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Biology - Unit 2 > Adaptations for nutrition > Flashcards

Adaptations for nutrition Flashcards

1
Q

Autotrophic Organisms

A
  • Make their own food from the simple inorganic raw materials carbon dioxide and water
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2
Q

Photoautotrophic

A
  • Use light as an energy source and perform photosynthesis.
  • Green plants, some protoctista and some bacteria
  • This mode of nutrition is called holophytic
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3
Q

What are the two different things do autotrophic organisms use for energy

A
  • chemicals
  • light
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4
Q

Chemoautotrophs

A
  • Use energy from chemical reactions
  • All prokaryotes and perform chemosynthesis
  • Less efficient then photosynthesis
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5
Q

Heterotrophic Organisms

A
  • Cannot make their own food and consume complex organic molecules produced by autotrophs, so they are consumers
  • Eat other autotrophs or organisms
  • Animals, fungi and some proctoctista and fungi
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6
Q

Parasitic Nutrition

A
  • Obtaining nutrition from another living organism, the host.
  • The host will always suffer harm or often death
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7
Q

Endoparasites

A
  • Live in the body of the host
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8
Q

Ectoparasites

A
  • Live on the surface of the host
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9
Q

Holozoic Nutrition

A
  • Used by most animals
  • Ingest food, digest it and egest the indigestible materials
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10
Q

Detritivores

A

Feed on dead or decaying materials

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11
Q

Saprotrophic

A
  • External digestion of food using secretion of enzymes followed by absorption of the products of digestion into the organism via active transport and diffusion
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12
Q

What broad category do Holozoic, Saprotrophic and parasitic nutrition fit into?

A

Heterotrophic Organisms

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13
Q

Why must food be digested in humans

A

1) Molecules are insoluble and too big to cross the membrane and absorb into the blood
2) Polymers must be broken down into their monomers, so they can be rebuilt into molecules needed by body cells

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14
Q

How is food pushed through the digestive system

A

Via peristalsis

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15
Q

Describe peristalsis

A

1) The muscular walls of the oesophagus contracts and relaxes and sequence to push the bolus of food down into the stomach
2)Circular muscles contract and then relax behind the bolus and longitudinal muscles do the same in front of the bolus
3) The wave of contraction pushes the bolus down the oesophagus into the stomach

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16
Q

Human Guts 4 main functions

A

1) Ingestion - through the mouth
2) Digestion - Mechanical and Chemical
3) Absorption - gut wall
4) Egestion - Elimination of waste

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17
Q

Name the parts of the human digestion system and their functions

A

Mouth - Ingestion; digestion of food via amylase
Oesophagus- Carry food to stomach, peristalsis
Stomach - digestion of proteins via protease
Duodenum - Digestion of carbs, fats and proteins
Ileum - Absorption
Colon - Absorption of water
Rectum - Storage of faeces
Anus - Egestion

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18
Q

What acid works in the stomach and what is the pH?

A
  • Hydrochloric Acid
    pH 1-2
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19
Q

Name the gut wall layers.

A
  • Serosa
  • Muscularis
  • Submucosa
  • Mucosa
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20
Q

Serosa

A
  • The outermost layer of the gut wall
  • Tough connective tissue, used for protection
  • The gut moves while processing food and the serosa reduces friction with other abdominal organs
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21
Q

Muscularis

A
  • Comprises of 2 layers in different directions
  • Inner circular muscles contract behind the bolus and longitudinal muscles relax pushing it forward. These coordinated waves of contractions are called peristalsis
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22
Q

Submucosa

A
  • Connective tissue containing blood and lymph vessels, which remove absorbed products of digestion, and nerves that coordinate peristalsis
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23
Q

Mucosa

A
  • Inner most layer of the gut and lines it.
  • Its epithelium secrets mucus, lubricating and protecting the mucosa ( HCl from stomach)
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24
Q

What needs to happen in order for absorption of nutrients by the gut epithelial cells?

A

Macromolecules need to be digested into smaller molecule

25
Q

Describe carbohydrate digestion

A
  • Carbohydrates (polysaccharides) digested into disaccharides and then monosaccharides.
  • Amylase hydrolyses starch to the disaccharide maltose
  • Maltase digests the maltose to the monosaccharide alpha glucose
26
Q

Maltose, Sucrose, Lactose; name the enzymes which break down these disaccharides and therefore the monosaccharides they turn into

A

Maltose – Maltase – 2 Alpha glucose

Sucrose – Sucrase – 1 glucose, 1 fructose

Lactose – Lactase – 1 glucose, 1 galactose

27
Q

What are the general names for protein digestion enzymes?

A
  • Protease and Peptidase
28
Q

What are proteins digested into?

A

polypeptides, dipeptides then amino acids

29
Q

Epithelium

A

Layer of cells in contact with food

30
Q

Describe the 2 steps that happens in protein digestion

A

1) Endopeptidases hydrolyse peptide bonds within the molecule adjacent to specific amino acids and form peptides
2) Exopeptidases hydrolyse the terminal peptide bonds at the end of these shorter peptide molecules

31
Q

What are fats digested into?

A
  • Fatty acids and glycerol
32
Q

What enzyme digests fats?

A

lipase

33
Q

What are the 3 components of Saliva?

A

1) Amylase - beginning the digestion of starch to maltose
2) bicarbonate and carbonate ions in the mouth so the pH i slightly alkaline, perfect for amylase
3)Mucus- lubricating the foods passage down the oesophagus

34
Q

What are the 2 sphincters in the stomach and where are they located ?

A

Cardiac Sphincter - junction with the oesophagus
Pyloric Sphincter - At the junction with the duodenum

35
Q

How is food kept in the stomach?

A

By contractions of the two sphincters

36
Q

Where is gastric juice secreted from?

A

glands in the depression of the mucosa, called Gastric pits

37
Q

What does gastric juice contain?

A

1) peptidases are secreted by chief cells. Pepsinogen, an inactive enzyme, is secreted and activated by H+ ions to pepsin
2) Hydrochloric acid lowers the pH of the stomach, optimum pH for protease and also kills bacteria
3) Mucus secreted by goblet cells prevents autolysis of the stomach wall

38
Q

What is the role of bile?

A
  • Contains bile salts which are amphipathic (molecules have hydrophilic and hydrophobic parts)
  • These emulsify lipids, lowering the surface tension and breaking them into smaller globules
  • This increases the SA and makes digestion more efficient
39
Q

What is pancreatic juice secreted by ?

A

islet cells, which are exocrine glands in the pancreas

40
Q

Name some components of pancreatic juice and their function

A
  • Endopeptidase = hydrolyses proteins into peptides
  • Enterokinase = converts trypsinogen into trypsin
  • Sodium hydrogen carbonate = raises the pH to slightly alkaline and contributes to neutralising acid from the stomach
41
Q

What are the products of carb and protein digestion? Where are they absorbed

A

glucose and amino acids
Absorbed into the blood capillaries

42
Q

Where in the small intestine is well adapted for absorption?

A

the ileum

43
Q

What are some adaptations of the ileum?

A

lining is highly folded to increase surface area
On the surface of the folds are villi and their epithelial cells have microscopic projections called microvilli

44
Q

Absorption of amino acids

A
  • by the epithelial cells by active transport and as individual amino acids they pass into the capillaries by facilitated diffusion
  • They are water soluble and dissolve in plasma
  • then transported via the hepatic portal vein to the liver
45
Q

Glucose Absorption

A
  • passes into the epithelial cells with sodium ions by co-transport
  • Glucose and 2 Na+ ions bind to the carrier protein
  • Then released into the epithelial cell, diffused across the cytoplasm of the cell separately
  • Move into the blood capillaries
  • Sodium = active transport via carrier proteins
  • Glucose - facilitated diffusion, dissolve in plasma
46
Q

How is glucose allowed to transport into the cell ?

A
  • The deficit of sodium inside the cell encourages it to bring in the attached glucose molecule as a concentration gradient in created
47
Q

What are lipids used for in the body?

A

Used in the cell membrane to make hormones

48
Q

How are amino acids used in the body and what happens with excess?

A
  • used in body cells for protein synthesis.
  • The liver deaminated excess and converts into urea which is carried to the kidney by the blood for excretion in the urine
49
Q

What parts make up the large intestine?

A
  • ceacum, appendix, colon and rectum
50
Q

What process happens in the colon and why?

A
  • Water absorption so by the time material reaches the rectum it is semi- solid.
51
Q

Describe the difference of the gut between a carnivore and herbivore?

A

Carnivore
- small intestine = short reflecting the ease of protein digestion
- straight large intestine with a smooth lining

Herbivore
- small intestine = long plant material is not readily digested needs longer time for absorption and digestion
- Large intestine is pouched and can accommodate for larger volumes of faeces produced, much of which is cellulose

52
Q

Describe the dentition of a herbivore

A
  • incisors on the lower jaw only and a horny pad on top to allow the manipulation of food
  • jaw moves in circular motions to grind down the food on cheek teeth or molars
  • Molars interlock like a W and M
  • Teeth have open unrestricted roots allowing growth
53
Q

Describe the dentition of a carnivore

A
  • Sharp incisors grip and tear muscle from bone.
  • Canine teeth large curved and pointed for piercing pray and killing
  • Jaw muscles are well-developed and powerful
54
Q

What is ruminants ?

A
  • herbivorous animal
  • with 4 chambers of the stomach
55
Q

How does cellulose digestion take place?

A

1) Grass is cut by the teeth and mixed with saliva to form cud, which is swallowed down the oesophagus to the rumen.
The rumen is the chamber where food mixes with microbes. The microbes secrete enzymes which digest cellulose into glucose.
The glucose is fermented to organic acids that are absorbed into the blood
The waste products, carbon dioxide and methane are released.
2) The fermented grass passes to the reticulum and is re-formed into cud. Then regurgitated into the mouth for further chewing.
3 ) Cud may be swallowed and regurgitated to the mouth several times.
4 The cud passes next into the omasum. Water absorption takes place
5 In the last chamber - the abomasum protein digestion occurs
6 All products of digestion are absorbed into the blood in the small intestine

56
Q

What is the structure of a pork tapeworm?

A

Its anterior end, the scolex, is made of muscle carrying suckers and hooks, attaching it strongly to the duodenum wall of its host.
- thin and flat body allowing products of digestion to be absorbed
- contains both male and female organs so can reproduce and gametes pass out in the hosts faeces

57
Q

What are the 2 hosts of pork tapeworm?

A
  • The primary host is the human and the pig is the secondary host.
  • The pig becomes infected when its food is contaminated with human faeces.
  • Humans are infected by eating undercooked, infected pork.
58
Q

What challenges does the pork tapeworm overcome?

A
  • It lives in mucus surrounding by digestive juices and mucus.
  • Peristalsis produces constant motion.
  • It is exposed to the host’s immune system.
  • If the host dies so does the parasite.
59
Q

Pediculus - an ectoparasite life cycle

A
  • The nits are empty eggs easily seen on the hair or on clothing.
  • After 1-2 weeks, an egg hatches into a nymph, which is an adult, but smaller.
  • Nymphs become adult after about 10 days and, like the adult, the nymphs feed on blood, which, in the case of head lice, they suck from the scalp of the host.

Biology - Unit 2 (6 decks)

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