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Experiments Flashcards

1
Q

What is starch?

A

An energy storage polysaccharide found in plants

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2
Q

What happens to iodine when starch is present?

A

Turns from brown to blue/black

Control remains brown.

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3
Q

What is a reducing sugar?

A

A monosaccharide and a source of energy

Glucose is an example of a reducing sugar.

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4
Q

What is the chemical formula for glucose?

A

C₆H₁₂O₆

Glucose is a type of carbohydrate.

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5
Q

What is the general formula for carbohydrates?

A

Cₓ(H₂O)ᵧ

Indicates the composition of carbohydrates.

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6
Q

What is the method for testing reducing sugars?

A

Add food sample to test tube, add Benedict’s solution, heat in water bath at 60°C for 15 minutes

Control is distilled water.

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7
Q

What color change indicates a positive result for reducing sugars?

A

Blue to brick red/orange

Control remains blue.

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8
Q

What are proteins made of?

A

Subunits called amino acids

There are 20 basic amino acids that form all proteins.

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9
Q

What color change indicates a positive result for proteins?

A

Biuret added in equal volume to food solution eg milk
Blue to purple

Control remains blue.

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10
Q

What are lipids composed of?

A

Triglycerides, which consist of glycerol and three fatty acids

Lipids provide protection, insulation, and energy.

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11
Q

What is a phospholipid?

A

A lipid with glycerol, two fatty acids, and phosphorus

Found in the cell membrane.

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12
Q

What differentiates oils from fats?

A

Oils are liquid at room temperature; fats are solid

Both are types of lipids.

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13
Q

What is the method for testing lipids?

A

Rub food sample on brown paper, hold up to light and check for aTRANSLUCENT spot

Control is distilled water.

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14
Q

What indicates a positive result for lipids?

A

A permanent translucent spot on brown paper

Control’s translucent stain disappears.

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15
Q

What are the three abiotic factors that affect the population size of an organism in an ecosystem?

A

Soil temperature, Soil pH, Wind speed

These factors include a combination of edaphic and climatic influences.

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16
Q

What does unsuitable abiotic factors lead to in an ecosystem?

A

Population decline

Unsuitable conditions for living organisms can result in reduced population sizes.

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17
Q

How is soil pH measured using a pH meter?

A

Insert the probe into the solution and wait 15 minutes

This method provides a direct reading of the pH level.

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18
Q

What is the procedure for measuring soil temperature?

A

Insert thermometer into soil and leave for 15 minutes, record
Measure three times
## Footnote

This allows for an accurate reading of the soil’s temperature.

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19
Q

How is wind speed measured with an anemometer?

A

Count the number of full rotations in 1 minute

This provides a quantitative measure of wind speed.

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20
Q

What is a qualitative survey in ecology?

A

Records if a species is present or absent

This type of survey focuses on species identification rather than abundance.

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21
Q

What is a quantitative survey in ecology?

A

Gives the number of species in an area

This type of survey provides numerical data on species counts.

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22
Q

What instrument is used to collect small moving insects like woodlice?

A

Pooter

The Pooter allows for the collection of small insects by inhaling them through a straw.

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23
Q

What is the purpose of a pitfall trap?

A

Helps capture organisms that live in the soil

This trap is effective for collecting soil-dwelling organisms.

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24
Q

How do you use a beating tray?

A

Place white tray under tree, hit tree with stick, collect organisms that fall

This method is used to collect animals living in trees.

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25
What is the function of a sweep net?
Collects airborne animals such as butterflies ## Footnote The sweep net is used to capture insects from vegetation.
26
What type of animals does a small mammal trap collect?
Mice, rabbits, foxes ## Footnote This type of trap is designed for larger small mammals.
27
What does a Tullgren funnel do?
Collects animals living in soil like centipedes, millipedes, beetles Place soil sample on gauze, turn on the light. The heat from the light forces insects to burrow into the soil and drop into the alcohol beneath 
28
Fill in the blank: A _______ trap is used to collect animals such as slugs and woodlice.
Cryptozoic ## Footnote This trap involves placing a flat stone on the soil surface.
29
What is the first step in a quantitative survey of a named plant using the percentage frequency method?
Throw pencil over the shoulder, this reduces bias, makes it random and for safety
30
How should the quadrat be placed during the survey of a plant?
Place quadrat where pencil lands after throwing it over your shoulder.
31
What should be done if a particular plant, such as dandelion, appears in the quadrat?
Give a 'tick' to the table.
32
What is not counted when surveying the presence of a plant in a quadrat?
The number of individual plants.
33
How many times should the experiment be repeated for reliable data?
10 times.
34
What is the formula for calculating the percentage frequency of a plant?
(number of throws in which plant appeared / total number of throws) X 100.
35
What method is used for a quantitative survey of a named animal?
Capture-Recapture Method. Eg snail
36
What equipment is suggested for collecting animals in the Capture-Recapture Method?
Pitfall trap.
37
On Day 1 of the Capture-Recapture Method, what should be recorded after capturing animals?
The number captured.
38
What is an example of a suitable way to mark captured animals?
Using a non-toxic marker.
39
What should be avoided when marking the animals?
Causing harm or attracting predators.
40
What should be done with marked animals after Day 1?
Release all marked animals back into the habitat.
41
On Day 2, what should be recorded in addition to the number of animals captured?
The number of marked animals captured.
42
What is the calculation formula for estimating the population size in the Capture-Recapture Method?
(number captured Day 1) X (number captured Day 2) / (number recaptured that were marked).
43
What is the first step in using a light microscope?
I switched on the light source
44
What lens should be used first when setting up a light microscope?
Low power lens
45
What is the purpose of the stage clips on a microscope?
To hold the slide in place
46
Which adjustment wheel is used to bring the low power lens closest to the slide?
Coarse adjustment wheel
47
What adjustment is made for correct illumination?
Adjusted the iris diaphragm
48
What is the purpose of the fine adjustment wheel?
To sharpen the focus
49
How do you calculate total magnification?
Magnification of objective lens × Magnification of eyepiece
50
What materials are needed to prepare an unstained animal cell?
Microscope, microscope slides, cover slips
51
What is the first step in preparing an unstained animal cell?
Swab the inside of your cheek and transfer the sample to the slide
52
What is applied to the sample to prevent it from drying out?
A drop of water
53
At what angle should the coverslip be placed when applying it?
45° angle
54
What is the purpose of supporting the coverslip with a mounted needle?
To prevent air bubbles forming
55
What stain is used for preparing a stained animal cell?
Methylene blue stain
56
What is the first step in preparing a stained animal cell?
Swab the inside of your cheek and transfer the sample to the slide
57
What is applied to the sample in a stained plant cell preparation?
Iodine stain
58
What two materials are needed to prepare an unstained plant cell?
Microscope, microscope slides
59
What is the first step in preparing an unstained plant cell?
Cut the onion and locate the epidermis
60
What should be done with the epidermis before placing it on the slide?
Cut it into small pieces and put them into water
61
What is used to apply the iodine stain in a stained plant cell preparation?
Dropper
62
What should be done after examining the slide of a cell preparation?
Draw labelled diagram of what you observe
63
What is the optimum temperature for plant enzymes?
30°C ## Footnote At this temperature, enzymes exhibit maximum activity.
64
What happens to enzyme activity at temperatures other than the optimum?
Activity decreases due to denaturation. ## Footnote Denaturation can alter the enzyme's shape, affecting its function.
65
Define denatured in the context of enzymes.
The active site has been destroyed, and the enzyme can no longer act on the substrate.
66
What substrate is used in the investigation of enzyme activity?
Hydrogen Peroxide.
67
What enzyme is contained in celery?
Catalase.
68
What is the role of the pH buffer in the experiments?
Keeps pH constant.
69
What temperatures were tested in the enzyme activity experiment?
0°C, 20°C, 30°C, 60°C.
70
What was recorded as a measure of enzyme activity?
Volume of foam produced after 2 minutes.
71
What pH levels were tested in the second investigation?
4, 7, 10, 13.
72
What temperature was maintained during the pH investigation?
30°C.
73
What was the purpose of the third investigation?
To investigate the effect of heat denaturation on the rate of enzyme activity.
74
What temperatures were tested for heat denaturation?
30°C, 100°C.
75
Explain why no foam was produced at 100°C.
The enzyme was denatured and lost its functional shape.
76
What does a large volume of foam indicate in the context of enzyme activity?
High enzyme activity.
77
Fill in the blank: The active site of an enzyme is destroyed during _______.
denaturation.
78
What are immobilised enzymes?
Enzymes that are attached to an inert material
79
What materials are needed for enzyme immobilisation?
* Sodium alginate * Water * Yeast * Beaker * Glass stirring rod * Syringe * Calcium chloride solution * Sieve * Distilled water
80
What is the first step in the preparation of enzyme immobilisation?
Sterilise all glassware to ensure no contamination from micro organisms
81
What is formed when the mixture of sodium alginate, water, and yeast is released into calcium chloride solution?
Beads containing yeast cells
82
What is the purpose of filtering the beads after they harden?
To remove any excess free enzyme
83
What is tested for in the application of the immobilised enzyme?
Glucose
84
What two solutions are poured into the separating funnels during the application of the immobilised enzyme?
* Free yeast and water * Sucrose solution
85
What is recorded during the test for glucose?
The results at intervals until glucose appears in both funnels
86
What three factors affect the rate of photosynthesis?
* Light intensity * Temperature * Carbon dioxide concentration
87
What aquatic plant is used in the photosynthesis experiment?
Elodea
88
What is the purpose of counting the number of oxygen bubbles produced?
To measure the rate of photosynthesis
89
What happens to the rate of photosynthesis as light intensity increases?
It increases up to a certain point, known as the saturation point
90
What is anaerobic respiration?
The controlled release of energy from food without the use of oxygen
91
What is produced during anaerobic respiration in the presence of yeast?
Ethanol (alcohol) and carbon dioxide
92
What is fermentation?
The production of ethanol through anaerobic respiration
93
What is the equation for the production of alcohol during fermentation?
C₆H₁₂O₆ + Yeast → C₂H₅OH + CO₂
94
What is the optimal temperature for yeast enzymes during fermentation?
30°C
95
What is the purpose of adding a layer of oil on top of the glucose solution?
To keep oxygen out
96
What indicates CO₂ production during the fermentation experiment?
Limewater turning milky
97
What is the iodoform test used for?
To confirm the presence of ethanol
98
What color change occurs in the iodoform test if ethanol is present?
Colorless to yellow
99
What is the control setup used for in the fermentation experiment?
To validate the experiment without yeast
100
What is osmosis?
The movement of water molecules from an area of high water concentration to an area of low water concentration across a semi-permeable membrane. ## Footnote This process is essential for maintaining cell turgidity and overall cell function.
101
What equipment is needed to demonstrate osmosis?
* Visking tubing (2 strips) * Sugar solution (80%) * Distilled water (control) * Beakers * Mass balance * Water ## Footnote Each item plays a crucial role in conducting the experiment effectively.
102
What is the first step in the method to demonstrate osmosis?
Soak two strips of visking tubing in water to soften them. ## Footnote This softening is essential for the tubing to function effectively as a semi-permeable membrane.
103
What is the purpose of tying a knot on one end of the visking tubing?
To prevent the contents from spilling out during the experiment. ## Footnote This ensures that the sugar solution or distilled water remains contained within the tubing.
104
What contents are filled in each piece of visking tubing?
* One with a sugar solution * One with distilled water (control) ## Footnote The sugar solution is expected to demonstrate osmosis, while the distilled water serves as a control.
105
How long should the tubing be left in the beakers of water?
15 minutes. ## Footnote This duration allows sufficient time for osmosis to occur if the conditions are right.
106
What was the starting mass of the tubing containing the sugar solution?
10.8g. ## Footnote This initial measurement is crucial for calculating the change in mass due to osmosis.
107
What was the ending mass of the tubing containing the sugar solution?
15.2g. ## Footnote This increase in mass indicates that osmosis occurred, as water moved into the tubing.
108
What was the starting turgidity of the tubing containing distilled water?
Not fully turgid. ## Footnote This indicates that the control did not experience any significant osmotic changes.
109
What conclusion can be drawn from the control tubing with distilled water?
No osmosis occurred, as the ending mass remained 10.8g. ## Footnote This demonstrates the necessity of a concentration gradient for osmosis to take place.
110
What is the first step in isolating DNA from plant tissue?
Chop the kiwi into small pieces. ## Footnote This step increases the surface area for the extraction process.
111
What role does detergent play in DNA isolation?
It dissolves the cell membranes. ## Footnote This action releases the DNA into the solution.
112
What temperature should the beaker be placed at during DNA isolation, and for how long?
60°C for exactly 15 minutes. ## Footnote This step denatures enzymes that could degrade DNA.
113
Why is the mixture cooled after heating during DNA isolation?
To stop the breakdown of DNA. ## Footnote Cooling preserves the integrity of the DNA extracted.
114
What happens when ice-cold alcohol is added to the filtrate?
DNA separates from the filtrate because it is insoluble in cold ethanol. ## Footnote This allows for the visualization and extraction of DNA.
115
What should be observed at the interface of the alcohol and the filtrate?
Changes indicating the presence of DNA. ## Footnote DNA will appear as a precipitate at this boundary.
116
What is the final step in the DNA isolation process?
Gently draw the DNA out from the alcohol layer using a glass rod. ## Footnote This step allows for the collection of the isolated DNA.
117
How is the percentage cover survey different from the percentage frequency survey
The percentage cover: use a pencil push down at the grid points record if the plant is touched by the pencil 

LC biology (46 decks)

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