2.4 Adaptations For Nutrition

Question 1

Why can’t living organisms use energy (light energy) directly from sun?

Answer 1

They can only use chemical energy

Question 2

Autotrophic nutrition

Answer 2

Make their own food from simple inorganic raw materials like CO2 and water. They’re producers

Question 3

What are phototrophic organisms

Answer 3

Organisms that use light energy for photosynthesis. Green plants.

Question 4

What kind of nutrition do photo autotrophic organisms use?

Answer 4

Holophytic

Question 5

What are chemoautotrophic organisms?

Answer 5

Organisms that use energy from chemical reactions. All prokaryotic. Organisms no longer dominant life forms

Question 6

What do all prokaryotic organisms perform

Answer 6

Chemosynthesis.
Less efficient than photosynthesis

Question 7

What are heterotrophs?

Answer 7

Organisms that can’t make their own food. Must consume complex organic material produced by autotrophs. Consumers.

Question 8

Who are consumers?

Answer 8

All animals are consumers and are dependent on autotrophs for food

Question 9

How do animals get food

Answer 9

Either eat autotrophs directly or eat other animals which have eaten autotrophs

Question 10

Heterotrophs include…

Answer 10

Animals, fungi, some Protoctista, and some bacteria

Question 11

Definition of autotroph

Answer 11

An organism that synthesises its own complex organic molecules from simpler inorganic molecules, using either light or chemical energy

Question 12

Definition of Heterotroph

Answer 12

An organism that obtains complex organic molecules from other organisms.

Question 13

Definition of Saprotroph/Saprobiont

Answer 13

An organism that derives energy and raw materials for growth from the extracellular digestion of dead or decaying material

Question 14

What are holozoic feeders

Answer 14

Includes all animals. Take food into their bodies and digest. Have specialised digestive system. Digested material absorbed into body tissues and used in body cells

Question 15

What are animals who feed solely on plant material?

Answer 15

Herbivores

Question 16

What are animals who feed on other animals

Answer 16

Carnivores

Question 17

What are animals who feed on both plant and animal material

Answer 17

Omnivores

Question 18

What are animals which feed on dead or decaying material

Answer 18

Detritivores

Question 19

What are saprophytes or saprobionts

Answer 19

Include all fungi and some bacteria. Feed on dead and decaying matter. No specialised digestive system.
Decomposers: essential in the decomposition of dead plant and animal material and the recycling of nutrients

Question 20

How do saprophytes or saprobionts feed? (What kind of digestion and how does it work)

Answer 20

With extracellular digestion.
1. Secrete enzymes onto food material outside body.
2. Absorb the soluble products across the cell membrane by diffusion

Question 21

What are parasites

Answer 21

Parasites are organisms that live in or on another living organism and causes harm to the host / obtain their nourishment at the expense of the host. Some live inside and some live outside host. Highly specialised

Question 22

What is mutualism

Answer 22

Close association between members of two different species. Both are benefited from the relationship

Question 23

Mutualism in cows and mutualistic bacteria

Answer 23

Cows feed on grass but don’t secrete cellulase to digest cellulose. So bacteria which can produce cellulase lives in rumen and digests the cellulose. Bacteria can absorb digested products to thrive, and cows can digest their food

Question 24

How do unicellular organisms take in nutrients

Answer 24

Take in nutrients across their cell membranes by diffusion, facilitated diffusion, or active transport

Question 25

What do unicellular organisms do to digest larger food particles or other unicellular organisms

Answer 25

Engulf larger particles or organisms using pseudopodia

Question 26

What is pseudopodia

Answer 26

A type of endocytosis to engulf larger particles or organisms

Question 27

Steps of holozoic nutrition

Answer 27

- food vacuole forms as pseudopodia fuse together. - lysosomes fuse with the food vacuole, releasing their digestive enzymes. - digestion carried out intracellularly (inside the cell)

Question 28

What is intracellular digestion

Answer 28

Digestion carried out inside the cell

Question 29

What kind of gut does hydra have

Answer 29

A simple, undifferentiated, sac-like gut. The mouth (in the middle oof the tentacles) is the only opening.

Question 30

What is gastrodermis

Answer 30

The inner layer of cells. Secretes digestive enzymes into the lumen of the gut

Question 31

How is digested food absorbed in multicellular organisms

Answer 31

Absorbed by gut wall

Question 32

How is undigested food egested in multicellular organisms

Answer 32

Egested by the mouth

Question 33

What kind of gut do earthworms have

Answer 33

Have a simple tube like gut with an opening at both ends; - mouth for ingestion - anus for egestion

Question 34

What does a simple tube like gut have

Answer 34

Different regions, e.g. oesophagus and intestine, each with a specific function

Question 35

Human digestive system

Answer 35

Human gut is highly specialised with distinct regions, each with a specific function

Question 36

Function of mouth in human digestive system

Answer 36

Ingestion and digestion

Question 37

Function of stomach in human digestive system

Answer 37

digestion

Question 38

Function of small intestine in human digestive system

Answer 38

digestion and absorption

Question 39

Function of large intestine in human digestive system

Answer 39

reabsorption of water and absorbing vitamins

Question 40

Function of rectum in human digestive system

Answer 40

storing faeces

Question 41

Function of anus in human digestive system

Answer 41

excretion

Question 42

What is ingestion

Answer 42

taking food into the body through the mouth

Question 43

what is mechanical digestion

Answer 43

cutting or crushing action of the teeth followed by rhythmical contractions of the gut.

Question 44

Why does the gut wall (especially stomach) have layers of muscle that contract and relax

Answer 44

Responsible for mixing the food with enzymes and pushing it along the gut (peristalsis)

Question 45

What is peristalsis

Answer 45

Wave-like muscular contractions in the wall of the gut. Mixes food with enzymes and propels food along the gut

Question 46

What is chemical digestion

Answer 46

The breakdown of large insoluble molecules into small soluble molecules using enzymes (chemical bonds are broken)

Question 47

What is absorption

Answer 47

The passage of digested food through the gut wall into the blood

Question 48

What is egestion

Answer 48

The elimination of undigested food from the body e.g cellulose cell walls of plants (fibre)

Question 49

Structure of mammalian gut

Answer 49

Throughout its length from the mouth to the anus, the gut wall consists of four tissue layers, surrounding the gut cavity or lumen

Question 50

Composition and function of serosa (in mammalian gut)

Answer 50

Layer of tough connective tissue. Protects the wall of the gut and reduces friction from other organs as the gut moves

Question 51

Composition and function of sub-mucosa (in mammalian gut)

Answer 51

Consists of connective tissue with blood and lymph vessels. Takes away absorbed food

Question 52

Composition and function of mucosa (in mammalian gut)

Answer 52

Innermost layer and lines wall of gut. Secretes mucus which lubricates and protects mucosa. In some it secretes digestive juices, and in others it absorbs digested foods.

Question 53

Composition and function of epithelium (in mammalian gut)

Answer 53

Outermost layer of cells of the mucosa. In direct contact with the food in the lumen. Secretes substances into the lumen

Question 54

Composition and function of muscle layers (in mammalian gut)

Answer 54

2 layers of muscle running in different directions. Causes waves of muscular contractions (peristalsis), which propels food along gut

Question 55

What do glands do

Answer 55

Produce many secretions, some of which contain digestive enzymes

Question 56

What are the 3 types of glands

Answer 56

1. large glands found outside the gut with secretions passing through ducts (tubes) into the gut cavity. 2. glands in the form of cells in the submucosa 3. glands in the form of cells in the mucosa

Question 57

Examples of large glands found outside the gut with secretions passing through ducts (tubes) into the gut cavity.

Answer 57

- salivary glands which secrete saliva into mouth. - liver which secretes bile into duodenum - pancreas which secretes pancreatic juice into the duodenum

Question 58

Example of glands in the form of cells in the submucosa

Answer 58

Glands which secrete mucus into the duodenum

Question 59

Examples of glands in the form of cells in the mucosa

Answer 59

-gastric glands in the stomach wall which secretes gastric juice into the stomach - glands found at the base of the villi in the small intestine, which secrete enzymes into the small intestine

Question 60

What does the pancreatic duct do

Answer 60

transports pancreatic juice to the duodenum

Question 61

What does the bile duct do

Answer 61

transports bile to duodenum

Question 62

the absorption of nutrients by the gut epithelial cells is only possible if...

Answer 62

if large insoluble molecules like polysaccharides, fats and proteins are broken down or digested into smaller soluble products by enzymes