Adaptations for nutrition

Question 1

Unicellular organisms

Answer 1

Amoeba pseudopodia move around prey and enclose it in a food vacuole.
2. Enzymes are released from lysosomes that fuse with the food vacuole and the prey is digested.
3. Products of digestion are absorbed into the cytoplasm and the undissolved waste is egested by exocytosis.
USE HOLOZOIC NUTRITION

Question 2

Types of nutrition

Answer 2

Autotrophic
Heterotrophic

Question 3

Heterotrophic

Answer 3

Saprophytic
Holozoic
Parasitic

Question 4

Autotrophic

Answer 4

Photoautotrophic
Chemoautotrophic

Question 5

Chemoautotrophic

Answer 5

Oxidise inorganic molecules to provide energy for the synthesis of food. (use energy from chemical reactions)
PERFROM CHEMOSYNTHESIS

Question 6

Photoautotrophic

Answer 6

Use light as a source of energy for synthesis of food.
USE PHOTO SYNTHESIS

Question 7

Saprophytic

Answer 7

External digestion of food using secretion of enzymes followed by absorption of the products of digestion into the organism, e.g. fungi.
EXTRACELLULAR DIGESTION of dead/ decaying material
DETRITIVORES

Question 8

Holozoic

Answer 8

internal digestion of food. Involves ingestion, absorption, assimilation and egestion.
HERBIVOURS, OMNIVOURS, CARNIVOURS, DETRITIVORES

Question 9

Parasitic

Answer 9

obtaining nutrition from another living organism, the host.
ENDOPARASITES- in body of host
ECTOPARAITES-on surface.
Parasites host will always suffer harm, often DEATH
-tapeworm, lice

Question 10

Multicellular organisms

Answer 10

Hydra – single food source Undifferentiated, extends tenticles- discharge and paralise prey.
prey digested extracellularly.
sac-like gut with a single opening

Earthworm – varied foods-A tube gut with different openings for ingestion and egestion and specialised regions for the digestion of different food
Human – omnivorous diet Specialised regions of gut.

Question 11

Structure of Human gut

Answer 11

Serosa, Muscle, Submucosa, Mucosa, Epithelium

Question 12

Serosa

Answer 12

Tough outer coat of connective tissue-reduces friction with other abdominal organs

Question 13

Muscle

Answer 13

Longitudinal muscle contracts to shorten the gut and circular muscle contracts to reduce diameter. These waves of contraction called peristalsis force food along the gut.
Inner Circular muslces and Outer longitudinal muscles.
circular behind food contract , longitudinal relax – punshin food along

Question 14

Submucosa

Answer 14

Connective tissue Contains blood and lymph vessels to remove digested food products and nerves that coordinate peristalsis

Question 15

Mucosa

Answer 15

Inner layer that secretes mucus for lubrication. In some areas it secretes digestive juices; in others it absorbs products.

Question 16

Epithelium

Answer 16

Layer of cells in contact with food.

Question 17

Functions of the gut

Answer 17

Ingestion-taking food into body through buccal cavity (mouth)
Digestion- breakdown of large insoluble molecules to soluble molecules small enough to be absorbed into the blood.
-mechanical digestion: cutting and crushing by teethand muscle contractions of the gut wall, inc surface area enzymes work.
-chemical digestion: digestive enzymes, bile and stomach acid contribute to breakdown of food
Absorption: passage of molecules and ions through gut wall into blood
Egestion-elimination of waste

Question 18

proteases

Answer 18

-Proteases called endopeptidases hydrolyse peptide bods between specific amino acids in the middle of the polypeptide chain to form shorter polypeptide chains. -Exopeptidases hydrolyse peptide bonds on the end of peptides, from the free amino end or the free carboxyl end.

Question 19

Buccal cavity

Answer 19

mechanical digestion of food occurs here.
The tongue moves food to the cutting and grinding surfaces of the teeth. Chemical digestion of starch and glycogen into maltose by the enzyme amylase. Saliva moistens food and also maintains the pH for the enzyme. The tongue then rolls the food into a bolus which is swallowed

Question 20

Oesophagus

Answer 20

peristaltic waves of muscle contraction push the bolus of food down to the stomach. Mucus lubricates the way.

Question 21

Liver

Answer 21

– produces bile.
Bile emulsifies lipids to increase the surface area available for lipase enzymes to digest them. It also neutralises stomach acid to create a slightly alkaline pH in the duodenum for the pancreatic enzymes.

Question 22

Gall bladder –

Answer 22

– stores the bile before delivering it to the duodenum via the bile duct.

Question 23

Pancreas –

Answer 23

produces enzymes that are transported to the duodenum via the pancreatic duct. Carbohydrase - pancreatic amylase

Question 24

Duodenum

Answer 24

– further digestion occurs on the epithelial cells of the villi.
• Sucrose digested by sucrase into glucose and fructose.
• Maltose digested by maltase into alpha glucose. • Lactose digested by lactase into glucose and galactose.
• Further digestion of polypeptides by endopeptidases and exopeptidases.

Question 25

Protease in duodenum

Answer 25

– trypsinogen that is activated into the endopeptidase Trypsin by enterokinase in the duodenum. Pancreatic lipase enzymes digest triglycerides into monoglycerides and eventually glycerol and fatty acids

Question 26

Ileum

Answer 26

Amino acids are actively transported into the epithelial cells of the villi; facilitated diffusion then occurs into the capillaries in the villi. • Glucose and other monosaccharides move into epithelial cells by co-transport with sodium ions; facilitated diffusion then occurs into the capillaries in the villi. • Fatty acids and glycerol diffuse into epithelial cells and are reassembled into triglycerides and carried by the lacteal to the lymphatic system.

Question 27

The small intestine

Answer 27

2 regions- duodenum and ileum.The pyloric sphincter muscle at the base of the stomach allows partially digested food into the duodenum little at a time.
duodenum- first 25cm recieves secretions from liver and pancreas.
-Bile is made in liver-stored in gall bladder passes thriugh ble ductinto duodenum
-no enzymes, bile salts which are AMPHIAPATHIC (hydrophobic and hydropyllic)- emulsifies fats, Alkaline (neutralises acid in food comig from stomach-suitable PH for enymes in small intestine
-PANCREATIC JUICE- secreted by islet cells, enters the duodenum through the bile duct

Question 28

Pancreatic juice

Answer 28

Enzymes-
Tripsinogen- inactive converted to endopeptidase trypsin by enterokinase Endopeptidases-hydrolise proteins and polypetides to peptides
Amylase- digests remaining starch to maltose Lipase-hydrolises lipids to fatty acids and monoglycerides
SODIUM HYDROCARBONATE- raises Ph to make pancreatic juice slightly alkaline - contibutes to:
neutralising acid from stomch, providing appropriet PH for pancreatic enzymes to work

Question 29

what happens to food coming from stomach

Answer 29

food lubricated with mucus and neutralised by alkaline secretions from cells at brunners glands

Question 30

villi

Answer 30

the villi increase the surface area in the small intestine for absorption of digested food into the blood.
synthesise digestive enzymes:
endopeptidases and exopeptidases
Carbohydrates

Question 31

Absorption

Answer 31

Absorption mainly occurs in small intestine by diffusion facilitated diffusion and active transport. Active transport requires ATP so epithelial cells have many mitochondria.
Region of small intestine called ilium well adapted to absorption long and lining is folded surface of the folds of village and microwave produce very large surface area full absorption

Question 32

Structure of a ileum wall

Answer 32

Epithelium, villi, capillary, lacteal, crypts of lieberkűhn, arteriole, venule,lymph vessel, circular muscle and longitude normal muscle

Question 33

Amino acids movement

Answer 33

Amino acids absorbed into epithelial cells by active transport as individual amino acids pass into capillaries by facilitated diffusion water soluble and dissolved in plasma

Question 34

Co-transport of glucose and sodium

Answer 34

Glucose pass into Apulia cells with sodium ions by cotransport, they move into the capillaries sodium by active transport and glucose by facilitated diffusion. and dissolve in the plasma diffusion and facilitated diffusion are slow and not all the glucose is absorbed to prevent the body and faeces is absorbed by active transport

Question 35

Fatty acids and monoglycerides movement

Answer 35

Fatty is a monoglycerides diffuse into the epithelial cells and into the lacteals lacked are finally ending lymph capillaries in the villi. They are part of the lymphatic system which transports fats soluble molecules to the left subclavian vein near the heart.

Question 36

Minerals movement

Answer 36

Minerals are taken into the blood by diffusion, facilitated diffusion and active transport and dissolve in the plasma

Question 37

Use of nutrients

Answer 37

Lipids used in membranes to make hormones
Glucose used by body cells and respired for energy or stored as glycogen ,
Amino acids taken the body cells for protein synthesis

Question 38

The large intestine

Answer 38

Comprises the caecum, appendix the colon and the rectum
Un digested food, mucus and bacteria and dead cells passed into the colon which has fewer than the ilium have a water absorption

Question 39

Adaptation of a Carnivorous gut

Answer 39

Carnivore eats only animals and so it’s diet is mostly protein. Its small intestine is short in relation to bodies length reflecting the ease with which protein is digested.
Carnivores large intestine is straight with smooth lining

Question 40

Adaptation of herbivore gut

Answer 40

Eats only plant material. it’s small intestine is long in relation to body length because plant material is not readily digested and a long gut allows enough time for digestion and absorption of nutrients.
Herbivores large intestine is pouched as it can Stretch to accommodate the larger volume of faeces produced in digestion plants much of which cellulose the large intestine is also long with where waters absorbed

Question 41

Omnivore gut

Answer 41

Gut of an omnivore such as a human is intermediate in length

Question 42

Dentition of herbivore

Answer 42

Diastema – space where tongue can push food to the grinding cheek teeth. Premolars and molars – cheek teeth. Fit together in a W M shape. Jaw moves in a horizontal plane so these interlocking teeth grind food. Teeth have open, unrestricted roots and so grow throughout life.
Loose articulation of the jaw.
Incisors – occur on lower jaw and cut vegetation against a horny pad on the upper jaw. Canines are absent or indistinguishable.

Question 43

Dentition of carnivore

Answer 43

Canines – long and pointed to pierce flesh and seize and kill prey. Carnassial teeth - act like shears, sliding past each other to rip muscle from bone. Premolars and molars - have sharp cusps that cut and crush. The jaw has strong muscles and moves in a vertical plane opening wide and strongly clamping down to hold prey.

Question 44

Gut of carnivore

Answer 44

Gut
•Relatively short gut.
•Usually a large stomach for digestion of mostly protein diet.
•Small caecum.

Question 45

Gut of non ruminants

Answer 45

•Very long gut for the difficult process of cellulose digestion.
•Large caecum containing bacteria that produce cellulase for cellulose digestio

Question 46

Ruminants

Answer 46

1Grass is mixed with saliva and then chewed (forming cud) before being swallowed.
2Cud enters the first chamber of the stomach – the rumen. Cellulose digesting bacteria produce cellulase, breaking down cellulose in the grass into glucose.
This ferments into organic acids which
are absorbed into the bloodstream. The process produces a lot of carbon dioxide and methane which is expelled.

3 Fermented cud from the rumen enters the second stomach chamber(the reticulum. ) The cud is regurgitated from here and the rumen back into the mouth to be rechewed.

4Rechewed cud is swallowed and enters the third chamber of the stomach – the Omasum. Water absorption occurs here.
5. From the omasum food enters the
fourth and final chamber of thestomach – the abomasum. Protein digestion occurs here.

6
The products of digestion are absorbed into the blood in the small intestine.

Question 47

ectoparasite

Answer 47

lives on the surface of another organism.

Question 48

endoparasite

Answer 48

An endoparasite lives inside another organism

Question 49

Example of ectoparasite

Answer 49

The head louse (Pediculus) feeds by sucking
blood from the scalp of the host.
•It has claws to hold onto the hairs.
•Lays eggs which are glued to the base of hairs.
•Transfer between hosts is by direct contact as it cannot jump, only craw

Question 50

Example of endoparasite

Answer 50

he adult pork tapeworm (Taenia solium)
lives in the gut of humans.
1. Primary host – a larval form develops in
pigs.
2. Secondary host – infection of humans occurs when a person eats pork containing live larval forms (tapeworm cysts in muscletissue). The gut is a hostile environment due to the presence of various secretions and peristalsis.
The tapeworm has adapted to living in the
gut as follows:
•Thick cuticle produces anti-enzymes.
•Scolex to attach to the gut wall.
•Taenia solium has a reduced gut and feeds by absorbing pre-digested nutrients through its cuticle.
•To increase the chances of infecting a secondary host, it produces large numbers eggs that pass out of feaces