B3 - Organisation and the digestive system

Question 1

What are cells

Answer 1

the basic building blocks of living organisms

Question 2

What is cell differentiation

Answer 2

becoming specialised to carry out particular jobs

Question 3

What are tissues

Answer 3

groups of cells with similar structures and functions

Question 4

What does muscular tissue do

Answer 4

contract to bring about movement

Question 5

What does glandular tissue do

Answer 5

contains secretory cells that can produce and release substances such as enzymes and hormones

Question 6

What does epithelial tissue do

Answer 6

cover the outside of the body as well as internal organs

Question 7

What are organs

Answer 7

groups of tissues that work together to perform a specific function

Question 8

What types of tissue are in the stomach
- what are their purposes

Answer 8

• muscular tissue churns food and digestive juices together
• glandular tissue produces the digestive juices
• epithelial tissue covers the inside and outside of the organ

Question 9

What are the two types of tissue in the pancreas
- what is the pancreas’ two main jobs

Answer 9

ones that make hormones and enzymes
- makes hormones to control blood sugar
- makes enzymes that digest food

Question 10

What is an organ system

Answer 10

a group of organs that work together to perform specific functions

Question 11

What are some organ systems in the human body

Answer 11

• digestive system
• endocrine system
• circulatory system
• gas exchange system

Question 12

What are some ways organisms can be adapted to perform their job well

Answer 12

• rich blood flow
• large SA
• short diffusion distances

Question 13

What are the levels of organisation in an organism

Answer 13

cells -> tissues -> organs -> organ systems -> organisms

Question 14

What is the function of the digestive system

Answer 14

to break down food into smaller, soluble molecules that can be absorbed and used by cells

Question 15

What organs and glands are contained in the digestive system

Answer 15

• mouth (salivary gland, teeth)
• gullet
• stomach
• liver
• pancreas
• gall bladder
• duodenum
• bile duct
• small intestine
• large intestine
• appendix
• rectum
• anus

Question 16

What do glands such as the pancreas and salivary glands do in the digestive system

Answer 16

produce digestive juices containing enzymes to break down food

Question 17

Where in the digestive system does most digestion take place

Answer 17

stomach and small intestine

Question 18

Where is soluble food molecules absorbed into blood

Answer 18

small intestine

Question 19

how is the small intestine adapted to have fast diffusion and active transport

Answer 19

lots of villi for greater SA
- good blood supply
- short diffusion distances

Question 20

what happens in the large intestine
- what happens to left-over material

Answer 20

water is absorbed from undigested food into blood
- forms faeces

Question 21

what is the function of the liver in the digestive system

Answer 21

produces bile which helps in the digestion of lipids

Question 22

What are the three main compounds that make up the structure of a cell

Answer 22

carbohydrates, lipids, proteins

Question 23

What do carbohydrates provide us with

Answer 23

fuel that makes reactions possible

Question 24

What are the two types of carbohydrates
- what are some examples

Answer 24

simple sugars contain only one sugar unit
- glucose, sucrose

complex sugars are made of long chains of units (polymers)
- starch and cellulose

Question 25

What happens to carbohydrates when they are eaten

Answer 25

they are normally broken down into glucose, used in cellular respiration to provide energy for metabolic reactions

Question 26

What are lipids

Answer 26

fats and oils, the most efficient energy store inthe body

Question 27

What are some properties of lipids

Answer 27

- made from carbon, hydrogen and oxygen - insoluble in water

Question 28

What are lipids made of

Answer 28

3 molecules of varying fatty acids to a molecule of constant glycerol

Question 29

What are proteins used for in the body

Answer 29

building up cells and tissues, and the basis of enzymes

Question 30

What are proteins made from

Answer 30

- carbon - oxygen - nitrogen - hydrogen

Question 31

What are proteins made from - how many are there

Answer 31

amino acids chained together - around 20 each combination gives a different protein

Question 32

why does the shape of protein structures get lost easily - what is this called

Answer 32

bonds are sensitive to pH and temperature - denatured

Question 33

What are some functions of proteins in the body

Answer 33

- structural components e.g. tendons and muscles - hormones - antibodies - enzymes

Question 34

What is the chemical test for starch

Answer 34

add iodine - yellow, red -> blue, black

Question 35

What is the chemical test for sugars

Answer 35

add benedicts solution and heat - blue -> brick red

Question 36

What is the chemical test for proteins - What is the danger of this experiment

Answer 36

add biuret reagent - blue -> purple - biuret reagent is corrosive

Question 37

What is the chemical test for lipids - what is the danger with this

Answer 37

add ethanol - cloudy white layer if lipids are present - ethanol is highly flammable

Question 38

what are enzymes

Answer 38

proteins that act as biological catalysts

Question 39

how are enzymes shaped

Answer 39

chains of amino acids are folded to produce molecules with a unique shape active site

Question 40

What is the lock and key model

Answer 40

substrate fits active site, like a lock and key, at the active site - substrate splits and leaves the active site - enzyme is reused

Question 41

What are some actions controlled by enzymes - give examples of each

Answer 41

- making larger molecules e.g. C, H and O -> glucose, glucose and nitrate ions to amino acids - changing molecules e.g. glucose to fructose - breaking down large molecules e.g. glucose in respiration

Question 42

What are some factors that affect biological reactions

Answer 42

concentration, temperature, surface area

Question 43

how does temperature affect enzyme action

Answer 43

the higher the temperature, the faster the reaction until the enzyme denatures

Question 44

What temperature do most human enzymes work best at

Answer 44

37 degrees

Question 45

Why does pH affect enzyme action

Answer 45

pH affects forces that hold the amino acid chains in place

Question 46

What is the difference between digestive enzymes and most other bodily enzymes

Answer 46

digestive enzymes work outside of cells

Question 47

Where are digestive enzymes produced

Answer 47

in the pancreas, salivary glands, lining of the digestive system

Question 48

Why does the digestive system squeeze food

Answer 48

because it is hollow and muscular - it breaks the food into smaller particles with large surface areas for enzymes to work on

Question 49

Why does the digestive system have varying pH levels

Answer 49

so that different enzymes can work as efficiently as possible

Question 50

What enzyme breaks down carbohydrates - where is it produced - where does digestion take place - what is made from this digestion

Answer 50

amylase / carbohydrase - salivary glands and pancreas - mouth and small intestine - small sugars

Question 51

What enzyme breaks down proteins - where is it produced - where does digestion take place - what is made from this digestion

Answer 51

protease - stomach, pancreas and small intestine - stomach and small intestine - amino acids

Question 52

What enzyme breaks down lipids - where is it produced - where does digestion take place - what is made from this digestion

Answer 52

lipase - pancreas and small intestine - small intestine - fatty acids and glycerol

Question 53

how is digestion made efficient

Answer 53

- changing pH - altering surface area -

Question 54

What is the pH of the stomach - How - How does it not burn the stomach

Answer 54

very low, acidic - HCl is produced - a thick layer of mucus is produced

Question 55

What happens when someone has a stomach ulcer

Answer 55

the mucus layer is lost and acid attacks the stomach lining

Question 56

How is the small intestine adapted for digestion - how is acidic substance from stomach neutralised

Answer 56

- alkaline pH for optimum functionality - bile

Question 57

What does the bile duct do

Answer 57

squirt bile on the acidic mixture from the stomach

Question 58

What are the two functions of bile

Answer 58

- neutralises acidic solution from stomach - emulsifies fats

Question 59

Why do fats need to be emulsified

Answer 59

it sticks together and therefore has a low surface area for lipase to act on, therefore digestion would be very slow

Question 60

What do gall stones do

Answer 60

block the gall bladder and bile ducts, not allowing bile to be released on to food and reducing the efficiency of digestion