2.5 Adaptations for Nutrition

Question 1

What are autotrophs?

Answer 1

Organisms that use simple inorganic materials to create complex organic compounds for energy.

Question 2

What are heterotrophs?

Answer 2

Organisms that consume complex organic food material.

Food is processed as it passes along the gut.

Question 3

How do saprophytes and saprobionts feed?

Answer 3

Bacteria and some fungi.
Secrete enzymes onto the food material outside the body and absorb the soluble products across the cell membrane by diffusion.
Extracellular diffusion.

Question 4

What are the 4 stages of advanced heterotrophic food processing?

Answer 4

Ingestion, digestion, absorption, egestion.

Question 5

What are the tissue layers of the alimentary canal?

Answer 5

Serosa, longitudinal muscle layer, circular muscle layer, submucosa, mucosa, epithelium.

Question 6

What are the parts of the human digestve system?

Answer 6

Buccal cavity, tongue, salivary glands, oesophagus, stomach, duodenum, ileum, colon, rectum, anus.
(associated organs: liver and pancreas)

Question 7

What are glands?

Answer 7

They produce digestive secretions.
Some found in the wall of the gut with the secretion passing directly into the gut cavity.
Organisms with a varied diet need more types of enzymes for digestion & usually more than one enzyme is needed for the complete digestion of a particular food.

Question 8

What enzymes are involved in digestion?

Answer 8

Proteins broken down by protease into polypeptides.
Polypeptides broken down by peptidase into amino acids.
Lipids by lipase into fatty acids & glycerol
Starch by amylase into maltose.
Maltose by maltase into glucose

Each specialised region of the mammalian digestive system has a different pH so the different enzymes have different optimum pHs.

Question 9

What does mucus do?

Answer 9

Lubricates the food as it passes along the guts and protects the gut wall.

Question 10

Where does absorption of the end products of digestion take place?

Answer 10

in the ileum.

The surface area is increased by villi and miicrovilli.

Question 11

How are glucose and amino acids absorbed?

Answer 11

By diffusion and active transport into capillaries and then travel via the hapatic portal vein to the liver.

Question 12

What happens to fatty acids and glycerol once they have been absorbed?

Answer 12

They are passed into the lacteal, then through the lymphatic system to the blood stream opening at the thoracic duct.

Question 13

What happens to water in the digestive system?

Answer 13

It is mostly reabsorbed, along with soluble nutrients in the small intestine. The colon absorbs the remaining water, along with vitamins in order to produce solidified faeces.

Question 14

What happens to residues of undigested cellulose, bacteria and sloughed cells?

Answer 14

They are passed along the colon to be egested as faeces.

Question 15

What is cellulose fibre required for?

Answer 15

To provide bulk and stimulate peristalsis.

Question 16

What is glucose used for?

Answer 16

It iis absorbed by the blood cells for energy release in respiration.
Excess glucose is stored as fat.

Question 17

What are amino acids used for?

Answer 17

Protein synthesis.
Excess cannot be stored as they are toxic so they are deaminated. The removed amino groups are converted into urea and the remainder is converted into carbohydrates and stored.

Question 18

What are lipids used for?

Answer 18

Membranes and hormones

Excess stored as fat

Question 19

What are teeth for?

Answer 19

Mechanical digestion in order to increase the surface area for enzyme action.

Question 20

What teeth are found in the mouth of mammals?

Answer 20

Incisors (biting, chisel shaped)
Canines (piercing skin, gripping, holding prey)
Premolars and molars (flat, slightly ridged, chewing, grinding)

Question 21

How does the jaw of herbivores and carnivores move?

Answer 21

Herbivores: horizontal plane
Carnivores: vertically

Question 22

How do the guts of carnivores and herbivores differ?

Answer 22

Carnivores: Large stomach, short small intestine
Herbivores: Small stomach, appendix & caecum extends as one unnit from the large intestine (full of mutualistic bacteria)

Question 23

What does the stomach of ruminant animals consist of?

Answer 23

Oesophagus
Rumen (contains mutualistic bacteria which breaks down cellulose so is anaerobic)
Reticulum (comes off the rumen)
Omasum
Abormasum

Question 24

What do ruminant animals eat?

Answer 24

eg cows and sheep
Eat mainly grass with cellulose cell walls.
Digest the bacteria in the abomasum for protein