Digestion Flashcards by Nelia Clarke

What is digestión?

The hydrolysis of large insoluble macromolecules to smaller soluble micromolecules

Breakdown and absorption and assimilation

How well did you know this?

Not at all

Perfectly

What is the exchange surface in digestion?

Ileum

How well did you know this?

Not at all

Perfectly

State the stages of digestión

Ingestion
Digestión
Absorption
Assimilation
Egestion

How well did you know this?

Not at all

Perfectly

Define assimilation

When nutrients are incorporated and used within a cell (make proteins)

How well did you know this?

Not at all

Perfectly

Name the organs involved in digestion

Salivary Glands
Oesophagus
Stomach
Ileum
 pancreas
Liver 
Colon 
Rectum 
anus

How well did you know this?

Not at all

Perfectly

What is the role of the salivary Glands?

Produce saliva (salivary amylase and mineral salts)

Hydrolyse starch to maltose

Maintain pH 7 for optimum function of amylase

How well did you know this?

Not at all

Perfectly

How does saliva get to the mouth?

Through a duct

How well did you know this?

Not at all

Perfectly

What and how is the esophagus adapted for?

Transportation

Thick muscular walls

How well did you know this?

Not at all

Perfectly

What is the function of the stomach and how is it adapted?

Store and digest and breakdown food

Endopeptidases

Hcl= acid =optimum for peptidase

Strong muscular walls= pummel food

How well did you know this?

Not at all

Perfectly

What is the function of the stomach and how is it adapted?

Store and digest and breakdown food

Endopeptidases

Hcl= acid =optimum for peptidase

Strong muscular walls= pummel food

How well did you know this?

Not at all

Perfectly

Why does the stomach produce mucus?

Protect linig cells from protease and acid

How well did you know this?

Not at all

Perfectly

What is the function of the pancreas and how does it achieve this?

Secrete enzymes for digestion

Secretes/empties pancreatic juices into ileum
Contains peptidase, lipase and amylase (pancreatic)

How well did you know this?

Not at all

Perfectly

What is the function of the liver?

Produce bile salts to lower pH the 7 optimum enzyme function and emulsify fats

How well did you know this?

Not at all

Perfectly

What and how is the ileum adapted for?

Absorption of soluble molecules

Villi and microvilli

How well did you know this?

Not at all

Perfectly

What is the function of the Colon?

Reabsorb water e.g from secretions

How well did you know this?

Not at all

Perfectly

What is the function of the Rectum?

Store feceas before egestion

How well did you know this?

Not at all

Perfectly

What are the two types of digestión?

Physical breakdown

Chemical digestion

What does physical breakdown involve? Why does it happen?

Teeth and stomach to breakdown food into smaller pieces.

Allow ingestion

Increase sa for enzyme action

What is chemical digestión and why does it occur?

Hydrolysis of bonds using enzymes

Allow substances to be absorbed

What is hydrolysis?

Breaking of a bond by adding a water molecule to it

Outline the steps of carbohydrate digestion

Starch to maltose in mouth due to salivary amylase

Digestión stopped in stomach due to acid
(de nature)

Further digestión to maltose in ileum due to pancreatic amylase

Digestión to alpha glucose due to membrane bound maltase

Absorption of glucose via co transport with sodium ions

Transport of glucose via bloodstream

Assimilation of glucose in cells

What components aid with strach digestion and why?

Salivary amylase: Hydrolyse alternage glycosidic bonds

Mineral salts: maintain neutral PH for optimum function of enzymes

Why do we chew our food?

To physically break down the food into smaller pieces

Increase sa for enzyme action

Allow food to be throughly mixed with saliva so enzyme and substrates come into contact, more es complexes

How do the pancreatic juices aid starch digestión in the ileum?

Juices secreted into ileum

Contain pancreatic amylase to Hydrolyse alternate glycosidic bonds

Contain alkaline salts to maintain neutral PH (neutralise stomach acid) for optimum function of amylase

Why is it important for the ileum to have strong muscular walls?

To move the contents along For egestion Allow substrates to come into contact with membrane bound enzymes

What are sucrase and lactase

Membrane bound dissacharidases Hydrolyse glycosidic bonds in dissacharides sucrose or lactose

Outline the stages of protein digestion

Endopeptidases in stomach Hydrolyse specific peptide bonds in the middle of polypeptide chain Exopeptidases and Endopeptidases in pancreatic juices Hydrolyse further (peptide bonds towards ends=exo) in ileum Membrane bound dipeptidases Hydrolyse glycosidic bonds between specific dipeptides Amino acid absorption via co transport with sodium ions Travel in blood stream Assimilation in cells

Where are endo peptidase found?

Ileum(Pancreatic juices) Stomach

What is the function of Endopeptidases?

Hydrolyse peptide bonds between specific Amino acids in the middle of the polypeptide chain. Prdoduce more ends for faster rate of protein digestion in ileum by Exopeptidases

Where are exo peptidase found?

Ileum (Pancreatic juices)

What is the function of Exopeptidases?

Hydrolyse peptide bonds between specific Amino acids at the end of the polypeptide chain

Compare the products of exo, endo and do peptidase reactions

Endo= small polypeptide chain Exo= dipeptides, Amino acids, shorter polypeptide chain Di= Amino acids

Outline the steps of lipid digestion

Bile salts emulsify lipid droplets into micelles Pancreatic lipase Hydrolyse ester bonds (monoglycerides and fatty acids) and package them into smaller micelles Micelles breakdown to release monoglycerides and fatty acids near epitheilal cells Monoglycerides and fatty acids absorbed via simple diffusion into epithelial cell Transported to ER where they are made into triglycerides Transported to golgi apparatus where lipoproteins and cholesterol are added to form chylomicrons Chylomicrons are removed via exocytosis into lacteal (lymphatic capillary) Pass into blood Lipases in endothelial cells Hydrolyse ester bonds to release monoglycerides and fatty acids which diffuse into cell

What are micelles? Why do they form?

Small droplets of lipids Adapted to transport poorly soluble monoglycerides and fatty acids to epithelial cells

Why must the micelles break down before the lipids can diffuse into the cells?

Micelles are to big to diffuse across the plasma membrane Monoglycerides and fatty acids are non-polar and lipid soluble

What are chylomicrons and why do they do?

Lipoprotein made of cholesterol, monoglycerides and fatty acids Adapted to transport lipids Water soluble

Why are bile salts produced (by what organ)?

Liver Emulsify lipid droplets Increase sa Increase rate of reaction

How is the ileum adapted for absorption?

Villi and microvilli increase sa Villi= one cell thick surface layer = short diffusion pathway Muscular walls and contract and good blood supply= maintain conc gradient Membrane bound enzymes= short diffusion pathway

Function of lipid droplets

Allow more sa for enzyme action

Contrast lipid droplet and Michelle function

Lipid droplet= increase sa | Micelle=transport fatty acids and monoglycerides to epithelial cells