Adaptations For Nutrition Flashcards
What type of nutrition do some protists such as the amoeba use?
Holozoic
How do amoeba obtain nutrients such as oxygen and glucose?
Diffusion, facilitated diffusion and active transport
How do amoeba take in large food molecules such as bacteria?
By endocytosis, where the food molecules are surrounded by membranes forming vacuoles
How are indigestible remains excreted in amoeba?
By exocytosis
How are food vacuoles digested in amoeba?
The food vacuoles fuse with lysosomes containing hydrolysis enzymes which digest the contents of the food vacuoles. The products of digestion are then absorbed into the cell cytoplasm
What are hydra?
Multicellular fresh water animals who are in the same phylum as jellyfish
Do hydra have a differentiated or undifferentiated immune system?
Undifferentiated
How does digestion work in hydra?
Tentacles move paralysed prey in through the mouth and into a body cavity where it is digested, and the products are absorbed into body cells and the indigestible remains are egested through the mouth.
What is a tube gut?
A digestive system that is a tube with two openings, where food is ingested at the mouth and indigestible waste is egested at the anus
Why must food be digested?
-So we can absorb all the nutrients out of it
-Molecules must be soluble to be transported into blood
-Waste can be excreted easily
-Food molecules are too big to cross membranes
What is ingestion?
Taking food into the body through the mouth
What is digestion?
The breakdown of large insoluble molecules into soluble molecules that are small enough to be absorbed into the blood
What are the two types of digestion?
1.Mechanical digestion, where food is cut up and crushed by teeth and muscle contractions of the gut wall, which increases the surface area over which enzymes can act
2.Chemical digestion, where food is broken down using digestive enzymes, bile and stomach acid
What is absorption?
The passage of small soluble molecules and ions through the gut wall and into the blood
What is egestion?
The elimination of indigestible waste
What is the gut?
A long, hollow, muscular tube, where digestion and absorption occur. It allows movement of contents in one direction only. Each section is specialised and forms particular steps in digestion
What is peristalsis?
The wave of muscular contractions and relaxations of the gut wall which propel the contents along the whole length of the gut. Circular muscles contractions behind the bolus of food and then relax after the wave of contraction has passed
What is the function of the mouth?
Ingestion, mechanical digestion of food by teeth and chemical digestion of starch by salivary amylase
What is the function of the oesophagus?
Carriage of food to the stomach by peristalsis
What is the function of the stomach?
Contraction of stomach muscles to mechanically digest food. Secretion of hydrochloric acid. Chemical digestion of proteins by enzymes
What is the function of the duodenum?
Receives pancreatic juice from the pancreas and bile from the gall bladder. Chemical digestion of carbohydrates, fats and proteins by enzymes
What is the function of the ileum?
Chemical digestion of carbohydrates, fats and proteins by enzymes, and absorption of digested food
What is the function of the large intestine?
Absorption of water
What is the function of the rectum?
Storage of faeces
