Expectations• How well you do is dependent on how hard YOU

work. • You have to take notes by hand in class (and at

home)• Use the textbook, my website, IB guide, and past

exam questions as your resources – Buy the exam question bank!

• You will only speak English• You will ask for help if you need it

Expectations• Bring pen/pencil, paper, textbook and laptop to

lesson • You are to have a binder just for Biology with

dividers. This will hold all your handouts, notes in class, and the notes you make

How does the DP Biology work?

• Core (SL): Topics 1 – 6 (40hrs lab)• AHL: Topics 1-11 (60hrs lab)• Everyone: 1 option for the exam• 7 Prescribed practicals• Final exam is broken down to 3 papers (80%)• Independent international assessment(IA)

(20%)

Topic 1: Cells biology

1.1 Introduction to cells

Understandings and Applications

• U: According to the cell theory, living organisms are composed of cells

• U: Organisms consisting of only one cell carry out all functions of life in that cell

• A: Questioning the cell theory using atypical examples

• A: Investigation of functions of life in Paramecium and one name photosynthetic unicellular organism

1.1 Introduction to cells

Cell Theory:1. All organisms are

made up of one or more cells

2. Cells are the smallest units of life

3. All cells come from pre-existing cells

http://upload.wikimedia.org/wikipedia/commons/b/b1/Optical_microscope_nikon_alphaphot_%2B.jpg

Exceptions to the cell theory!

Muscle cells (Myocytes)

http://scvp.net/acr/images/grum3.jpg

http://www.medical-labs.net/wp-content/uploads/2014/04/Forms-of-hyphae-Septate-and-Coenocytic-Hyphae.jpg

Fungal hyphae/Aseptate

fungi

Giant Algae: up to 100mm in size but only contains one nucleus!

The functions of life

Paramecium

They also divide!

• Metabolism• Growth• Reproduction• Response• Homeostasis• Nutrition

Function Paramecium Chlamydomonas

Nutrition Endocytosis Photosynthetic

Growth Food (organic molecules + minerals)

Photosynthesis and absorption of minerals

Response Reacts to stimuli Reacts to stimuli

Excretion Expels waste Expels waste

Metabolism Enzymes catalyse chemical reactions

Homeostasis Maintains internal environment within limits

Reproduction Asexual/sexual

http://www.mikrowelt.info/02_Einzeller/03_Protozoen/IMAGES/PARAMECIUM_BURSARIA_201005A.JPG

https://wiki.umn.edu/pub/IBS8102/030410-Molnar/Krieger_Chlamydomonas165.jpg

The functions of

life in unicellular organisms

How do we know the sizes of these organisms?

The largest to smallest:Cell >> organelles >> bacteria>>virus>>membranes>>molecules

How do we calculate magnification?

Magnification = image size

actual sizeI

M A

Problem: What is the magnification if the actual size of the amoeba is 800 m?μ

*Make sure all measurements are in the SAME units

What is the scale bar?

Magnification = image sizeactual size

I

M A

Problem: What is the magnification if the actual size of the amoeba is 800 m?μ

Practice problems

Complete and SHOW ALL WORK in section A of handout:1. The width of a human hair is 0.1mm. What is the width in

micrometers?2. The diameter of the drawing of the an amoeba is 100mm. The

actual diameter of the amoeba is 100 micrometers. What is the magnification of the drawing?

3. E. coli has a diameter of 10 micrometers. The drawing is 200cm. What is the power of magnification?

4. A drawing of a virus has a length of 35 millimeters. The actual length is 1 nanometer. What is the magnification of the drawing?

5. The width of the plasma membrane of a cell is 9nm. In the drawing, it is 15mm. What is the magnification?

How do we use a scale bar?• Measure the length of scale bar. In this example, it is 1cm =

3.33 mμ

What is the magnification of the human cheek cell?1cm = 10mm3.33 m = 0.0033mmμ

Magnification = 10mm/0.0033mm= 3003x

The magnification of the human cheek cell is 3003x

Practice problems

• Complete section B of handout