b3 - organisation and the digestive system

Question 1

what do cells do as a multicellular organism develops?

Answer 1

they differentiate

Question 2

define tissues

Answer 2

group of cells with similar structure and function

Question 3

give three examples of tissues

Answer 3

muscular tissue - contracts for movement
glandular tissues - produces substances like enzymes or hormones
epithelial tissue - covers some parts of body

Question 4

what tissues is the stomach made up of?

Answer 4

muscular tissue - churn contents
glandular tissue - digestive juices
epithelial tissue - covers outside and inside

Question 5

give two types of glandular tissue the pancreas has

Answer 5

1) hormones to control blood sugar
2) some of the digestive enzymes

Question 6

give some examples of organ systems

Answer 6

digestive, circulatory, gas exchange

Question 7

what do all these organ systems have to be efficient exchange surfaces?

Answer 7

• short diffusion paths
• rich blood supplies
• mechanisms for ventilating surfaces or moving materials

Question 8

role of the digestive system

Answer 8

takes the food you eat from insoluble molecules into soluble molecules, then absorbing them into the blood

Question 9

what does the digestive system include?

Answer 9

• glands, e.g pancreas, salivary glandss
• stomach
• liver, producing bile
• small intestine
• large intestine

Question 10

how are villi adapted?

Answer 10

• large surface area to absorb soluble molecules by diffusion/active transport
• thin wall for short diffusion path
• good blood supply to carry food molecules away to maintain concentration gradient

Question 11

what are all carbohydrates made of?

Answer 11

units of sugar

Question 12

how many units of sugar does glucose have?

Answer 12

one unit

Question 13

how many units of sugar does sucrose have?

Answer 13

two units linked together

Question 14

give two examples of simple sugars

Answer 14

glucose, sucrose

Question 15

give examples of complex carbohydrates

Answer 15

starch and cellulose made of long chains of simple sugar units that are bonded together

Question 16

define lipids

Answer 16

molecules made of three molecules of fatty acids linked to a molecule of glycerol

Question 17

define proteins

Answer 17

• made of long chains of amino acids which are folded to form a specific shape
• other molecules can fit into these specific shapes

Question 18

what happens if the protein is heated?

Answer 18

shape is changed and becomes denatured

Question 19

give examples of protein functions CHANGE THIS

Answer 19

e.g structural components of tissues, such as muscles or hormones, antibodies or enzymes

Question 20

test for carbs; starch

Answer 20

yellow-red iodine solutions turns blue-black if starch is present

Question 21

test for carbs; sugars

Answer 21

use blue Benedicts solution turns brick red on heating if sugar e.g glucose is present

Question 22

test for protein

Answer 22

blue Bierut reagant turns purple if protein is present

Question 23

test for lipids

Answer 23

ethanol added to a solution gives a cloudy white layer if lipid is present

Question 24

safety when using ethanol

Answer 24

wear eye protection, ethanol is highly flammable and harmful

Question 25

what are chemical reactions in cells controlled by?

Answer 25

proteins called enzymes

Question 26

define enzymes

Answer 26

- biological catalysts - speed up reactions - shape is vital for function - large area called active site where substrate molecule can fit

Question 27

define lock and key theory

Answer 27

1) substrate fits into active site 2) substrate splits into products which leave active site 3) enzyme then ready to use again

Question 28

what can enzymes do?

Answer 28

- build large molecules from many smaller ones, e.g building starch from glucose molecules - change one molecule into another - break down large molecules into smaller ones

Question 29

define metabolism

Answer 29

sum of all chemical reactions taking place in a cell or the whole body

Question 30

why do reactions take place faster when it is warmer?

Answer 30

at higher temps the molecules move around more quickly and collide with eachother more often, with more energy

Question 31

what happens when temp increases in an enzyme-catalysed reaction?

Answer 31

- the rate of an enzyme catalysed reaction increases

Question 32

what happens if enzymes get too high/

Answer 32

stop working and becomes denatured

Question 33

in what way could the active site change?

Answer 33

folded shape of protein molecule forming an enzyme is held together by forces, change in pH affects these forces

Question 34

why does enzyme work more efficiently at optimum pH?

Answer 34

this is where active site has the best shape

Question 35

what happens if pH is too acidic or alkaline?

Answer 35

enzyme becomes denatured so shape of active site changes

Question 36

how are digestive enzymes produced?

Answer 36

- by specialised cells in glands and in the lining of the small intestine - pass out of the glands into cavity of the digestive system - work outside the cells - come into contact with food so digested

Question 37

what does the digestive system do?

Answer 37

- food into smaller to increase surface area for enzymes to work on - mixes food with digestive juices containing enzymes - has muscles to move food along - areas with different pH - absorbs small, soluble food molecules into blood in small intestine

Question 38

define amylase

Answer 38

- a carbohydrase - produced by salivary glands, pancreas, small intestine - catalyses digestion of starch into sugars in mouth and small intestine

Question 39

define proteases

Answer 39

- produced by stomach, pancreas and small intestine - catalyse breakdown of proteins into amino acids in stomach and small intestine

Question 40

define lipase

Answer 40

- produced by pancreas, and small intestine - catalyses breakdown of lipids to fatty acids and glycerol

Question 41

what temp do human digestive enzymes work best at?

Answer 41

body temp, 37 degrees

Question 42

what conditions do protease enzymes work best at?

Answer 42

acidic conditions - glands in stomach wall produce hydrochloric acid to create very acidic conditions

Question 43

what conditions do other proteases, amylas and lipase work best at?

Answer 43

best in small intestine where conditions are slightly alkaline

Question 44

why does the pH of food leaving stomach need to be changed?

Answer 44

food leaving stomach is very acidic

Question 45

what does bile do?

Answer 45

- neutralises stomach acid - makes conditions in stomach slightly alkaline - emulifies fatws to increase surface area of fats for lipase enzymes to act on

Question 46

where is bile stored?

Answer 46

gall bladder