Biology Flashcards
1
Q
What is the word equation for aerobic respiration?
A
Glucose + oxygen -> carbon dioxide + water + ATP
2
Q
What is the balanced chemical equation for aerobic respiration?
A
C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP
3
Q
What is the word equation for anaerobic respiration in animals?
A
Glucose -> Lactic acid + ATP
4
Q
What is the form of the energy released by respiration?
A
ATP
5
Q
What is ATP?
A
ATP (adenosine triphosphate) is the energy-carrying molecule used in cells because it can release energy very quickly.
6
Q
What are 3 differences between aerobic and anaerobic respiration?
A
Aerobic:
- occurs in the mitochondria
- in presence of oxygen
- produces more energy, slower
Anaerobic:
- occurs in the cytoplasm
- oxygen is not present
- produces less energy, more quickly
7
Q
What is the word equation for anaerobic animals in plants and yeast?
A
Glucose->ethanol + carbon dioxide + ATP
8
Q
How can you measure the rate of respiration?
A
Rate of respiration = up-taken oxygen/ time
Units = cm3/min
9
Q
What factors affect the rate of respiration?
A
- availability of oxygen (reactant)
- temperature (enzymes)
- substrate (reactant, usually a form of glucose)
10
Q
How would you investigate the evolution of heat in respiring seeds?
A
C: change the contents of the boiling tube (germinating seeds, dead seeds)
O: seeds used of same age, species and size
R: each type of seed will be repeated 3x and average calculated
M: temperature in the boiling tube, measured using a thermometer after 3 hrs
S: same material of the boiling tube, same starting temperature
11
Q
How would you investigate the evolution of CO2 from living organisms?
A
By carrying out experiments to show the production of carbon dioxide. These experiments could be:
- measuring the distance the stained water drop has travelled over a timeframe
- measuring the time taken for the limewater to turn cloudy
- counting how many bubbles have been produced over a timeframe
12
Q
How would you investigate the rate of anaerobic respiration by yeast in different conditions?
A
1) measuring how much CO2 has been produced by measuring how far the stained water drop has moved over the time frame. REPEATED AT DIFFERENT TEMPS
2) measuring the time taken for the limewater to go cloudy. REPEATS AT DIFFERENT TEMPS
3) counting bubbles to determine how much CO2 has been produced.
4) using a gas syringe to measure the volume of CO2 produced.
13
Q
What is ingestion?
A
The intake of substances (food, drink…) into the body through the mouth
14
Q
What is digestion?
A
The break down of large, insoluble food molecules into small, water-soluble molecules that can be absorbed into the bloodstream
15
Q
What is absorption?
A
The movement of digested food molecules across the walls of the intestine into the blood or lymph
16
Q
What is assimilation?
A
Movement of digested food molecules into the cells where they are used, becoming part of the cells (uptake and use of food molecules by cells).
17
Q
Egestion
A
Passing out of undigested food as faeces, through the anus
18
Q
Label a diagram of the alimentary canal.
A
SEE PHOTOS
19
Q
What is the function of the alimentary canal?
A
Provides a channel through which food can flow through the body.
20
Q
What is the function of the mouth?
A
Where food enters the alimentary canal and where both chemical and mechanical digestion begin - chemical by the amylase enzyme in the saliva beginning to break starch down into maltose, and mechanical by the teeth chomping.
21
Q
What is the function of the oesophagus?
A
Moves the bolus from the mouth to the stomach by the process of peristalsis
22
Q
What is the function of the stomach?
A
Begins the digestion of protein into amino acids; small molecules such as alcohol are absorbed
23
Q
What is the function of the duodenum?
A
Continues the digestion of carbohydrate and protein; begins the digestion of lipids
24
Q
What js the function of the ileum?
A
Digested food/small molecules are absorbed into the blood stream here
25
What is the function of the colon?
Faeces is formed here
26
What is the function of the rectum?
Faeces is stored here
27
What is the function of the pancreas?
Produces digestive enzymes carbohydrase, protease and lipase. These enzymes are secreted from here into the small intestine
28
How is food moved through the gut by peristalsis?
The bolus is forced along the gut / oesophagus by the antagonistic pair of muscles (the circular and longitudinal muscles), as when one of them contracts, the other relaxes- squeezing the food along.
29
What happens when the longitudinal muscles contract?
Length reduced
30
What happens when the circular muscles contract?
Diameter is reduced
31
What is the role of amylase?
Breaks starch down into maltose
32
Where is amylase found?
Mouth, duodenum
33
What is the function of maltase?
Breaks down maltose into glucose
34
Where is maltase found?
Small intestine
35
What is the function of the proteases?
Break down protein into amino acids
36
What are the three proteases?
Pepsin, trypsin, peptidase
37
Where is pepsin found?
Stomach
38
Where is trypsin found?
Duodenum
39
Where is peptidase found?
Small intestine
40
What is the function of lipase?
Breaks lipids down into glycerol and fatty acids
41
Where is lipase found?
Duodenum
42
state 4 types of digestive enzymes
Amylase, maltase, proteases, lipase
43
Where is bile produced?
In the liver
44
Where is bile stored?
Gall bladder
45
What are the 2 roles of bile?
1) emulsification of lipids
2) neutralise stomach acid
46
What is emulsification?
The process by which large drops of lipids are broken into smaller droplets, but are not altered chemically.
47
How does bile neutralise stomach acids?
It provides an alkaline fluid in the duodenum that neutralises the acidic pH of the stomach
48
How is the ileum lining adapted for absorption?
- has micro-villi (on the villi): increasing surface area, meaning that the rate of diffusion is increased
- thin walls: wall of the ileum lining are one cell thick, meaning there is a short diffusion ditance
- network of capillaries: causes blood flow, which maintains a high concentration gradient meaning the rate of diffusion increases
49
What are the elements present in carbohydrates?
Carbon, hydrogen, oxygen
50
What elements do lipids contain?
Carbon, hydrogen, oxygen
51
What elements do proteins contain?
Carbon, hydrogen, oxygen, nitrogen
52
What is a polymer?
Large molecules made up of smaller basic units
53
Describe the structure of starch
A polymer of glucose
54
Describe the structure of sucrose.
Composed of glucose and fructose subunits (but it is not a polymer).
55
Describe the structure of lipids
Made up of a molecule of glycerol joined to 3 fatty acids. NOT A POLYMER
56
Describe the structure of proteins
A polymer of amino acids, of which there are 20 types. The amino acids are linked together in long chains, which are usually twisted into spirals
57
What is the role of an enzyme?
Enzymes are biological catalysts meaning that they alter the rate of metabolic reactions without being altered or used up themselves.
58
What factors affect enzyme activity?
- temperature
- pH
- enzyme concentration
- substrate concentration
59
Describe how the rate of reaction if an enzyme changes as the temperature is increased.
- Initially increases steadily with temperature
- After the rate peaks, it decreases rapidly
60
Explain how the rate of reaction if an enzyme changes as the temperature is changed.
Enzymes work best at an optimum temperature. Below this, an increase in temperature provides more kinetic energy to the molecules involved. The numbers of successful collisions between enzyme and substrate will increase so the rate will too. Above the optimum temperature, the enzyme begins to denature. Bonds holding the structure together will be broken down and the active site loses its shape so that it is no longer complimentary to the substrate and they will no longer be able to bind to form enzyme-substrate complexes
61
Describe how the rate of reaction of an enzyme changes as the pH is changed.
As the pH changes from the enzyme’s optimum, the rate of reaction of the enzyme decreases
62
Explain the changes in rate of reaction of an enzyme when pH is changed.
Enzymes have an optimum pH, one at which they work best. If the pH changes much from the optimum, the chemical nature of the amino acids changes. This results in a change in the bonds and so the tertiary structure will be broken down. This causes the active site to change shape, meaning it is no longer complimentary to the substrate and can no longer bind with it to form enzyme-substrate complexes.
63
Describe how increasing enzyme concentration affects the rate of reaction of enzymes.
Initially, increasing the concentration of enzymes will causes a greater rate of reaction, however, after some time, it will simply plateau and increasing enzyme concentration will have no effect on the rate of reaction.
64
Explain why changing enzyme concentration affects the rate of reaction of enzymes.
At low enzyme concentration, there is great competition for the active sites and the rate of reaction is low. As the enzyme concentration increases, there are more active sites and the reaction can proceed at a faster rate. Eventually, increasing the enzyme concentration beyond a certain point has no effect because the substrate concentration becomes the limiting factor.
65
Describe how increasing substrate concentration affects the rate of reaction of enzymes.
Initially, increasing the concentration of substrates will causes a greater rate of reaction, however, after some time, it will simply plateau and increasing substrate concentration will have no effect on the rate of reaction.
66
Explain how changing substrate concentration affects the rate of reaction of enzymes.
At a low substrate concentration, there are many active sites that are not occupied. This means that the rate of reaction is low. When more substrate molecules are added, more enzyme-substrate complexes can be formed. So, the rate of reaction increases. Eventually, increasing the substrate concentration yet further has no effect. The active sites will be saturated so no no more enzyme-substrate complexes can be formed.
67
What is an enzyme?
An enzyme is made up of protein, and is known as a biological catalyst as it speeds up metabolic reactions without being altered or used up itself
68
How can we explain how enzymes work using the lock-and-key model?
Each enzyme has a specifically shaped are called the active site. The shape of this area is complimentary to the substrate molecules with which they form an enzyme-substrate complex. Once the product has been formed the molecules leave the active sites which can then be reused. This is known as the lock-and-key theory as the substrate fits into the active site the way a key fits into a lock.
69
What experiment could be done to investigate the effect of temperature on enzyme action. Do the CORMS for this.
C: changing the temperature (from 30°C-80°C)
O: trypsin is the enzyme used and will be extracted from the same source
R: each temperature will be repeated 3x and an average will be calculated
M: the transparency of the solution, measured by timing how long x takes to become visible using stopwatch
S: same volume of milk, same pH
70
What experiment could be done to investigate the effect of pH on enzyme action. Do the CORMS for this.
C: pH of the buffer (1-14)
O: trypsin, extracted from same source
R: 3 repeats of each pH will be made + average calculated
M: transparency if solution, measured by timing how long x takes to become visible using stopwatch
S: same volume of milk, same temperature
71
What experiment could be done to investigate the effect of substrate concentration on enzyme action. Do the CORMS for this.
C: concentration of hydrogen peroxide (0.5-3 percent)
O: catalase= enzyme used, extracted from same source
R: 3 repeats of each concentration
M: time taken for disc to reach surface in s, using stopwatch
S: same temperature, same pH
72
FOOD TESTS- GO TO QUIZLET
REFISE THER / IPORT FLASHCARDS
73
Where does aerobic respiration occur
Mitochondria
74
Where does anaerobic respiration occur?
Cytoplasm
75
Label an animal cell
CHECK ONLINE
76
Label a plant cell
CHECK GOOGLE
77
What are the organelles in an animal cell?
Nucleus, mitochondria, cytoplasm, cell membrane, ribosomes
78
What organelles are present in plant cells?
Nucleus, cytoplasm, cell membrane, cell wall, mitochondria, chloroplasts, ribosomes and vacuole
79
What is the function of the nucleus?
Controls activities of the cell
80
What is the function of the cytoplasm?
Location of many chemical reactions
81
What is the function of the cell membrane?
Allows things to enter and exit the cell
82
What is the function of the cell wall?
Supports and strengthens the cell
83
What is the function of the mitochondria?
Location where aerobic respiration occurs and most of the cell's ATP is produced
84
What is the function of the chloroplasts?
Location where photosynthesis occurs and glucose is produced
85
What is the function of the ribosomes?
Produce proteins
86
What is the function of the vacuole?
Water storage and maintenance of turgor (rigidity) within the cell
87
What are the levels of organisation in organisms?
Organelles, cells, tissues, organs, organ systems
88
What is an organelle?
Specialised structure found within a cell
89
What is a tissue?
A group of cells with similar structures, working together to perform a shared function
90
What is the apparatus required for the stained water drop method (used to calculate the rate of CO2 produced)?
- conical flask
- bung (prevents CO2 from escaping and oxygen from entering)
- yeast in glucose solution
- stained water drop
- ruler
91
What is the apparatus required for the oil method and limewater method (used to calculate the rate of CO2 produced)?
- yeast in glucose solution
- oil layer (prevents oxygen from entering the solution)
- bung (prevents CO2 from escaping)
- capillary tube
- limewater (indicator for CO2)
- 2 test tubes
92
What is the apparatus required for the counting bubbles method (used to calculate the rate of CO2 produced)?
Conical flask
Bung (prevents CO2 from escaping and oxygen from entering)
Yeast in glucose solution
Capillary tube
Beaker of water
93
Name the plant organs, and label on a diagram
Roots, stem, leaf, flower
94
What is the function of the roots?
Roots absorb water (by osmosis) and mineral ions (by active transport) from the soil.
95
What is the function of the stem?
Provide support + transport water and nutrients up the plant
96
What is the function of the leaf?
This is where photosynthesis occurs
97
What is the function of the flower?
To enable plant gametes to come together in fertilisation. In other words, it is necessary for reproduction in plants
98
Label a diagram with the structure of the leaf.
-
99
What is the function of the cuticle?
A protective layer that allows light to enter the leaf. It is waterproof in order to prevent water loss by evaporation.
100
What is the function of the upper epidermis?
Transparent layer of cells enabling all the light to enter the palisade layer
101
What is the function of the palisade layer?
Where photosynthesis occurs
102
What is the function of the spongy layer?
Important for gas exchange in plants as it enables CO2 to diffuse into the spongy mesophyll cells, and for the oxygen to diffuse out of them.
103
What is the function of the vein?
To support the leaf and transport water and sugars
104
What is the function of the guard cells?
These open and close the stomata, which are important for gas exchange in plants.
105
What is the function of the stomata?
Control gas exchange by opening and closing and are involved in loss of water from leaves
106
What is the word equation for photosynthesis?
Carbon dioxide + water -> glucose + oxygen
N.B. Sunlight should be on the arrow
107
What is the chemical equation for photosynthesis?
6CO2 + 6H2O -> C6H12O6 + 6O2
N.B. Sunlight should be on the arrow
108
What is a limiting factor?
Anything that limits a process
109
What are the limiting factors for photosynthesis?
Light intensity, carbon dioxide concentration, temperature
110
What do plants require for growth?
Mineral ions- these are nitrate, phosphate, potassium, magnesium
111
Why do plants require nitrate ions?
Makes proteins and DNA
112
Why do plants require phosphate ions?
Makes DNA and cell membranes
113
Why do plants require potassium ions?
Makes enzymes
114
Why do plants require magnesium ions?
Makes up part of the chlorophyll molecule
115
What is the deficiency impact of nitrate ions in plants?
- Growth severely restricted
- few stems
- yellow foliage
116
What is the deficiency impact of phosphate in plants?
Poor root growth + discoloured leaves
117
What is the deficiency impact of potassium ions in plants?
Poor growth of flowers and fruits + brown spots on leaves
118
What is the deficiency impact of magnesium ions in plants?
- No photosynthesis will occur
- yellow leaves
119
How is the leaf adapted for photosynthesis?
- large surface area: to absorb a lot of light at once
- thin walls: lowers the diffusion distance for CO2
- waterproof waxy cuticle: water (a reactant in photosynthesis) cannot escape
- Many chloroplasts: contain chlorophyll, which absorbs sunlights for photosynthesis
120
LABEL THE CROSS SECTION OF A LEAF
121
How is carbon dioxide concentration a limiting factor in photosynthesis?
Initially, increasing the concentration of CO2 will provide more reactants for photosynthesis to occur, causing the rate of photosynthesis to increase. However, after a point, the rate of photosynthesis plateaus as light intensity or temperature become the limiting factor.
122
How is temperature a limiting factor in photosynthesis?
Enzymes are involved in photosynthesis, so photosynthesis is affected by temperature. This is because: enzymes have an optimum temperature, when temperature is not a limiting factor. Below this, an increase in temperature will provide more thermal and, therefore, kinetic energy so there will be more successful enzyme and substrate collisions. As a result, the rate of photosynthesis will increase.After the optimum, the enzyme denatures, meaning the bonds holding the enzyme’s structure are broken down, meaning the active site changes shape and is no longer complimentary to the substrate, so no enzyme-substrate complexes can be formed, causing the rate of photosynthesis to decrease. Temperature once again becomes a limiting factor.
123
How is light intensity a limiting factor in photosynthesis?
At low light intensity, the rate of photosynthesis is low as light is required for photosynthesis. Initially, as this is increased, the rate of reaction increases too as more photosynthesis can occur as there is more light. After a point, increasing light intensity is no longer the limiting factor and the rate of photosynthesis plateaus, so increasing light intensity has no effect.
124
What is a variegated leaf?
Leaves with different colours, such as green and white
125
What is the method for the leaf starch experiment?
Equipment: leaves, beakers, ethanol, white tile, tweezers, hot water, boiling tube, iodine
Method:
1) Place the leaves in a beaker of boiling water for 1min
2) Half fill a boiling tube with ethanol and place the 2 leaves in it using the forceps.
3) Place this boiling tube in the beaker of hot water and leave it for a further 5mins.
4) Take the leaves out of the boiling tube and wash them with water
5) Place the leaves on a white tile and add 5 drops of iodine solution to each leaf- if a blue/black colour appears then starch is present.
126
Conclusion for the leaf starch experiment
Only the green parts of the leaf went blue-black when iodine was added.
The green parts of the leaf show the presence of chlorophyll.
Iodine shows the presence of starch.
Plants store glucose as starch.
Glucose is produced in a process called photosynthesis.
Therefore, for photosynthesis to occur, chlorophyll must be present
127
Write out the method to show the evolution of oxygen in a water plant
Apparatus: beaker, pondweed, funnel, boiling tube, splint, bunsen burner, heat proof mat
Method:
1) Take 2 shoots of a type of pondweed
2) Submerge them in a beaker of water underneath an upturned funnel
3) Fill a boiling tube with water and place it over the end of the funnel
4) As oxygen is produced, the bubbles of gas will collect in the boiling tube and displace the water.
5) Place a glowing splint in the test tube of O2. It will relight in the presence of oxygen.
128
What would the method be to investigate the requirements of CO2 for photosynthesis?
Use the leaf starch experiment. Before doing it, place the leaves in a dark cupboard for 24hrs + place the leaves in a conical flask containing potassium hydroxide (absorbs CO2 from surrounding air).
129
How would you investigate whether chlorophyll is needed for photosynthesis?
Do leaf starch experiment, but use a variegated leaf.
130
How do plants use the glucose produced in photosynthesis?
It is used for respiration, in order for the plant to have energy to perform its life processes
131
What is the process of photosynthesis?
It is an endothermic reaction in which light energy is transferred to chemical energy, which can be used for respiration. Respiration is needed for the plant to do its life processes
132
What is an autotroph?
An organism that synthesises its own glucose. Plants are photo-autotrophs as they synthesise their own glucose using light energy.
133
What is transpiration?
The evaporation of water from the surface of a plant
134
How is water absorbed into the plant?
Water is absorbed by osmosis from the soil to the root hair cells. Water moves from the root to the leaf by the process of the transpiration stream. Transpiration involves the water moving up the xylem. Water moves because of the transpirational pull caused by evaporation of water on the underside of the leaf
135
What is the role of the phloem in the plant?
The phloem transports sucrose and amino acids between the leaves and other parts of the plant
136
What is the role of the xylem?
The xylem transports water and mineral ions from the roots to other parts of the plant
137
What are the vascular bundles in a plant?
The bundles in which the xylem and phloem tissues can be found
138
Label the xylem and the phloem on a diagram of a stem
-
139
Label the xylem and the phloem on a diagram of a root
-
140
What are the factors affecting transpiration?
Humidity + wind speed + temperature + light intensity
141
How would you investigate how humidity affects the rate of transpiration in a leafy shoot?
C- humidity
O- Leafy shoots (same age, species, size)
R- 3 repeats of each humidity level + average calculated
M- distance moved by the bubble along the tube using a potometer after 5 mins
S- temperature + wind speed
142
How would you investigate how wind speed affects the rate of transpiration in a leafy shoot?
C- wind speed
O- leafy shoots (same species, age and size)
R- 3 repeats of each wind speed + average calculated
M- distance moved by the bubble along the tube using a potometer after 5 mins
S- humidity + temperature
143
How would you investigate how temperature affects the rate of transpiration in a leafy shoot?
C- temperature
O- leafy shoots (same size, age and species)
R- 3 repeats of each temperature + average calculated
M- distance moved by the bubble along the tube using a potometer after 5 mins
S- humidity + wind speed
144
How would you investigate how light intensity affects the rate of transpiration in a leafy shoot?
C- light intensity
O- leafy shoots (same age, size and species)
R- 3 repeats of each light intensity will be made + average calculated
M- distance moved by the bubble along the tube using a potometer over 5 mins
S- temperature + humidity
145
How are mineral ions absorbed into the plant?
Mineral ions move by active transport into the root hair cells from the soil, dissolved in the water.
The dissolved mineral ions then move in the water from the roots to the leaf by the process of transpiration.
Transpiration involves the water moving up the xylem.
Water moves because of the transpirational pull caused by evaporation of water from the stomata on the underside of the leaf
146
What are the adaptations of the phloem?
- sieve tubes -> specialised for transport and have no nuclei (more space to transport sucrose + amino acids).
Companion cells - transport of substances in the phloem requires energy. One or more companion cells attached to each sieve tube provide this energy.
Sieve plates - contain holes so that sap can flow through
147
What are the adaptations of the xylem?
- no end walls between cells- continuous hollow tube
Dead cells - no cytoplasm- hollow centre, minimising the resistance to water flow
Walls strengthened by lignin - means the xylem is waterproof and the vessel is strong and upright
148
Explain how humidity is a factor affecting transpiration
As humidity decreases, the rate of transpiration increases
A decrease in humidity reduces the concentration of water molecules outside the leaf, so the rate of diffusion of water from inside the leaf to outside increases
149
Explain how wind speed is a factor affecting transpiration.
Increasing wind speed increases the rate of transpiration
An increase in air movement removes water vapour from outside the leaf, so the rate of diffusion of water from inside the leaf to outside increases
150
Explain how temperature is a factor affecting transpiration
Increased temperature causes an increased rate of transpiration
An increase in temperature increases evaporation, so the rate of diffusion of water from inside the leaf to outside increases
151
Explain how light intensity is a factor affecting transpiration
As light intensity increases, so does the rate of transpiration.
An increase in light intensity generally increases the number of open stomata, so the rate of diffusion of water from inside the leaf to outside increases
152
Sit up straight
153
Drink water
154
Revise y8 spedialised cells
