
Serosa

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20
Q

(g)

Epithelium

A

A single layer of cells that line the gut wall and are in contact with food.

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21
Q

(g)

Mucosa

A

Inner layer that secretes mucus for lubrication. In some areas it secretes digestive juices; in others it absorbs products.

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22
Q

(g)

Submucosa

A

Contains blood and lymph vessels to remove digested food
products.

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23
Q

(g)

Muscle

A

Longitudinal muscle contracts to shorten the gut and circular muscle contracts to reduce diameter. These waves of contraction called peristalsis force food along the gut.

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24
Q

(g)

Serosa

A

Tough outer coat of connective tissue.

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25
# (h) Buccal activity
The oral cavity through which food enters the body.
26
# (h) Type(s) of digestion take place in the buccal cavity
Mechanical digestion and chemical digestion of starch.
27
# (h) normal pH range of the buccal cavity
pH 6.5 to 7.5
28
# (h) Function of teeth
Crush and grind food into smaller pieces, increasing its surface area.
29
# (h) Tongue
A muscular organ in the buccal cavity that is vital in the chewing and swallowing of food
30
# (h) function of salivary glands
Secrete amylase, mineral ions and mucus into the buccal cavity.
31
# (h) Function of oesophagus
peristaltic waves of muscle contraction push the bolus of food down to the stomach. Mucus lubricates the way.
32
# (h) function of gastric glands
Secrete endopeptidases, hydrochloric acid and an alkaline mucus into the stomach.
33
# (h) pH of the stomach
pH 2
34
# (h) role of the liver
Produces bile which emulsifies lipids (↑ surface area for lipase) and neutralises stomach acid (alkaline pH for enzymes in duodenum).
35
# (h) two main divisions of the small intestine
● Duodenum ● Ileum
36
# (h) Duodenum
The first section of the small intestine where proteins and lipids are hydrolysed.
37
# (h) Ileum
The second section of the small intestine that serves as the main site of absorption of the products of digestion.
38
# (h) pH range of the small intestine
pH 7 to 8
39
# (h) pancreas
produces enzymes that are transported to the duodenum via the pancreatic duct
40
# (h) rectum
The segment of the large intestine that stores faeces prior to egestion.
41
# (h) enzymes involved in carbohydrate digestion
* Amylase in saliva and pancreatic juice * Maltase, sucrase, lactase on the membrane of the epithelial cells of the small intestine
42
# (h) substrates and products of the carbohydrases
* Amylase hydrolyses starch to maltose * Sucrose digested by sucrase into glucose and fructose. * Maltose digested by maltase into alpha glucose. * Lactose digested by lactase into glucose and galactose.
43
# (h) optimum pH of amylase
pH 8
44
# (h) enzymes are involved in protein digestion
Endopeptidases - hydrolyse non-terminal peptide bonds within a protein to form smaller peptides Exopeptidases - hydrolyse the terminal peptide bonds of a protein to form dipeptides and amino acids
45
# (h) examples of endopeptidases
● Trypsin ● Pepsin
46
# (h) Production of trypsin
* Secreted by the pancreas as inactive trypsinogen * Enterokinase converts inactive trypsinogen into active trypsin in the duodenum
47
# (h) Inactive form of pepsin
Pepsinogen
48
# (h) Where is pepsinogen secreted from?
Gastric glands
49
# (h) Describe how inactive pepsinogen is converted into its active form, pepsin.
Hydrochloric acid converts inactive pepsinogen into active pepsin.
49
# (h) Where are lipids digested?
Small intestine
50
# (h) What must happen before lipids can be digested?
They must be emulsified by bile salts produced by the liver. This breaks down large fat molecules into smaller, soluble molecules called micelles, increasing the surface area.
51
# (h) Digestion of lipids
Lipases hydrolyse lipids into monoglycerides, fatty acids and glycerol.
52
# (h) Location of lipases
In pancreatic juice.
53
# (h) Processes by which absorption takes place in the ileum.
* Simple diffusion * Facilitated diffusion * Active transport * Osmosis
54
# (h) Which molecules are absorbed by simple diffusion in the ileum?
Monoglycerides, fatty acids and glycerol.
55
# (h) Why can monoglycerides, fatty acids and glycerol be absorbed via simple diffusion?
They are non-polar molecules so can easily diffuse across the membrane of the epithelial cells.
56
# (h) What happens to monoglycerides, fatty acids and glycerol once they are absorbed into cells?
They are reformed into triglycerides, absorbed into the lacteals and transported via the lymphatic system into the blood.
57
# (h) How are amino acids absorbed from the lumen of the gut?
Via active transport into epithelial cells and then into the bloodstream by facilitated diffusion.
58
# (h) Which molecules rely on co-transport from the lumen of the gut into the cytoplasm of the epithelial cells?
Glucose and other monosaccharides.
59
# (h) Explain how sodium ions are involved in co-transport.
Sodium ions (Na+ ) are actively transported out of the cell into the lumen, creating a diffusion gradient. Nutrients are then taken up into the cells along with Na+ ions.
60
# (h) How do monosaccharides pass from the epithelial cells into the bloodstream?
Via facilitated diffusion
61
# (i) Herbivores
Animals that only eat plants
62
# (i) adaptations of herbivores to a high cellulose diet
* Long gut * Loose articulation of the lower jaw * Horny pad on the upper jaw * Specialised dentition for grinding tough plant material
63
# (i) Describe how the dentition of a herbivore is adapted to its diet.
* Small, flat incisors on lower jaw for cutting grass against upper horny pad * Diastema between incisors and premolars - space where tongue can push food to the grinding cheek teeth * Premolars and molars- W/M-shaped interlocking teeth for grinding; jaw moves sideways. Open roots mean they grow throughout life
64
# (i) Ruminants
Mammals that digest plant material slowly in a specialised four-chambered stomach and regurgitate it to chew it again, enabling the efficient breakdown of fibre.
65
# (i) four chambers of the ruminant stomach
* Rumen * Reticulum * Omasum * Abomasum
66
# (i) Rumen
The first stomach of a ruminant. It contains mutualistic bacteria that are able to hydrolyse cellulose into glucose.
67
# (i) Carnivore
An animal that preys on and eats other animals.
68
# (i) adaptations of carnivores to a high protein diet
* Short gut * Powerful jaw muscles * Specialised dentition for cutting and tearing meat
69
# (i) Describe how the dentition of a carnivore is adapted to its diet.
* Sharp incisors to remove flesh from bone * Large, pointed canines required to grip and kill prey * Sharp carnassials (modified premolars and molars) to slice and shear meat * Molars with sharp, flattened edges to crush bone
70
# (j) Parasite
live on or in a host organism, obtaining their nutrition from the host and harming the host.
71
# (j) Two types of parasite
Ectoparasites and Endoparasites
72
# (j) Ectoparasites
Parasites that live on the host e.g. Head louse, Pediculus humanus.
73
# (j) Endoparasites
Parasites that live in the host e.g. Pork tapeworm, Taenia solium.
74
# (j) How does the head louse feed and transfer from one host to another?
* Feeds by sucking blood from the host’s scalp * Transfers between hosts by direct contact
75
# (j) Where does the pork tapeworm live?
Primary host - adult tapeworm lives in the human gut Secondary host - larval form can develop in pigs
76
# (j) How can humans and pigs become infected by the pork tapeworm?
* Humans become infected by consuming undercooked pork (containing larval forms of the tapeworm) * Pigs may become infected by ingesting contaminated faeces
77
# (j) How does the pork tapeworm feed?
Absorbs pre-digested nutrients in the gut through its cuticle.
78
# (j) How is the pork tapeworm adapted to living in the gut?
* Thick cuticle * Secretes anti-enzymes that prevent its digestion by host enzymes * Scolex has suckers and hooks for attachment to gut wall * Long, thin body proves large surface-area-to-volume ratio for absorption

Biology Unit 2 (4 decks)

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