IB B IOLOGY Q UARTER 1 E XAM R EVIEW IB topics 1 (statistical analysis) & 2.1 (cell theory)

G UIDELINES 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

T OPIC 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 T OPIC 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 T OPIC 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: 1 mm = _____ µm 1 µm = ______ nm 1000 µm 1000 nm

IB T OPIC 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 T OPIC 2.1 As a cell increases in size, which increases faster: surface area or volume? Volume

IB T OPIC 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 T OPIC 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 – S TATS 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 – S TATS What is standard deviation used for? To summarize the spread of values around the mean

IB TOPIC 1 – S TATS What causes a high standard deviation? A wide range of data points

IB TOPIC 1 – S TATS What is a t-test used for? Deducing the significant difference between two sets of data

IB TOPIC 1 – S TATS 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 – S TATS How do you calculate the degrees of freedom? Sum of two sample sizes – 2

IB TOPIC 1 – S TATS 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 What is the confidence level of this particular test? Confidence level = 80% Degrees of freedom = – 2 = 98 T value = 1.29 Probability = 20%

IB TOPIC 1 – S TATS Compare correlation and causation Observation  correlation Data/experimentation  causation Correlation does not mean causation

IB TOPIC 1 – S TATS When using the t-test to compare two sets of data, the p-value of the data according to the t-table is 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 – S TATS 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 = negative correlation 0 = no correlation +1 = positive correlation

IB TOPIC 1 – S TATS 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 – S TATS What percentage of values lie within 1 SD of the mean? What about 2 SD of the mean? 68% 95%

Y OUR T EST T OMORROW IB Topic 1 – Statistical Analysis IB Topic 2.1 – Cell Theory (up to page 19) 33 multiple choice questions 1 short answer You need a calculate and a pencil