Digetsion Flashcards
What are enzymes
Proteins that act as biological catalysts, meaning they speed up reactions without being used up
How do enzymes work?
They work on molecules known as substrates. The enzymes are complimentary in shape so they only work on certain substrates causing a reaction leaving products
What is it called when enzymes and substrates collide?
Enzyme-substrate complex
Which enzyme breaks down carbohydrates and what does it get broken into
Carbohydrase, simple sugar, glucose
Which enzyme breaks down starch and what does it get broken down into
Amylase. Starch gets broken down into simple sugar glucose
What enzyme breaks down protein and what are products of this reaction
Protease, amino acids
What does fats/lipids get broken down into and which enzyme reacts with them.
Lipase. Glycerol and fatty acids
What is an inhibitor
They are molecules that fit loosely or partially into the active site of some enzymes. They occupy the active site of the enzyme. This means the substrate cannot enter and be broken down leading to a reduced rate of reaction.
What factors affect enzyme activity
Temperature, pH and enzyme concentration
How does temperature affect enzyme activity?
Higher temperature, more kinetic energy resulting in more collisions between substrates and enzymes. Although eventually enzymes can become too hot and denatured as their complimentary shape will change due to heat.
How does pH effect enzyme activity
Deviating from the optimum pH causes the enzymes active site to become denatured and the active site loses its important complimentary shape.
How does the concentration of enzymes effect the enzyme activity
The more enzymes the more enzyme-substrate complexes. Eventually this plateaus as there will not be enough substrate molecules
What is a thermostable enzyme
An enzyme which can work at a wide range of temperatures
Define molecular breakdown
The breakdown of large, complex, insoluble molecules into small simple soluble ones
How is food digested in the mouth physically and chemically
Physical: food is torn into smaller pieces by teeth. Food is mixed with saliva
Chemical: Saliva breaks down carbohydrates
Physical and chemical digestion in the stomach?
Physical: food, hydrochloric acid and other digestive juices are mixed by the muscular contractions of the stomach wall to form chyme
Chemical: proteins broken down by hydrochloric acid
Physical and chemical digestion in small intestine?
Physical: muscles in small intestine help the chyme mix with digestive juices
Chemical: fats, proteins and carbohydrates are broken down into smaller different molecules that can be absorbed by the body’s cells. Most digestion happens here
Large intestine physical and chemical digestion?
Physical: water is absorbed back into the body
Chemical: bacteria break down some undigested materials and help produce certain vitamins
What is the ileum?
To absorb the digested food products
Adaptation of the ileum for absorption?
Large surface area due to it being long and folded
Thin so digested food doesn’t have to travel far to reach the bloodstream.
Permeable so digested food can pass through easily
Good blood supply to maintain the concentration gradient for diffusion between ilium and bloodstream
Villi
What are villi
Finger like projections that further increase surface area.
Features of the villi that aid absorption?
Good blood supply- large network of Capillaries
Lacteal- a tube that absorbs the products of fat digestion before returning them to the blood
Single layer surface epithelium cells- this reduces the diffusion distance that digested food products have to travel in order to enter the bloodstream.
Permeable- digested food can pass through easily
