Organisation 1 Flashcards
Cell organisation, The digestive system.
1
Q
What are cells?
A
The basic building blocks of all living organisms.
2
Q
What is a tissue?
A
A group of cells with similar structure and function.
3
Q
What is an organ?
A
A group of tissues performing specific functions.
4
Q
What do organ systems work together to form?
A
Organisms.
5
Q
What do specialised cells do?
A
Carry out a particular function.
6
Q
What do specialised cells form?
A
Tissues, which form organs, which form organ systems.
7
Q
Give examples of tissues in mammals.
A
-Muscular tissue
-Glandular tissue
-Epithelial tissue
8
Q
What does muscular tissue do?
A
Contract to move whatever it’s attached to.
9
Q
What does glandular tissue do?
A
Makes and secretes chemicals like enzymes and hormones.
10
Q
What does epithelial tissue do?
A
Cover some parts of the body, e.g. the inside of the gut.
11
Q
What is an organ system?
A
A group of organs working together to perform a particular function.
12
Q
How is the stomach (organ) adapted for its role in digestion?
A
It is made up of three types of tissue:
-Muscular tissue
-Glandular tissue
-Epithelial tissue
13
Q
What is the function of muscular tissue in the stomach?
A
It contracts, causing the wall of the stomach to move and churn up food.
14
Q
What is the function of glandular tissue in the stomach?
A
Secretes acid and enzymes (in digestive juices) which help to break down food chemically in the stomach cavity.
15
Q
What is the function of epithelial tissue in the stomach?
A
To cover and protect the outside and the inside of the stomach.
16
Q
How much longer is the stomach than an epithelial cell?
A
Over 1000x longer.
Epithelial cells are less than 0.1mm in length.
17
Q
What is the digestive system?
A
An example of an organ system in which several organs work together to digest and absorb food.
18
Q
Give an example of an organ system.
A
The digestive system.
The respiratory system.
The circulatory system.
The urinary system .
19
Q
What organs is the digestive system made up of?
A
-Salivary glands
-Oesophagus (gullet)
-The liver
-The gall bladder
-The stomach
-The pancreas
-The small intestine
-The large intestine
-The rectum
20
Q
What is the role of glands in the digestive system?
A
To produce digestive juices containing digestive enzymes
21
Q
Which glands are involved in the digestive system?
A
-Salivary glands
-Pancreas
22
Q
What is the role of the stomach?
A
To digest food
23
Q
What is the role of the large intestine?
A
To absorb water from undigested food, leaving faeces.
24
Q
Knowledge of enzymes relates to…
A
Metabolism
25
Why do chemical reactions need to be carefully controlled?
| (inside organisms)
So that organisms get the right amount of substances.
26
Why is raising the temperature inside of a living creature not an effective way of increasing the rate of the chemical reactions occurring in it?
-Raising the temperature would increase the rate of unwanted reactions, not just the useful ones.
-If temperature becomes too high inside a living creature, it's cells start to become damaged.
27
What are enzymes?
Large proteins that act as biological catalysts.
28
What is a catalyst?
A substance which increases the speed of a reaction without being changed or used up in the reaction.
29
What do enzymes reduce the need for?
High temperatures?
30
What do enzymes speed up?
ONLY USEFUL chemical reactions in the body.
31
What are enzymes made up of?
They are large proteins, so are made up of chains of amino acids.
These chains are folded into unique shapes, allowing enzymes to catalyse specific reactions.
32
Enzymes catalyse specific reactions in living organisms due to what?
The shape of their active site.
33
If the substrate doesn't match the enzyme's active site, then...
the reaction won't be catalysed.
34
What is the name for the substance that an enzyme acts on?
The substrate
35
Lock and key theory
A simplified model used to explain enzyme action.
36
Explain why enzymes have an optimum pH.
If the pH is too high or low, it can interfere with the bonds holding the enzyme together.
This changes the shape of the active site and denatures the enzyme.
37
What happens if enzymes become denatured?
The substrate will not bond to the active site (as the active site is no longer complementary) and so the reaction will not be catalysed.
38
Explain why enzymes have an optimum temperature.
If the temperature is too high, some of the bonds holding the enzyme together break.
This changes the shape of the active site and denatures the enzyme.
39
When the enzyme is most active, it it at its...
-Optimum temperature
or
-Optimum pH
40
What is often the optimum pH for enzyme action?
pH 7
41
What is the optimum pH for pepsin?
pH 2 so that it is well suited to the acidic conditions of the stomach.
42
What is pepsin?
An enzyme used to break down proteins in the stomach.
43
What does the 'induced fit' model show?
How the active site of an enzyme changes slightly as the substrate binds to it in order to get a tighter fit.
44
Rate
A measure of how much something changes over time.
45
If an experiment measures how much something changes over time, how do we calculate the rate of reaction?
Divide the amount that it has changed, by the time taken.
46
How do we calculate the rate of reaction from the 'investigating enzymatic reactions' practical?
rate = 1000/time
units s⁻¹
47
When explaining the lock and key model...
draw it and annotate it!
label the:
-enzyme
-active site
-substrate
-products
48
Why do we need digestive enzymes?
To break down large food molecules into smaller, soluble ones...
That can easily pass through the walls of the digestive system...
And be absorbed into the bloodstream.
49
Give examples of large molecules
Starch
Proteins
Fats
50
Give examples of small molecules
Amino acids
Glycerol
Fatty acids
51
What is the action of carbohydrases?
To break down carbohydrates to simple sugars.
52
What is amylase?
A type of carbohydrase which breaks down starch (a type of carbohydrate).
53
What is the word equation for the breakdown of starch?
Starch → Simple sugars (Maltose/Glucose)
(Amylase enzyme)
54
What are the products of the breakdown of starch?
Glucose and other simple sugars e.g. fructose, lactose, maltose.
55
Where is amylase produced?
-The salivary glands
-The pancreas
-The small intestine
56
Where are proteases made?
-The stomach (where it's called pepsin)
-The pancreas
-The small intestine
57
Where are lipases made?
-The pancreas
-The small intestine
58
What is the action of proteases?
To break down proteins to amino acids.
59
What is the word equation for the breakdown of proteins?
Proteins → Amino acids
(Protease enzymes)
60
What is the action of lipases?
To break down lipids to glycerol and fatty acids.
61
What is the word equation for the breakdown of a lipid molecule?
Lipid → Glycerol + (3) Fatty acids
(lipase enzymes)
62
What are the products of the breakdown of a lipid molecule?
1 molecule of glycerol
3 fatty acid molecules
63
What are lipids?
Fats and oils.
64
What are the products of digestion used for?
To build new carbohydrates, lipids, and proteins.
Some glucose is used in respiration.
65
Where is bile produced?
The liver.
66
Where is bile stored?
The gall bladder.
67
Where is bile released into from the gall bladder?
The small intestine.
68
Why is bile alkaline?
To neutralise hydrochloric acid from the stomach.
69
Why must hydrochloric acid from the stomach be neutralised in the small intestine?
So that enzymes in the small intestine can work properly.
Else the pH is too low, interfering with the bonds holding the enzyme together, changing the shape of the active site and denaturing the enzyme.
70
How does bile emulsify fat?
It mixes with fat globules, causing them to break down into smaller molecules called emulsification droplets.
71
Why does bile emulsify fat?
To increase surface area, increasing the rate of fat breakdown by lipase from the pancreas.
72
What do alkaline conditions do in the small intestine?
Increase the rate of fat breakdown by lipase from the pancreas.
(make digestion faster).
73
The enzymes used in digestion are produced by what?
Specialised cells in glands and in the gut lining.
74
What does bile do?
Neutralises hydrochloric acid from the stomach and emulsifies fats.
75
What happens in the mouth?
The teeth start digesting food mechanically.
76
Where is the amylase enzyme found in the salivary glands?
In the saliva, starting the chemical breakdown of starch.
77
Why does the stomach produce hydrochloric acid?
-To kill bacteria
-To give the right pH for the protease enzyme pepsin to work
78
Rectum
Where the faeces are stored before they are egested (via the anus).
79
What is faeces made of?
Mainly indigestible food.
80
What is the role of the small intestine?
To produce protease, amylase, and lipase enzymes to complete digestion.
To absorb soluble food molecules into the blood.
81
What is the role of the oesophagus?
To swallow the bolus of food through peristalsis.
82
What is the role of the pancreas?
To produce protease, amylase, and lipase enzymes and release them into the small intestine.
83
Sudan lll test for lipids
-add Sudan III stain solution to test tube and gently shake
-if lipids are present, the mixture will separate into two layers - the top will be bright red.
84
How can we test for proteins?
The Biuret test
-add biuret solution to a pre-prepared sample of food and gently shake
85
Results from Biuret test if proteins present
Solution will change from blue to purple.
86
Results from test for starch if starch present:
if starch is present, the iodine solution will change from browny-orange to black or blue-black
87
What are the main organs where food is digested?
-stomach
-small intestine
88
Reagents
Used to test (in this case) for a specific chemical.
89
Steps in any food test: (1 and 2)
1. Break up your food sample using a pestle and mortar.
2. Transfer the ground up food to a beaker and add some distilled water.
90
Steps in any food test: (3, 4, and 5)
3. Stir the mixture with a glass rod to dissolve some of the food.
4. Filter the solution using a funnel lined with filter paper to get rid of the solid bits of food.
5.Carry out the food test.
91
How can we test for reducing sugars?
Use the benedict's test:
-Prepare food sample
-Heat with benedict's solution
92
Results from Benedict's test if reducing sugar present:
Solution will turn from blue to green, yellow, or BRICK RED
93
How can we test for starch?
Use iodine solution
-add to food sample and gently shake
94
Explain the lock and key theory of enzyme action.
- Enzyme binds to the substrate because they are complementary
- Substrate is broken down into products
- Products are released and the enzyme does not change
95
How can living things be grouped?
As animals, microorganisms, and plants.
96
Describe how mitochondria help a sperm cell to do its job. [2]
They release energy IN RESPIRATION so the sperm cell can swim.
97
Does the left or right side of the heart have thicker walls?
The left side of the heart has thicker walls due to the higher pressure needed to pump blood to the body.
98
Lactic acid is broken back down into glucose by the...?
liver, using oxygen.
99
what is a balanced diet?
One that includes appropriate proportions of all the different biological molecules, including carbohydrates, proteins, lipids, vitamins, minerals, fibre, and water.
100
What is humans main source of energy?
Carbohydrates
101
What food types can be used for energy?
Carbs
Lipids
Proteins
102
What 3 things does the amount of energy we need daily depend on?
activity level
Age
Pregnancy
103
Which biological molecules do we need in large quantities?
Carbohydrates
Proteins
Lipids
104
Why do we need carbohydrates?
To provide energy for chemical reactions (and movement)
105
Why do we need lipids?
To provide energy for chemical reactions
To insulate us and regulate our body temperature
106
Legumes
A protein rich food source, including lentils, chickpeas, pinto beans
107
Which vitamin is important for good vision, healthy hair and skin?
Vitamin A
108
Which mineral is important for strong bones?
Calcium
109
What disease can be caused by a lack of vitamin C?
Scurvy
110
Explain why it os important that we get enough iron in our diet.
Iron is an important component of haemoglobin, the protein in red blood cells that allows them to transport oxygen around the body.
A lack of iron (and hence a lack of haemoglobin) can lead to anaemia, where we can’t transport enough oxygen to our tissues = tiredness, weakness
111
Why do we need fibre (a type of carbohydrate) ?
To help food move through our intestines.
112
What are the three main ways we lose water from the body?
Breathing, Sweating, and Urinating.
113
Vitamin D?
Helps us to absorb calcium.
Can be made by the body, using sunlight.
114
What is the difference between oils and fats?
Oils- liquid at room temperature
Fats- solid at room temperature
115
What percentage of humans are water?
70%
116
What nutrients can be gained from leafy greens?
Iron
Vitamin A
117
what nutrients can be gained from fruit and veg?
Carbohydrates
Fibre
Vitamins
Minerals
118
What are biological molecules?
Molecules found in living organisms, produced by cells.
119
What are nutrients?
Substances needed for growth, repair, and metabolism.
Carbs/proteins/lipids are both biological molecules and nutrients.
120
What are carbohydrates?
Molecules made from the atoms carbon, hydrogen, and oxygen.
121
Name a simple sugar/ ‘monomer’
Glucose/Fructose
122
What makes a carbohydrate complex?
When the carbohydrate is in the form of carbohydrate polymers such as glycogen and starch
There are chemical bonds between monomers
(can be broken to form simple carbohydrates - monomers)
123
What atoms are amino acids made from
Carbón
Hydrogen
Oxygen
Nitrogen
124
What is a key difference between lipids and carbohydrates?
Carbohydrates are polymers whereas lipids are not.
125
what is starch?
A polymer of glucose, produced by plants.
Most of the carbs we eat are in the form of starch.
126
How are carbohydrates broken down in the body?
Starch is broken down by the enzyme amylase into maltose.
Maltose is broken down by maltase into glucose (which had molecules small enough to absorb)
