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Biology > Digestive system > Flashcards

Digestive system Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What is digestion?

A

The breakdown of large, insoluble food molecules into smaller soluble molecules to be absorbed into the bloodstream

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2
Q

Function of the mouth/salivary glands

A

Where food enters and is broken down mechanically by teeth or chemically by amylase produced in salivary glands

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3
Q

Function of the oesophagus

A

Moves food to the stomach

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4
Q

Function of the stomach

A

Where digestion continues, churns the food mechanically as it is a muscular organ = turn into a liquid to increase surface area digestion
produces enzymes for digestion of proteins
Produces HCl to aid enzyme digestion

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5
Q

Pancreas

A

Produces enzymes that are taken to the duodenum (top of small intestine)
CONTINUE digestion of starch and protein and START the digestion of lipids

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6
Q

Function of the liver

A

Produces bile

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7
Q

Function of the gallbladder

A

Stores bile before releasing it into the duodenum (top of small intestine)

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8
Q

Function of the duodenum

A

Where food is mixed with enzymes + bile and neutralised to be broken down even further

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9
Q

Function of the small intestine

A

Where nutrients are absorbed into the blood via villi
Continue digestion of protein and lipids

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10
Q

Function of the large intestine

A

Where water is reabsorbed

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11
Q

Function of the rectum

A

Where faeces is stored

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12
Q

Function of the anus

A

Where faeces leaves the body

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13
Q

Adaptations of the stomach

A

Secretes HCl to kill off any harmful bacteria
Produces enzymes to speed up digestion, also they work best in acidic conditions
Stomach muscles tissues that can contract rapidly to churn food, contain lots of mitochondria to get energy

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14
Q

Adaptations of the small intestine

A

Contains microvilli for a larger surface area so more diffusion happens at the same time
Thin walls with capillaries on the outside so a shorter diffusion distance into the bloodstream
Good blood supply for higher diffusion gradient

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15
Q

Adaptations of oesophagus

A

Can expand and contract (muscular) to let food and liquid pass to the stomach

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16
Q

What are digestive enzymes?

A

Biological catalysts that speed up the rate of digestion of large molecules into smaller ones without changing the reaction

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17
Q

How do enzymes work in digestion?

A

Through the catabolic lock and key method
An enzyme’s active site and food molecule are complementary in shape: only works on that specific molecule.
Attached together then large molecule broken down
Then repeat

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18
Q

Amylase

A

Produced in salivary glands and pancreas
Breaks down starch to simple sugars
Needs slightly acidic to neutral

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19
Q

Protease

A

Produced in stomach, pancreas and small intestine
Breaks down protein to amino acids
Both acidic and alkali proteases

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20
Q

Lipase

A

Produced in pancreas
Breaks fats into fatty acids and glycerol

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21
Q

Pepsin

A

Produced in stomach but works in duodenum
Breaks protein into peptides
A more neutral-alkali optimum pH so bile works alongside it

22
Q

Denaturing

A

When an enzymes active side changes and can’t work on that substrate anymore
Due to the temperature or pH getting too high

23
Q

Factors effecting how effective the enzyme is

A

Temperature
pH levels
Pressure
Surface area
Enzyme and substrate concentration

24
Q

Optimum

A

All enzymes have an exact pH and temperature where its activity is highest
If it goes above the enzyme denatures

25
Q

How does Bile help digestion?

A

Enzymes in the duodenum’s optimum pH is alkali
After being in the stomach the food molecules are acidic
Bile neutralises the small intestine to be less acidic to help the enzymes

26
Q

How does bile help lipase?

A

Emulsifies (breaks down) fat globules into fat droplets to give a larger surface area for lipase to work on.

27
Q

Enzyme rate of reaction

A

Amount of product formed / reactant used
———————————————————————
Time

28
Q

What are enzymes made out of?

A

Proteins that are made up of chains of amino acids

29
Q

Where is amylase produced?

A

Salivary glands
Pancreas

30
Q

Where is protease produced?

A

Pancreas
Stomach
Small intestine

31
Q

Where is lipase produced?

A

Pancreas

32
Q

What are the main nutrients in foods?

A

Carbohydrates (starch)
Protein
Lipids (fats)

33
Q

Where are digested molecules absorbed into the bloodstream?

A

In the small intestine via diffusion and active transport

34
Q

How does the small intestine have a large surface area?

A

Is 5m long
Contains villi (many shapes) that are divided into microvilli

35
Q

How does the small intestine having a good blood supply help?

A

It can rapidly remove away the products of digestion
To increase the concentration gradient

36
Q

How does the small intestine having a thin membrane help digestion?

A

Shortens the diffusion path

37
Q

If molecules aren’t absorbed by diffusion how are they absorbed in the small intestine?

A

Via active transport

38
Q

How are enzymes structured?

A

Made out of proteins (amino acids)
Have a groove (cut) called active site where substrate attaches to

39
Q

Where is protease produced?

A

Stomach
Pancras
Small intestine

40
Q

How does digestion of proteins work?

A

Proteins = chains of amino acids
Protease breaks it into singular amino acids to be absorbed into bloodstream
Once absorbed in cells = chains again then formed into human proteins

41
Q

How does digestion of starch work?

A

Starch = chain of glucose
Amylase breaks it into simple sugars (no chain)

42
Q

Where is amylase found?

A

Salivary glands
Pancreas

43
Q

How does digestion of lipids work?

A

Lipid = glycerol + 3 fatty acids
Lipase breaks it down into glycerol and fatty acids (no longer attached)
With help of bile

44
Q

Where is lipase found?

A

Pancreas
Small intestine

45
Q

How does bile work?

A

Emulsifies lipid globule into smaller lipid droplets
Increases the surface area
Increases rate of breakdown helping lipase

Also neutralises stomach acid as it is alkaline to increase rate of lipid digestion as lipase works best in neutral conditions

46
Q

How does temperature effect enzyme activity?

A

Increasing temp = enzyme moves faster so more collisions per second between substrate and active site
At certain temp it acts at fastest possible rate (optimum)
Beyond that activity falls to 0
Because the shape of active site has changed = no longer fits substrate = denatured = no activity

47
Q

How does pH effect enzyme activity?

A

Has the optimum at a more specific pH, any above or below that and it will begin to denature
Much less gradual than temperature

48
Q

If the temperature of an enzyme is too low, has it denatured?

A

No
In terms of temperature it only denatures if it exceeds ABOVE the optimum not below
Unlike pH, denatures above or below

49
Q

What are the products of digestion used for?

A

Build new carbohydrates, lipids and proteins
Some of the glucose for respiration

50
Q

What is the optimum temperature for most human enzymes?

A

37°C
Because it’s our average body temperature

Biology (55 decks)

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