Practicals Flashcards Preview

Ppqs > Practicals > Flashcards

Flashcards in Practicals Deck (38):
1

What is the null hypothesis

There is no significant difference between two variables

2

T test

Comparing two means
Significant difference between two means

3

Chi squared

Looks at difference between observed and expected
Compare to critical value
N-1 (N=number of data you are looking at)
>=significant

4

Explain why rate of bubbling can measure photosynthesis

More o2 oxygen bubbles released per second
Higher rate of photosynthesis and greater rate of photolysis

5

Paper chromatography

Pen ink would run with solvent

6

What is the syringe used for
Why is it more accurate than measuring bubbles of gas
Don’t put leaf in blender

To fill with gas to measure air given off and measure phs
There is a scale and quantity of gas can be seen/quantitative

There are hardly any chloroplasts

7

Control experiment

If there was a colour change without solution then colour change was not because of phs

8

Why not shake the tubes

Oxygen gets in
Acts as a terminal electron acceptor
Turns blue
Methyl blue gains electrons from etc from aerobic respiration from glucose and yeast from produced reduced bad and fad from kerbs cycle

9

Reason for selecting specific data

Remove selective bias
Random sample
Remove bias

10

Transects

Measure with quadrat at intervals

11

Told to wipe inside of maze between experiments. Explain why?

Maggots follow each other
Maggot particles for heat
Chemotaxis


Equal light at each turn
Low light because heat might be a factor
Dim and evenly distributed

12

Keep temperature constant

Put temperaturethermometer in
Add hot/cold water

Use water bath
Air temperature fluctuates more than liquid temperature

13

Why use a big sample

Large sample size to identify anomalies
Time constraints
Calculate a reliable mean

14

Use maggots more than once

No, may have gone a different way . Show turn alternation

15

Control

Set a base to get expected values
To allow comparison

16

Reversing maggots direction affects movement of animal

Could artificially increase results
Not reliable
Can
Go over same part

17

Observations

Dry and smooth/not spherical

18

Why repeat

To standardise results
Can compare
Get standard deviation/means

19

Variables for temperature

Time
Which hand used
Position of arm on surface

20

Why people matched for factor

Older people have eye sight differences/stimuli so longer reaction times as muscles are weaker

Some races have different alleles so different reaction times

Body size the length of neurones are longer

More caffeine- quicker at synapses- drugs- sympathetic neurone

Humans have taxis? Taxis to music/warm environment- kinesis/ where they live

Brain involved so not protective mechanism

21

Hydrogen carbon lit indicator

Colour change has no scale
Not impirical
No numerical value
Binary

Use colorimeter
Check light intensity

22

Can you get an average from two values

No, some people hold for longer

Yes,can get concordant results

23

Properties of co2

Forms carbonic acid with water (blow into limewater experiment)

24

Hand variation can you roll your tongue

D

25

Phenotype

Is the physical phenotype applied to organisms

26

Why hardy Weinberg is not applied to human populations

There is migration
Different alleles
Higher mutation rate than animals

27

Continuous and discrete data

Continuous-controlled by multiple alleles and environmental factors e.g.

28

Why plot as scatter diagram

Easier to see correlation
One variable against another

29

Things you
Compare

If means overlap in sd
Size of sd
If they do, no significant difference

30

Why do you use leaves of same plant species

Different plants have different size and length and width
Less genetic variation

31

Why don’t you cut the leaves

May damage shape/environment
Ethics/damages habitat
May shrivel up

32

True length v measured length

Harder to measure true value
Standardise to compare

33

Differences in standard error interpreted

When hw does not work

34

Why not use mark release recapture on humans

Unethical to mark humans
People don’t want to
Hard to recapture

35

Gel electrophoresis
Pcr

Make a gene machine/ select gene
Heat to 95 so hydrogen bonds break
Bases join complementary
By DNA polymerase
Annealed
One strand can get other strand
Is a chain reaction
Cooked to 72
Cooled to 55
All split act as templates
Exponential increase

36

Spearmans rank

Association between two variables

37

Not necessary to get pigments out

Crushing can get pigments out

38

Aseptic techniques when transfers broth culture to agar plate

Keep lid on Petri dish
-Open lid as little as possible
-prevent unwanted bacteria contaminating the dish
Wear gloves
Prevent contamination from bacteria on hands/mouth
Wash hands/wear mask
Use sterile pipette by flaming the loop
- to maintain a pure culture of bacteria