IB B IOLOGY Q UARTER 1 E XAM R EVIEW IB topics 1 (statistical analysis) & 2.1 (cell theory)
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Transcript of IB B IOLOGY Q UARTER 1 E XAM R EVIEW IB topics 1 (statistical analysis) & 2.1 (cell theory)
GUIDELINES
Get into a group of 4 Designate a recorder (you may rotate) In order to get points, your answer must be
written on the dry erase board When time is called, each group will raise
their answer/board up If your answer is correct, award yourself a
point (we’re on the honor policy ) I will take away points for disruptive behavior 1 minute per question
TOPIC 2.1
List the three main principles of the cell theory
All organisms are composed of one or more cells
Cells are the smallest units of life
All cells come from pre-existing cells
IB TOPIC 2.1
Describe the work of Robert Hooke.
First described cells in 1665 while observing cork with a microscope he built.
IB TOPIC 2.1
Describe the work of Antoine van Leeuwenhoek.
Observed the first living cells are referred to them as “animalcules,” meaning, little animals
IB TOPIC 2.1
Describe the work of Mathais Schleiden and Theodor Schwann
Schleiden: botanist; stated that plants are made of cells (1838)
Schwann: zoologist; made similar statement about animals
IB TOPIC 2.1
Describe the work of Louis Pasteur. Which principle of the cell theory did he give provide evidence?
1860s; after sterilizing chicken broth by boiling, Pasteur showed that living organisms would not spontaneously reappear
Only after exposure to pre-existing cells was life able to re-establish itself in the sterilized chicken broth
Cell theory principle; cells come from pre-existing cells
IB TOPIC 2.1
Compare light microscopes and electron microscopes
Light: passes light through the living or dead specimen to create an image
Electron: uses electron; provides us with the greatest magnification (over 100,000x) and resolution
IB TOPIC 2.1
Put the following cells in order from smallest to biggest:
Bacteria, viruses, molecules, membranes, and organelles
(Smallest) molecules membranes viruses bacteria organelles (Biggest)
IB TOPIC 2.1
Convert the following: 50 mm = _____ µm 750 µm = _____ mm.250 mm = _____ nm
Answers 50,000 µm.750 mm .250 x 1000 x 1000 = 250,000 nm
IB TOPIC 2.1
State the equation for linear magnification
Magnification = size of image / actual size
IB TOPIC 2.1
If a white blood cell has a diameter of 2 µm and a student shows it with a diameter of 20 mm in a drawing, what is the magnification of the drawing?
10,000x
Image = 20 mm (convert to µm) = 20,000
Actual = 2 µm
IB TOPIC 2.1
Explain why the surface area to volume ratio is a limiting factor to cell size.
As a cell grows, volume increases faster than surface area
The surface area to volume ratio decreases This means there is less surface area to bring
in needed materials and to rid the cell of waste than a small cell (diffusion slows down)
To prevent this, cells are limited as to the size they can attain and still be able to carry out the functions of life; modifications: long & thin; folding
IB TOPIC 2.1
What is the equation for: Surface area of a cub Volume of a cube Surface area to volume ratio
SA = L x W x 6 Volume = L x W x H Ratio
Surface area divided by volume : volume divided by volume
IB TOPIC 1 – STATS
Define error bar
A graphical representation of the variability of data
Used to show the range of data or the standard deviation on a graph
IB TOPIC 1 – STATS
What is standard deviation used for?
To summarize the spread of values around the mean
IB TOPIC 1 – STATS
What is a t-test used for?
Deducing the significant difference between two sets of data
IB TOPIC 1 – STATS
When using a t-test, what is the level of confidence that is considered a significant difference when comparing two sets of data?
95%
IB TOPIC 1 – STATS
An experiment was performed which measured the size of salmon that spawned in two different streams. Fifty salmon were sampled for each stream. The value of t was found to be 1.29. What is the confidence level of this particular test?
Confidence level = 80% Degrees of freedom = 50 + 50 – 2 = 98 T value = 1.29 Probability = 20%
IB TOPIC 1 – STATS
Compare correlation and causation
Observation correlationData/experimentation causation Correlation does not mean
causation
IB TOPIC 1 – STATS
When using the t-test to compare two sets of data, the p-value of the data according to the t-table is 0.05. What is the probability that chance alone can produce the difference seen? How confident can I be in my data?
5% probability (due to chance) 95% confident the difference is
significant (real)
IB TOPIC 1 – STATS
When using a mathematical correlation test, the value of r signifies the correlation. The value of r can vary from ___ to ____ to ___. What does these values tell us?
-1 to 0 to +1 -1 = negative correlation 0 = no correlation +1 = positive correlation
IB TOPIC 1 – STATS
What is the average and standard deviation of the following set of data:
4, 5, 6, 6, 6, 5, 5, 4, 3,
Average = 4.88
Standard Deviation = 1.05
IB TOPIC 1 – STATS
What percentage of values lie within 1 SD of the mean? What about 2 SD of the mean?
68%95%