Ch1- Heterotrophic Nutrition

Question 1

Digestion

Answer 1

It’s the conversion of polymers to monomers by hydrolysis by the help of enzymes

Question 2

Importance of digestion

Answer 2

LOs obtain ready made complex compounds (as proteins and carbohydrates) that cannot diffuse through cell membrane, so large food molecules are broken down to small simple structures (as amino and glucose) so it can be easily absorbed by the cell by diffusion or by active transport.

Question 3

Properties of enzyme

Answer 3

1. They are specific molecules that activate specific chemical reactions, the enzyme fits with the substrate as lock and key
2. They’re made of proteins
3. Affected by PH and temperature
4. When the reaction is completed, the product breaks away from enzyme
5. Only works in watery medium
6. Some are secreted in an inactive state and are activated by a substance
7. Some have reversible effect

Question 4

Substrate

Answer 4

The food material which the enzyme acts on

Question 5

The Digestive Canal:

Answer 5

It’s a long canal that starts from the mouth and ends by Anus

Question 6

Teeth are differentiated into:

Answer 6

Incisors
Canines
Premolars and molars

Question 7

Function of incisors

Answer 7

Cutting food

Question 8

Function of canines

Answer 8

Tearing food

Question 9

Function of molars and premolars

Answer 9

Grinding and crushing food

Question 10

Function of tongue

Answer 10

1. Mixing food to be chewed by teeth
2. Tasting food
3. Pushing food to the pharynx

Question 11

Salivary glands

Answer 11

3 pairs which open in mouth cavity and secrete saliva

Question 12

Function of chewing food

Answer 12

Increase the SA of enzymatic action of food

Facilitate swallowing

Question 13

Saliva contains:

Answer 13

1. Mucus: to help swallow food

2. Salivary amylase: weak alkaline medium, starts the digestion of starch in the mouth

Question 14

GR Digestion starts in the mouth

Answer 14

Because saliva contains salivary amylase which starts digestion of starch inside the mouth.
Starch+H2O-(Ptyalin/pH 7.5-8)——-> Maltose (disaccharide)

Question 15

GR Food doesn’t pass through respiratory tract

Answer 15

Because during swallowing larynx and trachea are elevated causing epiglottis to close over the glottis (entrance of air passage)

Question 16

GR Swallowing is a reflex action

Answer 16

Because it takes place involuntarily when trachea and larynx are elevated and epiglottis covers them which forces the food to oesophagus

Question 17

Pharynx

Answer 17

It’s a cavity at the back of the mouth which leads to two tubes, oesophagus and trachea

Question 17

Peristalsis

Answer 17

Contractions and relaxations of circular muscles

Question 18

Function of oesophagus

Answer 18

It’s lined with glands that secrete mucus, and it delivers food to the stomach by peristalsis

Question 19

Cardiac sphincter

Answer 19

Circular muscle that separates stomach from oesophagus

Question 20

Pyloric sphincter

Answer 20

Circular muscle that separates stomach from the small intestine

Question 21

Digestion in the stomach

Answer 21

Gastric digestion, affects proteins only

Question 22

Gastric juice

Answer 22

A colorless acidic liquid
90% water
The rest is HCL and digestive enzymes

Question 23

Function of HCL

Answer 23

1. Creates an acidic medium, so ptyalin action stops
2. Activates gastric enzymes
3. Kills harmful bacteria

Question 24

GR Cells produce protein digesting enzymes inactively

Answer 24

In order not to digest the muscular wall of the organ

Question 25

Digestion in stomach

Answer 25

Proteins + H2O -(Pepsin/PH1.5-2.5)-----> Polypeptides(Peptones)

Question 26

GR Stomach digestive juices don't digestion the stomach wall

Answer 26

1. Stomach is lined by mucous 2. Pepsinogen is not activated except in the stomach cavity by HCL 3. HCL is diluted when it mixes with gastric juice

Question 27

Partially digested food from stomach that passes to the small intestine

Answer 27

Chyme

Question 28

If enzymes reach the stomach wall and digest the epithelial cells it causes ....

Answer 28

an ULCER

Question 29

Functions of Stomach

Answer 29

1. Churns food to mix it with gastric juice and converts food to chyme 2. Stores food till it's digested 3. Secretes pepsinogen 4. Secretes HCL

Question 30

Membrane that coils the small intestine together

Answer 30

Mesentery

Question 31

Duodenum

Answer 31

Receives secretions from pancreas and liver

Question 32

Illuem

Answer 32

Digested food is absorbed and food is completely digested

Question 33

GR Bile salts convert fats into fatty imulsions

Answer 33

To increase the exposed SA for enzymatic effect

Question 34

Gall bladder

Answer 34

Stores bile salts | When it contracts it forces them to duodenum through bile duct

Question 35

What are bile salts formed of

Answer 35

The liver cells destruct RBCs after the end of their life and the resulted substance forms bile salts

Question 36

Liver is considered an excretory organ

Answer 36

Because it gets rid of RBCs and changes them to bile salts

Question 37

Pancreatic juice includes

Answer 37

1. Sodium bicarbonate 2. Pancreatic amylase 3. Trypsinogen 4. Lipase

Question 38

Function of sodium bicarbonate in pancreas

Answer 38

Neutralizes HCL to create an alkaline medium

Question 39

Function of pancreatic amylase

Answer 39

Starch and glycogen into maltose | Starch and glycogen -(Pancreatic amylase/PH7.5-8)-----> maltose

Question 40

Pepsin vs Trypsin(activation)

Answer 40

Pepsinogen is activated by HCL | Trypsinogen is activated by Enterokinase

Question 41

Function of lipase

Answer 41

Changes fatty emulsions to fatty acids, and glycerol | *Equation*

Question 42

Peptidases

Answer 42

Hydrolyzes polypeptides into amino acids

Question 43

Maltase

Answer 43

Maltose into 2 glucose

Question 44

Sucrase

Answer 44

Sucrose into glucose and fructose

Question 45

Lactase

Answer 45

Lactose into glucose and galactose

Question 46

Absorption of food

Answer 46

It's the transfer of digested food from ileum to blood and lymph

Question 47

Villi and their function

Answer 47

They are folds on the ileum surface to increase SA area of food absorption

Question 48

Micro villi and their function

Answer 48

Tiny projections from epithelial cells of villi to increase absorption area

Question 49

GR vitamin A passes through lymphatic route while vitamin B passes through blood route

Answer 49

Vitamin A is fat soluble | Vitamin B is water soluble

Question 50

Fat soluble vitamins

Answer 50

ADEK

Question 51

Absorption takes place due to

Answer 51

Diffusion: spread of molecules by diffusion through plasma membrane of villi Active transport: using chemical energy obtained from respiration stored in ATP

Question 52

Metabolism

Answer 52

It's the process by which the body utilizes the food absorbed in blood It's a group of biochemical reactions that take place inside LO's bodies

Question 53

Anabolism

Answer 53

Using simple molecules to build more complex ones | Consumes energy

Question 54

Catabolism

Answer 54

Release of energy stored in chemical bonds of carbohydrates by oxidation of food Releases energy

Question 55

GR Food can pass from oesophagus to stomach

Answer 55

By peristalsis, followed by relaxation of cardiac sphincter

Question 56

What is defecation

Answer 56

1. Food remains pass from small intestine to large intestine 2. Water is absorbed by convolutions 3. Food becomes semi solid, containing cellulose fibers and destroyed cells from intestinal wall 4. Bacteria breaks down food remains into simpler form to feed on it. The large number of bacteria may cause putrification producing bad odur 5. Faeces pass out by the contraction of rectum and relaxation of 2 anal sphincters

Question 57

What happens if there's a lack of cellulose fibers

Answer 57

Affects the peristalsis of large intestine muscles and decreases it causing constipation and putrification