Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology > Required Practicals > Flashcards

Required Practicals Flashcards

1
Q

What is the aim of RP 1? (Enzyme Activity)

A

Investigation into the effect of a named variable on the rate of an enzyme-controlled reaction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How can a control be set up in RP 1? (enzyme activity)

A

Replace the enzyme solution with distilled water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How can the results of RP 1 be used to find the initial rate of reaction? (enzyme activity)

A

Plot the results on a graph of ‘rate of reaction’ against ‘time’
Draw a tangent at time = 0 to find the initial rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Outline the practical procedure used to measure the effect of temperature on enzyme activity, using trypsin and milk. (RP 1)

A

Immerse equal volumes of trypsin and milk stored in different test tubes, in a water bath for 5 mins for the temp to equilibrate

Mix together and start timing, record the time taken for milk to become colourless- hydrolyse, use the control

Test at least 5 temps with 3 repeats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is the rate of reaction calculated?

A

RoR = 1/ time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the effect of temperature on enzyme activity? RP1

A

As temperature increases, kinetic energy increases so more ES complexes form. The rate of reaction increases up until optimum

Beyond that, bonds in the enzyme tertiary structure breaks, which changes the shape of the active site. The substrate and enzyme are no longer complementary so RoR decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the title of RP 2? (mitosis)

A

Calculating the mitotic index using plant cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the mitotic index? (RP 2)

A

The ratio of cells undergoing mitosis to the total number of cells in the sample

mitotic index = number of cells with visible chromosomes/ number of cells in the sample

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Outline the procedure to prepare a root tip slide ( RP 2)

A
  1. Warm 1M HCL to 60 degrees water bath
  2. cut a root tip using a scalpel and add to the HCL, leave for 5 mins
  3. Remove from HCL and wash with distilled water
  4. cut the tip of the root and place on a slide
  5. add a few drops of the stain to make chromosomes visible.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the title of RP 3? (water potential)

A

Production of a dilution series of a solute to produce a calibration curve with which to identify the water potential of plant tissue.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the purpose of calibration curves RP 3? (water potential)

A

They are used to determine the concentration of an unknown sample by comparing it to a set of standard values with known concentrations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is a calibration curve used in RP 3? (water potential)

A

To find the concentration of plant tissue
Plot a calibration curve of percentage change in mass against concentration
Find the X- intercept where the plant tissue is isotonic to the sucrose solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What occurs to the potato in RP 3 when in hypotonic and hypertonic solutions? (water potential)

A

Hypotonic- water moves into the plant tissue by osmosis and the potato increases in mass

Hypertonic- water moves out of the plant tissue by osmosis, plant tissue decreases in mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why are the potato discs left in solution for 20 mins in RP 3?

A

To allow time for osmosis until the plant tissue reaches equilibrium with its surrounding solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Outline the procedure of RP 3? (water potential)

A
  1. Make a simple dilution of 1M sucrose to produce 5 concentrations. Add 5cm3 to 5 different test tubes
  2. cut a potato into equal sized chips and weigh
  3. Place a chip in each test tube and leave for 20 mins
  4. take out, dab the excess water and weigh them again
  5. change percentage change in mass
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why is the percentage change used in RP 3 rather than actual change in mass? (water potential)

A

Potato chips may not all have the same starting mass

Allows for comparison

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Explain the results of RP 3. (water potential)

A

The potato chips with concentration lower than the sucrose solution loses mass as there is a net movement of water out of the cells

The potato chips with concentrations higher than the sucrose solution gains mass as there is a net movement of water into the cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why are the potato chips dabbed in RP 3?

A

To remove access water to not change any results

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the aim/ title of RP4? (cell membranes)

A

Investigation into the effect of a named variable on the permeability of cell-surface membranes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How is beetroot used in RP4? (cell permeability)

A

To measure the permeability of cell membranes
The higher the permeability, the more red pigment leaks out into the surrounding solution- then a colourimeter can be used to determine the absorbance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Outline the procedure of RP 4? (membrane permeability)

A
  1. cut beetroot into 6 identical cubes with a scalpel
  2. Place each cube in a different test tube with equal volumes of distilled water
  3. Place each test tube into water baths ranging from 20-80 degrees. leave for 20 mins
  4. Filter each solution out into a cuvette and measure absorbance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the result of RP 4? (cell permeability)

A

Increasing temperature increases membrane permeability causing a higher absorbance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the title of RP5? (dissection)

A

Dissection of an animal or plant gas exchange system or mass transport system or of organs within such a system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Name some precautions to be wary of in RP5? (dissection)

A
  1. wear disposable apron or lab coat
  2. Cover cuts
    3, cut away from yourself and use forceps to hold tissue when cutting
  3. wear disposable gloves
25
Give 2 precautions for clearing in RP 5. (dissection)
1. Disinfect hands 2. Disinfect instruments 3. carry sharp instruments by pointing down 4. Put organs/ paper towels/ gloves in a seperate bag
26
Discuss ethical issues of dissection
1. morally wrong to kill animals for dissection purposes only 2. Animal raised for disection may be in bad conditions
27
What is the title of RP6? (aseptic technique)
Use of aseptic techniques to investigate the effect of antimicrobial substances on microbial growth
28
State aseptic techniques. (RP6)
- wipe down surfaces with antibacterial cleaner before and after experiment - use a bunsen burner in the work space so convection currents draw microbes away from the culture - Flame the wire hoop before using to transfer bacteria - Flame the neck of the bottles before using to prevent bacteria entering the vessel - keep all vessels with bacteria open for minimum amount of time - close windows and doors to limit air currents
29
Why is bacteria incubated at 25degrees? (RP6)
To prevent the growth of pathogens which occurs at higher temperatures
30
How do you measure effectiveness in RP6? (aseptic technique)
Measure the diameter and calculate the area of the zone of inhibiton
31
What is the name of RP7? (chromatography)
Use of chromatography to investigate the pigments isolated from leaves of different plants
32
What are the factors affecting rate of migration in RP7? (chromatography)
Solubility Mass Affinity to paper
33
What is the formula for RF value? (RP7)
Distance moved by pigment/ distance moved by solvent
34
What is the purpose of finding the RF value of the pigment? (RP7)
Compared to a standard value to identify the pigment
35
Talk about the procedure of RP7? (chromatography)
1. Draw a horizontal pencil line 1cm above the bottom of the filter paper 2. add some acetone to a leaf sample and grind it up to release pigments. 3. use a capillary tube to transfer the pigment onto the pencil line 4. Suspend the paper in the solvent so the level of liquid doesnt lie above the pencil line and leave the paper until the solvent has run up 5. Remove the paper and draw a pencil line marking where moved up to 6. calculate RF value
36
What is the title of RP8? (dehydrogenase)
Investigation into the effect of a named factor on the rate of dehydrogenase activity in extracts of chloroplasts.
37
What is the function of dehydrogenase in RP8? (chloroplasts)
It catalyses the acceptance of electrons by NADP in the light dependent reactions
38
What is the purpose of DCPIP in RP8? (dehydrogenase)
Redox indicator dye and acts as an alternate electron acceptor instead of NADP. Blue to colorless when reduced
39
Why is the plant extract chilled in an ice water bath in RP8? (dehydrogenase)
Lower the activity of enzymes to prevent them from breaking down the chloroplasts
40
How is a control set up in RP8? (dehydrogenase)
Fill cuvette with chloroplast extract and distilled water
41
Outline the procedure of RP8 using light intensity (dehydrogenase)
1. set the colorimeter to the red filter. zero using cuvette control 2. place test tube in the rack 30cm from light source and add DCPIP. Immediately take the sample and add to cuvette and measure absorbance 3. take a sample and measure it's absorbance every 2 mins for 10 mins 4. repeate at many distances
42
What is the title of RP9? (respiration)
Investigation into the effect of a named variable on the rate of respiration of cultures of single-celled organisms.
43
What is the function of methylene blue in RP9? (respiration)
Redox die acting as an electron acceptor of the electrons transferred during ATP synthesis- blue to colorless
44
Outline a procedure of RP9 using temperature and yeast (respiration)
1. set up a water bath at 35 degrees. 2. add equal volumes of the yeast and glucose solution to three test tubes and place them in a water bath for 10 mins 3. add 2cm3 of methylene blue and start timer- shake for 10 secs and place in water bath again. time how long to turn colourless for each tube 4. repeat at different temperatures
45
How do we calculate rate of respiration for RP9? (respiration)
rate = 1/ time taken for methylene blue to decolourise
46
Why does the yeast solution need to be buffered in RP9? (respiration)
maintain a constant pH
47
What are the results of RP9? (respiration)
as temperature increases, so does rate of respiration to an optimum until decreases
48
What is the title of RP10? (animal responses)
Investigation into the effect of an environmental variable on the movement of an animal using either a choice chamber or a maze.
49
What factors must be controlled when repeating RP10? (animal responses)
No. Animals Environmental conditions time allowed for animals to choose
50
How is a choice chamber used in RP10? (animal responses)
Setting up chambers in different quadrants with different environmental conditions- move to one they find favourable
51
What stats test is used in RP10 and why? (animal responses)
Chi Squared Compares the expected and observed values and tests if there is a significant difference
52
What is the title of RP 11? (urine)
Production of a dilution series of a glucose solution and use of colorimetric techniques to produce a calibration curve with which to identify the concentration of glucose in an unknown ‘urine’ sample.
53
What is a serial dilution in RP11? (urine)
A dilution where successive concentrations increase in a logarithmic fashion
54
Outline the procedure of RP11? (urine)
1. Make a serial dilution of glucose from 0 to 10 mmol dm-3 2. Place 2cm3 of each unknown sample in separate boiling tubes 3. Add 2cm3 of benedict solution in each boiling tube. 4. Place boiling tubes in a water bath at 90 degrees for 4 mins 5. zero the colorimeter using cuvette with distilled water to the red filter 6. place the known sample into the cuvette and measure the absorbance of each 7. plot a calibration curve 8. Measure the absorbance of unknown samples to find glucose concentrations
55
How do you increase the accuracy of the estimate of the unknown glucose solutions? (urine)
Increase the number of concentrations for the calibration curve within the range of concentrations that the unknown solution belongs
56
What is the title of RP 12? (distribution)
Investigation into the effect of a named environmental factor on the distribution of a given species
57
How is percentage cover calculated in RP 12? (distribution)
Use a quadrat with squares. Count how many squares the species is present (if over half)- calculate the% of squares
58
Outline the procedure of RP12? (distrubution)
1. Choose an area to take samples from- use a random number generator to generate 10 sets of random coordinates 2. use two tape measures to create a set of axes coordinates can be read 3. Place the quadrat at each coordinate- bottom left corner 4. Record the % cover for chosen species 5. At each coordinate, a measure of the independent variable should be taken

Biology (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions