Organisation

Question 1

What is digestion? (2)

Answer 1

It is a process during which mechanical and chemical breakdown of large insoluble food particles are broken down into smaller, soluble food particles so that they can be absorbed into the bloodstream.Digestive enzymes help to break down the large food molecules.

Question 2

Mechanical digestion involves

Answer 2

biting, grinding, chewing, mixing (mastication)

Question 3

Chemical digestion involves

Answer 3

It is the breakdown of larger food particles into smaller soluble food particles by digestive enzymes.

Question 4

What is an enzyme?

Answer 4

• It is a biological catalyst
• It is a protein molecule
• It speeds up chemical reactions without undergoing only permanent chemical change

Question 5

ENzymes, hormoNes and aNtibodies are all

Answer 5

proteins

Question 6

Name the 3 enzymes

Answer 6

Protease, Amylase, Lipase

Question 7

Protease

Answer 7

Breaks down large insoluble protein molecules into smaller, soluble amino acids (acts in an acidic medium).

Question 8

AmyLase

Answer 8

It converts large insoluble starch molecules into smaller soluble sugar molecules eg: glucose, acts in an aLkali medium.

Question 8

AmyLase

Answer 8

It converts large insoluble starch molecules into smaller soluble sugar molecules eg: glucose, acts in an aLkali medium.

Question 9

Lipase

Answer 9

It converts insoluble lipids (fats) into soluble smaller fatty acids and glycerol (acts in an alkali medium).

Question 10

Whar organs are the enzymes (PALs) found in?

Answer 10

• small intestine
• pancreas
• aMylase: found in the Mouth –> salivary amylase

Question 11

State the factors that effect the efficient functioning of an enzyme (STEP^2PS)

Answer 11

Substrate concentration
Temperature
Enzyme concentration
PH
Pressure
Surface area

Question 12

What are the differences between (U)secrete and (W)eXcrete?

Answer 12

secrete - useful substances are released
eXcrete- Wate products/ substances are removed from the body eg: CO2, urea into urine, excess water vapour, H2O (g), faeces (egestion)

Question 13

Describe the process of digestion

Answer 13

• After masticating, the food is in the form of a ‘ball’, bolus
• The bolus is ‘forced down’ by muscular contractions called peristalsis (oesophagus)
• Liver- it secretes biLe- Bile is an alkalie, it neutralises stomach acid (HCL) (aq). It emulsifies fats, increases the surface area to volume ratio- larger molecules are broken down to smaller molecules. It provides an alkali medium for amylase and lipase to functions.
• stomach- secretes hydrochloric acid (HCL)–>it kills bacteria, it provides an acid medium for protease to act efficiently.
• Gall bladder- stores bile and releases when needed
• pancreas-secretes the digestive enzymes as well as hormONes, insulin, glucagON.
• small intestine is approximately 6-8 m (ileum) - maximum absorption of soluble food particles (secretes digestive enzymes= PALs)
• large intestine absorbs water

Question 14

What does a large SAVR help organisms to do?

Answer 14

To absorb, gaseous exchange, diffusion, photosynthesis, respiration

Question 15

How is the small intestine adapted for efficient absorption? (4) - SM^2 ART

Answer 15

• Large surface area
• mitochondria, moist surfaces
• area
• rich blood supply
• 1 cell thick
• Small intestine has microvilli (large SAVR) maximisies absorption of food particles
• surfaces are moist so food particles can be solub;e/ absorb.
• mitchondria helps in cellular respiration to provide energy for active transport
• rich blood supply- presents high concentration gradient
• 1 cell thick - rate of diffusion is increased

Question 16

What pH values do the enzymes work most efficiently in?

Answer 16

Protease works efficiently in a pH value of 2. It works well optimally in an acid medium- rate of reaction is the highest.
AmyLase and lipase- these enzymes function optimally in an aLkali medium. The rate of reaction is very high (or pH values greater than 7)

Question 17

What temperature allows enzymes to function optimally?

Answer 17

37 degrees Celsius.

Question 18

CTOSO

Answer 18

• cells
• tissues
• organs
• organ systems
• organisms

Question 19

tiSsue

Answer 19

a group of similar cells which perform a specific function

Question 20

Organ

Answer 20

a group of similar tissues which perform a specific function

Question 21

Rep

Answer 21

• respiratory system
• excretory system
• endocrine system
• reproductive system
• digestive system
• circulatory system
• nervous system
• skeletal system