Lecture #29 - Chemical digestion Flashcards
1
Q
Chemical digestion:
- The chemical hydrolysis of food by enzymes are secreted by what three things?
- And also hydrolysis by enzymes attached to ______ (contact digestion)
- What are the main nutrients that undergo chemical digestion? (3)
- Why break them down>
A
- Because they’re too big. And once break down, the proteins can recognise them and bring them into epithelium
2
Q
Carbohydrates:
- Just know that this is the main and i_____ source of energy (but how much do we eat?)
- Consist of chains of m_____ and _____ is a typical monosaccharide
A
- Important
3
Q
Composition of ingested carbohydrates:
- What two main carbohydrates in diet?
- They are _____ polysaccharides
- What’s their bond?
- Okay, cellulose - ____ polysaccharide, what bond? Can we digest? What does it provide and what does it not provide?
- We also digest disaccharides - what are the of them?
- Do we ingest monosaccharide?
A
- Only a limited amount
4
Q
Proteins:
- How much do we ingest in our food?
- The intestine also has to digest an equivalent (70/100g per day) amount of ____ ____ such as enzymes and immunoglobins
- Required for the ____ ____
- 20 of them
- How many are essential? - What bond links them?
A
-
5
Q
Lipids:
- How much consumed?
- Consist mainly of what?
- contains fat soluble _____ (what are the 4?) - What are the components of triglycerides and what bond?
- Fatty acids have variable chain lengths - leads to different ____
A
- Properties
6
Q
Just to reiterate, why do we need chemical digestion?
A
-
7
Q
Digestive enzymes (carry out chemical digestion)
- Are e_____
- Are o____ c_____
- Are s____
- Will only act on specific _____
- Require different enzymes for different ____ - Function optimally at specific ____
A
-
8
Q
Chemical digestion is a two step process:
- L____ digestion
- initial digestion involving enzymes secreted into ____
- what is released by salivary glands, stomach, and in SI? (by pancreas) - C____ digestion
- Digestion completed by enzymes produced by ____
- There enzymes are attached to what of enterocytes?
- So substrates/molecules need to…
- So at the brush border (microvilli), the huge SA helps with increasing amount of enzymes as well as a___
A
- ….come into contact with them
9
Q
Chemical digestion of carbohydrates
- Luminal digestion: salivary and pancreatic (double hit bc….) digest and convert polysaccharide into what?
- Contact digestion: what are the disaccharides broken down into?
- By what?
A
-
10
Q
Chemical digestion of proteins:
- Luminal digestion:
- involves what 3 enzymes and where are they secreted?
- Convert proteins into p___ and p____ (which is…)-
- . What two places does it occur? - Contact digestion:
- involves _____
- attahced to what?
- ____ types (specific for different short chain proteins)
- convert polypeptides into individual ___ ___
- since they enzymes are right on epithelium, the cell can what?
A
- Last bit - absorb good bc right next to it
11
Q
Chemical digestion of lipids:
- All in L____
- so no c____ digestion - Digestive enzymes are dissolved in _____ fluid so can cause problems for fats because?
A
-
12
Q
What are the 4 overall steps for chemical digestion of lipids?
What is emulsification and stabilisation (in yellow)
A
-
13
Q
1 Emulsification of lipids:
- What separate large fat droplets into smaller droplets? (how many micrometes are the smaller droplets)
- What does this do to the SA?
- Where does it occur in? (2)
A
-
14
Q
2 Stabilisation of lipids:
- What two things are involved?
- What fluid are they secreted into?
- Stabilise the _____ droplets
- Allow for formation of ____ droplets
- increase sA even more - Where does this occur?
A
-
15
Q
3: Hydrolysis of lipids:
- Occurs where and at the surface of what?
- no contact digestion! - Involves what enzyme and what is its cofactor and they’re both released by?
- Co-lipase ____ lipase to surface of emulsion droplet
- Lipase concretes TAGs to what two things? What bonds are broken?
A
-
