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Biology 2nd Secondary > Ch1- Heterotrophic Nutrition > Flashcards

Ch1- Heterotrophic Nutrition Flashcards

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AP® Biology flashcards
1
Q

Digestion

A

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

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2
Q

Importance of digestion

A

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.

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3
Q

Properties of enzyme

A
  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
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4
Q

Substrate

A

The food material which the enzyme acts on

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5
Q

The Digestive Canal:

A

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

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6
Q

Teeth are differentiated into:

A

Incisors
Canines
Premolars and molars

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7
Q

Function of incisors

A

Cutting food

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8
Q

Function of canines

A

Tearing food

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9
Q

Function of molars and premolars

A

Grinding and crushing food

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10
Q

Function of tongue

A
  1. Mixing food to be chewed by teeth
  2. Tasting food
  3. Pushing food to the pharynx
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11
Q

Salivary glands

A

3 pairs which open in mouth cavity and secrete saliva

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12
Q

Function of chewing food

A

Increase the SA of enzymatic action of food

Facilitate swallowing

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13
Q

Saliva contains:

A
  1. Mucus: to help swallow food

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

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14
Q

GR Digestion starts in the mouth

A

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

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15
Q

GR Food doesn’t pass through respiratory tract

A

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

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16
Q

GR Swallowing is a reflex action

A

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

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17
Q

Pharynx

A

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

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17
Q

Peristalsis

A

Contractions and relaxations of circular muscles

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18
Q

Function of oesophagus

A

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

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19
Q

Cardiac sphincter

A

Circular muscle that separates stomach from oesophagus

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20
Q

Pyloric sphincter

A

Circular muscle that separates stomach from the small intestine

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21
Q

Digestion in the stomach

A

Gastric digestion, affects proteins only

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22
Q

Gastric juice

A

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

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23
Q

Function of HCL

A
  1. Creates an acidic medium, so ptyalin action stops
  2. Activates gastric enzymes
  3. Kills harmful bacteria
24
Q

GR Cells produce protein digesting enzymes inactively

A

In order not to digest the muscular wall of the organ

25
Q

Digestion in stomach

A

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

26
Q

GR Stomach digestive juices don’t digestion the stomach wall

A
  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
27
Q

Partially digested food from stomach that passes to the small intestine

A

Chyme

28
Q

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

A

an ULCER

29
Q

Functions of Stomach

A
  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
30
Q

Membrane that coils the small intestine together

A

Mesentery

31
Q

Duodenum

A

Receives secretions from pancreas and liver

32
Q

Illuem

A

Digested food is absorbed and food is completely digested

33
Q

GR Bile salts convert fats into fatty imulsions

A

To increase the exposed SA for enzymatic effect

34
Q

Gall bladder

A

Stores bile salts

When it contracts it forces them to duodenum through bile duct

35
Q

What are bile salts formed of

A

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

36
Q

Liver is considered an excretory organ

A

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

37
Q

Pancreatic juice includes

A
  1. Sodium bicarbonate
  2. Pancreatic amylase
  3. Trypsinogen
  4. Lipase
38
Q

Function of sodium bicarbonate in pancreas

A

Neutralizes HCL to create an alkaline medium

39
Q

Function of pancreatic amylase

A

Starch and glycogen into maltose

Starch and glycogen -(Pancreatic amylase/PH7.5-8)—–> maltose

40
Q

Pepsin vs Trypsin(activation)

A

Pepsinogen is activated by HCL

Trypsinogen is activated by Enterokinase

41
Q

Function of lipase

A

Changes fatty emulsions to fatty acids, and glycerol

Equation

42
Q

Peptidases

A

Hydrolyzes polypeptides into amino acids

43
Q

Maltase

A

Maltose into 2 glucose

44
Q

Sucrase

A

Sucrose into glucose and fructose

45
Q

Lactase

A

Lactose into glucose and galactose

46
Q

Absorption of food

A

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

47
Q

Villi and their function

A

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

48
Q

Micro villi and their function

A

Tiny projections from epithelial cells of villi to increase absorption area

49
Q

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

A

Vitamin A is fat soluble

Vitamin B is water soluble

50
Q

Fat soluble vitamins

A

ADEK

51
Q

Absorption takes place due to

A

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

52
Q

Metabolism

A

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

53
Q

Anabolism

A

Using simple molecules to build more complex ones

Consumes energy

54
Q

Catabolism

A

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

55
Q

GR Food can pass from oesophagus to stomach

A

By peristalsis, followed by relaxation of cardiac sphincter

56
Q

What is defecation

A
  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
57
Q

What happens if there’s a lack of cellulose fibers

A

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

Biology 2nd Secondary (3 decks)

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