6.1 Digestion Flashcards Preview

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Flashcards in 6.1 Digestion Deck (36):
1

Explain why digestion of large food molecules is essential

Foods are made up of large complex biological polymer molecules. These tend to be insoluble and chemically inert. Therefore, we must break them down into soluble products, so that they can be absorbed, transported and reassembled into new products.

2

Explain the need for enzymes in digestion

Enzymes allow the digestive process to occur at body temperature (37C in humans) and at a sufficient speed to meet the organism's survival requirements.

3

State the enzyme type of Salivary Amylase

Amylase

4

State the source of Salivary Amylase

Salivary glands

5

State the substrate of Salivary Amylase

Starch

6

State the products which Salivary Amylase produces

Maltose

7

State the optimal pH for Salivary Amylase

pH ~7 (neutral)

8

State the enzyme type of Pepsin

Protease

9

State the source of Pepsin

Secreted by chief cells in stomach lining. Found in gastric juices (stomach).

10

State the substrate of Pepsin

Large polypeptides

11

State the products which Pepsin produces

Smaller peptides and amino acids

12

State the optimal pH for Pepsin

pH ~2 (highly acidic)

13

State the enzyme type of Pancreatic Lipase

Lipase

14

State the source of Pancreatic Lipase

Pancreas

15

State the substrate for Pancreatic Lipase

Tryglycerides

16

State the produces which Pancreatic Lipase produces

Glycerol + Fatty acid chains

17

State the optimal pH for Pancreatic Lipase

pH ~8 (slightly alkaline)

18

State the two major organ groups associated with human digestion

Alimentary Canal and Accessory Organs

19

Describe the Alimentary Canal

Contains organs through which the food actually passes (esophagus, stomach, small intestine, large intestine, etc.)

20

Describe the Accessory Organs

Organs that assist in digestion but no food passes through them (liver, pancreas, gall bladder, salivary glands, etc.)

21

Outline the function of the stomach

Breaks down food into a liquidly mixture called chyme. Secretes HCL to kill off bacteria which could cause food poisoning. Secretes pepsin for protein digestion. Provides optimum pH for pepsin. Slowly empties that chyme into the small intestines.

22

Outline the function of the small intestine

Final stages of digestion occur. All soluble food substances (e.g. nutrients) are absorbed into the bloodstream.

23

State the three sections of the small intestine

Duodenum
Jejunum
Ileum

24

Outline the function of the Duodenum

Food particles broken down into soluble components. Sodium bicarbonate neutralises stomach acid in the chyme. Bile emulsifies large fat droplets into smaller droplets, increasing their surface area, pancreatic lipase breaks them apart.

25

Outline the function of the Jejunum

Majority of absorption occurs. Lined with villi, which are in turn lined with microvilli. These absorb nutrients into the blood via active transport, maximizing absorption.

26

Outline the function of the Ileum

Absorbs bile salts, vitamin B12, and whatever usable products of digestion were not absorbed by the jejunum

27

Outline the function of the large intestine

Absorbs water. Converts what remains from fluid state to semi-solid faeces. Faeces stored in rectum and eliminated out the anus.

28

Define absorption

Movement of fluid or dissolved substance across a membrane. Soluble products of digestion are absorbed into bloodstream, or the lymphatic system in the case of lipids.

29

Define assimilation

When food products become part of the body's tissue. Products of digestion are absorbed into cells from the blood to be stored or used within cells/tissues.

30

State 6 of the features of the villus which are related to their roles in absorption and transport of products of digestion

Microvilli
Rich capillary networks
Single-cell epithelial layer
Lacteals
Intestinal crypts
Mitochondria

(MRS LIM)

31

Explain how microvilli assist the villus in the absorption and transport of products of digestion

Greatly increase the surface area of the villus, allowing for a greater rate of absorption.

32

Explain how the rich capllary network assists the villus in the absorption and transport of products of digestion

Help to maintain a concentration gradient for absorption by rapidly transporting absorbed products away.

33

Explain how the single epithelial layer assists the villus in the absorption and transport of products of digestion

Ensures minimal diffusion distance between the intestinal lumen and capillary network.

34

Explain how the lacteals assist the villus in the absorption and transport of products of digestion

Absorb lipids from the intestine into the lymphatic system (which are later reabsorbed back into normal circulation).

35

Explain how intestinal crypts assist the villus in the absorption and transport of products of digestion

Located between villi and release juices that act as a carrier fluid for nutrients.

36

Explain how mitochodria assist the villus in the absorption and transport of products of digestion

Produce sufficient ATP to enable active transport into cells (contents then passively diffuse into bloodstream).