Digestion

Question 1

What is heterotrophic nutrition

Answer 1

Organisms that must ingest complex organic molecules and break them down into simple ones to absorb

Question 2

What is autotrophic nutrition

Answer 2

Organisms that synthesise their own food from simple organic molecules to make complex ones

Question 3

What is a holozoic feeder

Answer 3

Organisms that break food down in digestion

Question 4

What is a saprophyte

Answer 4

Feed on dead and decaying matter using secreted enzymes and absorbing through skin. Do not have a specialised digestive system

Question 5

What is a parasite

Answer 5

An organism that lives in or on a host, for their nutritional benefit and to the host’s disadvantage

Question 6

What is symbiosis

Answer 6

When organisms live on or in a host to the host and the organisms benefit

Question 7

Describe unicellular digestion

Answer 7

Food is ingested by engulfing in phagocytosis, and is digested intracellularly by lysosomes.

Question 8

Describe hydra digestion

Answer 8

The mouth (in the middle of the tentacles) is the only opening. The inner layer of cells is called the gastrodermis; the gastrodermis secretes digestive enzymes into the lumen of the gut. Digested food is absorbed by the gut wall. Undigested food is egested via the mouth.

Question 9

Describe earthworm digestion

Answer 9

A tube-like gut with an opening at both ends; a mouth for ingestion and an anus for egestion. The gut has different regions

Question 10

Through which organs does food pass in humans for digestion

Answer 10

Oesophagus
Stomach
Small intestines
Large Intestines

Question 11

Which organs create secretions for digestions

Answer 11

Liver
Pancreas
Stored in gall bladder

Question 12

How is food moved through the gut

Answer 12

Peristalsis

Question 13

What is mechanical digestion

Answer 13

Cutting or crushing of large pieces of food into smaller pieces to increase surface area

Question 14

What is chemical digestion

Answer 14

Break down of large insoluble molecules into smaller soluble molecules

Question 15

What are the layers of the gut

Answer 15

Serosa
Longitudinal muscle
Circular muscle
Sub-mucosa
Mucosa
Epithelium

Question 16

How are polysaccharides digested

Answer 16

Salivary amylase secreted begins breakdown. Amylase denatured in the stomach in the acid. Pancreatic amylase secreted in the duodenum breaks polysaccharides into disaccharides. Maltase in the cell wall of epithelium cells breaks down maltose into glucose which is then absorbed into the bloodstream.

Question 17

How are polypeptides digested

Answer 17

Pepsinogen secreted in gastric juice. Endopeptidases turn proteins into smaller polypeptides. Exopeptidases break down polypeptides in the duodenum into amino acids and absorbed in the ileum.

Question 18

How are fats digested

Answer 18

Bile emulsifies fats. increasing their surface area. Pancreatic lipase is secreted to break them down into fatty acids and glycerol to be absorbed.

Question 19

How are the small intestines adapted to absorption

Answer 19

They contain villi to increase surface area, and the epithelial cells have microvilli. They also have large numbers of mitochondria for active transport.

Question 20

How are the following absorbed into the gastric cells

Fatty acids
Glycerol
Vitamins
Amino acids
Monosaccharides

Answer 20

Diffusion
Diffusion
Diffusion
Active transport
Active transport

Question 21

How are the following absorbed into the blood capillaries

Fatty acids
Glycerol
Vitamins
Amino acids
Monosaccharides

Answer 21

Diffusion
Diffusion
Diffusion
Diffusion
Diffusion

Question 22

How do herbivore and carnivore guts differ

Answer 22

Herbivore guts are much longer

Question 23

How do herbivore and carnivore teeth differ

Answer 23

Herbivore jaws move laterally and carnivore jaws move vertically
Herbivore teeth are flat for grounding, and carnivore teeth are sharp for ripping
Herbivores have a diastema and carnivores have carnassials

Question 24

Describe ruminant digestion

Answer 24

Grass is eaten and swallowed, and digested by bacteria. Then its regurgitated and rechewed, then passed back to the rumen, reticulum, omasum and abomasum before continuing to be digested in the intestines.

Question 25

How are tapeworms adapted to living in human guts

Answer 25

They have a thick cuticle outside to protect from the immune system, secrete antienzymes to denature enzymes, produce thousands of eggs, and attach to the inside of the small intestines

Question 26

How do tapeworms reproduce

Answer 26

They are hermaphroditic

Question 27

What type of parasite is a tapeworm

Answer 27

Endoparasite

Question 28

What type of parasite is a head louse

Answer 28

Ectoparadise